The surrounding rock mass of underground powerhouse in the rig ht bank of the Three Gorges is cut by well-developed joints. The constitutive law and the damage evolution equation of the anchored discontinuous jointed rock mass are set up by damage mechanics, and they are used to evaluate the stability and deformability of the surrounding rock mass during excavation and supporting.

Through triaxial compressive tests of frozen sandy soils under 4 kinds of different consolidating processes (-5 ℃), it is found that the consolidating process strongly affects the strength and deformation of frozen soils. The frozen soil that is subject to K0 DCF( drainage consolidating and then freezing)has the greatest ultimate strength and the lowest failure strain, on the contrary the frozen soil that is subject to FC ( first freezing and then consolidating)has the lowest ultimate strength and the greatest failure strain . For the frozen soil of undergoing the isobaric pressure drainage consolidating and then freezing ( EDCF) and the isobaric pressure undrainage consolidating and then freezing ( EU CDF), their ultimate strength and failure strain are between those of K0 DCF and FC.

There is a stress jump on the interface between the elastic and the plastic zones. Using the stress jump values as mesh refinement criteria, one can not only greatly improve the accuracy of the stresses calculated but also solve the form of plastic zone. For the specific problems of tracing the interface between the two zones, a modified mesh refinement criterion is presented. By changing several main factors that effect the shape and size of plastic zone, a lot of numerical computations are carried out. The results have shown that the criterion used in this paper is effective for determining the shape and size of the plastic zones of caverns.

According to the nonlinear characteristics of slope displacement-time series , the information offered by the time series datum sets can be fully exploited and the trend of slope displacement evolution can be precisely predicted by making real-time forecasting based on phase space reconstruction. The method of local function approximation and the prediction based on Lyapunov exponents are discussed in this paper. The examples suggest that the methods based on phase space reconstruction are more accurate and more adaptable than the decomposition model of non-stationary time series.

In this paper a yield surface of anisotropic and small-strain constitutive mo del(ASM)is presented based on energy equation and compared with yield surface of modified Cam-Clay Model ( MCC), yield surface from testing result . I t is clear that the new yield surface is closer to testing result than MCC . A function of distance between initial stress-strain point and point at state boundary surface is adopted to simulate stress-strain behaviour of soil in condition of small-strain. The new constitutive model is compiled into FEM program and calculation result is compared with experiment. It is show n that the model in this paper can better simulate main characteristics of soil than MCC

The stability of the up-stream lock head of Three Gorges ship lift is analyzed with elasto-plastic limit equilibrium method in which the critical instability state is defined as the state where the plastic zone runs through the rock foundation , and the pre-determined sliding surface is unnecessary. The limit equilibrium state is approximated stepwise with decrement of material strength. The construction sequence is taken into account in the study , and the stresses of rock after excavation are treated as initial stresses when reloaded . And because of the consolidation grouting in rock after excavation , rock reloading begins in elastic state. Results show that the safety factor of stability of the up-stream lock head is 3. 3.

In this paper, the not proper deformation computation method of cantilever supporting piles in the codes in force is pointed out , the mathematical power series precise method and the simplified computation method based on the codes are put forward. In-situ measurements have shown that the new methods proposed in the paper are more precise and rational but the method required by the co des give a calculated result about 20% less than the measured one.

In this paper, an elasto-plastic model is proposed for soil with initially stress-induced anisotropy. T he hardening axis in the presented model is between the axes of the Cam-clay model and the Sekiguchi-Ohta model. A transformed stress based on the SMP criterion is used for making the model become a reasonable three-dimensional model. Comparisons with experimental data from drained shear tests on K0 normally consolidated clay in different stress paths show that the proposed model gives excellent predictions. Therefore, the model is more realistic than the Cam-clay model or the Sekiguchi-Ohta model in predicting the deformation and strength of soils.

Based on previous researchers, this paper establishes a rheology model of rockfill used in the rheology analysis of concrete face rockfill dam despiting the rockfill microstructure. In this model, the instantaneous elasto-plastic deformations of rock fills are computed by the oblong-parabola two yield surface model, and considering the time effects, the time dependent visco-plastic deformations are derived from the empirical equation of hyperbolic function .The reliability of this rheology model is proved to be good after perfo rming inverse problems with deformation records in-situ .

The designed rainfall process and infiltration curve are defined on the basis of analysis of typical rainfall process, which would induce Huanglashi slope. Moreover, unsaturated and unstable seepage analysis for the slope is studied on the condition of rainfall. Disaster and drainage effect of Shiliushubao slope is studied comprehensively .

Based on model tests of one or two piles pressed into soft clay, the effect of squeezing against soil is studied . The laws of soil displacements changing with horizontal distance and depth during the process of pressing piles are obtained, and the testing results of pressing one or two piles are also compared and analyzed .

