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2007, 26 (01): -0 doi:
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2007年第1期目录

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SEISMIC REACTION OF EARTH AND ROCKFILL DAM：CENTRIFUGE MODELING TEST AND NUMERICAL SIMULATION

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2007, 26 (01): -1 doi:
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The numerical analysis results from LIQCA are compared with the centrifugal testing results；and the response of earth and rockfill dam during seismic load is also studied. In general，the acceleration is amplified from the base of foundation to the top of earth and rockfill dam；and the predominant period and band width of soil acceleration are almost the same along the depth. The excessive pore water pressure is accumulated during the base shaking；and the final excessive pore water pressure increases with depth. This fact can also be explained by the stress path analysis from conventional cyclic triaxial testing result and LIQCA analytical results.

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INVESTIGATION ON RESPONSE PROBABILITY OF MICRO- AND MESOSCOPIC STRUCTURES IN ROCKS TO EXTERNAL FORCE AND TEMPERATURE

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2007, 26 (01): -15 doi:
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In Preisach-Mayergoyz(PM) space，whether the hysteretic mesoswpic units(HMU) response to the applied forces and temperature or not is uncertain，these responses will lead to the instability of hysterisis loops of rocks under cycle loading. The transformation probability of meso structure varies with the external forces and temperature. It could be concluded from the experiments of the uniaxial compression and conventional triaxial compression that when the frequency turns higher，the transformation probability of meso structure reduces；the times of the self-consistent adjustment become shorter and the hysteresis loops tend to be stable more easily. Meanwhile，with the increase of temperature，the transformation probability of meso structure increases；the times of the self-consistent adjustment become longer and the hysteresis loops disperse and tend to be unstable with the increasing of the strain. Thus，reducing frequency and raising temperature could lead to the same result，i. e. the instability of hysteresis loops. All these might show that reducing frequency and raising temperature are equivalent. These results of the equivalence of the frequency/time and the temperature are meaningful to the large-scale underground project and the deep disposal of nuclear waste and CO2.

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METHOD OF THREE-DIMENSIONAL STABILITY ANALYSIS OF A SYMMETRICAL SLOPE

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2007, 26 (01): -22 doi:
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A new method is proposed for three-dimensional stability analysis of symmetrical or approximately symmetrical slopes. By using a simple equilibrium condition，the normal stress distribution over the three- dimensional slip surface is assumed，which is then multiplied by a modification function involving two unknown parameters. According to three equilibrium conditions of three-dimensional symmetrical slope，three equilibrium equations in terms of the factor of safety and two parameters are derived that are then reduced to a cubical equation in terms of the factor of safety and finally yield the explicit solution to the three-dimensional factor of safety. The presented method does not need consideration of the inter-column forces，rigorously satisfies the equilibrium conditions，and costs fewer computation efforts than the conventional methods of columns. Example studies show that the assumption regarding the initial normal stress distribution over the slip surface and the selection of modification functions has relatively insignificant effect on the value of factor of safety，thus ensures the reasonableness and effectiveness of the proposed method.

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STUDY ON NUMERICAL SIMULATION OF DYNAMIC RISK REGIONALIZATION DURING EXPLOITATION
APPROACHING TO FAULTS

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2007, 26 (01): -28 doi:
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In order to study the mechanism and predict the occurrence range of dynamic risk caused by underground mining，the dynamic events in a practical exploitation approaching to faults are investigated by using numerical method following the actual mining sequence on a typical cross-section E5200 in Laohutai colliery，Fushun. The dynamic risk area regionalization is specifically investigated，in which the criterion in terms of 3 g occurrence is proposed to diagnose the rockburst in responding positions. Based on the concept of 3 g envelope，the potential domain with dynamic risk is primarily identified. The effect of the faults is clarified when dynamic regionalization is carried out. The mining depth and the existence of faults are the main controlling factors of dynamic tremors under the complicated field situations. The presented work shows that there are directly proportional relationship between the radii of 3 g envelope and the mining induced tremor depth，and the deeper the mining is，the larger the radii of 3 g envelope will be. With regard to this discovery，the radii of the 3 g envelope are determined when sequential convergence methodology is employed.

