Based on the elastic theory of orthotropic material, the 2-D and 3-D constitutive equations are obtained in off-axes coordinate system. The stress distribution near the borehole is amended by applying stress calculus of variation, and in addition, the equation for calculating radial displacement of wall of borehole is gotten. With the character of borehole radial deformation in ground stress measurement, a method is put forward for measuring the geostatic stress of orthotropic rockmass. It is verified in a practical project comparing with the conventional isotropic method, and its validity is proved.

An analysis model is proposed for evaluate rigid evolution of displacement jump in elastoplastic solid, which based on displacement jump condition and a specific single freedom degree dynamic system, i.e. condition of displacement jump is educed with strength theory of materials; after displacement jump occurs, the part of free movement is taken as a rigid body; and evolution of displacement jump depends on the stiffness of jump joint (or called interface), friction law of rate and state dependent, input loading and other parameters of the dynamic system. An example of frictional solid is given to illuminate the model how to work, in which the transformation of static to dynamic and loosing of material cohesion as input are stated especially.

Based on the derived finite element formulations of Cosserat continuum, progressive failure phenomena of the soil foundation, characterized by strain localization due to strain softening, are numerically analyzed. The influence of progressive failure process on the limit bearing capacity is illustrated by the developments of equivalent plastic strain. Numerical results demonstrate the effectiveness of the Cosserat continuum finite elements in preserving the well-posedness of the localization problem and simulating the progressive failure phenomena characterized by strain localization due to strain softening, necessity of the progressive failure analysis for earth structures such as the soil foundation etc.. Simultaneously it is pointed out that the unsafe results are to be obtained as the limit bearing capacity of strain softening soil foundation is analyzed by traditional theories of limit equilibrium and limit analysis.

An algorithm that combines the viscoelastic stress-strain relationship with the three-dimensional spectral element is proposed to solve the problems of three-dimensional viscoelastic multi-layer system subjected to an impulsive load. The four-parameter Burgers differential constitutive model is utilized in frequency domain for the formulation of viscoelastic spectral elements. Furthermore, the time domain response of three-dimensional layered system is obtained through fast Fourier transforms (FFT). As to a numerical structure, a three-layer pavement system, both proposed method and finite element method are applied to analyze the dynamic response subjected to an impulsive load. And the two results have a good agreement. Besides, the analysis and comparison of various elastic and viscoelastic models are shown in the cases.

Conventional constitutive model is not good at simulating the failure range and depth for hard rock under high geostress. The complicated evolvement of stress load, which produced by excavating underground engineering under high geostress in Laxiwa, is simulated through true triaxial experiment.Based on analysis of Mohr-Coulomb strength criterion, Griffith strength criterion, Drucker-Prager strength criterion, twin shear theory and Hoek-Brown strength criterion, a new three shear strength criterion is proposed for hard rock. The effect of three principal shear stress and three normal stress acting on the dodecahedral element and average principal stress are taken into account in the establishment of strength criterion. Based on the experimental result about Laxiwa new granite, the parameters of three shear strength criterion are searched using the global optimum features of genetic algorithm. The results of predicting samples and comparing with Mohr-Coulomb strength criterion, Drucker-Prager strength criterion, twin shear theory show that three shear strength criterion agrees with the experiment and is the same with hard rock. Based on the stress-strain relation curve obtained by experiment, three shear strength criterion and strain softening law, the elastic-brittle-plastic constitutive model is established, which is implanted in FLAC3D through UDM. The parameters of elastic-brittle-plastic constitutive model are searched using genetic algorithm- FLAC method. Calculating results agree with the fact and show that the elastic-brittle- plastic constitutive model can be used in the safety and stability analysis of hard rock underground engineering under high geostresses.

