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2005, 24 (S2): -0 doi:
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COUPLED ANALYSIS OF DAHUASHUI ARCH DAM WITH TRIAL LOAD METHOD AND BLOCK ELEMENT METHOD

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2005, 24 (S2): -5281 doi:
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[PDF 535 KB] (905)

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The coupled analysis method of the trial load method and the 3D elasto-viscoplastic block element method is applied to analyze the stress and stability of Dahuashui arch dam. In the analysis，the foundation is divided into block elements，and the arch dam is treated as an arch-cantilever system. On the interface between the dam and foundation，it is assumed that the base nodes of the dam are fixed on the surface of the block elements. So the displacements of the base nodes have relationship with the displacements of the block elements. According to the virtual work theory，the stiff coefficients about the displacements of the base nodes are transformed into the stiff matrix of the block elements. After assembling all stiff matrixes，the total equilibrium equation can be established. Then it can be solved to obtain the displacements of the interior nodes of the arch dam and those of the block elements of the foundation. Then the stress and stability status can be analyzed separately. The calculation results indicate that the dam abutment slope is stable on the whole.

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IMPROVED METHOD TO DETERMINE THE CRITICAL
STATE OF SLOPES BASED ON FLAC3D METHOD

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2005, 24 (S2): -5287 doi:
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[PDF 215 KB] (1431)

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The criteria of critical state need to be specified in determining the safety factors of rock and soil slopes when the elastoplastic shear strength reduction method is used，but there are some subjective factors in this kind of method and the precision of computation results always depends on the experience of researchers. In this paper，the critical state of rock slopes is studied based on FLAC3D numerical technique and a new method is presented. The convergence of curves of the maximum nodal displacement with time steps is closely related with the stability of slopes. This kind of curve can be used as criterion to determine the stability of slopes. The safe state of slopes can be estimated by whether the maximum nodal displacement-increment decreases during certain time-steps after a specified time-step. This method overcomes the randomness of some criteria in which the permissible error is artificially specified and the computation precision can be controlled according to the need of projects in order to obtain more objective and exact safety factors of slopes. Finally，an example of highway rock slope is studied by this method and more satisfied results are obtained compared with those by Bishop¢s method.

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INFLUENCE OF THE EARTHQUAKE PARAMETERS ON THE DISPLACEMENT OF ROCK CAVERN

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2005, 24 (S2): -5292 doi:
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[PDF 297 KB] (1049)

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It is not always reasonable that the distributing shape of earth pressure in the back of retaining wall is triangular along the height of the wall on the basis of the Rankine and Mohr-Coulomb theories. The distribution of earth pressure presents different curve shapes with different displacements and its form of the wall. The friction between the back of the wall and the filling plays an important role in earth pressure distribution. It is assumed that potential sliding surface of the soil in the back of the retaining wall is composed of logarithmic spiral arc and line. Based on the limit equilibrium of the soils¢ thin-layer elements in the back of retaining wall，calculation formula of the active earth pressure for the clayey soils is suggested. Complex simulated annealing (CSA) calculation method with better searching properties is attained by introducing complex method into simple simulated annealing method to search for local optimization solution. And it is used for searching for the potential sliding surface of the filling and computing the corresponding active earth pressure. Two case studies are given to verify the proposed method. The active earth pressures calculated by the presented method are more close to the in-situ ones comparing to traditional Rankine¢s and Mohr-Coulomb¢s theories.

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APPLICATION OF GREEN ECOLOGICAL MATERIAL TO MINE
HIGH SLOPE PROTECTION

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2005, 24 (S2): -5297 doi:
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[PDF 283 KB] (1088)

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This work tries to study an eco-type revetment material named ZZLS that can combine vegetation recovery with mine high slope protection. ZZLS is a kind of green ecological material with high strength and great erosion resistance. It also be named“the artificial soil”in which such vegetable as grass and bush can grow well. Then，the microscopic and mechanical properties are analyzed. Based on the principle of“jet”，ZZLS is injected to the slope，and the green material which is suitable for vegetable growth is formed. By planting grass，bush，and flower in the green material，the object of slope protection is achieved，thus the price is lower. With successful protection and beautification of environment，the ecological sustained development can be reached.

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STABILITY ANALYSIS OF GUSHUBAO LANDSLIDE IN QINGJIANG RIVER WITH NONLINEAR FINITE ELEMENT
METHOD DURING RAINFALL

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2005, 24 (S2): -5301 doi:
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[PDF 432 KB] (852)

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The Gushubao landslide had ever blocked the traffic of the Shuibuya water control project site. Based on the geological background and the site engineering geological characteristics of the Gushubao landslide of Qingjiang River，the nonlinear finite element method is applied to study the stability of the slope during rainfall. The sensibility of influence of the underground water and the rainfall on landslide stability is analyzed. The influence of transient saturated zone in the slope due to rainfall to the stability on the slope is discussed. The conditions of re-sliding of the Gushubao landslide are discussed. The basis of prevention and control works of the landslide is provided.

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LARGE DEFORMATION FINITE ELEMENT
RELIABILITY ANALYSIS OF SLOPE STABILITY

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2005, 24 (S2): -5308 doi:
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[PDF 297 KB] (956)

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In the reliability analysis of a slope，by using finite element method(FEM)，which only considers the property of elasto plasticity or material nonlinearity. However，it exists the locally large strain in most soil slopes. It has been proven by experiments that the local strain can reach the value of 40% while the average strain is only 10%. Therefore，it¢s necessary to carry out large deformation finite element analysis of a slope in order to simulating its real failure property. In this paper，the constitutive relationship of the soil is considered as realistic elasto plasticity one and the Mohr-Coulomb yield criteria is adopted. Based on the basic principal of nonlinear continuum mechanics，a kind of elasto plastical large deformation finite element analysis model is built by using updated Lagrangian method，which can consider both the nonlinearity of material and geometry. Then，the method of strength reduction is adopted to calculate the factor of safety (Fs) of a slope. Among the several methods of reliability analysis such as mean first order second moment method (MFORM)，advanced first order second moment method (AFORM) and Monte Carlo simulation method (MCSM)，the AFORM is used in this paper since it is the most popular method. Through the comparative calculations of factor of safety and reliability index( ) by FEM of small and large deformation and the sensitivity analysis of parameters，the conclusion is that when the large deformation property is considered，the value of Fs will arise while the value of will drop. The reason is that the value of Fs is more sensitive to the value of cohesive c in this situation. Therefore，the limit state function Z has larger variation and smaller reliability index. From this point，it¢s unsafe if the large deformation property in the finite element reliability analysis of a slope is not considered.

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APPLICATION OF LIMIT EQUILIBRIUM METHOD TO STABILITY ANALYSIS OF JINPING HIGH SLOPE BASED ON 3D
MULTI-GRID METHOD

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2005, 24 (S2): -5313 doi:
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[PDF 367 KB] (994)

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Based on 3D nonlinear FEM analysis of Jinping high slope，the rigid limit equilibrium method in the stability analysis of high slope is discussed. The first stage hydropower station of Jinping locates between in Yanyuan county and Muli county in Sichuan province. It is an important cascade hydropower station in Yalong River. The high slopes of both left and right banks of Jinping Hydropower Station are on large scales，and the geology is complicated too. The excavated slopes of this project include the excavated slope of spandrel groove and cable machine platform. The concept and method of multiply mesh are put forward，and the stress result of FEM is tranferred to any sliding surface(plane or surface). In this way，the stability state of sliding surfaces can be analyzed. The stress distribution on sliding surfaces of sliding blocks is computed，including the safety factor of the sliding surfaces and blocks at each load step，yield area，normal strength and shear strength of sliding surfaces during overloading. Based on the results，the process of sliding blocks' failure due to deformation is discussed systemically. This findings can provide a more profound cognition on limit equilibrium analysis for stability analysis of high slope in practical engineering.

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EFFECT OF WATER TABLE ON SOIL SLOPE STABILITY

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2005, 24 (S2): -5319 doi:
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[PDF 198 KB] (1759)

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Slope stability safety factor is influenced by many factors，in which the condition of water table change affects greatly. The analysis and calculation of the stability safety factor based on diversified slope models indicate that there are certain rules of effect of water table on soil slope stability. Through calculation of the stability factor of the slope with two different software based on theory of limit equilibrium，it is shown when the water table changing between the range of 3/10-4/10 the height of the slope，it affects the stability of the slope negligibly. With the water table rising，the safety factor linearly reduces，and it is likely to induce landslide.

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GEOLOGICAL DISASTER ALONG SANHUI—KAILI HIGHWAY IN GUIZHOU AND CONTROL MEASURES

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2005, 24 (S2): -5323 doi:
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[PDF 398 KB] (954)

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The paper summarizes and classifies basic geological condition and environmental factors of landslides and high slope disasters along Sanhui—Kaili Highway and analyzes the resulting mechanism，deformation mechanism and developing reason of different types of disasters. The paper expounds the design principle of geological disaster and also presents some stabilized measures adopted in engineering and their merits and shortcomings. Finally，the paper summarizes experience and lessons for preventing and controlling geological disasters during the construction of express highway.

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STABILITY ANALYSIS OF INCLINED ANCHORAGE PILE FOR REINFORCED CEMENT-SOIL IN BRACING EXCAVATION STRUCTURE AND ITS APPLICATION

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2005, 24 (S2): -5331 doi:
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[PDF 231 KB] (1189)

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The inclined anchorage pile of reinforced cement-soil can form a gravity bulkhead in excavation. It is an active reinforcement method by agitating earth mixed with cement and buried anchor bar. The working principle of reinforced with steel strips and inclined cement-soil pile are introduced，and its mechanism on the strain and stability of excavation is also analyzed. By using slice method and Kranz theory，a simplified model of stability analysis in excavation structure braced by the anchoring pile is established. This method can overcome the shortcoming in Kranz theory，and it can simplify the calculation of slice method. So it has practical value，and an actual example using this method in Guangzhou underground station to analyze the stability is studied，which indicates its feasibility.

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RELIABILITY ANALYSIS OF STABILITY OF
GRANITE RESIDUAL SOIL SLOPE

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2005, 24 (S2): -5337 doi:
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[PDF 208 KB] (1217)

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As widespread usage in engineering，the simplified Bishop method is used to establish the limit state function. Considering the unit weight，cohesive strength and internal friction angle as random variable，the utility optimal method as well as the Microsoft Excel¢s solver are applied to solve the reliability index，which can avoid the problems of orthogonal transformation and derivation of the limit state function. For the slope of granite residual sandy clay in Fujian Province，the reliability analysis is carried out. By comparison the results of non-correlation and correlation between parameters，it is shown that the reliability correlates with not only the mean value of parameters，but also the coefficient of variability and the correlation between parameters which have a major influence on it. Thus，there is a possibility of instability while the slope is considered as stability by the traditional safety factor calculation method.

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PREVENTION COUNTERMEASURE INTEGRATIVE DESIGN OF
CHUANSHAN LANDSLIDE AT TAIZHOU—JINYUN EXPRESSWAY

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2005, 24 (S2): -5341 doi:
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[PDF 365 KB] (926)

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Chuanshan landslide is a typical low and gentle rock slope. Its natural inclination angle is 15°–17°，and its sliding surface angle is 8°–15°，which is singular in calamity of sloping field. It shows that the low slope is not always safe in highway slope design，and geology governs the slope stability. It has taken AO technology to translate the map with scale 1∶2 000 into the intuitionistic 3D landform，and the property and stability of landslide are researched. Theory of finite difference method has been used to analyze elastic stabilizing pile and integrative design of both calculation and CAD technique，which are credible decision-making for landslide prevention measures.

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STUDY ON BEHAVIORS OF SOIL-NAILED WALL PROTECTION
WITH HIGH BEDDING STONE SLOPE

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2005, 24 (S2): -5346 doi:
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[PDF 184 KB] (981)

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The study is expected to research the performance，behaviors and strength of soil-nailed wall by field test，on the basis of the engineering of soil-nailed wall protection with the high bedding stone slope in Yuhuai railway in China. We test the nail force of different station on different row soil-nailed wall with steel-string transducer in the upper and bottom wall are tested. Some conclusions are achieved as follows：(1) the distribution of soil nailing tension along each soil nailing is curved，and there are one or two maximum tension points；(2) the soil nailing tension increases with time；(3) the latent failure surface position of testing value and the theoretical value is close to each other at the upper and bottom wall，but far away near the flat roof；(4) the earth pressure in the soil nailing wall is larger on middle and smaller on two sides along the height. These test results can be used as reference to the design and construction of soil-nailed wall.

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SENSITIVITY ANALYSIS OF HIGH SOIL SLOPE STABILIZING FACTORS

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2005, 24 (S2): -5350 doi:
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[PDF 240 KB] (1303)

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In the design of high soil slope，the influences of soil parameters are usually more significant than different calculated methods for the result of slope stability calculation. This paper will test and calculate the results of the safety monitoring，which is introduced by the Yuegan highway¢s high slope. As comparing and analyzing the abundant results of test and calculation，it was shown the significance of the rate of soil water in the analysis of the slope stability，and then, the water content is regarded as the one of the important parameters in slope stability analysis. Finally this paper presents the recommendation that the unsaturated soil has theoretically important applied value and it can be widely used in the design，construction and safety monitoring of high slope.

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SLOPE STABILITY ANALYSIS BY COMBINING FEM WITH LIMIT EQUILIBRIUM METHOD

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2005, 24 (S2): -5355 doi:
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[PDF 612 KB] (1811)

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A method combining the elastoplastic finite element method (FEM) with the limit equilibrium method is proposed to analyze the slope stability problems. The stress，strain and displacement distributions of the slope are calculated by elastoplastic FEM. Then，the stability factor of safety of the slope is calculated with method of slices based on limit equilibrium in which the finite element computed stresses are used to compute the normal stress and the mobilized shear stress at the base center of each slice. The proposed method can not only consider the influence of the deformation of the slope on the stability，but also evaluate the stability of the slope with single stability factor of safety which is well known in geotechnical engineering. The proposed method will have broad application to the slope stability analysis.

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PRIMARY ANALYSIS CAUSES OF SLOPE SLIP BASED ON IN-SITU MONITORING

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2005, 24 (S2): -5360 doi:
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[PDF 211 KB] (883)

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Presently，scientists often perform the simulated analysis of the mechanism of slope slip with the aid of tests in laboratory. Based on the tests in laboratory，many models of slope slip have been established. The experimental models have different characteristics and different adaptabilities. The representative of actual landslide with laboratory results leaves relatively large errors，even great falsehood，sometimes. How to recognize fundamentally the actual mechanism on landslide is one of the problems on which the author and his research group have studied for more than ten years. The method on which the author and his research group study depend is prototype monitoring analysis method. Based on ten years¢ in-situ monitoring data，this article analyzes the external cause and internal cause of landslide，and concludes primarily the relevant relations between the slide and the various factors of landslide with the aid of the mathematic simulation theory are primarily achieved. Also，it depicts some effective methods and techniques on slope slip field monitoring (including GPS，measuring robot，etc.).