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RESEARCH ON STABILITY OF LEFT ABUTMENT SLOPE OF
JINPING HYDROPOWER STATION AND REINFORCEMENT MEASUREMENTS OF PRESTRESSED ANCHORAGE CABLE

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2007, 26 (01): -36 doi:
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Using a special contact interface element and a proposed bolt element to simulate the slip surface and prestressed anchorage cable respectively，stability analysis for an instable block located in left abutment slope of Jinping Hydropower Station is carried out by software FINAL. The influence of discontinuous structures and the stiffness and prestress of the prestressed anchorage cables on the stability，the stress and displacement fields of the high rock slope are fully considered. The results of the numerical analysis indicate that the prestressed anchorage cables obviously improve the stability of the slope，especially when the slope is subjected to seismic loads. At the same time，the results also explain the reinforcement mechanism of the prestressed anchorage cables. The obtained results are of great significance to optimize the design of the prestressed anchorage cable.

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STUDY ON SITE MONITORING OF LARGE-SECTION HIGHWAY TUNNELS WITH SMALL CLEAR SPACING

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2007, 26 (01): -44 doi:
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Heshang tunnel is the first large-section highway tunnel with small clear spacing in Fujian Province. It is critical to make a comprehensive monitoring on the mechanical characteristics of the tunnel during construction. According to its characteristics，some monitoring tasks have been performed in Heshang tunnel，including the ground settlement，crown settlement，convergence，surrounding rocks displacement，surrounding rocks pressure and internal force in lining，etc. Based on the measured data，the deformation and stress properties of surrounding rocks and supporting system are analyzed；the interaction time-space range in the construction of two-arch tunnels with small clear spacing is presented；and the best time of support and secondary lining is given. Meanwhile，the real-time monitoring information is applied to optimizing the supporting system. The experiences and conclusions presented can be adopted in the design，construction and research of similar tunnels.

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SAFETY THRESHOLD OF BLASTING VIBRATION VELOCITY TO HIGH ROCK SLOPE OF XIAOWAN HYDROPOWER STATION

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2007, 26 (01): -51 doi:
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Based on the domestic and foreign research achievements about the safety threshold of blasting vibration velocity，the dynamic responds of high rock slope of Xiaowan Hydropower Station under blasting vibration，are carried out；then due to the statistical relation between the peak value of tensile stress and peak particle velocity at the slope step，and according to the rule of limit tensile stress，the reasonable monitoring position and the safety threshold of rock slope during its excavation were made certain. The results of the detailed research indicate that the reasonable monitoring position for blasting vibration control is at the inside of the slope step；and the peak particle velocity safety threshold is 10 cm/s for rock slope excavation.

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STABILITY ANALYSIS OF ANCIENT DEBRIS LANDSLIDE

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2007, 26 (01): -57 doi:
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In order to accurately evaluate the stability of ancient debris landslide，through the collection，arrangement and analysis of related data，the site investigation and exploration of engineering geology，indoor and outdoor physico-mechanical tests，adopting the analytic means of mathematic statistics，unbalanced-thrust method and three-dimensional large deformation contact elastoplastic finite element algorithm，and the theory of groundwater pipe network drainage system，connected with the engineering concrete example of Zhezhouling revived ancient debris landslide in Zhejiang Province，its process of the reviving and failure under rainfall was analyzed. Furthermore，this landslide stability was analyzed and computed also. Meanwhile，with other engineering concrete examples，the applicability of contact elastoplastic finite element algorithm used to analyze the debris landslide stability was studied. The research results show that to analyze the stability of ancient debris landslide by the three-dimensional large deformation elastoplastic finite element contact algorithm may consider the spatial effect of landslide mass，which makes computation result still be more accurate. Secondly，adopting the three-dimensional large deformation contact elastoplastic finite element algorithm with the action of rainfall may better reflect the actual locating state and sliding process of ancient debris landslide under the action of rainfall；and it may afford one method that can be used as a reference to the stability analysis，accurate evaluation and forecast of this type of landslide. Additionally，for shallow debris landslide，medium and deep one，and ancient one，two-dimensional and three-dimensional small deformation contact elastoplastic finit element algorithm and three-dimensional large deformation one were separately adopted to analyze the stability of corresponding debris landslide，in which the satisfactory computation result according with the reality can be achieved.

