In order to investigate the behaviors of rock meso-cracking under chemical erosion，a new experimental system was developed on the basis of the rock meso-mechanics device. Microfracturing process of rock under uniaxial compression can be observed using microscope and color video camera and recorded by computer. A series of water and chemical erosion tests on granite taken from permanent shiplock site of the Three Gorges Project were conducted in uniaxial compression. The meso-fracturing process of inter-granular cracking, transgranular cracking，or grain boundary cracking is real-time observed.

Progressive cracking of granite plate under uniaxial compression had been investigated by using a loading frame，which could be well equipped with optical microscope and video recorder. For revealing the details of the process at mineral grain level，a double replica technique had been employed to copy the mineral grains and the crack patterns on the specimen surface. Based on these replicas，observation study on the failure behavior of different minerals and fractal analysis on the crack patterns can be carried out. It is found that the cracking of granite appears locally and begins with the opening of quartz grain boundaries，which are nearly located in the compressive direction. Different minerals present their distinct behaviors during failure，which are believed to depend on their microstructure natures. The cracks developing in loading direction are dominant under uniaxial compression. Their propagation and coalescence finally result in the splitting failure of the specimen. Quartz acts as a crucial mineral to mainly control the failure of granite. The fractal dimension of surface crack pattern increases continuously with the cracking development before the final collapse takes place.

The failure forms of rock materials in axisymmetric compression are studied based on the discontinuous bifurcation theory, and a set of experimental data of marbles are simulated. The results are that the brittle fracture form of rock in uniaxial compression is always the tensile fracture，and that of rock in routine triaxial compression is the shear fracture. The inclination angle of the shear band would decrease in steps with increment of lateral pressure. Furthermore，the localization shear band bifurcation takes place at the point in the strain softening area，and the point would be far from the peak point with the increment of lateral pressure.

The elasto-viscoplastic block element method is illustrated for the excavation and reinforcement analysis of rock slope. The rock blocks delimited by the discontinuities are considered as rigid bodies. The discontinuities and the reinforcement components are of elasto-viscoplastic characteristics. The governing equation is formulated by the consideration of the force and moment equilibrium conditions of the rock blocks， the deformation compatibility conditions together with the elasto-viscoplastic constitutive relations of the discontinuities and the reinforcement components. A complicated arch dam abutment slope excavation and reinforcement engineering are studied，and the deformation and the stability of the abutment slope during the construction are obtained. Based on these results，the optimal reinforcement scheme is suggested.

Based on the general principle of DDA，discontinuous deformation analysis，and the engineering geologic characteristics of Xintan landslide，the numerical simulation is carried out by DDA on the movement process of Xintan landslide. It is concluded that the middle part of the old landslide is reactivated firstly and then causes subsequent failure of the lower part due to the actions of pushing and pulling of sliding blocks，and finally the whole slope slides down.

The application of artificial neural network and genetic algorithm is made into the Shuibuya concrete face rock-fill dam project. The vertical compressive moduli of rock-fill dam are controlled and predicted based on BP network. Then the other deformations of concrete face rock-fill dam are predicted by the controlled values. Based on the conclusion of BP network learning，the multi-parameters of the design for Shuibuya project are researched with genetic algorithms.

According to the measured displacements of Geheyan dam during the running period，the back analysis of elasto-plastic mechanic parameters of its rock foundation is performed with the combination of FEM orthogonal numerical experimentation，regression analysis and optimization. It serves as a scientific ground for further study on weakened mechanism and weakened degree of mechanic parameters of foundation rock，on the allowance degree of safety of dam caused by limiting water level，and on the establishment of forecasting model of the service behavior of dam.

The study on 3-D modeling of rock discontinuity network and its engineering application are introduced. Based on 3-D modeling of rock discontinuity network, the structural model of rock mass can be found and the structural feature of rock mass can be studied. The 3-D modeling of rock discontinuity network can be used for evaluating the quality of rock mass and searching for separated blocks，and takes important function on the study of the problems of rock mechanics.