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LANDSLIDE HAZARD PROBABILITY ANALYSIS FOR SICHUAN PROVINCE USING LANDSLIDE INVENTORY

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2005, 24 (S2): -5366 doi:
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[PDF 191 KB] (1220)

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Landslides，defined as the movement of a mass of rock，debris or earth down a slope，can be triggered by a variety of external stimulus，such as intense rainfall，earthquake shaking，water level change，storm waves，rapid stream erosion or some human activities that cause a rapid increase in shear stress or decrease in shear strength of slope-forming materials. They can result in enormous casualties and huge economic losses in mountainous regions. Based on the published records of landslides，it is found that Sichuan Province takes up the highest percent in China. This paper presents a landslide-inventory-based framework for systematic landslide hazard analysis by employing historical landslide data in Sichuan Province，coupling with geological，geomorphologic，climatic，and rainfall data. Based on 400 landslide data from 1949 to 2001，the seasonal distributions of landslides are established and compared with the seasonal rainfall variation. The cumulative fatalities and injuries caused by landslides increase with the cumulative rainfall in Sichuan Province，indicating a strong correlation between rainfall and landslide consequences. The frequency-volume relationship for landslide in Sichuan has been considered. Based on previous study，the cell size is selected as logarithmic. While the data available for analysis is only 89，the relationship is not sufficiently representative. However，it is obvious that it has the same distribution as Hong Kong，except that the scale of landslides is different：most of the reported landslides have volume exceeding 100 000 m3，and the majority of the landslides in Hong Kong have a volume less than 500 m3. In addition，the relationship in Hong Kong is updated on the basis of landslide data from 1992–2001. And in the analysis，the data that just has a dim range is not included and for those that have clear range，the average values are used. The average annual fatality and injury rates in Sichuan Province caused by landslide are 49.88% and 28.06%，respectively.

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NEW TECHNIQUE AND EQUIPMENT OF ANCHORING
ON STEEP SLOPE

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2005, 24 (S2): -5371 doi:
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[PDF 201 KB] (932)

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With respect to the problem of lack of boring method on steep high slope，a boring construction method and corresponding equipment are introduced. A cable and a windlass on ground are used to drag the boring machine moving freely，and the boring machine can be fixed on the steep high slope at the boring position. So，with low cost and simple method，the difficult problem of boring construction on steep high slope is solved.

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EFFECTS OF SPRAYING TECHNIQUES AND SOIL TEXTURE ON ECO-ENGINEERING FOR ROCK SLOPE PROTECTION

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2005, 24 (S2): -5374 doi:
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[PDF 221 KB] (864)

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The effects of spraying technics，water supply and soil texture on the developing and growth of vegetation are studied quantitatively. The results show：(1) the germination rate，late growth height and the maximal contraction rate decrease with spraying press increasing，while increasing with supply water increasing；(2) shearing resistance and resilience rate of substrate increase with spray press increasing，while decreasing with water supply increasing；and (3) spray press，water supply and soil texture are not notably for erosion. The variety of several treatment sediment yield of substrate exceeds 5%. In the same technical condition，germination rate，late growth height and the maximal contraction rate，shearing resistance and resilience rate of substrate vary with different soil texture. Germination rate，late growth height and the maximal contraction rate，shearing resistance and resilience rate of substrate are selected as integrated evaluation indexes. Then the effect model of spray construction is founded. The studies can provide theories to eco-engineering for rock slope protection.

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NUMERICAL SIMULATION OF STABILITY ASSESSMENT AND DESIGN-MAKING OF A SUBGRADE RETAINING WALL ON SLOPE

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2005, 24 (S2): -5382 doi:
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[PDF 464 KB] (1045)

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Usually，the retaining wall on the slope is constructed in the section of the half-filling and half-excavating subgrade. Nevertheless many failure cases of this type of retaining wall have been reported in recent years. Combined with a practical subgrade construction project of retaining wall in one section (K59+470–K59+630) of Qixia—Laixi expressway of Shandong Province. First，a Lagrange numerical simulation is taken to analyze two main failure factors(slope angle and dynamic vehicle load) of the retaining wall on the slope；then，a double anchor constructing plan of the retaining wall is proposed；finally the concrete engineering technical parameters and method are obtained by comparison. The monitoring results indicate the stability of the retaining wall and the slope，and the success of the project means the double anchor constructing technique is feasible and applicable for similar engineering project.

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CALCULATION OF LAND SUBSIDENCE DUE TO WITHDRAWAL OF WATER-SOLUBLE NATURAL GAS FROM DEEP MARINE SEDIMENTS

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2005, 24 (S2): -5389 doi:
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[PDF 412 KB] (1087)

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There is a large-scale land subsidence due to withdrawal of water-soluble natural gas and medicine iodine in Boso Peninsula，Japan. Land subsidence surveying started in 1969. Till 2002，the accumulated maximum subsidence was 0.85 m. In order to alleviate subsidence， extractable volume of groundwater should be forecasted. A 3D finite element model was established based on the structure of Kanto Groundwater Basin. This model can calculate groundwater seepage and land subsidence in one process. The parameters used in the model are determined from consolidation test under high pressure on the samples of outcropped soft rock at the south part of the peninsula. Calculation results indicate that from 1956 to 2002 the groundwater head dropped to 190 m in the center of groundwater withdrawal area. The results also indicate that at the beginning (in 1957) groundwater flows from elevated mountain area to sea，however，in 2002，groundwater flew from sea to the withdrawal area. This result is coincident with the structure of Kanto groundwater basin with syncline aquifer overlain/underlain by aquitards. Therefore，the land subsidence can be alleviated by limiting the withdrawal volume even if groundwater withdrawal is not stopped. The calculation value of land subsidence from 1969 to present agrees the measured value well.

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DISCUSSION ON OPTIMIZATION OF ALLOWABLE CRACK WIDTH FOR DIAPHRAGM WALL OF METRO STATION

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2005, 24 (S2): -5395 doi:
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[PDF 206 KB] (1274)

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In the soft region，the optimisation design of diaphragm wall is very important to decrease total investment of whole project. From the survey results of some metro excavations in Shanghai，the designs of diaphragm wall are conservative：both the stress of reinforcing steel and the moment of wall are less than those of the design value. These conservative designs must waste a large amount of fund and urge engineers find ways to solve this contradiction. Through the theory of diaphragm wall design analysed，the allowable width of structure crack wlim= 0.2 mm is confirmed to be the most important factor which caused the negative design. According to the national codes，the ratio of Ms and Mu should be between 0.73 and 0.89. When the criterion of wlim= 0.2 mm was adopted in the design of metro excavation，the ratio value of Ms and Mu of the diaphragm wall was normally less than 0.6. Compared with the wlim= 0.2 mm，this paper points out when the allowable width of structure crack broaden to wlim= 0.3 mm，the design will be more reasonable. By calculating and comparing，a conclusion can be drawn that when the allowable width of structure crack broaden to wlim= 0.3 mm，not only can the complex wall which is composed by diaphragm wall and lining can meet the reduced demand of structure crack under the natural conditions，but also the safety of the excavation can be guaranteed and project investment will be reduced.

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ANALYSIS OF TIME-SPACE EFFECT OF DEEP-FOUNDATION PIT
BASED ON GA-ANN MODEL

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2005, 24 (S2): -5400 doi:
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[PDF 200 KB] (790)

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Methods such as numerical simulation and experience function imitated and so on were adopted to study on time-space effect of deep foundation pit. Because of complexity in influence factors and difficulty in measure of various factors，normal analysis methods were not strong in adaptability. At present，only time or space effect was considered in analysis of time-space effect，and analysis method of time-space effect considered simultaneously based on artificial intelligence was not established. It is shown that high non-linear complex problems can be solved easily by artificial neural network as well as the method of ANN(artificial neural network) based on GA(genetic arithmetic) has optimizing function in the whole field of solution. The structure and weight value of the network are optimized in-phrase in GA-ANN model，and the weight value of the network and influence factors of problem are two kinds of different qualities. When the two kinds of variables are regarded as input variables to train the network，it may lead to chaos of the network，thus it will decrease identification precision of the network. The model of time-space effect on deep foundation pit is established that the structure and weight value of the network can be optimized by stages with GA based on labor of influence factors. The comparative analysis with the BP(back propagation) model and the GA-ANN model optimized in-phrase shows the model optimized by stages can improve identification precision and analysis efficiency of the network，thus it will be closer to the fact.

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WANG Jing-chun，XU Ri-qing，HUANG Bin

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2005, 24 (S2): -5405 doi:
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[PDF 247 KB] (1082)

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The construction methods are complex and changeable，which influence the performances of soil around the site. For a long time the excavating theory and stability analysis of deep excavation are based on the original soil. In this paper，on the basis of the previous researches，the concept of construction disturbance is discussed，and an expression of disturbance degree is set up and the calculation model against heave for the stability of deep excavation is established. In additional，the calculation example is also given. The study shows the construction disturbance can exert an obvious effect on the safety factor. And some engineering measures to control the construction disturbance are taken.

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ANALYSIS OF SLOPE INSTABILITY FOR A DEEP FOUNDATION PIT

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2005, 24 (S2): -5410 doi:
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[PDF 196 KB] (1491)

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Soil-nailed wall used to support the slope of deep foundation pit is an economic method. Due to the supporting system mainly relying on the soil stability and the soil intensity，it will limit the depth of the supported slope. For increasing the supported depth of slope，the composite soil-nailed wall to support slope is considered. But what kind of construction used to soil-nailed wall supporting system lies on the stress state of the slope. To understand that the slope stress state is the premise of slope supporting design and construction，the paper gives two cases of deep foundation pit slope supported by composite soil-nail wall，and provides the valuable cases to the designers and the builders when they consider soil-nail wall to support deep foundation pit slope. Through the analysis of these cases，much attention should be paid to the stability of slope toe，improving the overall stability of slope with soil anchors，when composite soil-nail wall is used to support the slope of deep foundation pit.

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STUDY ON REINFORCEMENT OF A CERTAIN SLOPE ALONG
HUZHIMING ROAD IN VIETNAM

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2005, 24 (S2): -5413 doi:
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[PDF 420 KB] (794)

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The study on reinforcement of a certain slope along Huzhiming Road in Vietnam is introduced. It is pointed out that the mechanical indexes used in slope design had better adopt the data obtained from the combination of geologic reconnaissance and back analysis of results achieved from in-situ investigation. Case study indicates that geological condition is the main intrinsic factor that influences the stability of slope and the water action is the main external cause. Thus，it is an essential problem to be solved to control and deal with the action of water in slope reinforcement.

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EXPERIMENT STUDY ON ANCHOR FOR DEEP EXCAVATION OF HUAXIN BUILDING

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2005, 24 (S2): -5418 doi:
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[PDF 194 KB] (1005)

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The retaining of anchors is widely used in China，but the principle and calculating method for soil anchor are not clearly understood. In this paper，the tests on soil anchors are carried out based on a deep excavation. The distribution of the friction force on the interface between soil and mortar is obtained through test. The test result shows the distribution of the friction force is not uniform and the stress attenuates along the length of anchor，which is maximal in the orifice of hole and related to the level of friction force. The pullout resistance of anchor is obtained by the test，which is correlative to the mode of grouting and sensitive to the excavating. All provide the basis for engineering design.

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APPLICATION OF MULTIPLE SOLUTIONS TO DESIGN OF DEEP EMBEDDED PILES

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2005, 24 (S2): -5423 doi:
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[PDF 198 KB] (999)

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Based on the earth pressure acting on piles，the retaining piles used in the deep foundation excavation can be divided into three types. They are shallow embedded piles，cantilever piles，deep embedded piles. There is only one solution in shallow embedded piles or cantilever，but many solutions in deep embedded piles. It¢s completely possible to select an optimal scheme in the design of deep embedded piles according to special condition. By analyzing a deep foundation excavation case，the significance of multiple solutions of deep embedded piles in the design of deep excavations is explained.

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RESEARCH ON APPLICATION OF LONG-SHORT PILES TO DEEP-THICK SOFT SOIL AREA

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2005, 24 (S2): -5427 doi:
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[PDF 249 KB] (1098)

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Long-short pile composite ground can achieve great economical benefit when it is used in low-high-rise building in deep-thick soft soil area. Previous approaches mainly depend on experts¢ experience，so relevant papers are seldom seen in this field. This paper presents a synthetic approach to resolve how to design long-short pile composite ground，which includes choosing foundation schemes，calculating long-short pile length and cushion in a typical project. Long-short pile composite ground was chosen according to the factors such as loading，soil condition and ground bearing capacity，price and soil squeezing effect. The length of short pile is decided by soft soil strength of short pile tip in terms of analysis on bearing capacity of short pile. The length of long pile is determined by total settlement after specific bearing layer is chosen. Compared with experiments on cushion materials and thicken，a better cushion composed of mixed gravel，slab stone and sand is proposed in this project. Experimental data show that bearing capacity and settlement in this project meet the requirements of design.

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APPLICATION OF CONCRETE SLIDING RESISTANT KEY TO TREATING LIMESTONE BEDDING LANDSLIP

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2005, 24 (S2): -5433 doi:
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[PDF 237 KB] (948)

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When the foundation rock at the workshop of Pengshui tobacco redrying factory is excavated，the slope foot of the limestone along-bedding landslip is cut. The three mud interlayers are exposed one after another at the slope foot，forming a huge along-bedding landslip with the size of 250 m×230 m×20 m. Through systematic research，the method setting concrete sliding resistant keys with section of 2.5 m×5.0 m horizontally and prestressed anchors is adopted to keep the slope stable. This method is very effective and 2/3 investment is saved in comparison with the method setting concrete sliding resistant key vertically.

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CASE OF EXCAVATION SUPPORT STRUCTURE DESIGNING
IN DEEP SILTY-FINE SAND PIT

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2005, 24 (S2): -5438 doi:
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[PDF 256 KB] (1451)

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The concept design method is applied to excavation in deep silty-fine sand combining with retaining and protection design of a deep foundation pit. The concept design method in excavation is proposed based on several reinforcements. Those reinforcement measurements include setting jet grouting pile in the middle of slope or the slope toe，installing steel bar in the slope and injecting concrete in the surface of slope. It is found that the reinforcement measurements can effectively improve the stability of the slope surface. It is also described that the continuous distributed mucky-silty-clay can be used effectively as the horizontal bedding of the foundation pit to seal the bottom，and that improving by adding some bentonite the jet grouting pile technology can effectively improve the reliability of the curtain for cutting off water at the same time. It has been proved that the proposed method can decrease cost and time and provides reference to similar design.

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MODELING STUDY ON EXPLOSIVE COMPACTION OF
SATURATED SAND

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2005, 24 (S2): -5443 doi:
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[PDF 210 KB] (800)

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Although used for over 70 years，explosive compaction(EC) has not attained widespread acceptance despite the attraction of low cost and ease of treating large depths，due to empirical design approach without solid theoretical basis. The charge weight，charge placement (in profile) and depth of charges are important factors in design of explosive compaction for saturated loose sand. Six laboratory tests are conducted to investigate the effect of charge weight，charge placement (in profile) and depth of charge on densification，two of which are concentrated charge，the others are decked or tiered charges. Variation of pore water pressure，cone penetration tests and surface elevation changes are measured. The results of laboratory tests prove that the decked and tiered charges are more effective for ground treatment in explosive compaction. The more uniform distribution of energy release，the more effective for ground treatment. However，the evaluation of uniform distribution of energy is only qualitative，not quantitative.

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STUDY ON EFFECT OF DEEP-WELL DEWATERING ON SUPPORTING STRUCTURE AND SURROUNDING BUILDINGS

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2005, 24 (S2): -5449 doi:
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[PDF 245 KB] (1365)

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Groundwater controlling is the critical step in design and construction of deep excavation. Effect of the groundwater on deep excavation is discussed briefly，and fundamental treating method is put forward. Taking Baofeng Times Square deep excavation as an example，effect of the deep-well dewatering on supporting structure and surroundings is analysed. Monitoring data show that deformation of the retaining structure and surrounding buildings developed rapidly during excavation. When earthwork is finished，the supporting structure tends to be stable，but surrounding buildings subside continually because of dewatering. Not only dewatering but also the foundation form and height of the surrounding buildings will influence their own settlement.

