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2004, 23 (22): -0 doi:
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TESTING STUDY ON CREEP CHARACTERISTICS OF MARBLE

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2004, 23 (22): -3745 doi:
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[PDF 240 KB] (1287)

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Rheological characteristic is one of the most important mechanical characteristics of rock. It controls the creep deformation. By continuously loading and multi-stage loading，the creep test on Nanyang marble is performed by using the self-developed UCT-1 apparatus of creep test. The creep strength is compared with the instantaneous strength based on the test results，and the ratio of creep strength to instantaneous strength is about 0.9. An empirical formula of creep curve is obtained by data fitting and it approaches to the logarithmic rule. The Burgers theoretical model by Kelvin model and Maxwell model is established by analyzing the features of the curve and its parameters are obtained.

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TESTING STUDY ON THE EFFECT OF CRYSTAL SIZE AND SPECIMEN LENGTH ON THE ROCKBURST TENDENCY

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2004, 23 (22): -3750 doi:
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[PDF 238 KB] (905)

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The rockburst tendency of rock specimen is an important parameter in describing the rockburst in underground excavation. In this paper，the complete stress-strain curves under uniaxial compression of marble specimens with different crystal size and length are studied. The crystal size of marbles are 0.2～0.5，0.5～1，1～4 and 4～6 mm respectively. And the ratio of length to diameter is 1，1.5，2，2.5 and 3，respectively. The rockburst tendency increases with the crystal size and decreases with the specimen length. The strength of marble decreases with the specimen length，which may results from the friction between the specimen ends and the loading head of the testing machine. But the relation of the strength to the crystal size is not clear.

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EFFECT OF LENGTH OF FINE AND COARSE CRYSTAL MARBLE SPECIMENS ON UNIAXIAL COMPRESSION TESTS

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2004, 23 (22): -3754 doi:
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The uniaxial compression strength of marble specimens with diameter of 50 mm increases with their length shortening，but the strength will decrease when soft cushions are used between the specimen ends and loading heads of testing machine. It shows that there is friction at the specimen ends. However the friction effect varies with characteristics of rock. For the two marble blocks of fine crystal with grain size of 0.5～1 mm，the relations of specimen lengths to the uniaxial strength are the same. The strength increases to 130% when the ratio of length to diameter decreases from 2 to 1，and the strength increases to more than 150% when the ratio decreases to 0.6. But the two marble blocks have different strength and Young¢s modulus. The specimen with higher strength has failure crack in cone shape and the other has failure crack in plane. For the marble blocks of coarse crystal with grain size of 5 mm，the influence of their length on the strength is not apparent. The stress-strain curves are very similar after the peak stress of specimens with the ratio of length to diameter smaller than 2.5. For a specimen with diameter of 50 mm and length shorter than 50 mm，the uniaxial compression strength can also be obtained by using soft plastic cushion，which is 0.5 mm in thickness and compressed two times before use. However，as its length gets shorter，the influence of the quality of specimen ends on the strength and Young¢s modulus becomes greater.

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SHEAR PROPERTIES AND STRENGTH OF WEAK INTERCALATED LAYERS IN DAM FOUNDATION OF MAJIAYAN RESERVOIR

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2004, 23 (22): -3761 doi:
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For gravity dam with weak intercalated layer in foundation，the shear strength of the weak intercalated layers is the main factor in the control of the dam stability. It is the key point of geological and experimental work to ensure the shear strength to satisfy safety and economy of dam. The material composition，mineralogical composition and structure，genetic type and characteristics of shear stress and strain of weak intercalated layer in dam foundation of Majiayan reservoir are analyzed，the valuation rule of the shear strength of weak intercalated layer with plastic failure mode is discussed，and finally the recommended geological value of shear strength of weak intercalated layer in this project is proposed.

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TESTING STUDY ON THE PEAK SHEAR STRENGTH BETWEEN GROUT AND BORE WALL IN THE INTERIOR BOND SECTION OF
PRESTRESSED ANCHORAGE CABLE

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2004, 23 (22): -3765 doi:
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At present，very little test data is available about the peak shear strength between the grout and the bore wall in the interior bond section of prestressed anchorage cable. The drawing test data of the three rocks，granite，gritstone and limestone，are presented and the effect of different rocks，different drawing methods and different length of test section on the test results is analyzed. The peak shear strength of the three rocks is given. Contrary to normal recognition，it comes to the conclusion that the higher the rigidity of rock is，the lower the peak shear strength is.