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METHOD AND PROCEDURE FOR TRANSFERRING MECHANICAL FIELDS BETWEEN DIFFERENT MESHES OF ADAPTIVE FINITE ELEMENTS

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2007, 26 (01): -66 doi:
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A transfer procedure plays an important role in adaptive finite element applied to the load history-dependent problems in connection with evolving meshes. Based on the improved mathematical interpolation of distance-weighted average，the method of mapping the calculated mechanical results from the old mesh to the new one is studied as the loads are applied step by step in a calculating process of adaptive finite elements. In order to make transferred results reasonable and reduce calculation time，several measures，for example，selecting known points near an unknown point，paying attention to the direction effect of data point，moderately smoothing the mapped state fields and making the fields including all known points，are employed in the method. According to the characteristics of material changing，excavation face moving and the discontinuity of displacement and stress fields between different materials introduced into the structure at different load steps or excavating steps in the simulation of excavation processes，a procedure for transferring the calculated results of stresses and displacements between different meshes is designed by means of subarea mesh refinement and interpolation. The transfer procedure is useful in adaptive finite element analysis for the simulation of excavation process，the elastoplastic iteration of increment load，and other calculation problems of loading step by step. Finally，numerical examples are presented to demonstrate the applicability of the approach described in this paper. Based on initial stress iteration algorithm of load increment，the results of numerical analyses for elastoplastic hollow cylinder subjected to internal pressure agree with that of analytic solution of the problem. Another numerical simulation for an engineering case of excavation process also shows the transfer procedure is effective.

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COUPLING MESHLESS METHOD AND FINITE ELEMENT METHOD FOR SEEPAGE OF JOINTED ROCK MASS

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2007, 26 (01): -75 doi:
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The seepage analysis is important to many engineerings including seepage failure of the jointed rock mass，petrolic seepage in the jointed rock mass and waterproof design of the underground engineering. The analytical method can be restricted by some practice factors such as the non-homogenous and anisotropy of the seepage medium for the jointed rock mass，uncertain initial conditions，the boundary condition and the complex geometrical shape etc. The coupling meshless method and finite element method for the seepage of the jointed rockmass are developed in the paper. The seepage problems of the jointed rock mass are mainly solved by the meshless method. The discrete equations and relational computation formula of the method are derived by the variational principle. The boundary conditions are considered by the coupling method. At last，the validity and accuracy of the present coupling method solution are illustrated by two numerical examples.

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STUDIES ON GEOSTRESS BY COMPARING RESULT OF AE METHOD WITH THAT OF HYDRAULIC FRACTURING TECHNIQUE IN DONGJIANGKOU GRANITE IN EAST QINLING

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2007, 26 (01): -81 doi:
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The result of earthquake mechanism solutions shows that the maximum principal stress axes of the modern tectonic stress field are close upon horizontal and the direction of the maximum principal stress is close to EW in east China；but the result of geostress measurements show that the direction of the maximum horizontal principal stress is close to NS in the Qinling—Bashan Mountain. In order to find the reason，the geostress measurements by AE method and by hydraulic fracturing technique were carried out in the same borehole. The borehole with depth of 600 m was drilled in granite rock mass at Dongjianhkou，Shaanxi Province. From 30 to 596 m，20 valid data of horizontal principal stresses and 25 data of the directions of the fissure by the hydraulic fracturing technique are achieved；from 75 to 599 m，11 data of the maximum principal stresses by AE method are gained. Above 200 m，the data of the hydraulic fracturing technique is consistent with that of AE method at different points in the same depth；but below 200 m，the maximum horizontal stress by the hydraulic fracturing technique is 10 MPa larger than those by AE method. At the same time，the data are larger than those by the hydraulic fracturing technique in its neighbouring region. On the contrary，the data by AE method are consistent with it. The result is that the paleotectonic residual stress exists in granite rock mass below 200 m，and the geostress field is composed of the modern tectonic stress field and the paleotectonic residual stress field. The data by AE method are modern tectonic stress，but the data by the hydraulic fracturing technique are the geostress. The result shows that the paleotectonic residual stress is an important composition of the geostress in the Qinling—Bashan Mountain which is the Mesozoic-Cenozoic orogenic belt.

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UNSATURATED-SATURATED SEEPAGE ANALYSIS OF MUNICIPAL SOLID WASTES

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2007, 26 (01): -87 doi:
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Combined with a project carried out at Qizishan landfill in Suzhou，the status of leachate in the landfill was investigated；and the saturated hydraulic conductivity and soil-water characteristic curve of municipal solid waste were measured in laboratory. The hydraulic conductivity function was deduced using Campbell¢s equation. Then unsaturated-saturated seepage analyses were carried out to investigate the movement of water in a landfill element，in which the existence of intermediate covers and the efficiency of cutoff ditch were considered. The obtained results show that matric suction in unsaturated zone of the landfill remains between 3 kPa and 6 kPa，with the corresponding volumetric water content between 35% and 40%. This is consistent with the borehole investigation，which shows that the deduced hydraulic conductivity function was applicable to simulate the seepage of leachate in municipal solid waste. The existence of intermediate covers can significantly reduce the infiltration of rainfall into a landfill element. But it becomes an important factor that causes perched leachate as the ineffectiveness of cutoff ditch is concerned. The obtained results are also consistent with those of field investigation.