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INFLUENCE OF LARGE FOUNDATION PIT CONSTRUCTION CAUSED BY SHANGHAI SOUTH RAILWAY STATION ON ENVIRONMENT IN SHANGHAI

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2005, 24 (S2): -5454 doi:
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[PDF 266 KB] (1157)

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The main underground structure of a certain square project in Shanghai has two stories. The area of the foundation pit is more than 20 000 m2，and the depth is 13.38 m. The construction of foundation pit adopts the method of slope associating with mid-island excavation and inverse method with circularity soleplate around. The monitoring results of stability and influence of environment show that，not only can such method of construction and design ensure stability of pit，but also shorten period of construction and decrease impact on the environment around. So the method applied in the project will be taken as an example for large foundation pit in soft soil.

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APPLICATION OF MICRO STEEL PIPE PILES TO DEAL WITH PIT DESTRUCTION

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2005, 24 (S2): -5459 doi:
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[PDF 228 KB] (1568)

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Recently，the quantity and scale of underground building increase rapidly with the development of city construction，which triggers the development of technique of deep excavation and support. Because pit engineering is a complex geotechnical engineering and affected by many factors，support failure often occurs. Therefore，how to reinforce pit slope after its loss of stability，collapse and slide is a key problem which designer，builder，supervisor and manager who are engaged in pit engineering have to face. It is proved by practice that micro steel pipe piles used to reinforce failure slope is effective. This method is adaptable，safe and convenient with immediate effect and small displacement on top of piles. The principal problems of designing and making of micro steel pipe piles and the measures to solve them are put forward by analyzing the attribute of this method through a case，in which micro steel pipe piles are used to reinforce failed slope. The technique will be helpful for similar engineering.

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STRESS CALCULATION FOR GATE PIER OF CONCRETE DAM DURING ANCHORING PROCESS AND ITS REHABILITATION TECHNIQUES

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2005, 24 (S2): -5459 doi:
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[PDF 215 KB] (1318)

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The thermo stresses in the concrete dam will produce because of changing of weather temperatures. The local fractures in gate pier of dam occur while the thermo stresses exceed the tensile strength of concrete，and sometimes，some fractures can extend from dam top to the spillway surface. Combining with the pier rehabilitation project of Fengman concrete dam，the nonlinear finite element method is applied for calculating the stress changes of concrete piers during anchoring process in the different load cases. The optimization arrangement method for prestress scales and anchoring locations are presented in order to deal with local stress larger than concrete tensile strength. The practical application shows that numerical simulation approach with finite element method is feasible to guide the design and operation of pier rehabilitation，and the proposed engineering measures are effective for preventing dam pier from local fracturing during anchoring process.

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STUDY ON QUASI-STATIC SETTLEMENT COMPUTATION METHOD OF HIGHWAY IN SOFT GROUND INDUCED BY VEHICLE LOADS

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2005, 24 (S2): -5464 doi:
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[PDF 305 KB] (1442)

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Based on the characteristic of vehicle loads and the actuality of over loading of most vehicles in China，vehicle loads are simplified as equivalent static load which was assumed as three kinds of distribution forms： concentrated distribution，rectangle distribution and zonal distribution；and their computational formula were educed respectively by using Boussinesq and Flamant answers. And then the lay wise summation method was applied to calculate the settlement of highway in soft ground induced by super-heavy vehicle loads. By applying the quasi-static method，the influence of settlement of highway on the soft ground induced by super-heavy vehicle loads performed on four sections of Shanghai-Nanjing highway were studied in the three different distribution forms of vehicle loads，which indicate that the settlement can reach to several centimeters and the depth influenced by super-heavy vehicle loads is about 7.1-11.9 m.

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FINITE ELEMENT ANALYSIS OF INFLUENCE FACTORS FOR TIMBERING DESIGN OF DEEP FOUNDATION PIT

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2005, 24 (S2): -5478 doi:
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[PDF 331 KB] (1323)

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Deep foundation pit engineering is one of pop and difficult problems in rock soil engineering. How to effectively control deformation of foundation pit and make foundation pit engineering safe and economical is the task that people always probe. Deformation for retaining structure of foundation pit is the important factor for effect on the deformation of foundation pit. This paper simulates the stress path in the excavation of foundation pit by large numbers of true triaxial tests in allusion to the silty clay，which is representational in Wuhan area. The deformation properties of soil mass in the excavation of foundation pit have been founded out and the parameters of the Duncan-Zhang soil model have been gained，and nonlinear elastic model of retaining structure of deep foundation pit is established. At the same time，the foundation pit deformation of a piazza in Wuhan is calculated by using the methods of the plane strain finite element. The factors of design，construction and nature environment on effect of the deformation of timbering structures are studied. These factors include the rigidity of timbering structures，the digging width of foundation pit，the deformation modulus of soil mass，the inserted depth，the bracing location and the reinforcing of soils，space-time effect of pit excavation and water environment of foundation pit etc. The deformation of timbering structures in foundation pit excavation and the developing and changing rules of the settlement of surrounding stratum have been founded out. Some measurements，which offer the reference to the design and construction of deep foundation pit，to control the deformation of foundation pit have been put forward.

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ANALYSIS OF DEEP PIT EXCAVATION ADJACENT TO TUNNEL

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2005, 24 (S2): -5485 doi:
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[PDF 249 KB] (1862)

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Engineering activities are inevitable in the urban region adjacent to the current metro tunnel with the continuous city development and increased needs for land of building. But the deep excavation of the foundation pit adjacent to the tunnel will change the stress state of the neighboring soil. And the deformation of tunnel will be induced which will cause impair to the daily operation and the safety of tunnel. According to the practice of deep excavation neighboring the tunnel in Shanghai，the application of elastoplastic finite element method with Mohr-Coulomb model to simulate different construction stage of deep pit excavation is presented. The results show good agreement with the field test data which show that the finite element method can provide good simulation for this kind of engineering activity and provide convincing computing results for the design and construction. Different construction method，furthermore，is simulated by the numerical method and the calculated results suggest that the rational excavation method will reduce the negative influence of the tunnel and ensure the success of the whole project.

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STUDY ON INFLUENCE OF VACUUM PRELOADING
METHOD ON SURROUNDING ENVIRONMENT

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2005, 24 (S2): -5490 doi:
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[PDF 204 KB] (1070)

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Based on the mechanism of vacuum preloading method to improve the soft foundation，the influence of this method on surrounding environment is studied. From the perspective of side-discharging，the stress and deformation of soil out of vacuum preloading field are discussed. Combined with the results of observed field data，the characteristic of the horizontal displacement and vertical settlement of surrounding environment is analyzed. The results show that，because the border of improved area is unable to seal totally，with the decreasing of groundwater level in the vacuum preloading field，the groundwater level of surrounding area will decrease in various degrees too. Then the soil will keep on consolidation and surface settlement continues after unloading. The measures to reduce its influence have been described and the conclusions can be used for reference to the similar engineering project.

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FUZZY MODEL FOR ANALYSIS OF GROUND MOVEMENT
AND DEFORMATION DUE TO DEEP EXCAVATION

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2005, 24 (S2): -5495 doi:
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[PDF 276 KB] (892)

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Based on the results of the statistical analysis of a large amount of measured data in excavation，a fundamental theoretical model of ground surface movement due to deep excavation is established by using the fuzzy measures theory of fuzzy mathematics. The formulae of ground surface displacement and deformation are developed and applied to the prediction of the ground surface movement due to deep excavation. The agreement of the theoretical results with the field measurements shows that the model is satisfactory and the formulae obtained are valid and thus can be effectively used for predicting the ground movement due to deep excavation in the city.

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PRESSURE-RELIEF PRINCIPLE IN ROOF CONTROL AND ITS APPLICATION TO ROADWAYS IN COMPLEX GEOLOGICAL STRUCTURE AREAS

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2005, 24 (S2): -5499 doi:
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[PDF 273 KB] (1077)

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This paper proposes the pressure relief principle of roof control and the corresponding“three bolting”support technique to solve the problem in supporting coal roadways with high ground pressure，cracked surrounding rock and support difficulty. The practical process of this technique involves two steps in coal roadway excavation. The first step involves the lead-excavation in small section and the only bolting support in time to the roof plate stratum with high strength bolts，but no support to the side coal seam，which allow some deformation and fracture to the side coal seam，and the loosening circle is formed gradually，the high stress in surrounding rock is released. Then the enlargement is carried to the two sides of the coal roadway and the bolting support to the side coal seam and the top of the roof plate is added with high strength bolts in time after the enlargement when the side coal seam appears sloughing. In the second step，the prestressed cable is used as reinforced support to the roof plate，and the reinforcement by bolting and grouting with inside grouting bolt is applied to base angle. As a result，a suit of technique of the pressure relief principle to the roof control and the corresponding“three bolting”support technique is formed. These principle and technique have been applied to the coal roadway support in complex geological structure areas of Taoyang coal mine at Feicheng mining area. After the support practice and observation on rock pressure，satisfactory benefits both in technology and in economy are gained，which provides a new approach in support of the coal roadways under difficult conditions.

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STUDY ON TUNNEL LINING WITH REACTIVE POWDER
SHOTCRETE IN SOFT ROCK STRATA

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2005, 24 (S2): -5505 doi:
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[PDF 203 KB] (1094)

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In the light of the drawbacks met in the double-layer lining in soft rock strata，permanent tunnel lining by single-layer reactive powder shotcrete is studied by using numerical simulation and test. The support mechanism of the different kinds of shotcrete lining over the surface of surrounding rock in soft rock tunnel and the influence of the advance rate on the early strength of the shotcrete material are analyzed by means of numerical modeling and the test of reactive powder concrete. Reactive powder concrete (RPC) is a new kind of concrete which has ultra-high strength，high ductility and low permeability. The results of numerical simulation and the test show that the method is satisfactory and the results obtained are valid and thus can be effectively used for design of tunnel lining by reactive powder shotcrete in soft rock strata. The double-layer lining of the tunnel can be substituted by single-layer reactive powder shotcrete lining.

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ANALYSIS OF STRESS MONITORING OF A LARGE-SPAN HIGHWAY TUNNEL IN HANJIALING MOUNTAIN

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2005, 24 (S2): -5509 doi:
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[PDF 282 KB] (1133)

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Hanjialing Mountain Tunnel is a key engineering in reconstructing the expressway from Shenyang to Dalian，and it is a highway tunnel with the greatest across span of arch in Asia. The tunnel consists of a single tube with four lanes，and was excavated with the layer-step method，which is a new attempt in constructing the tunnel with large across span. In order to clarify the mechanical behavior in the process of digging the large span tunnel and provide the technological data for design and construction，the research of stability stress monitoring for Hanjialing Mountain Tunnel is performed. In this paper，it expresses mainly the method adopted for monitoring the stress of tunnel structure，and analyzes the data of touch stress changing with time between shotcrete lining and surrounding rock，as well as the change of internal force of rock bolt. The research results show：(1) because the width，height and space of digging tunnel is large and the touch stress measured between surrounding rock and shotcrete lining is small，for the initial supporting structure，shotcrete lining and rock bolts only act as cooperation and auxiliary on resisting the deformation of rock，but main support action can be result from the steel arch frame and the bearing ability of rock itself. The greatest touch stress is 0.097 MPa，the largest axial force of bolt 4.73 kN. (2) after reaching the peak value，the touch stress of shotcrete lining and the axial force of bolt are still wavy to a certain extent. Although it will not affect the stability of tunnel with the progress of dig engineering，the loading action on the initial supporting lining from surrounding rock deformation is in a change state. (3) for the measured section of tunnel，on the side in which the surrounding rock is stable，the touch stress is tensile between the surrounding rock and the shotcrete lining，on the other side，the surrounding rock is unsteady. The touch stress is compressive，so it expresses that the horizontal displacement of this across section originate mainly from the side of unsteady rock. (4) the way of layer-step constructing is feasible for large span highway tunnels，by means of short driving and short supporting，so that the ground pressure can be released and the surrounding rock displacement can also be controlled.

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DESIGN AND FEM ANALYSIS OF PILE-RAFT FOUNDATION OF CUT-AND-COVER TUNNEL AT JIADI TUNNEL PORTAL

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2005, 24 (S2): -5516 doi:
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[PDF 545 KB] (940)

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Jiadi tunnel is one of important structures of landscape road－Ouhai road in Wenzhou city. Elongated cut-and-cover tunnel has been designed in entrance for improving environmental design and landscape design. Pile-raft foundation has been introduced based on the characteristic of the entrance design in order to avoid negative effect due to excessive settlement，considering the soft subsoil of portal section. Primary study has been performed on pile raft foundation applied on soft subsoil treatment at tunnel portal based on a 3D FEM model set up for combined action of cut-and-cover tunnel，pile-raft foundation and soil. It¢s indicated by numerical analysis that the applied pile-raft foundation will give the full play of pile bearing capacity and effective control the differential settlement of the cut-and-cover tunnel on the soft subsoil as a result of asymmetric dead load.

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RESEARCH ON LARGE DEFORMATION AND ITS MECHANISM OF
MUZHAILING TUNNEL

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2005, 24 (S2): -5521 doi:
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[PDF 369 KB] (1280)

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The Muzhailing tunnel，a key project of reconstruction of the national highway G212，is located in the northeastern Qinghai-Tibet plateau and traverses the Muzhai mountain. The very complex geological environments，such as high earth stress，deep-buried，rich groundwater，five faults zone with total width of 375 m (21.9% of the tunnel) and very weak and cracked rock masses influenced by groundwater and above-mentioned faults，make self-stability of the tunnel be unfavorable. During construction，intense deformation and serious failure happened. The monitoring data show that deformation was rapid with long duration. The maximum cumulative vertical and horizontal displacements reached to 1.712 m and 1.081 m，respectively in fault F2. Many serious failures happened due to large deformation，for example，roof subsidence，wall crushing，shotcrete flaking，S-shape twisted steel support，broken lining，floor upheaval，invert crazing and lots of cracks distributed everywhere. The surrounding rocks were reinforced and the tunnel was repaired for many times，but large deformation and bad damage did not stop；and previous intrinsic characteristics continued. By analyzing surrounding rocks，groundwater，earth stress as well as deformation characteristics，the reason and mechanism of large deformation of this tunnel were discussed. It is plastic flow and swell of surrounding rocks that are resulted in large deformation jointly. Based on correct understanding of dynamic evolution mechanism of the surrounding rocks，a new reinvention and reinforcement program was adopted from the viewpoint of controlling surrounding rocks. Those parts including large deformation and serious failure were repaired successfully. The construction of the tunnel through the rest of fault F2 and other faults benefited from the research results. The Muzhailing tunnel is achieved safely and successfully at last.

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EXPERIENCE OF MULTI-ARCH TUNNEL DESIGN OF ROADS IN ZHEJIANG PROVINCE

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2005, 24 (S2): -5527 doi:
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[PDF 251 KB] (1311)

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The article expounds and summarizes some experience and lesson achieved in the process of multi-arch tunnel design and construction in Zhejiang Province. Traditional multi-arch tunnel adopts linear middle-wall，which consists of complicated construction steps. In general，as a V-shape rock area up，the middle-wall will be disturbed several times in construction process，and plastic deformation is so obvious as to result in collapsing. Besides，the longitudinal construction joint between the arch part and middle-wall，which always becomes the penetration passage of underground water，as well as incidentally clogging vertical drainage tube in middle-wall greatly affects waterproof performance. Due to the shortcomings mentioned above on structure mechanical and waterproof performance in traditional multi-arch tunnel with linear middle-wall，a novel multi-arch tunnel with curvilinear middle-wall is put forward. It¢s proved by numerical analysis that the new structure has much more excellent mechanical performance. As a result，the plastic deformation in the V-shape rock area up the middle-wall is controled effectively. As for waterproof performance，the second lining of the new structure is separated from the middle-wall. For the unattached second lining has no construction joint，water penetration via construction joint，which is a common quality defect in traditional multi-arch tunnel，is avoided. What is more，the new structure can simplify construction steps and shorten construction period taking advantage of mechanical operation.