In order to research the influences of cyclic variation of temperature on the deformation, strength, damage and fracture, the contrast test of the uniaxial compression and triaxial compression, which is about the whole stress-strain behaviors of the marble under the action of cyclic (repeated 8 times) temperature from 100 ℃ to 800 ℃ and high confining pressure(60 MPa), is done by using hydraulic pressure servo rigidity rock mechanics experiment system MTS815.03. The specimens of the marbles come from the diversion tunnel of Liangshan Yalongjiang Dahewan Jinping Hydropower Station in Sichuan Province. We analyse the Influence of the high temperature and high cyclic temperature on the stress-strain behaviors, peak stress, peak strain, stress, residual strain and elastic ratio; it is shown that the peak strength, residual strength and elastic modulus decrease when the samples suffer more high temperature; at the same time, the peak strain and residual strain increases; at the same temperature, when the times of the cycle increasing, the elastic modulus, peak strength and residual strength of marble will decrease; and the higher temperature, the more obviously the decrease; after multiple cycle, the plastic characteristics of marble increase, the stress-strain curve behind the peak is not smooth, and residual strain diminish. The achievements mentioned above provide the basis for the diversion tunnel of Jinping Hydropower Station.

A quantitative comprehensive structural parameter is defined using ratio of principal stress difference of intact loess to that of disturbed saturated loess under triaxial stress condition, which can not only reflect arrangement but also coherent structure of soil particles. The relationship between variation quantity of the structural parameter - and axial strain can be fitted with hyperbola ( is initial structural parameter), equation of the structural parameter obtained with which can reveal the influence of confining pressure, water content, density, stress and strain on structure of intact loess. The structural parameter can make stress- strain curves of intact loess under different water content normalize to structural stress-strain curves which can be described using that of disturbed saturated loess at the same confining pressure simulated with the model proposed by Duncan and Chang. A constitutive relation describing stress-strain behaviour of intact loess is presented by introducing the structural parameter to that of disturbed saturated loess, which can consider structural effect and describe both hardening and softening stress-strain behaviour. Its rationality is confirmed by the agreement of results calculated by using this relation with that tested.

The dynamic elastic modulus and damping ratio of normally consolidated soft clay subjected to undrained cyclic triaxial loading are investigated at different initial deviator stresses. It’s observed that the effect of initial deviator stress on dynamic soil behavior is very significant. With increase of the initial deviator stress, the dynamic elastic modulus Ed, Edmax, normalized modulus Ed/Edmax and material damping ratio D increase greatly. Predictive equations for estimating dynamic elastic modulus Ed, Edmax, normalized modulus Ed /Edmax and damping ratio D are presented. The equations are based on an exponential function. The equations for damping ratio are expressed in terms of normalized modulus Ed /Edmax. Comparisons between the predictive equations developed and the earlier previously published curves show exponential function can better model dynamic damping ratio than quadratic function.

Based on analyzing the experimental results of saturated clay under the consolidated drained condition, a micromechanical damage constitutive model of consolidated drained saturated clay is presented by micromechanical analysis about every phase in clay. This model views that clay is composed of pore water and joint solid skeleton at the onset of loading until the joint solid skeleton is subjected to damage. The damage of the joint solid skeleton is defined as the slide of clay grain interface. In the damage deformation stage, the clay specimen is composed of three phase, such as pore water, joint solid skeleton and sliding solid skeleton. The volume fraction and the shear modulus of the sliding phase vary with loading process. This paper gives a method to calculate the volume fraction of the sliding phase in terms of Mohr-Coulomb law and the modulus decrease of the sliding phase in terms of conventional triaxial test. In addition, this work explores the hypothesis under which the nonlinear response of the clay is entirely due to the increase of the sliding phase volume fraction and the decrease of the sliding phase shear modulus. An averaging schemes based on self-consistent method are found to get a realistic transition from the relevant information available at the microscale to the overall nonlinear response at the macroscale. This paper also gives an approach to obtain micro-parameter and loading-unloading principle. Finally, tests on the versatility of the proposed model, including varying consolidated pressures and stress paths, indicate that the proposed model is capable of predicting deformation behavior for various conditions.