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NUMERICAL ANALYSIS OF ULTIMATE BEARING CAPACITY OF LARGE-DIAMETER CYLINDRICAL STRUCTURES DEEPLY EMBEDDED IN CROSS-ISOTROPIC SOFT SOIL AGAINST LATERAL LOADS

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2007, 26 (01): -94 doi:
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A modified three-dimensional plastic limit analysis method of bearing capacity of large-diameter cylindrical structure in cross-isotropic soft ground is presented. The most likely failure mechanism is assumed to be of a composite rupture surface which is composed of an individual wedge in passive zone or two wedges in both active and passive zones near the mudline，depending on separation or bonding state at the interface between the cylindrical structure and neighboring soils in the active wedge，and a truncated spherical slip surface at the base of the cylinder when the structure tends to overturn around a point which is located on the symmetry axis of the structure. The cylindrical structure and soil interaction system under consideration is also numerically analyzed by the finite element method with software ABAQUS，in which the soil is assumed to obey the Hill¢s yield criterion. Both the failure mechanism assumed and the plastic limit analysis predictions are validated by numerical computations based on FEM. The effects of strength anisotropy of soil，height of loading action point above the mudline and coefficient of friction of the soil-structure interface on bearing capacity of deeply-embedded large-diameter cylindrical structure are examined through comparative analyses.

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C-SHAPED STRATA SPATIAL STRUCTURE AND STRESS FIELD IN LONGWALL FACE MONITORED BY MICROSEISMIC MONITORING

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2007, 26 (01): -102 doi:
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In order to study the results of relieving pressure above the seam which leads to rockburst while mining the liberation layer，China-Australia co-operation research group used microseismic monitoring techniques in Huafeng Mine of Xinwen Mining Group Co.，Ltd.，Shandong Province. The spatial fracturing rules of surrounding rock in longwall face surrounded by three sides mined areas were observed and researched. On the basis of the achievement of 3D strata fracturing situation and the section plane of microseimic events in different areas，the relationship between the spatial structure of overlying strata and mining pressure field is found，and the conclusions are drawn as follows：(1) the overlying strata forms C-shaped strata spatial structure. Microseimic events distribute in the outside of the C-shaped strata spatial structure and form fracture area of rockmasses. High stress area is in the C-shaped strata spatial structure. The shift of high stress area and the stresses of the different high stress areas are also described. (2) most concave of the C-shaped strata spatial structure lies on the top of the coal pillar when the coal pillar is smallest. The distribution of the supporting stress is that the hard thick rock layers above the main roof fracture near the intake airways，which produces the pressure-relieved area；and the hard thick rock layers above the main roof near the return airways are not fractured，which forms stress concentration area. According to the analysis of the reversal development of pressure，the diversion of high pressure is shown. The differences of pressure in different positions are found；and the areas where the pressure is not relieved are confirmed. So，by monitoring the area of the liberation layer and distinguishing the dangerous areas of rockburst，the measures to control rockburst are taken and succeeded.

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STUDY ON DYNAMIC STRESS-STRAIN RELATIONSHIP OF XIAOSHAN SOFT CLAY BASED ON MODIFIED MASING RULES

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2007, 26 (01): -108 doi:
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Earthquakes，waves and traffic often induce severe undrained cyclic loading. Degradation of stiffness and strength will occur in soft clay under cyclic loading because of the generation of pore water pressure. Unfortunately，previous work rarely incorporated the effect of cyclic degradation behavior on dynamic stress-strain relationship of soft clay. The Masing rules，often used in modelling the behavior of soils under cyclic loading，are unreliable when there is significant cyclic degradation of the stress-strain curves. The cyclic degradation characteristics of normally consolidated Xiaoshan soft clay subjected to undrained cyclic triaxial loading are investigated at different numbers of cycles，cyclic stress level and initial deviator stress. The variation of normalized stiffness Gsec/Gmax with variation amplitude of axial strain under different loading conditions in each unload-reload loop is presented. It can be observed that when the cyclic stress is smaller，the curves of Gsec/ Gmax- are composed of two parts，one for hardening and the other for softening. There is only the decreasing part left to the curves when the cyclic stress is larger than 58 kPa. An empirical degradation model for Xiaoshan soft clay is also proposed by normalizing the secant shear modulus in each unload-reload loop. The model takes account of the degradation behavior of soft clay inside a cycle. Based on the degradation model，concepts of Masing rules are modified to model the stress-strain behavior of Xiaoshan soft clay.