A nonlinear concentrated spring model is presented in this paper, and the model is applied to the analysis of elastic plate-nonlinear subgrade interaction . The computation result shows that the subgrade reaction , the deflection and bending moment are improved greatly if the non-linear property of subgrade is considered.

In this paper, GM( 1, 1)grey models for observed data of the slope displacement with grey system are given, unequal time series are considered in process. T he models obtained are accordant with the slope displacement tendency .

The elasto-visco-plastic constitution has been employed for 3D-FEM programming of soft saturated clay in Shanghai. The program has also been applied to predicting the settlement of earth-fill bridge-slope on the soft clay basement after construction .The comparison between the predicted and measured values have proved that the constitution is reliable.

Based upon the study of the mechanism of reinforced geotextiles and upon the loading tests both in site and in lab, a design method about the reinforced sand cushion is presented in this paper. It is successful applied to treating the soft ground of 8 4～ 7-storey.

A new search method of arc slipping method, which is called three orientation search method in the article, is given. It is pointed out that there always exists an arc with the least safe coefficient between one slope top line and each of those lines which is below the slope top line; In order to find all these arcs, a concrete method is given, and finally some examples are described.

The engineering property of cement treated soil is studied systematically in this paper. The field static loading tests of DJM sing le pile and compound foundation are performed. The compound foundation bearing capacity, stress ratio and load transfer behavior of DJM single pile are analyzed and studied , some useful results are obtained, these results have guidance meaning for DJM pile engineering practice.

In this article elasto-plastic stress analyses on ring with different tensile and compressive strengths are conducted using generalized twin shear stress strength theory. The elastic limiting inner pressure and plastic limiting pressure, which are dependent on the tension-compression ratio of the material, are obtained. The results are applied to determination of tensile strength of geomaterials.

Possessing a low strength, the cemented-soil pile usually is not used in retaining structures. This paper presents the testing results of reinforced cemented-soil beams. It is shown that the reinforced cemented-soil beams have a higher capacity to resist bending load than pure cement-soil piles. T his study provides experimental foundations for reinforced cement-soil being used in practice.

The paper sums up the background of Particle Flow Code in 2 Dimensions( PFC2D), compares the differences of PFC2D from the other numerical methods, and introduces procedures to solving problem using PFC2D. Some examples used in geo technical engineering are presented.

This paper puts forward 3D F EM-U EM program which can be used for numerical analysis on pile-raft-soil interaction . After validating its accuracy by comparing with field tests in Jinan, Shangdong province, we use this program to analysis the bearing capability of single piles .

The paper introduces excavation engineering and ex pert system technique, brings forward the method of using expert system to solve problems in excavation engineering , and illustrates an ex ample that it is feasible to use expert systems as a computer-aided means in excavation engineering

Based on the calculation of soil parameters’scale o f fluctuation of hundreds of soil layers, the problem of the calculation method, choice o f correlation function type and fitting range in the calculation of scale of fluctuation using the method of correlation function are discussed and analyzed

Based on the method of load transfer and Geddes formula, this paper calculates the load(Q)-settlement (s)curve of compacted cement-soil single pile. Then the variational regularity of the Q-s curve of a single pile with the pile length l , limit strength qu of pile shaft material, compression modulus Es of soil arround the pile tip are analysed . The relation of compression of pile shaft material, pile end resistance and settlement with the load of pile top are also analysed .

According to the requirement of studying for engineering mechanical properties of rock material, a loading apparatus for meso-mechanical experiment of rocks has been developed . The appratus can be used as an additional instrument for optical solid microscope, and with the microscope, the complete failure progress of the four faces of rock samples ( rectangular in shape)under loading can be observed. In this way, the stress-strain curve and the related graphic of the changing microstructure of rock smaples can also be attained.

Studies on large ground displacements induced by liquefaction are one of leading issues on geotechnical earthquake engineering. Based on references , field investigations and lab tests on large ground displacement are introduced , post-liquefaction characteristics , dynamic constitutive models and calculation methods are summarized .

In this paper, the history and the current situation of studies on piles in calcareous sands are systematically summarized, and the reason for low bearing capacity of piles in calcareous soils is analysed. Some important study tendencies in the future are proposed.

The relation between the yield surface and the plastic potential surface based o n the generalized plastic mechanics is discussed systematically, and the basic characters of the yield surface, especially of volumetric yield surface that can calculate dilatant volume strain and shear yield surface in stress Lode angel direction for the first time, are also discussed . T he stress-strain relation is obtained without hardening law , and the elastoplatic stiffness matrix is deduced with two methods .