The application of Karhunen-Loeve (KL) expansion to simulating the soil parameters random field is researched; and the characteristics of the KL decomposition are analyzed; and the Galerkin finite element method is adopted to solve the integral equation numerically in the irregular region and for arbitrary covariance function and to simulate the anisotropic conductivity field. It is shown that the KL expansion of lower truncated terms can duplicate the spatial structure of the random field accurately. The KL expansion method is superior to turning band method in simulating the anisotropy of a random field; and it has better convergence than the spectral representation method.

To study the slope stability with shear strength reduction technique, a large finite element (FE) software, ABAQUS, is customized and linked into our program with the function of automatic searching for the safety factor. Based on results from FE model developed, three indicators of slope failure, e. g. non-convergence of solution, the plastic zone extending from the slope toe to the top and the critical value of plastic strain along the potential failure surface, are discussed. Furthermore, the inherent association of three failure indicators is illustrated. The non-convergence criterion is fit for coding the program with automatic searching for safety factor, as well as less dependant on users’ experiences. In most cases the order of mesh elements slightly affects the safety factor, but linear elements tend to overestimate the safety factor sometimes. It is thus advised to adopt second-order elements. Large deformation FE analyses for slope stability were carried out in updated Lagrangian formulation; and it is found the non-convergence criterion can not be taken as a reasonable indicator of slope failure.

The conventional beam-spring FEM used in deep excavation retaining design is based on anchored pile or anchored diaphragm retaining; and it is not fit for prestressed anchor flexible retaining wall. Based on the construction characteristics of prestressed anchor flexible retaining wall, the beam-spring FEM is modified. A new technique to evaluate the excavating load for flexible retaining is given; and a new beam-spring FEM program is developed correspondingly. Lastly a practical engineering project is analyzed using the new beam-spring FEM code. The horizontal displacement of retaining wall and the axial force of each anchor are yielded and compared with the field data; and it is shown that the new beam-spring FEM suits prestressed anchor flexible retaining wall.

In anchored anti-sliding piles engineering for landslides, when constructing of pile body completed and prestress tension loads to anchor cables were applied, sliding force did not acting on piles within a short time. In this phrase, the prestress tension loads produced a sort of active defending effect to landslide immediately, which applied a thrust force to the landslide opposite its sliding direction, and primary internal forces in piles presented. The computing of active defending force and primary internal forces is based on combining two sorts of elastic foundation beam mechanical models, including unidirectional elastic subgrade reaction in pile’s cantilever section and biparameters elastic subgrade reaction in the embedding section. The calculating method is obtained concisely by associating finite difference method of cantilever section’s deflection curve and analytical solution of embedding sections. It is helpful to evaluate the stability of landslide in the phrase of constructing emergent remedial works of anchored anti-sliding piles.

A new kind of the fiber reinforced plastic(FRP) screw anchor has been trial-produced. Screw vane with involute shape applied to this anchor can crush out little stones around the vane, so the anchor can be turned into soil a desired length with less disturbance. FRP is adopted as anchor rod, which is flexible and not prone to corrosion, so the service life is extended. The material properties, structure and design, tensile and creep properties, the instrument and method of installation of the anchor are given in detail.

The three-dimensional nonlinear elastic finite element method has been developed to study the horizontal bearing capacity behavior of the rigid pile composite foundation subjected to different vertical loads. The influence of the different cushion layer thicknesses and ground property on the horizontal bearing capacity behavior of the rigid pile composite foundation is analyzed. The distribution law of bending moments and deflections along the pile subjected to horizontal load is also obtained. The study results show that vertical load changes the failure mode of the composite foundation under horizontal load, which influences the horizontal bearing capacity of composite foundation. With the cushion layer thickness at proper level, the horizontal load transferred to piles would be decreased and the pile would be safer.