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STUDY ON PARTIAL LEAST SQUARE REGRESSION ASSOCIATED WITH NEURAL NETWORK FOR DEFORMATION MODULUS OF ROCK MASS

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2004, 23 (22): -3770 doi:
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Partial least square regression method does not directly consider the regression problem of dependent variables and independent variables，but extract the new integral variables with relation to the system. It can determine the number of components，and especially in analysis of the correlation between the single dependent variable and multi-independent-variables，the results are more satisfactory. The neural network has the ability of self adaptive learning and remembering，and the three-layer BP network has wide application. By associating the two methods，with the deformation modulus of rock mass being the dependent variable and seven factors of rock mass being the independent variables，the data from the observation of the Jiaozuo-Jincheng highway are analyzed and the maximum error between calculation and observation is 5.43%，which is better than the error of 19.07% by the partial least square regression method. So the association method gives a new way for the selection of parameters.

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ANALYSIS ON STRENGTHENING EFFECT OF SKIN FRICTION
OF DEEP JETTING MIXING PILE

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2004, 23 (22): -3775 doi:
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The data of load tests on deep jetting mixing(DJM)piles of 10 building sites in Handan city show that the skin friction of DJM pile has strengthening effect. The mechanism of strengthening effect of skin friction of DJM pile is studied by using the Meyerhof theory and the constitutive model of soil. Based on the data of load tests at 3 building sites in Handan city，the relationships of strengthening effect of skin friction with pile strength，bearing capacity of the pile-tip soil，and load level are analyzed. It shows that it is important to improve bearing capacity of foundation and reduce building settlement by choosing soil layer with better bearing capacity as the sustaining soil layer. The conclusion is also useful for designing other types of composite foundations.

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INFLUENCE OF COVER ROCK CHARACTERISTICS ON TIME INFLUENCING PARAMETERS IN PROCESS OF SURFACE MOVEMENT

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2004, 23 (22): -3780 doi:
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The data of practical observation of rock movement and the Knothe time function are analyzed，the concept of cover rock characteristics is proposed as a supplement for the Knothe time function，and the determination method of the rock characteristic parameters and the time influencing parameters as well as the relations between them are discussed. The result has theoretical and practical value for predicting dynamic movement of surface and rock layer and mining designing.

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APPLICATION STUDY ON THE GEOMECHANICAL MODEL
EXPERIMENT TECHNIQUES

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2004, 23 (22): -3785 doi:
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The new achievements of the geomechanical model experiment techniques are introduced in the paper，including the functions and characteristics of the triaxial loading facility for the geomechanical model of underground structures of PYD-50 type which was awarded the first Prize of the National Science and Technology Progress，the apparatus for tensile strength or compression test on specimen with unequal load in triaxial directions which was awarded the third Prize of the National Science and Technology Progress and the multipurpose apparatus for geotechnical engineering model experiments of YD-A type. The development situations of several experiment techniques which are necessary and complementary for the above equipment in application are also introduced in brief，including simulation techniques for the material of rock mass，the technological process of shotcrete and bolting support construction，the technology for measuring the deformation in rock mass，the plane deformation control technology in the experiment model，the synchronizing technology for the flexible loading and the deformation in transverse direction on the model boundary surface，etc. and their applications in engineering.

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SIMULATION AND TESTING STUDY ON OUTBURST PREVENTION MEASURE OF PRESSURE-RELIEF SLOTS

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2004, 23 (22): -3790 doi:
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[PDF 255 KB] (920)

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Base on simplified model，a mechanical model is established to simulate cutting pressure-relief slots. The numerical simulation on multiple schemes is conducted. Coal seam displacements，failure mode and reasonable technical scheme are obtained. A device of cutting pressure-relief slots is designed according to the results，and cutting test is conducted in mining survey. Simulation and cutting test results show that pressure- relief slots efficiently relieves stress and drains out gas and the reasonable shape of pressure-relief slots is two-side slots.