The reinforcement effects of prestressed anchorage cable are studied on the high shiplock slope of Three Gorges Project by means of numerical simulation using the 3-D explicit finite difference method. The results show that a compressive zone is formed on the surface of rockmass during the tensile process. As a result of reinforcement of numbers of cables，the continuous compressive zone namely，rock anchored wall is formed under the combinative action of prestressed anchorage cables and system anchor bolts. Thus，the deterioration of the property of rockmasses is prevented，the deformation of slope decreased and the stability of slope improved.

Sensitivity analysis is one of important aspects in the research of landslide stability. Ordinary method about sensitivity analysis is introduced. But because of the limit of ordinary method，another method，orthogonal design is brought in to consummate the theory system of multiple factor sensitivity analysis. On the basis of theoretical discussion，a case study is made with Zhaoshuling landslide as an example.

Based on the geological simplification of the left powerhouse dam foundation of the Three Gorges Project，physical modeling on stability against sliding for this dam was performed. As a result，the safety factor and failure mechanism of a typical dam section are analysed. The reinforcement measure for the dam foundation is discussed. The presented research results provide a significant reference for safety evaluation and design of this dam.

Some regularities of reliability analysis on landslide stability are discussed by using the Monte-Carlo method. The influence of some factors and coefficients of variation of landslide stability on failure probability is put forward.

Factor analysis is a very efficient method to deal with a large quantity of data. On the basis of brief introduction on its principle and application method，factor analysis is applied to deal with the monitoring data of a given landslide. It is by means of factor analysis that the main factors to affect the diaplacement of landslide in its different evolution stages，the sliding pattern and the evolution regularity of the landslide could be quantitatively recognized.

The deposit thickness，water current field and wave height of Fengjie stream segment after the Three Gorges Project reservoir filling are analyzed，and three possible slope rebuilding forms are explored，i.e.，bank scour，landslide whole slip and rockmass collapse. Then，the prediction model of bank scour is established and used. The stability change regulation of typical landslides under different water level，scour，deposit and earthquake conditions are computed and analyzed. Finally，some prevention and cure measures are suggested against slope rebuilding.

Based on plastic limit equilibrium method in rockmass，a new definition method of safety factor is given by energy work rate. Furthermore，the reasonable value of the energy safety factor about single plane sliding of rockmass is studied，and the suitable data for energy safety design method in rockmass slopes with bolts are obtained. A simple design method for reinforcement of rockmass slopes with bolts is given with an engineering example.

In light of the open deformation of joints in the middle isolated pier of permanent shiplocks in the Three Gorges Project，a typically simplified joint model is set up，based on the geological conditions and the crack investigation. The method of joint interface element is used to analyse the open deformation of joints and to study the characteristic of open joint crack and its relation to the excavation-disturbed zone. The study results show that the open deformation and the open length of joints are directly related to their occurence and geometrical characteristic，and that the possible maximum open zone of joints has almost the same pattern with the plastic zone resulting from elasto-plastic analysis and the excavation-disturbed zone from in-situ test. If the prestressed anchor cables are rationally applied in good time，the open deformation and the open length of joints will be reduced.

According to the failure features of concrete lining under seepage load，a three-dimensional numerical coupling analysis of seepage field and stress field is made on the fracture regulation of underground concrete branch pipe lining. Based on cracking characters of concrete lining，the computing formulae of crack width and reinforcement rate for concrete lining under seepage load are given. Through compution to practical engineering, the infection of seepage induced by high pressure water inside pipe is demonstrated. An efficient computation method is provided for the design of underground concrete branch pipe with high pressure water.

A model for seepage analysis of the Dayantang landslide in Shuibuya is proposed according to its geological condition. Numerical studies for the seepage field are carried out using the new improved saturated-unsaturated seepage analysis method，and the variation rule of the underground water caused by rainfall and pulverization rain is obtained. Based on the analysis，the optimization scheme of the drainage system is presented through the comparison of the effects of the various seepage control measures.