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SURVEYING OF HYDROGEOLOGY CONDITION AND FORECASTING OF WATER INFLOW IN CANGLING TUNNEL TAIZHOU—JINYUN HIGHWAY

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2005, 24 (S2): -5531 doi:
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[PDF 243 KB] (1356)

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Taking Cangling tunnel of Taizhou—Jinyun Highway as an example，the permeability coefficient of rock masses with different joint developments in tunnel are found out by hydrological geology integrated exploration method. Then water inflow in tunnel is forecasted using groundwater dynamics and groundwater modulus of runoff. Results show that the predicted location where inflow happens and the quantity of inflow approximate the practical ones，which indicates that the prediction of water inflow is of guidance to design and construction of drainage.

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EXPERIMENT AND MODELING INVESTIGATION ON SHEAR RHEOLOGICAL PROPERTY OF JOINT ROCK

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2005, 24 (S2): -5536 doi:
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[PDF 259 KB] (1264)

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The shear rheology experiment on the shear rheology equipment is carried out for unfilled jointed rock specimens in the surrounding rock mass of a huge underground cave in Longtan hydropower station. The long-term shear strength parameters of jointed rock are gained. Compared with the short-term shear strength parameters gotten by rapid shear experiment，the long-term shear strength parameters have some reduction. What’s more，the sensitivity of cohesion on time is higher than that of internal friction angle. Based on the shear rheological curves of joint rock obtained on rock shear rheology equipment，five-component viscoelastic shear rheology model is used to identify the curves that show the viscoelastic rheological properties，and the viscoelastic shear rheological parameters of jointed rock are obtained. Then by connecting nonlinear viscoplastic body(NVPB) put forward by the author and five-component viscoelastic shear rheology model in series，a seven-component nonlinear visco-elastoplastic shear rheology model of rock is constructed. Then by using complete accelerative shear rheological curve of joint rock，the identification of the proposed seven-component nonlinear visco-elastoplastic shear rheology model of rock is carried out. The correlative parameters of nonlinear shear rheology model such as viscoelastic shear modulus and viscosity，etc.. are also gained. The comparison between the shear rheology model and experimental result shows that the proposed non-linear shear rheology model is right and reasonable.

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RISK ANALYSIS OF ENCOUNTERING ROCKFALLS ON HIGHWAY AND METHOD STUDY

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2005, 24 (S2): -5543 doi:
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[PDF 257 KB] (1126)

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As the rapid development of economy in China，a great number of highways in mountainous areas will confront with more and more rockfall problems. Obviously，risk analysis of encountering rockfalls along these traffic routes is of extreme importance for zoning of rockfall hazards and optimum scheme of mitigation costs. Based on the EGMS methodology，a comprehensive way is developed to estimate frequency of rockfalls occurred in difficult mountainous conditions by combining all the information from site investigation，experiences and theoretical analysis. It is supposed that human activities and potential rockfalls in a rockfall zone are uniformly distributed，and some formulas are obtained from Bernoulli formula to compute probability of encountering rockfalls under three situations，i.e.，immobile vehicles，mobile vehicles and foot passengers. Thus，risk levels of passing different rockfall zones can be successfully achieved from further vulnerability analysis and the annually averaged probability of encountering rockfalls.

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ANALYSIS OF CONSTRUCTION RISKS FOR PIPE-ROOFING
TUNNEL IN SATURATED SOFT SOIL

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2005, 24 (S2): -5549 doi:
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[PDF 281 KB] (1409)

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With the consideration of geological conditions，the pipe-roofing method―advancing method with relay station，is used in the project of Shanghai Hongxu—Beihong road. It is the first time to use pipe-roofing method to construct tunnel in China，and it is the largest and longest pipe-roofing tunnel in saturated soft soil. There are high construction risks because of large-section culvert box，novel construction method and unfarournble geological conditions. On the basis of risk analysis theory，the construction risks，which exist in advancing precisions of pipe-roofing，earth settlement (upheaval)，pipe damage，waterproof capacity of pipe-roofing，joint types，stability of excavation face，box damage，box advancing direction controlling，pipe settlement，enit safety of box，and ground deformation controlling，are discussed. Total risk level of the project is gained，and the preventing methods are presented.

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CENTRIFUGE MODELING OF SOIL-PILE INTERACTION
IN LIQUEFIABLE SOILS SUBJECTED TO STRONG MOTION

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2005, 24 (S2): -5555 doi:
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[PDF 528 KB] (1067)

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The evaluation of liquefaction hazard and the seismic design for the pile foundation built in the liquefiable soil is potentially significant. The problem of soil-pile interaction in liquefiable soils is a nonlinear and complicated problem. Now the dynamic centrifuge test is widely used to study the seismic performance of pile foundation. Four cases of 50 g dynamic geotechnical centrifuge model test，dry sine input-wave model 1，saturation sine input-wave model 2，saturation model 3 of level 1 scenario input-wave，and saturation model 4 of level 2 scenario input-wave，are conducted to study the seismic response characteristics such as acceleration，displacement，pore water pressure of pile foundation，and mechanism of soil-pile interaction. A rectangular rigid container with internal dimensions of 150 mm×450 mm×300 mm (W×L×H) was used in the centrifuge tests. The soil profile is comprised of one horizontal layer silica sand of about 10 m thick resting on stiff bedrock at prototype scale. The saturation soil profile is made by de-aired dry sand saturated by de-aired motolose solution of 50 times the viscosity of water that the deposit has the prototype permeability of sand. The model pile foundation consists of structure supported by a 2×2，10 times diameter spacing pile group. Moreover，the results from centrifuge modeling are compared. It is found that displacements of saturation models are larger than those of dry models. Compared with dry model 1，the acceleration value of saturation model 2 descended quickly during shaking. This is may be induced by liquefaction. Sand liquefis at two depths of 2.5 m，5.0 m in prototype scale of model 4 does not liquefy，and the excess pore water pressure dissipated slowly after shaking in model 3. The failure degree，state and mechanism of the site pile foundation in liquefiable soil subjected to the strong motion have been discussed and a good result is achieved. These results are consistent with the one obtained from numerical simulations. This study provides a reliable foundation for the seismic design of the oversize pile foundation.

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INVESTIGATIONS ON STUDIED SITUATIONS ASSOCIATED WITH MECHANICAL ASPECTS AND DEVELOPMENT FOR UNDERGROUND STORAGE OF PETROLEUM AND NATURAL
GAS IN ROCKSALT

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2005, 24 (S2): -5561 doi:
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[PDF 287 KB] (1630)

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Rocksalt is often utilized as underground storage media in which petroleum and natural gas are stored regarding as strategical and commercial resources，which have been extensively utilized in European countries because of mechanical characteristics of rocksalt such as lower permeability and rheology. On the base of the studies and investigations associated with mechanical aspects of rocksalt such as petroleum and natural gas，underground caverns are firstly divided into four stages as follows：(1) the stage of simple application for underground storage combination mechanical knowledge and experiences of mining engineering during the beginning of 1960s；(2) the stage of models researches utilizing large rocksalt samples in which simulating the process of natural gas or petroleum storage dated from the middle of 1960s to the end of 1970s；(3) the stage of numerical simulation and calculation by means of FEM or FLAC，considering experimental results of rocksalt samples from 1970s to the middle of 1990s；(4) the stage of damage and healing constitutive of rocksalt from the middle of 1990s up to now，and situations of each stage are analyzed and discussed. Dominant researchers and their studies associated with mechanical properties of rocksalt are also given. Then，some typical constitutive equations for rocksalt are summarized and discussed. Furthermore，the characteristics of constitutive equations are introduced，particularly，Norton model and Hou/Lux constitutive model of damage and healing for rocksalt are induced. The advantages and disadvantages between the two constitutive models are indicated. Finally，the development trends of mechanical studies of rocksalt as petroleum and gas underground storage are listed.

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MONITOR AND ANALYSIS OF RAILWAY LINE SETTLEMENT CAUSED BY CONSTRUCTION OF SUBWAY TUNNELS BENEATH A CLUSTER OF EXISTING RAILWAY LINES IN THE NANJING RAILWAY STATION

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2005, 24 (S2): -5569 doi:
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[PDF 315 KB] (979)

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Constrained by the Nanjing railway station，the Nanjing subway station of Nanjing metro No.1 is subdivided into three parts as following：(1) the southern cutting part；(2) the northern cutting part；and (3) the connecting tunnels part. The connecting tunnels as a part of main structure for the Nanjing subway station are just beneath a cluster of existing railway lines of the Nanjing railway station，which includes two separated tunnels. The connecting tunnels constructed with mining method have the features of large span，shallow coverage，and little distance between the two lines. Railway line settlement must be restricted to insure the safety of railway lines during construction. A large numbers of settlement points are placed on the railway roadbed and the beam support foundation. The railway roadbed settlement induced by tunnels construction is discussed and the settlement monitored results indicate that the rail reinforcement method and the connecting tunnels construction technique are reliable. At the same time，with the analysis of settlement data，some suggestions on similar engineering construction are presented.

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SEVERAL SPECIAL DISPLACEMENT SOLUTIONS AND COMMENTS UNDER CONCENTRATED FORCE

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2005, 24 (S2): -5576 doi:
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[PDF 216 KB] (1337)

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Using integration of the normal strain concerned，several special displacement solutions under the concentrated force for a few elastic problems are obtained. The end point of the finite integration is purposefully separated from the load application point. When this separation approaches to zero，the asymptotic singularity of the displacement solution is proved to be correct. Comparisons are made of the related solutions，and the difference and association are discussed. The solutions can be easily extended to orthotropic materials. An example is given to illustrate the application of present method for deriving special displacement solutions with integration method，where the physical meaning of the solution can be understood more directly and clearly. It is also pointed out in the example that the original solution presented in a reference for the deformation of rock surface under concentrated force is incorrect.

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APPLICATION OF GIS TECHNOLOGY TO GEOTECHNIC ENGINEERING IN YANGTZE RIVE BASIN

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2005, 24 (S2): -5580 doi:
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[PDF 411 KB] (1056)

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The application of geographic information system (GIS) technology to geotechnical engineering in Yangtze river basin is studied. GIS technology has been put into use in the field of landslide analysis，soil and water conservation，and levee construction monitoring. GIS is a set of systems which can be used to gather，manage，and analyze spatial data and the related attribute properties. GIS have two remarkable features as follows：(1) it can manage data and literal information like traditional database data base management system (DBMS)，and it can manage the spatial graphic data；and (2) the complicated spatial data can be analyzed by synthesis method with various of spatial analysis modules in the GIS software platform. Consequently，the interdependence of the spatial items has been established. The analyses of nature phenomena and process in some specific geographic areas are gained，and certain spatial relationship has been proposed，which enables researchers to employ a new synthetical method to solve various problems in geographic field. Presently，GIS technology is introduced in many fields and engineering in Yangtze river basin such as geotechnics，environmental science，water resources planning，river and forestry conservation and so on. With the development of remote measurement technology，it is possible to build on basic spatial geodata database on large scale. By implementing data conversion，data mosaic，overlap processing，GIS can carry out mass data processing and convey the useful information by fiber-optic transmission system. As a result，any special map which will be used in the engineering can be extracted，classified and combined on the computer aided software platform of professional geographic information system.

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STUDY ON DESIGN OF SAFETY PILLAR AGAINST WATER-INRUSH
THROUGH STOPE SILL FAULTS

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2005, 24 (S2): -5585 doi:
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[PDF 342 KB] (1128)

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The rational design of safety pillar against water-inrush through stope sill faults is very important to the safety of coal mines. The characteristics of faults and the underground pressure are considered in the design. The coal body around mining area can be divided into two parts：the elastic area and the non-elastic area，where the latter does not have water-resisting function. The formulas to calculate the range of non-elastic area are deduced according to supporting pressure distribution characteristics. Based on the floor stress distribution characteristics in the direction of face advance，the developing direction of peak stress for underground pressure in floor is simulated and the mechanical models of water-inrush from floor are constructed. The results show that the passageway of water-inrush from floor consists of fault and broken floor strata caused by underground pressure. The condition of water-inrush from floor is that the depth of broken floor strata，caused by underground pressure，is not less than that of the join of peak stress line of underground pressure in floor with the fault. The formulas to design safe pillar against water-inrush from faults are achieved according to above results and a case study shows that the formula is reasonable.

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STABILITY OF THE ANCHORAGE WALL ROCK OF TUNNEL FOR
CHONGQING EGONGYAN BRIDGE

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2005, 24 (S2): -5591 doi:
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[PDF 305 KB] (1050)

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The suspension bridge scheme is adopted for Chongqing Egongyan bridge. East anchorage is considered as one of anchors for tunnel anchorage，which is assigned in silty-sandstone and sand-mudstone layers. The deformation states of anchorage and wall rock have great influences on the stability and safety of the bridge directly. In order to understand the ultimate bearing capacity of wall rock and the deformation state of the anchorage and rock at tensile force，comprehensive studies are performed on the anchorage and wall rock，such as tests for the parameters of rock mass，tensile test for tunnel anchorage model with scale 1∶12.5，numerical analysis，and grey GM(1，1) model forecast，etc.. The studies show that the deformation of anchorage and wall rock is smaller，which is in the linear stage. The ultimate bearing capacity of wall rock is 6.09～6.15 times of its design load，which is forecasted by grey GM(1，1) model. The results can provide reliable basis for engineering design.

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STUDY ON DAMAGE CONSTITUTIVE MODEL
OF ROCK WITH PLASTIC STAIN

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2005, 24 (S2): -5598 doi:
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[PDF 201 KB] (784)

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Using the Eshelby equivalent inclusion method，a Helmholtz free energy function for damage rock with plastic strain is set up，and a constitutive relationship is derived based on CDM，and the corresponding evolvement equations for damage and plastic strain are presented. The model can reflect the mechanical properties of failed rock.

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EXPERIMENTAL STUDY ON MONITORING OF STRESS FOR PRESTRESSED ANCHORAGE CABLE USING DISTRIBUTED FIBER OPTIC SENSOR

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2005, 24 (S2): -5604 doi:
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[PDF 396 KB] (1340)

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The monitoring of the stress distribution along prestressed anchorage cables is one of the unsettled issues for prestressed reinforcement in geotechnical engineering. As a novel optical fiber sensing technique，BOTDR (Brillouin optical time domain reflectometer) can be used to measure the distributed strain along an optical fiber bonded to the support structure. Therefore，it is of great theoretical significance and practical value to study how to apply this technique to the monitoring of the stress distribution for the prestressed anchorage cables. A tensile test is carried out for one steel and three AFRP (aramid fiber reinforced plastic) prestressed anchorage cables while the strain distributions of the cables are monitored simultaneously with a sample resolution of 5 cm. The experimental results show that the distributed fiber optic sensing holds a rather high accuracy，with a relative error of the measurement results of no more than 3.8% between the fiber optic sensor and the strain gauge. The instantaneous prestressing loss of steel prestressed anchorage cable is 8.8%，while the instantaneous prestressing loss of AFRP prestressed anchorage cables were under 6.08%. After 30 days，the total prestressing loss of steel prestressed anchorage cable was 11.1%，while the total prestressing loss of AFRP prestressed anchorage cables were under 10.3%. Thus，the conclusion can be drawn herein that BOTDR distributed fiber optic sensing shows considerable applicability in monitoring the stress (strain) state of prestressed anchorage cable in geotechnical engineering.