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TESTING STUDY ON CREEP OF COAL ROCKS IN THE TUNNEL
OF WANKAI SPEEDWAY

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2004, 23 (22): -3794 doi:
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[PDF 205 KB] (1012)

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Triaxial creep tests on coal rocks are carried out by Step Method and the XTR01 electric-fluid servo compression machine. By using the five-parameter creep model，the three-dimensional constitutive equation of coal-rocks is discussed，which can reflect the full creep process of coal-rocks. The rheological parameters are calculated by analyzing the test results. The comparison of the theoretical results and the test results shows the good consistence between them.

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CHARACTERISTICS OF PLASTIC ZONE OF SECOND MINING PILLAR AND SUPPORT TECHNOLOGY OF GATEWAY IN SMALL MINES

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2004, 23 (22): -3799 doi:
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The small mines in Xinhua District of Pingdingshan City，Henan Province，one of the China National Key Coal Production Counties(or Districts )，is generally situated in the shallow abandoned mining levels of the large mine of Pingdingshan Coal Group of China. The small mines are mainly mining retained pillars that the large mines left. The pillar stress state can be simplified to plane stress state. Under the mining activities of long wall coalfaces at two sides，the width of plastic zone of pillar is big. Its main influential factors are coal seam thickness，coal seam hardness，bond properties of the interfaces between coal seam and its roof-floor stratum，and the coal seam buried depth. While the coal seam hardness is definite，the increasing velocity of the width of the plastic zone of pillar decrease with the increase of interfacial bond property between coal seam and roof. While the interfacial bond property is unchanged，the width of plastic zone of pillar increases with the increase of buried depth of coal seam. While the type of gateway support is fixed，the stability and deformation characteristics of gateway surrounding rock are related to its stress and property of surrounding rock，and they are the result of interaction between them. Therefore，the effective load coefficient C of surrounding rock can be used to study the stability and deformation characteristics of gateway surrounding rock. When C≤0.45，the gateway surrounding rock is in stable state and while C＞0.45，rheologic deformation begins to occur. At present，since the mining depth of small mines in Xinhua District is about 200～400 m，and the value of effective load coefficient of gateway surrounding rock is relatively small，the gateway surrounding rock is in a stable or relatively stable state. Therefore，from the practical point of view，the rigid timber supports employed in the gateways of small mines in Xinhua District are reasonable.

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STUDY ON LAWS OF LOAD-UNLOAD RESPONSE OF SLOPE
UNDER SEISMIC LOAD

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2004, 23 (22): -3803 doi:
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[PDF 298 KB] (1249)

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By taking seismic inertial force as load and unload on slopes，time-relied analysis is carried out with dynamic FEM and load-unload response ratio theory. A load-unload response model of slope under seismic load is established. And the variation of load-unload response ratio during earthquake is discussed. The results can be used for almost all slopes with periodic load character.

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CHAOTIC NEURAL NETWORK METHOD FOR SLOPE
STABILITY PREDICTION

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2004, 23 (22): -3808 doi:
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[PDF 185 KB] (954)

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The parameters in the slope system are uncertain and random due to the complexity of slope，and a series of chaos will appear in the course of the slope evolution. In order to provide a nonlinear method for slope stability analysis，the chaotic neural network method is established based on the combination of the chaotic theory and the neural network technology. The establishment of the prediction model and the process of application are discussed in detail. The application of the method to 64 cases of slopes shows its high precision.

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TESTING STUDY ON VARIATION REGULARITIES OF SOLUTION COMPONENTS IN SATURATION OF SOFT ROCKS

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2004, 23 (22): -3813 doi:
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[PDF 198 KB] (1012)