The parametric study on the effect of rain infiltration on unsaturated expansive soil slope is made. Transient seepage due to rain infiltration is computed using the finite element method. The results of numerical simulation show that crack is of a great influence on the distributions of both pore pressure and volumetric water content. The safety factors of slopes of expansive soils will decrease with increment of permeability coefficient，which is different from that of other clay slope. The deeper the crack，the smaller the safety factor of slope of expansive soil is. Moreover, rain duration can also strongly affect the transient flows and henee the stability of slope.

The rockmass shear strength is a fundamental parameter for dam design，and is normally obtained through the field or laboratory test with geological discount. The research result shows that it is very difficult to obtain the design value of rockmass shear strength because a lot of factors are necessary to be considered. In addition to the rock composition and structure，the stress state of rockmass is also a factor to influence the rockmass shear strength.

Partial least-squares regression method can resolve the problem of serious multicollinearity among variables，and the neural network can overcome the shortcoming that the conventional models must be the combination of linearity and non-linearity of imput data. The two methods, neural network model with partial least-squares regression of observation data of dam are combined. The result of an example shows that the prediction is of high precision with the proposed method.

Based on twin shear strength theory and some rock true triaxial strength testing data，a more reasonable twin shear strength criterion is proposed and verified. The corresponding parameters in the shear strength criterion are determined by simple traditional compressive and tensile triaxial tests，and some strength characteristics of rock are further revealed.

From the results of the laboratory tests，it is shown that the swelling pressure of sand-bentonite mixtures is dependent on the dry density and bentonite content of mixtures. The ratio of montmorillonite filled in voids of the mixtures is proposed. After analyzing the influence factors on swelling pressure and swelling volumetric strain，it is found that the swelling pressure can be attributed to the ratio of montmorillonite filled in voids of the mixtures.

According to the criteria for classification of engineering rockmass and the actual stability state of mining preparation tunnels，the engineering quality of rock mass at –302 m sublevel of Chenchao Iron Mine is determined and evaluated by qualitative and quantitative methods. The engineering quality of rockmass at low sublevels is predicted furthermore. According to the different evaluation results，different reinforcing methods are selected. The evaluated and predicted results coincide well with practical cases，and the reinforcing methods are effective.

Deep hole pre-grouting technique is applied to desist from water and reinforce country rocks in advance of tunneling. Using this technique in practical tunneling in a city，the stability of the country rocks was improved，and the tunnel had successfully passed bad geological region with fault，karst，water burst and large collapse. As a result，the safety of buildings on the ground and due data for water supply can be assured.

Based on the practical excavation case of Qingjiang Shuibuya Diversion Tunnel，analysis is made on the construction method，smooth demolition effect and treatment scheme of geological defects. The presented results can be valuabe reference for similar projects.

Combining with an excavation case of highway slope located in hill district，the rationalization problem of excavation sequence is discussed. Based on the monitoring，the concept that stabilization measures should be made in the meantime with excavation is proposed. The study shows that the construction funds can be saved up greatly and the time limit for a project shorten，too，with the proposed cutting meathod.

The train track-ground interaction is analysed under the moving load on the track and the induced ground vibration. The track is modeled by a bending beam. The ground is modeled by both a half-space and layered stratum on rigid base. First，the ground characteristic is studied by the frequency-wave number domain for the wave propagation. Secondly the loading on the ground interacted with the track is evaluated. The presented results make useful basis for predicting the dynamic response of track-ground systems under high speed moving load.

The restriction conditions of parallel-series connection millisecond blasting net for single hole blasting of once each time point are discussed. The problem of capping error is studied. The study result is applied in to roadbed project，and good effect is got.

The calculation method and the formulas of pile-soil stress ratio considering the interaction of pile-soil-cushion are deduced. They are based on the settlement model of CFG-pile composite ground. The problems of calculation parameters are also discussed.