The influences of age, cement-mixed ratio and EPS content on the permeability of LWS-EPS are studied mainly based on the permeability test. For simulating the change of coefficient of permeability of LWS-EPS in real situation, the permeability test is carried out under different consolidation pressures by routine triaxial apparatus. The results indicate that the coefficient of permeability decreases with the increasing of cement mixed ratio, age and consolidation pressure and the decreasing of EPS content, which have a power function relationship approximately. But the degree of decreasing to the coefficient of permeability varies with mixture ratio and age.

The results of triaxial creep experiments for unloading state show that the frozen soil has an obvious dilatancy,and its volume strain should not be neglected. To fully reflect creep deformation laws of frozen soil under unloading state, a rheological constitutive dynamic model of frozen soil submitting to ellipse-DP two-yield-surface is put forward by using Nishihara model as the basic element. And the model is embedded in ADINA finite element program on the base of secondary developing technique for finite element program. The results of numerical simulation for triaxial creep experiments show that the constitutive dynamic model of ellipse-DP two-yield-surface can reflect some deformation properties of dilatancy and volume strain of frozen soil very well; and it can coincide with the experimental data, which can provide references for frozen projects calculation.

In order to find the mechanism of the effect of freezing and thawing circulation on the cohesion of saline soil, saline soil samples have been tested in laboratory. By analyzing the variation of the crystalloid location, the microstructure, the salt property and unfreezing water content, the mechanism between freezing and thawing circulation and cohesion is obtained. The research results show that while moisture content is constant, adding either sodium sulfate (Na2SO4) or calcium chloride (CaCl2) to the soil samples, the cohesion reduces with freezing and thawing time increasing. And the primary phases of cohesion reduction are the first and second circulation. The degree of cohesion reduction by adding CaCl2 is minor than adding Na2SO4. The main reason of the reduction of both cohesion and density is that the variation of the crystalloid location occurs while they separate out during freezing and thawing circulation. From the scanning electron microscope (SEM) graph, it is easy to find out that the proportion of big pores of the samples shrink with freezing and thawing circulation time increasing. The content of CaCl2 solution in saline soil has an important influence on the cohesion variation in freezing and thawing circulation.

By now, most reinforced soil wall filled by sands can work successfully, but when filled by loess, mid-low liquid limit and high liquid limit clay, the reinforced soil wall can not work naturally. In this paper, systematic direct-shear tests in large direct-shear apparatus were carried out for the clay reinforced by geobelt under different normal stresses and water contents. Based on the test results, one destroyed reinforced soil wall created in Nanjing City of Jiangsu Province is analyzed under design condition and work condition by finite element method. Based on the calculation, the crack line of flexible reinforcement soil wall is analyzed; and some important failure reasons are found and the some essential advise and measures for the clay-filled reinforced earth wall are also brought forward, which is very useful to design and research in the future.

The load transfer mechanism and deformation characteristics of cast-in-place piles in composite foundation with rigid-flexible piles are different from that in free state. Working property of pile is complex due to interaction between rigid pile, flexible pile and soil .Static load tests of the same pile under different situation are carried out in Wenzhou. On the basis of monitoring data in the process of static load test, settlement characteristics, load transfer mechanism and compression of pile shaft are analyzed; the conclusions can benefit to engineering design and construction.

Based on a major construction project in Shanghai of which the ground consists of a silty clay layer in surface and underlying a sandy silt layer, in-situ test study on the fitness of low-energy dynamic consolidation method (LEDCM) is done. By analyzing the variation of excess pore water pressure with depth, distance and the impact number, and considering the increasing and dissipation regularity of excess pore water pressure in different soil layers, a method to choose the construction parameters of LEDCM such as the optimal impact number, the appropriate impact space, the effective strengthened depth and the reasonable interval between two impact passes, by experimental means is proposed. At the same time, the field detective trials including the static cone penetration tests and the standard penetration tests are given to evaluate the effectiveness of improvement, and the results indicate the validity of LEDCM to treat the silty clay ground and also further broaden the application range of LEDCM.