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STUDY ON NUMERICAL SIMULATION OF TECTONIC STRESS FIELD BEFORE AND AFTER RESERVOIR IMPOUNDING IN THE HEAD AREA OF THE THREE GORGES

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2005, 24 (S2): -5611 doi:
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[PDF 591 KB] (1185)

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The main problem on simulation of tectonic stress field after reservoir impounding in the head area of the Three Gorges is the influence of“canyon effect” and “rock soften”. For the first time，taking the terrain，water load distribution，infiltration range and the fault units into account，the 3D numerical modeling of the upper crust of the Head Area of the Three Gorges is established on the software platform of Marc to reflect the change of tectonic stress field under the load cases—water lever 175 m and 135 m. From the numerical simulation results，it is discovered that under water level 135 m，the maximum principal stress descends(3.5-5.0 MPa) is connected with the activities of high angle normal fault and these changes are more obvious under water level 175 m. The idea of“secondary induced earthquake”，“potential induced seismic source in reservoir”and “superposition seismic source”are presented first. Moreover，the effects on the stability of area fault and the seismogenic environment in Zhigui and Badong after impoundment are analyzed.

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ANALYSIS OF THE THREE TREATMENTS FOR FAILURES OF A HIGH-STEEP HIGHWAY SLOPE

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2005, 24 (S2): -5619 doi:
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[PDF 389 KB] (1141)

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Yunnan province is a mountainous region of China in southwest district，and there are many rainy days every year，thus the highway slope soaked with rainwater is reliable to slide during construction. A typical project case is discussed. The slope has been treated twice with many conventional methods，such as cutting slope，prestressed anchor rope，vertical anchor，combined bolting and shotcreting to the slope surface and slope surface drainage (for the first treatment)，and grouting and anchoring (for the second treatment). However，due to the requirements of project schedule，a detailed investigation is not conducted，resulting in the failure of the slope in the following rainfall seasons，and the slope is found to crack in the top，slope surface，shoulder，and upheaval in discharge ditch and asphalt pavement. In order to find incipient fault and ensure safety of slope，the employer decided to give an overall investigation，design，and treatment for the slope. Based on a more detailed investigation，more thorough understanding of landslide，the causes for landslide，slope calculation for checking reliability，and effective schemes are proposed including cutting slope，anti-slide piles，drainage，and slope protection measures. The treatment has been verified to be satisfactory through three rainy seasons. Practice shows that the groundwater is the main factor. So the treatments to the crack at the back of landslide mass and installation of drainage system are very important. Landslide treatment is a comprehensive process，and a satisfactory result could not be expected with single technical measure，and the prerequisite of treatment is a general and accurate understanding of landslide. The failure of treatment in the first and second time，and success in the third time could function as a valuable reference to other similar landslide treatment projects.

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A MODEL OF SOIL CONSTITUTIVE RELATION BASED ON ENERGY
DISSIPATION AND ITS PARAMETERS DETERMINATION

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2005, 24 (S2): -5625 doi:
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[PDF 419 KB] (1063)

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A model based on ideas of thermomechanics，the first and second laws of thermodynamics，is introduced to describe the elasto-plastic behavior of soil deformation，and the method of determining model parameters is provided. Once the forms of the free energy function and dissipation potential function have been specified，the corresponding yield surface，flow rule，hardening rule as well as the elasticity law are deduced in a systematic manner. The plastic work and dissipation energy are distinguished explicitly. Not all plastic work is dissipated，but some are stored and can be recovered under reversed plastic loading. The physical meaning and range of model parameters are discussed. The parameters can be determined by fitting the triaxial test curves，and the genetic algorithm is adopted by using obtained parameters，and a group of drained triaxial tests are computed，and compared with the experimental results to verify the validity of the model. The model automatically satisfies the laws of thermodynamics，and there is no need to invoke any other postulations.

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ELASTOPLASTIC FINITE ELEMENT SIMULATION ANALYSIS OF THE WHOLE PROCESSES DURING CULVERT CONSTRUCTION

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2005, 24 (S2): -5634 doi:
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[PDF 259 KB] (1058)

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An elastoplastic finite element program (2D) is developed，in which the processes of foundation pit excavation layer by layer and block by block，culvert construction，and the foundation pit filling by using the method of increasingly adding filling-element gravity and grinding force，are presented respectively. The whole continuous processes of culvert construction including foundation-pit excavation，the body construction，and foundation pit filling，are simulated and investigated. Especially，it shows that the differences of stress field and deformation field between those formed by excavating and natural gravity field are distinct. The results show that the stress field formed by excavation is lower than that of natural gravity field by 10%–18%，and there are some stress concentration zones. The deformation fields are different as following：(1) at the end of the filling，the maximal settlement is located at 1/2 to 1/3 height of fill but not at the top of the fill，which is in good agreement with the results of theoretical analysis；and (2) the maximal lateral displacement is under the foot of slope at a certain depth. It will shift to the central axes of excavation pit with the increment of excavation depth. These results can provide reasonable references to the analysis and design of culvert structure and construction in civil engineering practices.

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ON THE PAVEMENT PERFORMANCE TEST OF STABILIZED UNIFORMLY-GRADED GRAVEL SOIL WITH LIME

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2005, 24 (S2): -5641 doi:
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[PDF 240 KB] (951)

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The problem of stabilized uniformly-graded gravel soil with lime used in the top layer of subgrade of highway with semi-rigid basement and pitched road surface is discussed. The material property and basic physical-mechanical property of uniformly-graded gravel soil and its swelling-shrinkage behavior are performed on the spot. The reasonable construction distribution ratio is presented，which provides reference to the construction of highway in similar project.

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NUMERICAL SIMULATION OF INTERFACE BEHAVIOR IN ROCK-CONCRETE INTERACTION PROBLEM

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2005, 24 (S2): -5648 doi:
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[PDF 224 KB] (1135)

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Based on the review of some classic interface elements，a twin-body model is offered for research on mechanical performance of interface between rock and concrete for the assessment of stability of concrete dam foundation. In this paper，FLAC，a finite difference program，is utilized to model the mechanical behaviors of rock-concrete and rock-rock interface with the action of compressive and shear loads. The stress，displacements and plastic zone distribution are obtained to explain the model failure and the effect of interface. Results show that some different stages happen in the damage process and the interface roughness has an obvious effect on the mechanical behaviors of the model.

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CRACK GROWTH MECHANISM AND FAILURE BEHAVIOR OF SPECIMEN CONTAINING SINGLE FLAW WITH DIFFERENT ANGLES

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2005, 24 (S2): -5652 doi:
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[PDF 892 KB] (1175)

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Rock，concrete，ceramics and glass，as discontinuous，inhomogeneous，anisotropic，and not elastic brittle medium，are typically made up of defected material containing flaws and pores. Under differential compressive stress，the crack initiation，propagation，coalescence and interaction may cause the strength and stiffness degradation of such medium. Original study of specimen containing flaw defect is mainly focused on single flaw model. By employing a test system and numerical tool，this paper investigated crack growth mechanism and failure behavior of specimen containing single flaw with different angles. The experimental and numerical results show that crack growth and final failure behavior is strongly affected by the flaw angle under uniaxial compression. When the flaw angle is small，crack initiation is easy；crack growth velocity is stability，and specimen failure with mixed mode. When the flaw angle is large，the crack initializes and propagation is compressed. However，crack growth is rapid while loading is close to the peak strength，then specimen will be broken with shear or splitting mode. When the value of flaw angle is close to that of failure angle，the specimen is easy to emerge brittle failure with prominent stress decrease.

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STUDY ON SEEPAGE FIELD CHARACTERISTIC OF ROCK-FILL DAM IN DEEP OVERBURDEN FOUNDATION WITH ADOPTION OF HUNG- UPSIDE DOWN IMPERVIOUS WALL

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2005, 24 (S2): -5658 doi:
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[PDF 273 KB] (940)

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To build a rock-fill dam in deep overburden stratum，because of technique limit for current construction condition，the impervious walls can not cover or penetrate the deep overlay layers thoroughly. Therefore，analysis of hung-upside down imperious wall is adopted and considered in the rock-fill dam engineering. Seepage field analysis for this kind of project and its corresponding results are achieved，and the obtained results can provide references to similar engineering projects.

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SOME IDEAS OF STUDY ON HYDRAULIC FRACTURING OF CORE OF EARTH-ROCKFILL DAM

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2005, 24 (S2): -5664 doi:
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[PDF 181 KB] (1182)

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Hydraulic fracturing of core of earth-rockfill dam is an important issue related to the safety of the dam，and it attracts much attention. In this paper，the achieved results show as follows：(1) the conditions of hydraulic fracturing should include at least two conditions—physical one that includes fissures existing in core and low permeability of core material，and the mechanical one that is enough larger“water wedging”action；(2) the mechanical mechanism of hydraulic fracturing can be explained with the theory and method of facture mechanics；(3) the boundary and stress conditions of laboratory，field or model tests should be similar to those in up-stream face of core of the dam，for instance，some fissures should be included in sample，and the water pressure should be forced from the surface of the sample；and (4) the numerical simulation to the development course of hydraulic fracturing is deformed and the effective way to study the hydraulic fracturing in core of earth-rockfill dam is to reveal the induced condition and mechanical mechanism，to develop reasonable criterion and to estimate and simulate by using numerical analyses.

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FORMATION FRACTURE PRESSURE CALCULATION IN HIGH TEMPERATURES WELLS

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2005, 24 (S2): -5669 doi:
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[PDF 257 KB] (1703)

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Correct prediction of formation fracture pressure is the primary precondition for safe and speedy drilling. Many studies on this subject have been performed and many methods for formation fracture pressure prediction have been put forward. But few of them consider the influence of temperature on fracture pressure in high temperature wells. A new coupled temperature model for fracture pressure calculation by analyzing formation temperature and stresses change due to heat exchange between circulating drilling fluid and formation is established. The effect of temperature on fracture pressure is quantitatively analyzed. A calculation example is presented and the results show that the new model can greatly improve the accuracy of fracture pressure prediction.

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DISCUSSION ON GEOMECHANICAL PATTERNS FOR RIGHT BANK OF LONGPAN SLOPE DEFORMATION OF TIGER LEAPING GORGE HYDROPOWER STATION

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2005, 24 (S2): -5674 doi:
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[PDF 415 KB] (1180)

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Tiger Leaping Gorge hydropower station is a large project to be build on Jinsha River in southwest China. Longpan is one of the comparative dam addresses，but large-scale deviant rock mass was discovered on the right bank slope，where an old landslide once happened，so that Longpan dam was given up. In the latest studies，based on systematic field survey，especially through CSAMT exploration and comprehensive analyses of deformation characters of the rocks，it was proven not to be an old landslide but a deforming slope. The geologic structure of Longpan slope is very specific，and the dip direction of the stratums is opposite to slope. The sandstone stratums and slate stratums intercross alternately，and deep-seated stratums are dominate sandstone rock which are thick and hard，with large inclination angle. But the top of the slope stratums are with thin and small inclination，and the hard and soft rock-formations intercross mutually. Lake sediments at the foot of the slope account for the particular geologic structures. The results show the geomechanical deformation patterns are as follows：(1) the activities of the fractures induce deeply fragmentized phenomenon；(2) lithosphere raising，valley cutting downwards and transforming of the regional tectonic stress-field cause unloading rebound and cracking of lower rock mass；and (3) the main deformation pattern of top stratum was bend-creeping. By reason of the compressibility and plastic flowing of lake sediment and superficial stratum at the foot of the slope，rock mass is adjusting to the structure by the way of stagger-sliding and lateral expanding locally，but there is no weak zone of penetrating the slope. The mode can be named Longpan-pattern，which is universal in Tiger Leaping Gorge Reach in Jinsha River，and it is significant to choose the dam address and analyze the stability of reservoir banks.

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DISCUSSION ON GEOTECHNICAL PROBLEMS OF HANGZHOU METRO LINE NO.1

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2005, 24 (S2): -5680 doi:
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[PDF 449 KB] (1621)

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Hangzhou metro line No.1 project is encountered with complex problems of geology，hydrogeology，and anthropogenic surroundings. Based on the characteristics of the overhead stations，open excavation and excavation running tunnel，the main geotechnical preambles are analyzed，which may provide valuable references to engineering geology investigation，design，and construction.

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THE ADVANCES IN INVESTIGATION OF REPRESENTATIVE ELEMENTARY VOLUME FOR FRACTURED ROCK MASS

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2005, 24 (S2): -5686 doi:
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[PDF 221 KB] (1464)

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The investigation of the representative elementary volume(REV) of fractured rock mass is a fundamental problem in rock mechanics. Firstly，the general mechanical meaning of REV is discussed by analyzing its definition，and REV is considered as a basic mechanical conception that contains the dialectic relationships of microstructure-macrostructure，discreteness-continuousness，and randomness-determinacy. Then，the close relationship between the REV of fractured rock masses and the choice of mechanical models as well as mechanical parameters is explained. It shows that REV can be regarded as a quantitative criterion for choosing equivalent continuum approach or discrete approach to solve rock engineering problems and it can reflect the size effect of mechanical properties of rock mass. With the summarization of previous studies about REV，the general methodology for investigating the REV of fractured rock mass is presented and the results show that numerical method，based on the modeling techniques of discrete fracture networks，will become a mainstream for estimating the REV of fractured rock masses. Finally，Monte Carlo simulation approach is used to reproduce a two-dimensional rock mass region which contains two sets of random fractures，and the finite element method is adopted to obtain the equivalent elastic modulus of the rock mass under uniaxial loading. According to the variation of equivalent elastic modulus being changed with the size of rock mass，the REV size of the considered. rock mass is estimated to be 9 m×9 m.

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ANALYSIS OF STABILITY FOR SURROUNDING ROCK
CAUSED BY DEPTH OF THAWING RANGE DURING PLATEAU
PERMAFROST TUNNEL CONSTRUCTION

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2005, 24 (S2): -5693 doi:
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[PDF 239 KB] (971)

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During the tunnel construction in permafrost regions，construction heat and heat exchange of air inside and outside the tunnel caused by excavation，primary lining insulation，and secondary lining will affect original ground temperature field of the surrounding rock. This influence will destroy thermodynamics balance of the permafrost stratum and change mechanical characteristics (thawing and sinking，dilatability，stability of tunnel，etc.) of permafrost. So，it is one of the important controlling factors during tunnel construction in permafrost regions to protect permafrost and to reduce the influence of original ground temperature field caused by construction. According to the establishment of thermal model of frozen surrounding rock，primary lining structure，insulation material and circumstance air inside the tunnel and on basis of construction method，surrounding temperature，and ground temperature，the surrounding rock temperature fields of different working procedures are simulated with finite element program ANSYS. The rules of surrounding rock temperature fields and the depths of thawing caused by uncovered time of gross tunnel and primary lining are analyzed. According to different constructions，the effects of stability of tunnel surrounding rock caused by the depth of thawing are studied，which can provide theoretic basis and reference to the design and construction of similar projects.

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INITIAL EXCESS PORE WATER PRESSURE DISTRIBUTION AND SETTLEMENT ANALYSIS OF SATURATED SOFT SOIL UNDER EMBANKMENT

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2005, 24 (S2): -5698 doi:
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[PDF 306 KB] (869)

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Deformation and stabilization are two important questions encountered in geotechnical engineering，especially for embankments constructed on soft soil foundations. For calculation convenience，assuming that soft soil foundation be Biot medium and embankment loading be exerted instantaneously，initial excess pore pressure and effective stress distribution are obtained. Furthermore，the initial settlement and the consolidation settlement are achieved. Influences of thickness of the compression layer and Possion¢s ratio of soil skeleton on the settlement are analyzed. These solutions are convenient to be used to calculate the quantities of the embankment fill，the excess pore water pressure distribution，and the settlement. These formulas are employed to analyze a practical engineering case.