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Based on the research of classification and features of some typical soft rocks in a certain major project in Guangdong province，the authors design a series of tests for the interaction between soft rocks and water. Two typical rocks distributing in south China area，silty mudstone and mud siltstone，in natural state or saturated for 1，3，6 and 12 months，are studied to obtain variation regularities of concentration of cations，anions and pH value of solution and the dynamic evolution regularities of solution components for different soft rocks. The results show that during the saturation process，the pH value of the solution declines，the solution turns from light alkalescence to acidity，and the rates of that transformation are 2%～46%. Meanwhile，it¢s pointed out that the critical turning point of the interaction between water and rock appears at the time of 3 month. In the first 3 month，the exchanging and adsorption action of positive and negative ions are all active，the concentration of the ions declines during the reaction process，and in the following 3 month，the reaction gradually weakens，and the consistency of ions presents an ascending and stable trend. The concentration of ions in the reaction between soft rock and water are generally coincident with two types of curves，exponent curve and curve of dynamic stability equation. No matter what regularity the dynamic process is consistent with，it will ultimately turn to a stable state. In addition，the concentration of F－ and Mn2+，Al3+，Fe3+，Zn2+ in the tests on the two kinds of soft rock，almost maintains stable value，which suggests that these ions almost do not participate in the reaction between rock and water.

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COMPREHENSIVE ASSESSMENT ON SLOPE STABILITY OF WATER-INDUCTED TUNNEL OF TIANWAN NUCLEAR POWER STATION

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2004, 23 (22): -3818 doi:
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[PDF 401 KB] (1150)

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According to systematical analysis on the engineering geological conditions of the excavated slopes，the stereographic projection method，the limit equilibrium method and the two-dimensional finite element method are used for the assessment of the slope stability. Then，based on the orthogonal design method，the sensibility factors are obtained.

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TESTING STUDY ON SIMILARITY RULE OF SIMILAR MODEL AND FAILURE MODES OF FILLED-SOIL SIDE WALL (SLOPE)

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2004, 23 (22): -3824 doi:
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[PDF 296 KB] (882)

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The similarity rule of similar model of filled-soil side wall (slope) by Emori Ichiro¢s similar model theory is established and verified. A series of large-scale (L×W×H = 315 cm×60 cm×250 cm) model experiments and self-simulating (prototype) experiments on filled-soil side wall (slope) are carried out. It is shown that the deformation and failure of this medium have seven characteristics，its failure mode can be reduced to plane failure mode，and it is unreasonable to analyze the stability and determine the support parameters with the arc failure mode.

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RESEARCH ON CHARACTERISTIC INDEXES OF WEATHERING INTENSITY OF ROCKS

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2004, 23 (22): -3830 doi:
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Classification of weathering intensity of rocks and research on their engineering features are important to the selection of foundation elevation and the utilization of engineering environment or materials. The present classification of the weathering intensity of rocks is based on qualitative geological evaluation and is optional. Therefore it is necessary to establish the method for quantitative analysis and assessment. Fissures due to weathering action are in uncertain direction and irregular development，which are basically different from fine fissures due to tectonic process. Weathering fissures are important indicator of weathering intensity. Weathering action changes the mineral composition of rocks，and the periods of weathering process reflect weathering intensity. Based on qualitative analysis of the development of fine fissures of weathered rocks and the characteristics of secondary fillings，erosion of feldspar and variation of clay minerals，quantitative statistics is carried out and the criteria are established for classifying of weathering intensity of rocks. The quantitative indexes given can clearly reveal the change of the quality of weathered rocks，and agree well with the indexes of the physical and mechanical properties of rocks.

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HYPERSINGULAR INTEGRAL EQUATION METHOD OF MULTIPLE CRACKS IN BIMATERIAL PLANE

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2004, 23 (22): -3834 doi:
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Based on the fundamental solution of elasticity for two-half elasticity plane，the boundary integral equation method is extended to study the fracture problem in bimaterial plane with multiple cracks subjected to arbitrary loads. As the cracks lie in one side of the bimaterial plane，the problem is reduced with finite-part integral conceptions to a set of hypersingular integral equations，in which the unknown functions are the displacement discontinuities on the crack surfaces. According to the finite-part integral principles，a numerical method for the hypersingular integral equations is established. Then，based on the analytic results of the singular stress fields near the crack tip，a set of numerical formulas for stress intensity factors are proposed. Finally，solutions for stress intensity factors are given for conditions such as those with two collinear cracks in a finite plane and two cracks which are perpendicular to the interface in bimaterial plane. The interaction of cracks and the effects of the interface on stress intensity factors are investigated in detail. The numerical results show that the hypersingular integral equation method works effectively in solving the multiple cracks problem in bimaterial plane.