The dynamic tensile properties of rock material are the basic information to assess the safety of rock structure under dynamic loads such as explosion and earthquake. An apparatus to conduct direct dynamic tension tests with confining pressures for rock is introduced. In addition, a series of trial experiments are conducted by gypsum and granite samples. It is reported the change of strength for the gypsum and granite samples with strain rate and confining pressure are similar with that rock material under indirect dynamic tension tests, as well as the rock like material (concrete) under biaxial tension-compression tests. For this case, the apparatus is available to perform the dynamic direct tension test with confining pressure for rock material.

The mechanisms of the time lag phenomenon induced in piezometric level observations using open standpipes are analyzed. A new simple method is proposed to estimate the lag time; and it is compared with the Hvorslev’s solution. It is found from parametric studies that the estimated lag time by the proposed method is about 1/5 to 1/10 of that by the Hvorslev’s method. When the length of the intake portion of the standpipe is long enough, the open standpipes can be used in a soil with the coefficient of permeability of 10-5 or even 10-6 cm/s, without inducing significant time lag phenomenon. The degrees of sensitivity of 28 open standpipes were examined by field rising-head tests; and the results from the proposed method are verified by the tested results.

Ground movement pattern of shield tunnel is investigated. It is put forward that the direction of ground movement is conditioned by soil type, and the novel parameter “movement focus” alters its site between center and bottom of tunnel. Ground loss model of tangent double circles is adopted to establish a uniform ground movement pattern of shield tunnel by introducing the coordinate parameter of movement focus. This novel pattern includes Park pattern and Loganathan pattern. Assuming soil is undrained, the general calculation formula for surface settlement induced by ground loss is deduced with virtual image method. This method is applied to the construction phase. As shown in analytical calculation, the predicted surface settlements are in good agreement with the observed settlement; and this method is applicable for all different soil conditions. Loganathan’s formula only fit for bad soil condition. The predicted surface settlements for good soil condition are smaller than the observed settlements.

The technical thoughts, superiority and main characteristics of object-oriented method are introduced. According to the object-oriented analyses of the requirements of monitoring for underground powerhouse, 11 main objects have been withdrawn and on which a monitor information management system has been established. The object-oriented method can clearly hold logically the relations between main objects of monitoring system and form the function modules naturally. The modules have well encapsulation, high cohesion, low coupling, and the good easy to defend as well as good readability, extendibility and reusability. So, object-oriented method has the good application prospect in the monitoring software development.

A simplified procedure for evaluating aseismic stability of slope subjected to earthquake shaking, in which the effect of time-history vertical acceleration on the yielding angular acceleration of sliding block is taken into account is presented. The fundamental feature of this procedure is the vertical acceleration time-histories. The numerical computations are performed by using the proposed method. It is shown that the computed sliding displacement for a given embankment, in which time-history vertical acceleration is properly considered, is more rational compared with the conventional computational results. Finally, a dynamic parameter analysis is performed and shown to successfully offer the rational references and scopes of evaluation for the aseismic design of embankment.

There are three main forward selection schemes of line for the Xiaxindian-Yunmeng section of the Shanghai-Wuhan- Chengdu Railway, in which some parts would be located on the earth surface under which there are big salt stoped-out cavities for the scheme of small straight line and the scheme of reconstructing along the old line. The effects of time and space of the salt cavities would produce a harmful influence on the stability of the rockmasses on which the railway will be built. In order to select the right line scheme, the mechanical state of the concerned areas with salt stoped-out cavities should be studied quantitatively. So the 2D and 3D elastoplastic finite element computations are carried out for the stability of the relative rock masses against the typical sections of B52 and B63 mine areas through which the railway might pass; and the displacement distributions and plastic zones in the strata are obtained; and the settlements of the earth surfaces over the salt stoped-out cavities and the embankments are analyzed emphatically. Finally, the conclusions which could be used for the decision of line scheme are given taking the allowable settlement values of railway embankment as the control targets.