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FINITE ELEMENT RELIABILITY COMPUTATION AND SENSITIVITY ANALYSIS OF SLOPE STABILITY

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2007, 26 (01): -115 doi:
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In the finite element analysis，the soil is assumed to obey realistic elastoplastic and Mohr-Coulomb yield criterion. Based on the technique of sliding surface stress analysis and on the theory of elastoplastic finite element，the stress and the derivatives of the stress of the basic stochastic variables for the slope are computed by using partial differential technique and incremental initial stress method. In the reliability analysis，the limit state function is set up which can consider the direction of the sliding surface. And then the reliability indices of the whole slope are computed using the first order reliability method(FROM). In order to improve the efficiency of the computation of the reliability indices，it¢s necessary to carry out sensitivity analysis. Therefore，the formulas of the sensitivity of reliability indices to the basic parameters in the original space when they are correlated are derived. The advantage is that the transforming matrix，which is needed in the computation in the transformed space，is now unnecessary in this method. Considering the differences of the units of each parameter，the relative sensitivity formulas are suggested. An example is given to illustrate that the reliability indices calculated by this paper are the same as those of strength reduction method(SRM)；and reliability indices got from FORM are a little larger than those of mean first order reliability method(MFORM). Through sensitivity analysis，it¢s concluded that the effects of parameters c，j are much larger than the others；and their effects on the reliability indices increase when the negative coefficient of correlationship of c，j become large.

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STUDY ON WAVE VELOCITY AND ATTENUATION OF ROCK MASS IN 2D STRESSES FIELD

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2007, 26 (01): -123 doi:
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The results of elastic wave velocity from site testing of engineering rock masses indicated that elastic wave propagation velocity was influenced by stresses field. In order to study the stresses influence to velocity and attenuation of rock masses，the wave velocity and attenuation properties of rock masses in 2D stresses field were theoretically researched；and the theoretical relationships between elastic wave velocity and attenuation and stresses in jointed rock mass suffering 2D stresses field were proposed. At first，based on the deformation analysis of joints in rock mass under 2D loading，the volume changes of jointed rock mass was derived. Then according to the relationship between wave velocity and volume changes of jointed rock masses，an equivalent model analyzing the propagation of elastic wave in jointed rock mass was developed. The calculating formula of elastic wave velocity and attenuation of rock masses in 2D stresses field were proposed by using the equivalent analyzing model of the elastic wave propagation in jointed rock masses. In order to check the theoretical model and calculating formulae，an experimental research was performed on the samples of gypsum include cracks in the laboratory. The experimental results show that the elastic wave velocity and attenuation change distinctly with stresses in jointed rock mass in 2D uniform stresses field；and the testing results agree well with the theoretical model prediction.

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RELIABILITY ANALYSIS OF KEY BLOCK FOR A JOINTED ROCK SLOPE

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2007, 26 (01): -131 doi:
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With introduction of random probability into the block theory and considering a random distribution of geometry parameters and mechanics intensity of block，this paper used Monte Carlo method to conduct random simulation and calculate failure probability of block of different sizes under different failure modes. In the course not only the mechanics intensity，i.e. friction coefficient and cohesion，were taken into account，but the geometrical parameters such as angle of inclination of structural plane，volume of block，area of slip plane and so on were considered. Thereon the formation probability of different block sizes was calculated in the case that structural plane is discoidal. This paper put forward the concept of association probability which could be achieved from failure probability and formation probability of block，then the relationship between association probability and block size could be deduced. After subarea of block according to size，the association probability of distinct block regions was acquired and the block stability within distinct block regions was analyzed synthetically，which offered theory foundation to the reinforcement of jointed rock slope with significant application value.