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DYNAMIC ANALYTIC METHODS OF NUCLEAR POWER STATION STRUCTURES CONSIDERING SOIL AND STRUCTURE INTERACTION

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2004, 23 (22): -3840 doi:
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At present，there are many procedures that are used to analyze dynamic response of the nuclear power station structures. In these procedures，analytic methods are different. For example，CLASSI uses the substructure method，FLUSH uses the equivalent linear finite element approach，and DYNA3D is a nonlinear finite element procedure. Considering the soil-structure and structure-structure interaction，the three well-rounded procedures are used to analyze dynamic response of the containment shell of nuclear power station，and linear results are compared with nonlinear results in this paper. The uncertainties in analyzing a soil-structure system due to SSI analysis procedures are also discussed.

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AXIAL PULL-OUT CAPACITY AND BONDING SLIP BEHAVIOR OF CONNECTIONS BETWEEN PRESTRESSED CONCRETE
PIPE PILE AND PILE CAP

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2004, 23 (22): -3746 doi:
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The bonding slip behavior between the prestressed concrete pipe pile and pile cap belongs to interfacial bond properties of new and old concrete，which is related to the strength of the concrete of pipe pile and pile cap，surface roughness of pipe pile，interfacial agent and the stress state. According to results of the pull-out test of connections between the prestressed concrete pipe pile with 1 200 mm in diameters and pile cap，the bonding mechanism，influencing factors and failure form of connections are discussed. The bond stress sharply drops along the embedded length of the pipe pile as the axial load increases，the bond effect is weakened，and relative slip occurs，which will also lead to reduction of bond stress and ingression of the maximum point of bond stress. Based on the equilibrium of free body of the pipe pile，the bond stress distribution，the magnitude of stress in pipe pile and the relative slip deformation between the concrete of pipe pile and the pile cap are theoretically analyzed. It is inferred that the bond stress is of negative exponential distribution with the position function that reflect the bonding slip relationship between the pile and pile cap at different position. And when the position function is linear，the results are similar to Mindlin¢s elastic displacement solution of bolts in form. The calculation formula is proposed based on the results of bond strength of new and old concrete，which can estimate the ultimate capacity of connections between prestressed concrete pipe pile and pile cap. The results by this formula coincides with the test data. A reasonable connection type is finally suggested for practice.

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LIQUEFACTION BEHAVIORS AND STEADY STATE STRENGTH
OF SATURATED LOESS

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2004, 23 (22): -3853 doi:
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Steady state strength and undrained behavior of saturated loess are studied under stress-controlled undrained triaxial consolidation experiments. Static liquefaction behaviors of loess and sand are compared. Occurrence conditions of liquefaction for loess and the judgment method of flow slide of saturated loess by steady state strength are presented.

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TESTING STUDY ON PERMEABILITY CHARACTERISTICS
OF UNSATURATED SOIL

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2004, 23 (22): -3861 doi:
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For complexity and diversity of unsaturated soil behaviors，there lies a great difference in permeability characteristics between unsaturated soil and saturated soil. It is difficult to perform test of unsaturated soil because of many factors. With the special triaxial instrument of unsaturated soil，the permeability characteristics of unsaturated soil of the dyke of Yellow River are tested and studied，which sets up a basis for direct measuring the coefficient of hydraulic conductivity of unsaturated soil. According to the test results，the relation and changing law between confining pressure and permeability coefficient in different water content，and the relation and changing law of water content and permeability coefficient under different confining pressure are obtained. The relation curves are fitted to deduce correspondent fitting functions.

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TESTING STUDY ON CREEP CHARACTERISTICS AND CALCULATION MODEL OF GEOSYNTHETICS UNDER LONG-TERM LOAD

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2004, 23 (22): -3866 doi:
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Based on the creep experiments for geosynthetics under long-term load，the creep characteristics of Netlon CE131 geonet and their influencing factors are studied. The mechanism of occurrence，development and failure of creep fracture for Netlon CE131 geonet is studied too. Based on the experiments，the creep formula for the Netlon CE131 is obtained. When the exterior load is larger than 60% of the ultimate tensile strength and the temperature is higher than 25 ℃，the creep of Netlon CE131 is apparently affected by the change of the temperature. But it is no longer affected by the temperature when the stress level is below 40% or the temperature is lower than 25 ℃。