Since water seepage comes out of Kunlun Mountain tunnel at a valley, understanding the ground temperature at the valley is one of the most important things to treat the disease. The ground temperature is studied; it is traced back before tunneling by numerical simulation on the basis of geological observation information from March to May, 2004. So it is educed as follows: (1) there is an unfrozen channel underground the valley; (2) the ground temperature around the tunnel is affected by tunneling; (3) the maximum frozen depth is about 10 m; and the maximum thawing depth is not over 4 m.

Uncertainty information such as random, fuzzy, gray, unsure message widely exists in the geotechnical engineering. Due to the complexity of the practical situation and deficiency of experiment data, calculation parameters are usually the mixture of multi uncertainty. Against this character, using the blind data to express the uncertainty of the calculation parameters, the theory of blind information is applied to the rigid limiting equilibrium method for slope stability; and a new method of computing safety factor is put forward. The corresponding confidence level of safety factor in different numerical value intervals is computed by use of blind data algorithms; consequently the more comprehensive result is provided to judge the stability state of slope, overcoming the defect of absolutely definitive description in the traditional methods. The case study indicates that the blind data can consider the practical situation better in the slope stability analysis; and the result is more detailed and reliable, having good practical values.

The analysis of dominant orientations of discontinuities is a basic work for a further study on simulating with Monte-Carlo method and conforming the stability of rock mass. Traditional analysis of plots method is insufficient and inadequate. The result is only a simply classification of the orientations, and is inconvenient to be applied in practice. Because of the deficiency of traditional analysis method, a dynamic clustering algorithm is developed. According to the rule of right hand, a three-dimensional field coordinate system is constructed. A unit normal can be used to represent the orientation of discontinuity. Then the orientations are classified by the dots' spherical distance. A data investigated from a slope in the new town of Badong County in the Three Gorges Reservoir is used to be a case study. The study shows that the results of dynamic cluster algorithm are reliable and reasonable. And the dominant orientations and classification are more precision.

During constructing a dam in Tianjin Harbor, the geobag solidified soil technology was applied successfully. Because the soil strength underlying the dam was rather low, the PVC drains were adopted to accelerate the dissipation of pore water and to ensure the stability of the dam. The FEM technique with elastoplastic soil constitutive relations was used to simulate the consolidation process of foundation soil. In the analysis, the axial symmetric problem is transformed into an equivalent plane strain problem, which makes it much easier to carry out. The functions of the geotextile consisting of the geobag are considered by increasing the cohesion of the solidified soil and providing reinforcement to the structure. The load is applied step by step; the settlement and pore water pressure at the central settlement of the foundation and the lateral displacement at the edges of the foundation were calculated. The calculated results coincide well with the field investigation data.

Through analyzing the Monte Carlo random finite element and the system reliability method of βembranchment method, we consider to combine the two theories, and then a reliability analysis method is proposed to use in the process of underground caverns excavation. The method for evaluating the big cavern reliability in construction has researched. Taking the Hainan project for example, we analyze the every excavation step, and compare the two methods’ shortcomings and merits. So we can get a full knowledge about the several layers excavating method so as to provide reference for the fast excavating.

Based on a preliminary analysis, it is estimated that the soil layer at outer of the retaining structure could produce lateral unloading and loading stress paths. Therefore, a series of tests were performed with different lateral unloading and loading stress paths. Based on Duncan-Chang model and result of experiments, formulas to calculate tangent elastic modulus were developed for lateral unloading and loading conditions. A good agreement was observed between test data and results from finite element analyses using the previously mentioned tangent modulus model. These results show that excavation of foundation pit can be better simulated on condition that lateral unloading and loading stress paths are considered.