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ANALYSIS OF EFFECTIVE STRESS METHOD FOR SATURATED SANDY
SOIL UNDER EXPLOSION SEISMIC WAVE LOADINGS

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2005, 24 (S2): -5705 doi:
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[PDF 285 KB] (908)

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Liquefaction in saturated sandy soil can also be caused by explosive loadings. Compared with the investigation of seismic liquefaction，the study of explosive liquefaction is still in testing and its theoretic study is also primary and obvious. It is still unreported about the study of explosive liquefaction using effective stress models all over the world. In fact，because of its few parameters，sample and practical，the effective stress models are widely used. According to effective stress dynamic analysis method，Byrne¢s volume strain model is used to simulate the effective stress analysis of saturated soil under single-point，two-point and multi-point explosion seismic waves，respectively，with FLAC code which is a two-dimensional explicit program. Three kinds of fields are considered，such as the level，little-obliquity，and slope ground. The results of numerical simulation indicate that it is simple and practical to analyze liquefaction using volume strain model with few parameters，and the characteristics of saturated sandy soil are different with fields. For some depths of calculated soil，it has little effect on liquefaction with small angle while its effect can not be ignored after exceeding a certain degree. So the characteristic of liquefaction in saturated sandy soil is widely varied with different obliquity while the other conditions are the same. The graphs of isoline states after simulating can be presented with the effective stress and pore water pressure in dams under dynamic loadings while the effective stress analysis of dams are performed under explosion loadings.

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FINITE ELEMENT ANALYSIS OF SAFETY MEASURES FOR AFFECTED
SOFT GROUND AREA BY VACUUM PRELOADING

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2005, 24 (S2): -5712 doi:
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[PDF 206 KB] (890)

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Some safety measure effects in affected soft ground area by vacuum preloading have been analyzed by plane strain finite element method(PSFEM) with different parameters，such as depth of trenches，modules of piles，coefficient of permeability piles，and length of piles. The results show that excavated trench can effectively reduce both horizontal and vertical deformations. The increase of modulus ratio of pile versus soil has little effect on settlement in affected area if the ratio is greater than 100. The permeability coefficient of pile has certain effect on settlement in affected area. The value of settlement decreases when the permeability coefficient of pile becomes smaller. The settlement value in affected area decreases with the increase of piles length. It shows that longer pile with smaller permeability coefficient can reduce ground settlement in affected area. Thus，it can provide safer protection for the neighboring constructions.

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NUMERICAL SIMULATION OF A PERFORATED CASING DAMAGE IN STEAM INJECTION WELLS UNDER GEOSTRESS
AND TEMPERATURE LOAD

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2005, 24 (S2): -5716 doi:
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[PDF 744 KB] (1226)

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Casing damage of steam injection wells is widespread in many oil fields of China. A numerical simulation method based on finite element theory is used to simulate casing stress under the earth stress and temperature load to study the mechanism of the casing damage. A two-step computing method is put forward. The first step provides the temperature and earth stress near the casting using the coarse-mesh finite element model；the second computation provides more accurate results using the fine-mesh finite element model. The simulation shows that casing slotting results in sharp stress concentration and the maximum Von Mises stress increases by
30%–50%. The simulation also shows that injecting temperature can greatly influence the stress field. For example，the maximum Von Mises stress increases by 26.5% when the injecting temperature is 200 ℃. The research results are very helpful to the casing protect in oil field by selecting suitable injecting temperature.

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SHEAR STRENGTH PROPERTIES OF LIGHTWEIGHT BEAD-TREATED SOIL MADE FROM DREDGED SILT

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2005, 24 (S2): -5721 doi:
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[PDF 371 KB] (1019)

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Lightweight bead-treated soil made from dredged silt is a new type of lightweight geo-materials(LGM). The meso-cracks in lightweight bead-treated specimen are found to generate from the interface between expanded poly-styrene (EPS) beads and solidified soil particles .With the additive amounts of cement and beads of EPS，the Mohr-coulomb envelope curve of the lightweight bead-treated specimen has two types：folding line and straight line. Different from natural soils，the damage of cementation should be considered in the strength mechanics of lightweight bead-treated soil.

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STUDY ON CONSTRUCTION MECHANICS OF TWO KINDS OF CONSTRUCTION METHODS FOR DOUBLE-ARCH TUNNEL

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2005, 24 (S2): -5727 doi:
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[PDF 693 KB] (1007)

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At present，rock collapse is common existing in the construction of double-arch tunnel，and large area cracks are found in linings. Jindong tunnel is located in Yuhuan railway between Ganjiaba and Yuquan，and double lines tunnel is reserved for the second line，which lies to the right of the first line. The distance between the two lines is 14.09 m，which is wide enough to build the second one. The distance between the two lines in the tunnel exit is 5.03 m with tunnel segment of 150 m shaped coattail；and the length of the double-arch tunnel is 42.2 m. Various construction methods are available for double-arch tunnel construction. When the condition of wall rock is favorable，three-cavity or two-cavity is adopted to excavate tunnel. For the sake of the construction safety，FEM is considered to analyze the mechanics of two different construction methods，and the displacement，force of preliminary support，and safety factor are obtained. Finally，results that can provide some references to construction of double-arch tunnel are achieved.

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SANDSTONE STRAIN PROPERTIES UNDER UNIAXIAL-TRIAXIAL COMPRESSIVE AND SEEPAGE PRESSURE CONDITIONS WITH CT TECHNIQUE

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2005, 24 (S2): -5733 doi:
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[PDF 384 KB] (940)

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Understanding the deformation and fracturing processes is a key problem for rock engineering and earthquake prediction. Experimental rock deformation studies and structural analysis of exhumed fault zones have been used to investigate the mechanism of faulting and to develop models of fault evolution. Through the study which is based on devices including the multislice spiral CT(MSCT) and real-time loading machine and seepage machine，the strain properties of sandstone under uniaxial-triaxial compressive and seepage pressure conditions are found to be different from each other. With integrated analysis of CT images and CT number，the porosity randomly distributed in the stress process is calculated. Through the variant analysis of CT numbers，it is easy to know the strain properties and cracking patterns. When the variance of CT number is increasing rapidly，the strain and cracking pattern of sandstone is brittle. If the variance of CT number is stable or declines linearly slowly，the deformation and failure modes of sandstone are plastic. The strain properties under seepage pressure are different from others. The peak strength and residual strength of a sandstone increases remarkably under seepage pressure conditions. The dry sandstone crack is brittle under uniaxial compressive condition. When the compressive conditions are with seepage pressure and triaxial compression，the crack is on plasticity. With triaxial compressive without seepage pressure，the crack pattern is between the two patterns above. So，X-ray CT is a useful method for the study of the strain properties of sandstone under uniaxial-triaxial compressive and seepage pressure conditions.

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EXCESS PORE WATER PRESSURE CAUSED BY SINGLE PILE DRIVING
IN SATURATED SOFT SOIL

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2005, 24 (S2): -5740 doi:
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[PDF 272 KB] (1229)

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By analyzing the measured data during piles driving，distribution rules and range of the excess pore pressure caused in soil around single pile are discussed. Results indicate that the excess pore pressure declines in logarithm function with the distance from the pile，and the influencing range is about 30 times of the pile radius. The comparison between the theoretical results and the measured data shows that the measured results of the excess pore pressure fit better with the computed results by substituting the plastic area radius from fitting line of the measured data into the cylindrical cavity expansion theory.

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PRIMARY RESONANCE AND SINGULARITIES ANALYSES OF HARMONIC EXCITING OF THIN RECTANGULAR PLATE ON NONLINEAR ELASTIC FOUNDATION

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2005, 24 (S2): -5745 doi:
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[PDF 271 KB] (740)

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A nonlinear dynamical equation of the small deformation thin rectangular plates on nonlinear elastic foundation subjected to harmonic excitation is established. It is transferred to be a nonlinear vibration equation by Galerkin¢s method. By means of the method of the multiple scales the first approximate solution of the primary resonance of the system is acquired，and numerical calculation is carried out. The transition variety and bifurcation diagram of the unfolding parametric plane are given. The response curves of the primary resonance are affected by damping parameter，foundation parameter and geometry parameter. It is pointed out that with the increasing of foundation coefficient and damping coefficient，the amplitude reduces. With the increasing of the thickness of thin plate，the amplitude increases.

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STUDY ON STRESS STATE AND PROTECTION OF EXCAVATED
CUTTING OF HIGH SLOPE IN GENTLY INCLINED RED BEDS

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2005, 24 (S2): -5751 doi:
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[PDF 219 KB] (941)

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More and more rock slope problems are met in highway construction. Because of complex structure of rock body，there are many difficulties in calculating and protecting slope stability. The stresses and deformations of excavated cutting of high slope (height 40，50，60，70，80 m with slope ratio 1∶0.5，1∶0.75，1∶1，1∶1.25，1∶1.5) are calculated as the prototype in gently inclined red beds natural slope of an expressway in Sichuan province，adopting the numerical simulation technology of finite element method(FEM). The computed results indicate that shearing stress focus zone moves from slope foot to top slope as slope ratio changes from steep to slow and the surface of deformation-failure of slope will also move in this way，i.e.，as the excavated slope ratio is greater than 1∶0.75，slope body shearing stress is concentrated near the slope foot；when the excavate slope ratio is lower than 1∶0.75，shearing stress focus zone is not located near the slope foot，but lie in position on the upper side of the middle of slope body. According to this conclusion，a rational protection pattern of rock slope is presented for reference to engineering design.

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ADJUSTING METHOD FOR EARTH PRESSURE ON BURIED
RIGID STRUCTURE

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2005, 24 (S2): -5756 doi:
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[PDF 320 KB] (894)

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With the rapid development of expressway，more and more constructions such as culverts have been built under highly filled embankment. However，the damage and accident occur frequently. The main cause of culvert damage is that the formulas or empirical curves with a smaller copulating result are adopted by some designers to calculate the vertical earth pressure on the top of the culvert. The better way to resolve the problem is to pave the soft material whose compressibility is larger than earth fill on the top of the culvert，and as a result，the earth pressure can be regulated properly. Having studied the mechanical properties of expanded polystyrene(EPS) through experimental test and filled it on the top of the culvert with high embankment to in-situ test load shedding and compared the results，it is found that the deformations of EPS under two conditions are similar. Based on the combining recursive analyses，the empirical formulae to calculated the vertical earth pressure on the top of culvert under given regulation effects are presented. In addition，with the finite element calculation，the effects of the breadth of regulation material on earth pressure of culverts are studied and the propositional numerical values for different shapes of culverts are achieved. Furthermore，the method of rational and measurable height choice，and density and filling breadth of regulation material for given regulation effects，are put forward which can afford references to project design.

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STUDY ON TUNNELING EXPERIMENT AND MATHEMATICAL
MODEL OF EPB SHIELD

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2005, 24 (S2): -5762 doi:
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[PDF 381 KB] (1686)

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Orthogonal experimental design is applied to shield tunneling experiment with variable parameters combination. The effects of earth pressure，thrust force and cutting wheel rotation speed on the advance speed，and torque of cutting wheel are investigated by multivariate statistical analysis. The mathematical model of advanced speed and torque of cutting wheel of EPB(earth-pressure-balanced) shield in soft ground is proposed. The mean error of mathematical model is less than 10%. The achieved results show that the tunneling parameters which affect the advance speed and torque of cutting wheel are earth pressure，thrust force，and cutting wheel rotation speed in succession. The advanced speed and torque of cutting wheel are in direct proportion to the thrust force，but in inverse proportion to the earth pressure. The cutting wheel rotation speed has little effect on the advance speed.

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CALCULATION OF BED SEPARATION UNDER HORIZONTALLY AND GENERALLY INCLINED COAL SEAM MINING

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2005, 24 (S2): -5767 doi:
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[PDF 318 KB] (849)

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Surface subsidence induced by underground coal mining can have severe damage to civil-engineered structures and residential property on the ground surface. The technique of grouting into the separated strata to control the surface subsidence is a novel technique widely applied in some coalfields in China. It has been proved to be an economic and effective method to control the movement of the strata and the formation of the subsidence. Though great process has been achieved，the mechanism of controlling the subsidence remains unclear since the movement and bed separation characteristics of overburden strata above mine voids induced by underground mining are very complicated problems influenced by many factors. One of the important tasks in the technique of grouting into the mining induced separated strata to slow down the surface subsidence is to determine the location of the separated strata and the magnitude of bed separation. Despite many years of considerable descriptive research，an accurate quantitative method for bed separation does not appear. In the paper，the location and the magnitude of separated strata during coal mining operations was analyzed and the rationality of the boundary conditions was validated on the basis of the elastic shell theory and the correspondingly calculating equations of bed separation was formulated in the end. It will be helpful for a better understanding of the bed separation characteristics induced by mining extractions and a wide application of the technique of grouting into the separated strata to control the surface subsidence.

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NUMERICAL ANALYSIS OF GROUND SURFACE SUBSIDENCE CAUSED BY CONSTRUCTION ORDERS OF SHALLOW EXCAVATION METHOD
AT TIANTAN EAST-STATION

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2005, 24 (S2): -5773 doi:
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[PDF 472 KB] (981)

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Four construction-support methods of shallow excavation are simulated with FLAC2D combined with engineering situation of Tiantan east station. Regularities of stress，plastic region，and displacement in surrounding soil are studied and the optimal excavation method is put forward. The main results are as follows：(1) in excavation，plastic region of ground surface spreads from vertical lines of both sides of the station to the line at an angle of 45°with the vertical lines. Plastic region at both sides of the station is very large. The plastic region at top and bottom of the station is greatly restrained by canopy-shelter and bottom arch；(2) adverse effect is made by single vertical or horizontal excavation to ground surface subsidence，and better effect can be achieved by a combined method of the two excavations；(3) the partial arc support is better than vertical support in restraining subsidence of ground surface. The combined method of vertical and symmetrical excavation is optimal；and (4) that excavation-support design can meet the whole stability of the station is further proved by the in-situ measured result.

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EFFECT OF STRAIN RATE ON UNDRAINED SHEAR
STRENGTH OF CLAYS

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2005, 24 (S2): -5779 doi:
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[PDF 212 KB] (1218)

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For it¢s creep behavior，undrained shear strength of saturated clay is related to load rate. Strain-rate parameter (increase of undrained shear strength per log strain rate)is used to describe the change in undrained shear strength with strain rate by some researchers. Laboratory test data on a wide variety of clays show the value of this parameter is between 8% and 20%，most about 12%，and stress history，consolidation state (isotropic consolidation or anisotropic consolidation)，test type(compression test or extension test) have a little effect on this parameter. An anisotropic elastic viscoplastic model used to study the parameter is introduced. The theoretical equation of is deduced and shows it is only dependent on the ratio of secondary compression index to compression index，independent of the consolidation state and test type，which is shown by test results. Actually，this equation can be deduced from any model based on the delayed compression framework . For most clay，value of ratio of secondary compression index to compression index is about 0.03–0.05，and the value of calculated by the equation is 7.2%–12.2%. High value such as 20% shown by some tests for sensitive clay is related to the high value of ratio of secondary compression index to compression index caused by soil structure collapse. The validity of the equation is testified by some laboratory tests.