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ACOUSTIC EMISSION OF ROCKS UNDER DIRECT TENSION，BRAZILIAN AND UNIAXIAL COMPRESSION

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2007, 26 (01): -137 doi:
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Direct tension，Brazilian and uniaxial compressive tests were carried out with sandstone and limestone samples collected from mines of China，with a testing apparatus of direct tension developed by the authors. The results show that the acoustic emission(AE) detected from the two rock samples is similar. During the loading process of compressive tests，the observed AE event numbers at the beginning of loading are usually quite high；and then decrease to a lower level with the raising of loading，which is believed to be produced by closing of the micro cracks in the rocks. In Brazilian tests，the behaviour of AE is similar to that in compression，i.e. AE events appeared early in the loading stage and kept approximately the same level during the total loading process until sample¢s failure where AE events reaches its maximum value. However，the phenomenon that AE events show higher values at initial loading stage as those in compression does not observe in Brazilian tests. Moreover，in compression，a sudden large increase in AE cumulative events can usually be observed when a small crack appeared before sample¢s failure；while such a result is not obtained in Brazilian test. In the direct tension tests，the observed AE is completely different，and both the numbers of AE events and energy during the loading process before failure are much lower than those of the other tests. Moreover，AE under direct tension could hardly be detected until the failure of the samples. In fact，for most samples，AE events under direct tension are detected only when the peak loading stress is reached.

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DEVELOPMENT AND APPLICATION OF NEW TYPE COMBINATION 3D GEOMECHANICAL MODEL TEST RACK APPARATUS

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2007, 26 (01): -143 doi:
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According to the feature of geomechanical model test of rock mass，a new type combination 3D model test rack apparatus which is composed of rack body and rack bottom plate，is researched and manufactured. The rack body of the apparatus consists of various box type steel structure members connected by screw bolts with high strength；the rack bottom plate consists of shape steel plates with screw bolt grooves. The 3D combined geomechanical model test rack apparatus is formed by fixing rack body and rack bottom plate in the screw bolt groove through high strength screw bolts. Application of the apparatus to a large-scale offspur tunnel model test indicates that it possesses some remarkable technical superiorities such as original structure，great stiffness，good stability，flexible assembly and free regulation for its size.

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EFFECTS OF RETAINING WALL AND INTERFACE STRENGTH ON TRANSNATIONAL FAILURE OF LANDFILL ALONG UNDERLYING
LINER SYSTEM

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2007, 26 (01): -149 doi:
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To investigate the effects of retaining wall and interface strength on translational failure of landfill along the underlying liner system，a three-part wedge analysis is used to calculate the safety factor for the waste mass against possible translational failure. The landfill can be divided into three discrete parts：an active wedge lying on the back slope that tends to cause failure；a passive wedge；and retaining wall resting on the foundation or liner system that helps to resist failure. With the change of the interwedge forces，the upper and lower bound solutions for the landfill stability，i.e. FSmax and FSmin，can be readily determined. Using an average safety factor FSave to replace the true factor FStrue，the differences between FSave and FStrue are within 5% for all cases considered. The safety factors increase with the increase of the height of retaining wall and the friction angle beneath the retaining wall. It is found that the retaining wall affects significantly the stability of landfill，if not consider the retaining wall，the stability analysis of landfill is relatively conservative. A potential failure phase with a minimum safety factor cannot simply be determined by comparison of the values of inner friction angles and cohesions for a multilayer liner. The safety factor increases with the increase of inner friction angle and cohesion of the liner interface. The cohesion of the liner interface seriously affects the safety factor，especially for a liner interface with inner a low friction and high apparent cohesion.

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EXPERIMENTAL RESEARCH ON STABILIZED SOFT SOILS BY ALUMINA BEARING MODIFIER

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2007, 26 (01): -156 doi:
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The experimental investigation was carried out with the purpose of making a contrast of strength effects of two clay soil species stabilized by Portland cement(PC)，portland cement-gypsum(PC+G) and compound modifier(PC+G+Al)，which consist of Portland cement，gypsum and alumina expansive agent. The result illustrates that the strength effect of stabilized soft soils differ strikingly due to their respective addition. PC+G+Al modifier in both stabilized soil samples produces more significant improvement in strength development than the other two modifiers. The PC+G modifier produces positive effect on strength，compared with PC modifier，only in one stabilized soil sample，which is in high water content ratio and porosity and contains active soil mineralogical composition. Both PC+G+Al and PC+G modifiers，in both soft soil samples，form ettringite in their hydrates. The formation of ettringite provides pronounced solid-phase expansion to fill up the porosity of soft soils. Whether the formation of ettringite enhances the strength of stabilized soil depends on the concordance in formation of ettringite and calcium silicate hydrate(CSH) gel. The strength of the stabilized soil samples increases markedly when the formation of ettringite is prior to the formation of CSH gel structure，which benefits the pore filling as well as mitigates the expansion damage to the CSH gel structure.