The complete process of successive penetration of single jacked pile is simulated with finite element method based on the commonly used large-scale software ANSYS; and compacting displacements are analyzed in detail. The displacement fields caused by different modulus ratios of pile to soil, frictions between pile and soil and Poisson’s ratios of soil are given. Some complex problems, such as elastoplastic constitutive law, stress field of soil ’s dead weight, large deformation and sliding friction between pile and soil, are taken into account by using the displacement penetration method which is more reality and has the effect of animated simulation.

The interaction characteristics of the interface between geogrids reinforcement and soil as well as geogrids reinforcement and interlock concrete blocks are the two key indexes for the stability of interlock segmental reinforced retaining walls. It is found that the two-way geogrids reinforcement would be tension fracture when the normal stress is over 24.8 kPa from the results of pullout test, and under this condition the tensile strength of the geo-grid is lesser than that when the two-way geogrid is tensed in the air. The strength envelopes is composed by two straight lines, the frictional strength between two-way geogrid reinforcement and interlock concrete blocks increases with the increase of normal stress when normal stress is less than 24.8 kPa and is invariable when normal stress is over 24.8 kPa.

The seepage deformation of the foundation pit excavation of power-house of a hydro-project is evaluated, based on probing into the method of evaluating the seepage deformation. The results indicate that along the axis of dam, the soil mass on slope of foundation pit is unsafe without impervious wall; when setting impervious wall, the hydraulic gradient on slope steps down to the value lower than 0.05; but the hydraulic gradient of the common boundary of base rock and gravelly medium-coarse sand is somewhat high; so seepage deformation may occur if water seeps out from fine sand soil and gravelly medium-coarse sand. On the whole, the probability of seepage deformation is small when setting impervious wall because the hydraulic gradient reduces to very small value.

Reproductive concrete is a new type of concrete that made from the disuse concrete after a series of courses of disposal ,such as break up, washing, filtration, classification, combination on a certain proportion and so on. The research of the mechanical characteristics of reproductive concrete is very little. This article researches the mechanical characteristics of reproductive concrete by a series of tests. The influences of the substitute ratio and hydrated ratio on the mechanical characteristics of reproductive concrete are studied. The ultrasonic parameters when reproductive concrete is loaded are detected; the rule of the development of ultrasonic parameter with the change of the distortion of reproductive concrete under static load is analyzed. In order to research the cyclic dynamical characteristics of the reproductive concrete, we have made a experiment that operate cyclic load on the reproductive concrete, in order to research the rule of the development of the distortion of the reproductive concrete. All of these can provide a referrence for similar engineerings.

The basic theory of extension method is introduced and the method is applied into risk zoning of geological disaster. Eight evaluation indexes were selected to be synthesis appraising system; they are the number of the existed geological diseases, the objects involved by the diseases, the lithology and the weathering degree of the rock mass, the relation between the dip of the discontinuities and the strike of the slopes, the features of the fractures, the influence intensity of human activities, the hydrogeolgy conditions and the dip angle of the slope surface. The risk grading standard is established; and corresponding value assignment is done. During the process of evaluation, the square of 100×100 m2 grid on geographical map is designed as the basic assessment element, and the corresponding zoning grade is obtained by means of grid data processing through computer program. The practical situation of the evaluation area is exactly reflected from the characteristic value of grade. The application practice proves that the extenics method is feasible in risk zoning of geological disaster in Xiangjiahe Bridge bank of Three Gorges Reservoir area in Zhongxian County of Chongqing.

In terms of stress wave theory and complex function, analytical solution for the interaction between blasting seismic wave and arbitrary shape underground chambers is deduced. The detail process is that through the conformal mapping method, the arbitrary shape hole in physical plane can be mapped into unit circle in mapped plane; the problem is translated into solving the interaction between blasting seismic wave and unit circle chambers. Taking the interaction between blasting seismic wave and an arch tunnel with vertical sidewalls for example, the distribution of stress and vibration velocity of rock mass is presented and analyzed under the acting of the incident blasting seismic wave with different frequencies and incident angles, and then the critical particle vibration velocity is decided basing on the tensile strength of rock mass.