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STRAIN LOCALIZATION AND COMPLETE STRESS-STRAIN CURVE OF
ROCK SPECIMEN IN UNIAXIAL TENSION

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2005, 24 (S2): -5784 doi:
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[PDF 200 KB] (1004)

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Analytical solution of complete stress-strain curve of rock specimen in uniaxial tension is proposed based on gradient-dependent plasticity considering strain localization initiated at peak strength. Differential of total strain along specimen length is composed of recoverable elastic part and unrecoverable plastic part. Differential of elastic strain is a function of differential axial stress and elastic modulus according to Hooke¢s law. However，differential plastic strain on a gauge length depends on specimen length，softening modulus，differential axial stress，and thickness of tensile localized band. The thickness is determined by gradient-dependent plasticity where a characteristic length is included in yield function. According to the assumption that differential total strain on a gauge length is the sum of differential elastic and plastic strains，analytical solution of complete stress-strain curve is derived. Compared with numerical results presented by De Borst and Muhlhaus，the analytical solution of distributed plastic strain in localization band and effect of internal length on complete stress-strain curve are verified，respectively. Finally，influences of constitutive parameters，such as elastic and softening moduli，and specimen length on complete stress-strain curve are investigated.

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SIMULATION OF TREATMENT OF SOFT CLAY
FOUNDATION BY FEM METHOD

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2005, 24 (S2): -5789 doi:
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[PDF 353 KB] (1046)

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Tailing dam No.1 of Wushan copper mining is located in Jiangxi province China. The first stage of the tailing dam is the rock-fill dam prected on the soft clay foundation. The treatment of soft clay foundation and the schedule to build rock-fill dam are interpreted briefly. With the development of calculation techniques，the numerical method for consolidation problem has been widely used in engineering practice with satisfying results. Based on soil parameters gained from experiment，back analysis is used to adjust those parameters. By using nonlinear elastic rheology constitutive model and Boltzman inheritance method，the soft clay foundation of tailing dam treated by plastic board is simulated by finite element method (FEM). Comparing numerical results with observation by the displacements of the foundation，those calculated results have a good agreement with those observed results. Based on numerical results，relationships between pore pressure of foundation and time，the displacement of foundation and time，are analyzed. The stress，displacement，and stress state of the rock-fill dam are displayed by some graphs. Some valuable results are derired from those graphs. Condition with creep model and condition without are compared；and the effect on the soft clay foundation is analyzed. The model and those adjusted soil parameters are used to predict the safety state of the rock-fill dam. Numerical simulation proves that the rock-fill dam is safe in the long run and those results gained by numerical method may provide reference to engineering practice.

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LANDSLIDE ANALYSIS AND TREATMENT IN THE AREA OF
CHENGDU―NANNING EXPRESSWAY

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2005, 24 (S2): -5795 doi:
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[PDF 217 KB] (1058)

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The formation of the landslide，influencing factor of the landslide stability，characteristic of sliding surface and earth slide are analyzed，and the slope stability before and after landslide is calculated. According to the characteristics of the landslide，the synthesized measures of retaining and draining are considered for environmental geology. The economic developments of the human activity and the engineering activity should obey the nature regulation. At the same time，the mutual function of the engineering developments and the geology environment should be carefully considered. The derived results show that the method is feasible，and it can provide reference to other landslides treatment.

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RESEARCH AND APPLICATION OF THE GREY THEORY TO SLOPE DEFORMATION PREDICTION

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2005, 24 (S2): -5799 doi:
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[PDF 174 KB] (1313)

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By using investigation information of slopes development，the grey system theory can be applied to forecast the unknown deformation of slopes. When season factors become the main influencing to the deformations of slopes，still using equal interval time series which will destroy complete season factor can not reflect the correct deformation orderliness of slopes and then the wrong forecasting will be made. But applying the time series divided by season factor to forecasting the deformation of slopes，the prediction results agree well with the real deformations，which is much more accurate than the former.

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BLASTING VIBRATION ANALYSIS OF CONCRETE LINING TUNNEL

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2005, 24 (S2): -5803 doi:
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[PDF 294 KB] (990)

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Based on monitoring of blasting vibration safety of the 2nd term engineering for a tunnel in Shengzhen city，which is a newly excavated tunnel close to the existing one on the condition of small clear spacing. Blasting vibration analysis of concrete lining tunnel is described by analyzing the peak particle velocity(PPV) and its main frequency. First，it is mentioned how to settle monitoring line and position according the principles，which are the principles of the position and direction of the maximum PPV，the principle of monitoring of blasting seismic effects，and the principle of the blasting vibration waves decay. Then，the information and results of monitoring are given，in which results of blasting vibration velocity monitoring of different blasting methods are emphasized，and the attenuation formula of the PPV and explosives with distance between blasting center and monitoring position are obtained，and that the V-r relationship of blasting vibration is pointed out too. The results show that the maximum PPV appeared in radial direction and the position of the minimum distance between blasting center and monitoring position，and appeared in the center point of wall and the apex of arch in same section，and the main frequency is focused on 15-75 Hz which differs from various concrete linings，mainly 22-50 Hz. Finally，it is pointed out by analysis and discussion of the PPV and its main frequency of three kinds of blasting methods，which are semi-face blasting and bench stopping blasting and full-face blasting，that the PPV and its main frequency have close relation with explosive mode and distance between blasting center and monitoring position，and that degree of blasting seismic effects is affected mainly by distance and degree of blasting，and that full-face blasting is the best blasting method to control the blasting seismic effects.

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STUDY ON CALCULATION METHODS OF GROUND DEFORMATION INDUCED BY PIPE JACKING CONSTRUCTION

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2005, 24 (S2): -5808 doi:
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[PDF 338 KB] (925)

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By assuming that soil is not drained，the computing formulas of ground deformation induced by bulkhead additive thrust，force of friction between shield and soil，and force of friction between follow-up pipes and soil are derived from the Mindlin solution in elastic mechanics. Combining the formulas of ground deformation induced by ground loss，the formula of total ground deformation induced by pipe jacking construction is obtained. This method is applied to the construction phase. As is shown in analytical calculation，ground deformation induced by pipe jacking construction is three-dimensional and changing with the jacking-in of shield. Bulkhead additive thrust will make the frontal soil of excavation face heave and the rear soil subside. Surface deformation induced by bulkhead additive thrust is small during normal construction，and the curves are asymmetry with axes of excavation face. The surface deformation induced by force of friction between shield and soil is great. Its distribution curve is similar to that of bulkhead additive thrust with the axes at the middle of shield. The surface deformation induced by force of friction between follow-up pipes and soil is small during injecting slurry. Its distribution curve is similar to that of bulkhead additive thrust with the axes at the middle of follow-up pipes.

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INFLUENCES OF ORGANIC MATTER ON THE EFFECTS OF CONSOLIDATING SOFT SOIL WITH CEMENT

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2005, 24 (S2): -5816 doi:
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[PDF 572 KB] (931)

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In some projects using cement to improve soft soil foundations，it is found that organic matters in soil have great influences on the stabilization effects when the organic content soft soil is high，which makes the strength of stabilized soil not reach the expected one. So some indoor studies have been performed on this problem. It is found that the organic content of soil is changed by adding substance with high organic content in order to study the influence of organic content on the consolidation effect of cement，and the progress of consolidating soft soil with cement is modeled indoors. Then，the mechanical indexes of soft soil with different organic contents are determined with direct shear test and unconfined compression test after being consolidated by cement. A further analysis on the effect of organic matter in cement consolidating soft soil is made on the basis of soluble salt，exchange capacity of cation and microstructure. The derived results show that the more organic matters there are in soft soil，the worse the mechanical properties are. Moreover，data of soluble salt，exchange capacity of cation and microstructure pictures all make a compensating explain to the mechanical results，which exert the influences of organic on the effect of consolidating soft soil with cement much clearly. It can provide reference to the practical engineering projects.

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STUDY ON THE WORKING PERFORMANCE OF TUBULAR PILE COMPOSITE FOUNDATION OF FREEWAY

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2005, 24 (S2): -5822 doi:
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[PDF 226 KB] (1118)

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Soft soil foundation reinforced by tubular pile is a type of rigid cushion composite foundation under flexible base，and it is different from flexible cushion composite foundation under rigid base. As one of the new consolidation type of soft soil foundation，the working performance of tubular pile composite foundation is not exactly known in design and construction the working performance of tubular pile composite foundation is studied and the composition and working mechanism of the tubular pile composite foundation are also analyzed. Finite element method is adopted to study cushion setting by imitating one section of the composite foundation of a freeway. The differences between composite foundation under road and composite foundation under rigid base are pointed out；and some reasonable suggestions about cushion treatment for the engineer are put forward，which can be used in similar engineering.

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STUDY ON ATTENUATION CHARACTERISTICS OF LONG-TERM STRENGTH FOR LANDSLIDE SOIL

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2005, 24 (S2): -5827 doi:
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[PDF 248 KB] (1034)

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Based on various examples for the long-term strength of landslide soil，influential factors of the long-term strength of landslide soil，such as water content，granulometric composition，mineral density，testing condition，composition of mineral，chemical composition of landslide soil，and water quality，are considered to analyze the attenuation characteristics of mechanical parameters of structural plane. The results show that it is possible to evaluate the attenuation characteristics of landslide soil with semi-quantification method，and the parameter values are not less than low values of saturation testing usually. It is feasible to use the dynamic and static evaluation method of slope stability to offer new dynamic and static methods to evaluate the mechanics parameter of landslide soil in the engineering working life. Through the application in the creep mass—B section of Longtan hydropower station，the reliability is proved to be successful.

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ANALYSIS OF BEHAVIOR FOR COMPOSITE SOIL NAILING
SUPPORT IN SOFT CLAY PIT

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2005, 24 (S2): -5835 doi:
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[PDF 245 KB] (1023)

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Based on the analysis of the stratum¢s location and composition in Fuzhou city，it is found that stratum structure is important and can be divided into two types. In order to get a further acquaintanceship about the pit¢s working behavior in soft clay，a planar strain finite element programme is employed for numerical analysis. Mohr-Coulomb model is used to simulate the soil¢s stress and strain relation. A series of calculations via FEM are executed for the displacement response of foundation pits when the type of stratum structure，length or obliquity of soil nailing are changed. Compared with the pit¢s parietal movement under different conditions，some significant conclusions are obtained that the prepositive pile is the most important affecting factor for composite soil nailing. The cement mixed pile should be chosen for the prepositive pile of double stratum，and timber pile for three stratum. Because of the clay¢s weaker properties and wider sliding route than those of the others，the length of the soil nailing should be added to two times of the pit¢s depth which is different from that of those located in favorable soil. Finally，two cases are optimized based on above analysis，indicating a good identicalness between the results of calculation and measurement.

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NUMERICAL ANALYSIS OF STABILITY FOR ROCK MASS IN ARCH DAM ABUTMENT IMPACTED BY FAULT AND SIMULATION
OF FAULT TREATMENT

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2005, 24 (S2): -5840 doi:
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[PDF 299 KB] (1012)

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Rock mass of arch dam abutment in a hydropower station is incised by a key fault. So the abutment is possibly instable under the combined action of huge water pressure and the disadvantageous geologic setting，and it is a key factor to control the safety of the whole project. In order to study the stability，a nonlinear 3D numerical simulation is conducted for rock mass in arch dam abutment incised by fault. Stability is studied by point safety factor method and overload method. Enhancement on key fault is simulated，and the influence on the stability of rock mass in abutment is analyzed. The results show the stability is increased evidently after fault enhancement，and thus it can provide reference to engineering practice.

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STUDY ON SETTLEMENT AND DEFORMATION LAWS OF HIGH LOESS-FILL EMBANKMENT

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2005, 24 (S2): -5845 doi:
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[PDF 279 KB] (1030)

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The study takes 69 m high loess-fill embankment of Lanzhou—Haishiwan expressway of 109th national highway as a case. Through centrifuge test，the distribution laws among high，route-longitudinal section，and transverse section with high loess-fill embankment are presented，and the theoretical results are compared with the actual measurement results. The derived results show that the subgrade settlement-deformation appears“sag”，i. e.，maximal settlement lies in center road and shoulder settlement is minimum；and in the place 1/3–2/3 of embankment height，the tendency shows outward“extrusion”. Embankment deformation change tendency is increasing inward and downward，and it suggests that it should be paid attention to the remarkable change of settlement deformation for high embankment in design and construction to guarantee the safety and stability.

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NUMERICAL SIMULATION OF TUNNEL WITH FREEZING METHOD CONSTRUCTION

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2005, 24 (S2): -5851 doi:
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[PDF 279 KB] (1304)

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The tunnel with freezing method contraction by nonlinear computer software FLAC3D is analyzed，and the effects of step excavation，step pouring，underground continuous wall，pile foundation to deformation and stress of freezing curtain and lining，are analyzed. The achieved results can provide references to similar projects.

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SYSTEM OF COMPUTER DATA SAMPLING AND PROCESSING FOR SOIL STATIC-DYNAMIC UNIVERSAL TRIAXIAL AND
TORSIONAL SHEAR APPARATUS

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2005, 24 (S2): -5857 doi:
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[PDF 311 KB] (886)

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An industrial control computer with high precision A/D board is used to control the soil static-dynamic universal triaxial and tensional shear apparatus，which was introduced from Tokyo Seiken，Inc.，Japan in 2001. The data sampling and processing systems are developed using the multithreading and direct-draw technology on the program platform of VC++6.0 language. The system can perform the collection of all the real time experimental data，including the dynamic stress，strain，and pore pressure through the whole experimental process. The experimental data can be curved on the screen，or be processed in real time，or be saved in a data file on line for processing later. In order to ensure the precision of data sampling cycle，the intramural clock frequency of the computer is used to complete the controlling of sampling frequency. The precision can be set to microsecond. The system can make data processing and data sampling entirely automatic，and succeeds in performing a series of difficult subsequent calculations，such as the calculation of the area of the hysteresis loop irregular cure and the common tangent of Mohr circle.

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AN ANALYTICAL SOLUTION FOR CONSOLIDATION AROUND A SPHERICAL CAVITY AND ITS APPLICATION TO IN-SITU TEST OF CONSOLIDATION COEFFICIENT

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2005, 24 (S2): -5862 doi:
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[PDF 211 KB] (860)

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Consolidation coefficient is a key problem in the calculation and design of foundations，and it is very important to gain consolidation coefficient accurately. Piezocone penetration test(CPTU) and BAT-system are the equipments which can gain the in-situ consolidation coefficient rapidly and accurately. Based on the spherical cavity expansion and one-dimensional consolidation，an analytical solution of consolidation around a spherical cavity is obtained，and the solution is used to analyze the dissipation of the excess pore water pressure around the probe tip of CPTU and BAT-system. Finally，the comparison shows that the analytic result is close to the in-situ value of excess pore water pressure. The deduced results show that the solution is valuable for the in-situ test of consolidation coefficient.

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RELIABILITY DEGREE ANALYSIS METHOD OF COMPLICATED RESPONSE SURFACE FUNCTION TO SEARCH CHECKING POINT WITH
GENETIC ALGORITHM METHOD

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2005, 24 (S2): -5868 doi:
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[PDF 202 KB] (1040)

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Response surface method(RSM)is an efficient method to analyze the stability reliability degree for complicated structure，such as underground structure. However，general response surface function can not simulate a character of curve surface of limit state equation for a complicated structure，for the curve surface has more than one peak-value on its parameter space. Quadratic equation that contains mixed terms of random variables can overcome the above-mentioned defect. Therefore，it is presented that function with mixed terms of random variables is adopted to replace function without mixed terms of random variables in response surface method and test procedure，which are used to decide coefficients of function without mixed terms of random variables and calculate reliability index. It is improved to make it suitable to response surface function with mixed terms of random variables. The analytical expression that contains mixed terms of random variables can be decided by the improved general test procedure. Due to more than one peak value on curve surface of the analytical expression containing mixed terms of random variables，genetic algorithm is adopted to search a globe optimal solution，reliability index，and checking point in the improved test procedure. The improved test procedure and response surface method，considering quadratic equation that contains mixed terms of random variables as response surface function，is to used to research stability reliability degree for a large-scale underground rock mass structure. Other method，to take quadratic equation without mixed terms of random variables as response surface function，is adopted to analyze the reliability degree of the same structure too. Calculated results of Monte Carlo method are regarded as criterion，and it shows that the calculated result of the former method is more accurate than the later.