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A METHOD FOR DETERMINING ENGINEERING TREATMENT SCOPE OF GOAF UNDER HIGHWAY

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2007, 26 (01): -162 doi:
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The goaf engineering treatment scope determination is one of the highway construction difficult problems，which until now there has no good computation method to settle with. A goaf-above ground surface deformation computation model which is based on the stochastic medium theory；and the achievements of stochastic medium theory¢s application to geotechenical domain is set up；and the computation programs(GSM and POBA) are also developed. The computation model and computation programs are applied to Leiyang—Yizhang highway¢s goaf ground deformation computation，which successfully solved the high way¢s goaf ground deformation computation problems. At the same time，the highway ground deformation controlling indexes and the method to determine goaf engineering treatment scope are provided. The goaf-above ground surface deformation controlling indexes and the goaf treatment scope determination method successfully solved Leiyang—Yizhang highway¢s goaf engineering treatment scope determination problem.

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INTERACTION ANALYSIS OF COMPOSITE BUILDING ENCLOSURE
OF SOIL NAILING AND CAST-IN-PILE

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2007, 26 (01): -169 doi:
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A new type of composite building enclosure is applied to deep excavations recently，which is composed of soil nailing and cast-in-pile. A finite element software is used to analyze this new kind of building enclosure and make a detailed comparison between the measured stresses and in-situ displacements. The interaction of these two parts of the enclosure is also analyzed；and some useful results on the interaction of these two parts are derived from the numerical analysis. Based on the comparison results，the elastic modulus of some given stiff clay in finite element analysis for excavation is suggested based on the laboratory test. In the designing procedure of this type of composite building enclosure，some practical methods are also recommended.

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STUDY ON STABILITY EVALUATION OF UNSTABLE ROCK MASSES ON RIGHT BANK HIGH ALTITUDE SLOPE IN THE FIRST STAGE JINPING HYDROPOWER STATION

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2007, 26 (01): -175 doi:
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A lot of investigation shows that these unstable rock masses can be classified into four failure modes：whole slide shear failure mode；rock block landslide failure mode；whole shear fall failure mode；compress-rip- slide failure mode. Unload cracks of forming unstable rock masses failure boundary don¢t store water usually；so the main loads to cause unstable rock masses failing in dam region are weight of unstable rock，seismic load. There are two types of load combination，the first one is only weight，the second one is weight and seismic load. According to limit equilibrium theory，the authors put forward different calculation methods of stability and criterion of stability state class for different failure mode. The limit equilibrium theory not only emphasizes that correlative intensity parameters must be exact，and correctly measure geometry parameters of unstable rock masses；the latter are commonly difficult，utilizing the measuring technique of three laser scan to get these credible geometry parameters. The authors put forward corresponding measures of prevention and monitoring unstable rock masses of different scales and stability states too.

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CHARACTERISTICS OF LAYERED GROUND RESPONSES UNDER TRAIN MOVING LOADS

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2007, 26 (01): -182 doi:
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Dynamic responses of track structure and layered ground due to moving train loadings were studied with an elaborated model of an Euler beam resting on layered half-space with periodical contacts. The Green function solution of track vibration was obtained by means of Fourier transform；and the flexibility matrix of layered ground was deduced with the matrix transfer method. The analytical solution of the track and ground dynamic interaction was given by solving the integrated system equations. Track and ground responses were obtained both in frequency domain and time domain. An illustrative case study was conducted to reveal the characteristics of ground motions induced by high-speed train runnings on layered ground. Wave motions at ground surface and inside ground have been found strongly dependent on train’s moving speed and ground media properties.

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APPLICATION OF DISTANCE DISCRIMINANT ANALYSIS METHOD TO CLASSIFICATION OF ENGINEERING QUALITY OF ROCK MASSES

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2007, 26 (01): -190 doi:
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Based on the principle of Mahalanobis distance discriminant analysis，a classification model of engineering quality of rock masses is established，including six indexes reflecting the engineering quality of rock masses：uniaxial compressive strength，P-wave velocity in rock，volumetric joint count，roughness coefficients of joints，weathering coefficients and permeability coefficient of joints. Linear discriminant functions are obtained through training a large set of expansive samples. The results show that the classification model of distance discriminant analysis has excellent performance，high prediction accuracy；and can be used in practical engineering.