The similarities and differences of California bearing ratio(CBR) test requirements in America, Britain, Japan and China are analyzed; The test technology and proceeding are emphasized. The CBR denotes the potential strength of subgrade material and it is the important index of evaluating its using performance in expressway. In order to study the main influence factors of the CBR value of clay, the physics and chemistry tests of fifteen groups of subgrade materials, taking from the Qingdao-Yinchuan Expressway in Hebei Province, are done. Based on the result of tests, which there are obvious difference between CBR value with the same plastic index clay, the influence factors of CBR of expressway subgrade materials, such as distribution of particle sizes in soils, mineral component and clay mineral component, are studied. The useful conclusions are drawn as follows: the main influence factors of CBR of expressway subgrade material are the type of mineral component and its content; secondly are the distribution curve shape of particle sizes in soils.

The interaction between soil nailing and soil is considered and a true three-dimensional finite element model has been developed to analyze the strain-stress and the deformation performances of soil nailings. The optimum design method with deformation control and stress control of soil-nail retaining structure is presented. Using genetic algorithms and complex method, the mathematical model of structural optimal design is established regarding the stress and the deformation as constraint conditions and regarding the project cost as objective function; and the calculation program is compiled correspondingly. Taking a case study and comparing with the result of specification method and the optimal results based on specification method, the present optimal method is more reasonable.

Based on test data of load sharing between pile and cap of single cap pile foundation below column in the tall building, the properties of load sharing between pile and cap, the reaction forces of pile top and soil between piles are analyzed. Pile and cap can together bear the loads. Pile and soil below cap can respectively share 80% and 20% of total loads. The ratio of loads shared by soil below cap and pile changes largely during early period of the engineering, and gradually becomes stable with the end of main structure. Reaction force of the middle pile is smaller than that of the edge pile and the corner pile. Reaction force distribution of pile top and soil below cap is saddle shape along side cap. The test results of this engineering are useful for design of single cap pile foundation below column in tall building.

The researches on vacuum preloading are summarized. The mechanism of vacuum preloading is analyzed; and some problems in practice are pointed out. Loading and unloading of vacuum preloading is derived and considered as loading and unloading from minor principal stress. Unloading from minor principal stress could weaken the resilience of the soil when unloading of vacuum preloading; the soil would not appear resilient obviously, even go sinking. We have needed to design the test of modeling vacuum preloading stress path more reasonably.

On account of the conclusion of L.Prandtl-H.Reissner topic, which thinks fracture plane behind retaining wall is made up of a logarithmic spiral and a straight line, and by using limit equilibrium and constrained optimization, the formulas of active earth pressure, the resultant force of earth pressure and its application point are obtained. The distribution characteristics of active earth pressure in the vertical direction are analyzed. The effects of main parameters on fracture plane, active earth pressure, the resultant force of earth pressure and its application point are investigated in detail.

The paper focus on the classification rockmass surrounding the Xiaolangdi underground powerhouse. Two rock mass classification systems, RMR and Q, have been used to classify the rockmasses surrounding the underground powerhouse. The supporting measures are suggested based on RMR and Q classifications. The shear strengths and deformation moduli of the rockmasses have been estimated based on the rockmass classification. The monitoring result shows that the underground powerhouse is under the situation of safety.

The differential equation of explosion loading in rock mass under ground stress field is established. The implicit method is adopted for the ground stress simulation of rock mass and the explicit method is adopted for the explosion loading simulation, which is completed through the implicit-to-explicit sequential solution. Numerical examples show that the shock wave plays the dominant role when the ground stress is lower much than the explosion loading near the charge chamber; and the higher ground stress can change the regulation of the wave spread.