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IMPROVED RESPONSE SURFACE METHOD AND ITS
APPLICATION TO RELIABILITY ANALYSIS

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2005, 24 (S2): -5874 doi:
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[PDF 253 KB] (1275)

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An improved response surface method，i. e.，the first order reliability method(FORM)-response surface method(RSM) is proposed. This new method can overcome the shortcomings of RSM，which is based on the iteration of response surfaces fitting(RSF). The first step of this method is to calculate the reliability index and the design point by using first order reliability method (FORM)，and the derivatives of limit state function can be gained by finite difference method (FDM) or rational polynomial technique (RPT)，which does not need the explicit expression of the limit state function. Then，a response surface can be fitted on the design point and the reliability index can be calculated by using FORM，and second order reliability method (SORM ) or Monte Carlo simulation method (MCSM) based on this RSF. Therefore，only one RSF is needed in this method. The accuracy and efficiency of this method are better than those of the general used RSM，which are validated by three examples.

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EXPERIMENTAL STUDY ON SEASIDE SATURATED SOFT SOIL
IN QINHUANGDAO

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2005, 24 (S2): -5880 doi:
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[PDF 206 KB] (974)

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In the seaside of Qinhuangdao，the surface soil usually consists of 2–5 meters of very soft soil layer. Its inner friction angle is very small or zero. The deformations of above saturated soil often lead to cracks in the building. In order to investigate its physical and mechanical properties，large numbers of undisturbed soil samples have been obtained with the rigid steel ring from the test pit. Laboratory tests including confined compression test and triaxial test are carried out. The seadside soft clay can be defined as silty clay，for its water content is 37%–44%. The shear strength，sensitivity，and bearing capacity of seaside soft clay are determined in-situ by using plate loading test，cone penetration test，and vane shear test. The test results show that the shear strength of field vane test can be determined as a function of testing depth with specific penetration resistance and shear strength. The average value of undrained shear strength is 27 kPa with medium or even higher sensitivity of 2.4–12.5. The characteristic values of subgrade bearing capacity are less than 80 kPa. Based on the field test，allowable loads and settlements of the foundation for some buildings during consolidation are theoretically analyzed. Problems arising from some buildings constructed on the soft clay in Qinhuangdao district are presented.

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STUDY AND APPLICATION OF DEFORMATION MONITORING TO TUNNEL WITH AMATEUR CAMERA

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2005, 24 (S2): -5885 doi:
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[PDF 200 KB] (1006)

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A new method is presented for monitoring the deformation of tunnel with amateur camera(non-metric camera). The method can easily and really measure 3D deformation values of many survey points of tunnel. It does not need any fixed exposure station or survey control point，and the method is not restricted by site conditions. At two suitable positions and more positions，the camera takes pictures against observation points，then these photographs are input to computer and the photo points are measured by computer to calculate 3D coordinates of all survey points. The analysis of deformation is processed by using 3D coordinates. The mean square error of 3D monitoring deformation is within ±2 mm. The results measured by new method have been compared with the values measured by mechanical convergence meter，which can provide reliable information for the safety of tunnel support structure .

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3D DYNAMICAL RESPONSE ANALYSIS OF HIGH ROCK SLOPE RELATED TO HYDROPOWER PROJECT IN HIGH INTENSIVE
SEISMIC REGION

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2005, 24 (S2): -5890 doi:
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[PDF 244 KB] (1023)

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Based on the principle and application condition of dynamical response time-dependent analysis of Wilson-q law，a 3D model of high rock slope related to a huge hydropower project is established. The dynamic finite element analysis of high slope is used to investigate the dynamic characteristics of high rock slope and analyze the acceleration response，displacement response，and stress response under the seismic action in different parts of high slope. In the end，the detailed accelerate values of different parts of high rock slope at different periods on the seismic response are discussed，which show that displacement value and stress value are of clear difference for the differences of shape and structure of high slope during the seismic action. The maximum accelerations and active displacements values mainly presented to the middle of high slope，and the middle and upside of high slope are sensitive to the seismic action compared to the other parts of high slope，which lead to failure easily under intensive seismic action. At the same time，the acceleration is enlarged by 2.03 times in the middle of the slope. Dynamic response results of slope in the seismic action are achieved by means of time-dependent analysis，which can be applied to reflect the dynamic characteristics of high rock slope and the disturbance action of high slope during seismic action.

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SLOPE STABILITY ANALYSIS WITH NONLINEAR FAILURE ENVELOPES

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2005, 24 (S2): -5896 doi:
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[PDF 314 KB] (968)

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The nonlinearity of shearing resistance in soil could be explained as “interlocking” or “dilatancy”. The dilatancy is generally stress level dependent and it lies on the stress range of interest in particular problems，especially for slope stability. Based on such a concept，analytical expressions for the nonlinear failure envelopes in terms of effective stresses are critically reviewed. They are classified in three major groups as power type，parabolic type，and hyperbolic type. The nonlinear failure envelopes can be obtained from routine laboratory shear test and triaxial test by optimization technique using commonly used SPREADSHEET software，and then they can be used in limit equilibrium，stress-stain analyses，and the development of the constitutive models as better approximation than the classical linear relation. On the base of Janbu¢s generalized procedure of slice(GPS)，an iterative method that incorporated several nonlinear failure envelopes in the SPREADSHEET setup by the authors is presented. The basic principle is to transfer equivalently the shearing resistance of each point on the concerned nonlinear envelope to the Mohr-Coulomb linear relation that is tangent to the nonlinear envelope with relevant cohesive and frictional parameters. Finally，an example is resolved to show the methodology that how the iterative technique is used.

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PROGRESS OF APPLICATION AND RESEARCH ON MECHANICAL VIBRATION TECHNOLOGY IN ENGINEERING

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2005, 24 (S2): -5901 doi:
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Mechanical vibration technology in engineering application (MVTEA) belongs to a comprehensive technology of multi-discipline，which has stretched to many fields in civil engineering. Its effects and prospects have increasingly caught many scholars¢ attentions in academic and engineering fields. Through near a hundred years，MVTEA has ripened and formed a technological and theoretical system of itself characteristic. MVTEA includes some typical vibration technologies，such as technology of vibration compacting foundation，technology of vibration compacting in pouring concrete engineering，technology of vibration driving pile，vibrofloatation，block vibration molding technology，technology of percussion drilling，and dynamic test technology. According to the properties of the typical vibration technologies，the progresses and present situations of MVTEA are introduced in detail. The key theories and technologies of MVTEA are preliminarily summed up and some critical scientific problems for further research are presented.

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MICROCOSMIC CHARACTER FOR METEORITE IMPACT
INCIDENT IN CANGSHAN REGION

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2005, 24 (S2): -5909 doi:
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One great meteorite crater was found in Cangshan region，Shandong Province，and main impact evidences are obtained from macroscopical geologic features，local region characters and so on. The crater¢s shape is approximately oblong whose remaining part has such radius as short axes and long axes1.3 km，2.5 km，respectively. After an extensive investigation，some important microcosmic evidences have been discovered. These evidences are achieved from lens-belowed identifying and chemical analysis of rock samples in laboratory. Using neutron activation analysis of apparatus and neutron activation analysis of radiation chemistry，some curves were charted that show how the contents of the elements Ni，Ir，Co，Sc and etc.，in the rock of the crater change with depth，and some dynamical structure characters and dynamically-metamorphosed phenomena are found. They include glass detritus structure，oolite-severed earmark in ash-stone，and assembled chipping macle extinction and the like. These evidences can forcedly explain the impact incident in Cangshan district.

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AN EXPERIMENTAL STUDY OF POLYMER SOLUTION FOR
UNDERGROUND DIAPHRAGM WALL

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2005, 24 (S2): -5914 doi:
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Current situation of construction stabilizing fluid for underground diaphragm wall is analyzed. Characteristic property of polymer solution is fully discussed. Optimum seeking method is used to study a new kind of construction stabilizing fluid for underground diaphragm wall-polymer solution. This solution is compared with slurry solution and displays its superiority-can meet the requirements of extremely loose floating sand layers，soft soil layers，and construction sections where slurry can¢t resist collapse，or collapsed construction section. Finally，the mechanism of protecting hole wall of polymer solution is discussed. It provides academic basis for the development of this new kind of construction stabilizing fluid for underground diaphragm wall.

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ROCK-SOIL NUMERICAL SIMULATION：A REFLECTION ON METHODOLOGY

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2005, 24 (S2): -5919 doi:
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As viewed from the ideas of systematic geosciences，the inherent development courses of rock-soil numerical simulation are reviewed by a way combining geology with mechanics. Furthermore，a thoughtful exploration of methodological significance is presented. Four characteristics of the current researches on rock-soil numerical simulation can stand for the latest development of aforesaid research. The first feature is basic work of geological investigation outdoor. Then，various mathematical analysis approaches have been used to explore and understand the complicated phenomenon of geologic movements. The third is related to numerical simulation，which should reflect the integration of technological flexibility and geological system in both space and time，i. e.，every interpretation and accounting for the truth of geologic movements are necessary to take the consideration of the adaptability of numerical methods and the actual requirements of engineering projects. Finally，the most effective ways and main direction to solve the current problems on rock-soil engineering are proposed to integrate reliability theory with mechanics numerical simulation technique.

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DISCUSSION ON DAMAGE CONSTITUTIVE RELATION OF NON-INTERPENERTRATED CRACK MEDIA UNDER UNIAXIAL STRESS

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2005, 24 (S2): -5926 doi:
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Based on the analysis of relationship between damage evolution of crack and evolution of micro-crack，singularity damage variable and distribution damage variable have been defined，which can illustrate two kinds of damages，and the damage constitutive equation of non-interpenetrated crack material under uniaxial compressive condition has been built and validated by tests.

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DYNAMIC STABILITY ANALYSIS OF ACCUMULATION BODY SLOPE OF XIAOWAN HYDROPOWER STATION UNDER BLASTING CONDITION

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2005, 24 (S2): -5932 doi:
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The dynamic stability of a slope in Xiaowan hydropower station is studied under the blasting load with the dynamic FEM. By means of a special dynamic interface contact element，the coupling behavior of the blast wave propagation property and the dynamic response of the contact element are also considered in the analysis. Numerical results indicates：(1) the stability of the whole slope can be ensured even under the largest blast loading conditions；(2) the local instability could happen at the vicinity of the blast holes because the particle velocities in this area are much larger than the allowable velocity；(3) interface elements on the sliding surface of the slope are most opened by the blast waves，which might be a dominant factor controlling the whole stability of the slope.

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TRIAXIAL SLAKING TEST RESEARCH ON ROCK FILL
DEFORMATION FEATURE

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2005, 24 (S2): -5938 doi:
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According to the result of high pressure triaxial slaking test of two different kinds of rock fills，the paper analyses the reasons of slaking deformation and the relationship between slaking stress and deformation，which is hyperbolic type. But the deformation parameter 1/a and s3 do not coincident with Janbu formula completely，and the relationship between slaking axial strain and volumetric strain is also different from the result of normal triaxial compression test，and it is not hyperbolic type.

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DISCUSSION ON SUPPORT SYSTEM BETWEEN TWO PARALLEL CLOSELY-SPACED SHALLOW TUNNELS

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2005, 24 (S2): -5943 doi:
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The support system between are analyzed and discussed. It is found that，if the forces in the lining are less than the limit ones during and after excavation，there is no need to consider bolt or other assistant support methods for the surrounding rock between two tunnels. The distance between two tunnels can be 1.0 m，or even more narrow，as Munich subway had done. For closely-spaced tunnels，the excavation sequence has visible impact on the both tunnels. If one tunnel is finished firstly and the other is completed subsequently，results show that the first tunnel has larger compression forces in the lining and even some tension happens at the invert of the lining during the excavation of the second tunnel. If the two tunnels are excavated by alternant way，the surrounding rock between the two tunnels has more disturbances. The crown of the second tunnel and the invert of the first tunnel are easy to be in tension. But generally，the forces are less than the ones when the tunnels are excavated in the first sequence. For both excavation sequences，the surrounding rocks between the two tunnels are both in compression. Munich subway which had been built successfully validated the dependability of the results.

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MEASUREMENT AND ANALYSIS OF SOIL DISTURBANCE CHARACTERISTICS INDUCED BY DOUBLE-O-TUBE SHIELD CONSTRUCTION

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2005, 24 (S2): -5950 doi:
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Based on the construction of Shanghai metro line No.6，the horizontal displacement，layered settlement，variation of pore water pressure caused by the construction of double-o-tube(DOT) shield in soft clay region are monitored continuously. Furthermore，the soil disturbance above sea-gulled segment is analyzed. The essential rules of soil disturbance induced by DOT shield excavation are summarized quantitatively and the characteristics of regional and time-dependent of DOT shield are brought forward.

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IN-SITU MONITORING AND STABILITY ANALYSIS OF SURROUNDING ROCK MASS FOR XILONGCHI UNDERGROUND CAVER

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2005, 24 (S2): -5956 doi:
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Composite rock mass of underground chambers is alternatively stratified and horizontal bedding in Xilongchi. Geological factors of chambers interact during excavation process. The comprehensive stability of rock mass induced by couple factors in complex environment is analyzed. The stability and deformation of rock mass near the wall of houses are determined by using several measurements. The characteristics of layer composite rock mass deformation are obtained. Through the calculation examples of an underground opening，the dynamic states of the surrounding rock are investigated，and some conclusions are drawn finally. Case study shows that the calculated displacements by the method agree well with the measured values. The results provide a reliable basis for project construction.

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RESEARCH OF VISUALIZATION OF STRATA AND PILE FOUNDATIONS BASED ON TRIANGULAR PRISM

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2005, 24 (S2): -5961 doi:
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[PDF 548 KB] (1113)

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3D visualization for geological information is employed to set up the digital model of geological characteristics by appropriate data structures；and with computer technologies，the digital description is expressed vividly. Using 3D visualization，the complicated geological structures，the physico-mechanical properties of strata and the interactive deformations of constructions are described. Based on rectangular meshes and irregular triangular meshes，a method of triangular prism element is presented to construct 3D entities of strata and pile foundations；and 3D visualization for geological objects and pile foundations is realized by OpenGL technology in the environment of visual C++.

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ACCURATE MATHEMATICAL MODEL OF VIBRATING WIRE
SENSORS AND ITS APPLICATION

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2005, 24 (S2): -5965 doi:
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An accurate mathematical model for vibrating wire sensors is introduced. The model can be used in the condition that the original frequency varies with temperature drifting and needs no any correction to compensate this drifting. Meanwhile，it is indicated that the model is similar to the linear one，and the variable difference will be estimated precisely just by setting the initial value to zero. Based on the two basic characters mentioned above，intelligent instruments adopting this model can show the measured parameters in digital forms，and help to process the measured data quickly and precisely. As a conclusion，a difficult problem which has been pensented for a long time in vibrating wire instruments field is then solved. In the end，some practical applications of this model are provided with initial frequency either measurable or immeasurable.