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CAPILLARY-TUBE MODEL FOR PIPING IN NONCOHESIVE
SOILS AND ITS APPLICATION

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2004, 23 (22): -3871 doi:
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Based on the analysis of the forces acting on the fine grains in the skeleton pores，a capillary-tube model is introduced to characterize the development of piping in noncohesive soils. With the model，the relationship among the washout of fines，the permeability of soils and the hydraulic condition of incipient motion of grains is investigated，and a set of formulae of the critical hydraulic gradient for the incipient motion of movable grains and the permeability coefficient considering the washout of fines are obtained. The application of the formulae to some examples of piping tests gives reasonable results in comparison with the experimental observations. The theoretical results illustrate that the washout of the fine grains has an important influence on the permeability of noncohesive soils. In addition，it is proved that piping failure takes place more easily in the piping-typed soils with a bimodal grain-size-distribution than in the soils with a unimodal grain-size-distribution after some fine grains are washed out.

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UNIFORM EXPERIMENTAL STUDY ON SUBSIDENCE CAUSED BY DEWATERING OF BOTTOM AQUIFER UNDER
EXTERNAL FIXED LOAD

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2004, 23 (22): -3877 doi:
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The uniform experimental study on the subsidence caused by dewatering of bottom aquifer under external fixed load，which is implemented on a self-designed dewatering experimental setup with high stress and water pressure，shows that the dewatering subsidence complies with exponential variation. Sandy soil with fine grains has more deformation than sandy soil with coarse grains. The compressibility modulus of the dewatering subsidence，，is mainly determined by the character diameter of the sand，，and the effective stress increment， . The value of increases with increasing of and . For the same soil sample，the value of is positively correlative to the value of . When is constant，if there is more fine particle，the value of and will be smaller and the value of dewatering subsidence bigger.

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STUDY ON SCHEMES FOR DISPOSING ABANDONED
STOPE IN MUJIA HILL

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2004, 23 (22): -3884 doi:
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[PDF 539 KB] (1091)

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Surface subsidence and rock movement is allowed in Mujia Hill. And 375 000 m2 continuous and gently inclined abandoned stopes were formed underground because of illegal mining. To prevent the potential danger of air shock wave resulted from sudden caving of roof and illegal mining，the abandoned stope of upside must be dilapidated. The method disposing abandoned stope is summarized，and it is proposed that the abandoned stope be disposed by roof cutting and pillar dilapidation. The 3D non-linear FEM code ANSYS is applied. The minimal roof span，the minimal cantilever roof span and roof cutting depth are studied by the 3D FEM. And then the influence of the disposing of abandoned stope on subsequent mine is analyzed. The results show that the diversification of pillar distribution necessarily results in whole change of excavating stress when the cover terrane thickness is thinner. If the minimal roof span of 102 m long or the minimal cantilever roof span of 76.5 m long and roof cutting of 8～11 m vertical deep are adopted，uncontrolled collapse of dolomite roof can be ensured. Subsequently，mining safety will not be affected by disposing abandoned stope. With sc，g known，the bigger the difference between H and covering thickness of field rock-mass is，the bigger the error calculated by the formula l=1.25H[sc /(g H)+0.001 2k]0.6 is.

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DEVELOPMENT OF OSMOTIC OEDOMETER

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2004, 23 (22): -3891 doi:
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[PDF 305 KB] (1189)

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The traditional oedometer can meet the basic engineering demand. But it has shortage in researching on the soft clay soil. By modifying the traditional oedometer，the osmotic oedometer is developed which has some new functions and merits as following：It has good watertight behavior and can capture water during consolidation of soil specimen. By controlling the drainage condition through the triple valve，not only the single drainage test can be done and the pore water pressure on the bottom can be measured，but also the double drainage test can be conducted. The consolidation tests and permeability tests can be carried out at the same time，and the permeability characteristics of the soil specimen under different load can be studied.