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A NEW-TYPE ELEMENT-FREE METHOD BASED ON KRIGING INTERPOLATION SCHEME AND ITS APPLICATION TO SOLVING BOUNDARY-VALUE PROBLEM OF MECHANICS

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2007, 26 (01): -195 doi:
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[PDF 324 KB] (1396)

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Presented in this paper is a new formulation of the element-free Galerkin method for the boundary-value problems of solid mechanics in which the moving Kriging interpolation procedure is employed instead of moving least squared procedure to construct shape function. The proposed procedure is characterized by the feature that the shape function constructed by moving Kriging procedure possess the property of Kronecker d -function and the consistency property. At the same time，the specified essential boundary conditions can be easily implemented while displacement boundary conditions are not easily imposed in the conventional element-free methods. The fundamental theory of this procedure is illustrated；and mathematical formulations are given. Then numerical examples are analyzed by the proposed procedure；and the computed results are compared with other solutions to verify the effectiveness and accuracy of the proposed method.

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EXPERIMENTAL STUDY ON CHARACTERISTICS OF STRENGTH AND DEFORMATION OF COAL UNDER CYCLIC LOADING

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2007, 26 (01): -201 doi:
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The strength，deformation and fatigue damage process of coal samples No.3 from Baodian Colliery under cyclic loading are studied through experiments by MTS 815.03 servo-controlled rock mechanical test system. The results indicate that the coal is more inclined to fatigue breakage than other harder rocks. Under uniaxial cyclic loading，the fatigue failure “threshold value” of coal samples No.3 from Baodian Colliery is smaller than 81% of the uniaxial strength；and there will also be a certain extant of fatigue damage when cyclic loading and unloading experiment are carried out below the fatigue failure “threshold value”. Axial deformation can be divided into three stages：initial deformation，constant velocity deformation and accelerating deformation. Radial deformation can be divided into two stages：stable deformation and accelerating deformation. When radial deformation obviously increases and the deformation resumes only a little while removing the load，the coal is going to break. Under cyclic loading，the fatigue damage process with cyclic loading times of coal reflects the process from compressive close，strain hardening to strain softening，as well as the damage evolvement process.

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EXPERIMENTAL STUDY ON STRENGTH REDUCTION EFFECTS OF LIMESTONE NEAR FRACTURE AREA DURING ACID FRACTURING

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2007, 26 (01): -206 doi:
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Reducing effects of limestone strength on the unconfined compressive strength of limestone are studied according to acid-rock reaction experiments of the static high temperature and the rock compressive strength tests，and analyzed stress-strain curve and mechanics of damage for limestone. Test results indicate that after reaction with the same gelled acid used on the test，elastic modulus highly decreased and Poisson¢s ratio increased a little，unconfined strength are about 20% compared with the same parts of limestone before acidized. During the acid-rock reaction，difference of reaction rate and acid etched pattern are obvious between matrix limestone with fractural limestone. Reaction with the same gelled acid used on the test，the reaction rate of Tazhong fractured limestone is about two times of Lungu matrix limestone. The etched pattern of fractured limes is local and deep，the matrix limestone is superficial and symmetrical. Different limestone pattern determined different etched pattern，and together with acid system，different etched patterns resulted in different strength reducing effects of limestone near fracture area during acid fracturing. The research results can provide effective technical parameters for designing and optimizing of acid fracturing.

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APPLICATION OF NONLINEAR SCIENCE TO MINE CALAMITY AND CONTROL RESEARCH
——ANALYSIS OF PROJECTS THAT FUNDED BY DIVISION I OF ENGINEERING SCIENCE，
NATIONAL NATURAL SCIENCE FOUNDATION OF CHINA

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2007, 26 (01): -211 doi:
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[PDF 166 KB] (1207)

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Reviewed the basic situation of projects about nonlinear science application to mine calamity and control that funded by Division I of Engineering Science，National Natural Science Foundation in the past six years. Main research contents of those projects include analysis of rock structure stability；calamity prediction and forecast；synergetic evolution of calamity system and structure fractal of coal(rock). According to basic concepts of nonlinear system science，the author discussed the research trend of mine calamity nonlinear nature，the whole course of nonlinear evolution and description and solving methods.

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赵海英博士论文摘要

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2007, 26 (01): -215 doi:
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[PDF 114 KB] (1244)

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赵海英博士论文摘要

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范庆忠博士论文摘要

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2007, 26 (01): -216 doi:
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[PDF 101 KB] (1170)

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范庆忠博士论文摘要