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SPACE DISTRIBUTION OF SAFETY FACTOR OF FOUNDATION PIT

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2004, 23 (22): -3896 doi:
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[PDF 229 KB] (1570)

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The traditional method of stability analysis on foundation pit is to calculate the minimum safety factor and to find the corresponding slip surface. This is easy in mathematics，but the depth and range in practical application are limited. The concept of space distribution of safety factor is an extension of the traditional analysis method in physics. The space distribution picture of the safety factor forms a series of potential slip surfaces，and every slip surface has one safety factor. In fact，The space distribution of the safety factor is indicated indirectly by the space distribution of the potential slip surfaces. This kind of expression can show the stability state of foundation pit directly，and can indicate whether there is any area which need to reinforce.

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ANALYSIS ON ACTIVE BULK-SOLID PRESSURES ON CURVY
WALLS AND ITS APPLICATIONS

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2004, 23 (22): -3900 doi:
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[PDF 275 KB] (1003)

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The method of wedges (or the limit equilibrium method) is employed to analyze the distribution of active bulk-solid pressure on curvy walls，and then the method called modified Coulomb¢s formula for curve retaining wall is developed by modifying the formula for beeline wall. The method considers the difference of the two slipping wedges behind the beeline wall and the curvy wall，and a volume-revising coefficient is introduced. Finally，the method is applied to the squat silo walls，and the results agree well with those of the full-sized silo experiment.

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FORECASTING BUILDING SETTLEMENT AROUND DEWATERING DEEP FOUNDATION PIT BY GREY SYSTEM THEORY

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2004, 23 (22): -3905 doi:
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[PDF 175 KB] (1004)

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During pits dewatering，non-uniform settlement of buildings has systemic and uncertain characteristics. The prediction model for the building settlement is suggested according to grey system theory. The engineering practice proves that MGM(1，n) model possesses rather better precision and forecast reliability comparing with GM(1，1) model，which will have positive influence on settlement prediction.

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APPLICATION OF CURTAIN GROUTING TO THE SOLUBLE ROCK FOUNDATION OF EXISTING SOIL DAM OF
WANGHUATING RESERVOIR

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2004, 23 (22): -3910 doi:
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[PDF 253 KB] (1296)

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The seepage of dam foundation of Wanghuating reservoir is analyzed according to the hydrogeological and engineering conditions. It is pointed out that the total width of the marble outcrop under the dam block between stake 0+165-0+430 is 265 m. The fifth and seventh layers of the marbles are 38% of the total width of dam site，but its seepage amount accounts for 69.7% of the total seepage amount. Thus there are hidden troubles of sinkholes，swamps of big area，piping of the highly permeable layer and contact erosion. Therefore，the treatments of curtain grouting and hole-top enclosure curtain grouting to the dam foundation are considered. According to the requirement for the preliminary design phase，the method of sectioned grouting from top to bottom with hole-top enclosure is adopted. But the grouting test results show that the method is difficult to carry out and the grouting effect is unsatisfying. Problems such as trouble watertight plug，serious grout-recycling in the hole，considerable emission of slurry to the dam body and out the top of dam occur. By many tests，the sectioned grouting from top to bottom in bedrock with slurry cycling within hole and enclosure at dam body and hole top is employed. The results of testing and practical grouting show that the grouting effects is excellent in spite of some difficulties in execution. The development of this new method，testing，construction techniques and quality inspection are introduced.

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INFORMATION CONSTRUCTION OF THE TUNNEL IN A FAULT
AND CRUSH ZONE

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2004, 23 (22): -3917 doi:
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[PDF 359 KB] (1234)

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The fault and crush zone is the very difficult and catastrophic sector of the tunnel during the course of excavation and support. The fundamental data collection is emphasized in the case of Xinqidaoliang tunnel with regarding to the geological condition. By means of geological survey of ground surface along the tunnel，measurement of wave velocity，and geologic sketching of both tunnel face and walls within the tunnel，the long-term geology prediction which forecasts basic geological conditions，such as lithology，scope，location，of Fault 4，and the short-term geology prediction are conducted. At the same time，the analysis results of measured data such as convergence，subsidence of crown，and pressure of surrounding rock are dynamically fed back to the construction. These processes are called the information construction of the tunnel in a fault and crush zone，which is applied to the tunneling through Fault 4 and gives a satisfying effect.