Jinping II hydropower station includes four diversion tunnels，two auxiliary tunnels and one drainage tunnel，with a total tunnel length of 118 km. These tunnels are characterized as thick overburden，long length，large size in diameter，high geostress，complicated engineering geological conditions and high difficulty for project layout，which make the tunnel project the largest and most difficult hydro-tunnel group in the world. Key technical problems were met during the tunnels excavation，including the forecast and treatment of groundwater，and the prevention of rock burst. The studies and measures adopted against rock burst，the gushing water and the instability of surrounding rock mass during the construction of tunnels are summarized. The experience accumulated during the construction of the tunnels in Jinping II hydropower station shall provide valuable reference for similar projects.

Six conventional triaxial strength criteria are studied based on test data of six rocks cited from public literatures. The least square method used to determine parameters in criteria may result in the deviation of fitting solution from main regular data for a few abnormal data；and the linear regression of equations transferred from criteria，such as Hoek-Brown criterion and Fairhurst criterion，may bring totally untrue outcome. The parameters should be searched directly according to the least absolute deviation. The Mohr criterion with the form of normal-shear stress does not describe the real physical phenomenon，in which the parameters are also difficult to be determined mathematically. The explicit criterion of principal stresses is the best choice for rock. The parabolic criterion with a single parameter，uniaxial compression strength，may fit test data of many rocks better than Coulomb criterion and Hoek-Brown criterion with two parameters. The exponential strength criterion with three parameters，which are determined on the least absolute deviation，will approximate to a great number of normal test data，and open out the abnormal data points. It can describe the relationship between strength and confining pressure in the entire experimental range better than that from the generalized Hoek-Brown criterion and quadratic polynomial criterion.

Based on the established rock dilation angle model considering both confining pressure and plastic shear strain from previous study by authors，the relationship between peak internal friction angle( ) and dilation angle( ) for different rocks is established. Based on the conclusion of  ＜  and  at the zero confining pressure from theoretical analysis and experimental observations，an important assumption is made，i.e. the dilation behavior of a rock mass resembles that of the intact rock. The rock dilation angle model is generalized for rock mass using Hoek-Brown criterion and GSI system；and subsequently the proposed rock mass dilation angle model is implemented in FLAC3D using VC++ language. Utilizing extensometer data from Donkin-Morien tunnel project in Canada，the dilation angle model is verified by investigating the ground deformation near the excavation boundary. It is demonstrated that constant dilation angle values can not capture the displacement distributions near the excavation boundary satisfactorily. However，when the confining pressure and plastic shear strain dependent rock mass dilation are considered，the predicted rock mass displacements induced by gradual excavation are in good agreement with the field measurement results. This model provides a reasonable means to consider dilation during rock mass failure near the excavation boundary.

Components and contents of clay minerals in mudstone in cap rock in Banxin well #803 are tested firstly. Then some mechanical tests including uniaxial and triaxial compression，creep tests are performed to obtain the strength parameters and deformation features of mudstone. Thirdly，FLAC3D is used to simulate the rock deformation around the well and analyze the creep deformations at different times. Based on the calculation，shrinkage law of wellbore and sealing features of cap rock are studied. The results show as follows：(1) Several clay minerals such as kaolinite，illinite and mixed layered illite/smectite are the main contents of mudstone which made the mudstone around the well easier to collapse；(2) Creep deformation of mudstone is significant under long-term confining pressure conditions and the deformation rates increase with the role of drilling fluids；(3) Mudstone around well logs would creep and extrude into annulus space slowly. After 30 years，the annulus space between rocks and casing fish would be filled without considering the expansion and collapse roles. When considering the expansion and collapse roles，after 35 years，the annulus space would be filled by the fragment and the creep deformation which made the layer sealed at present.

The mechanical and flow characteristics of rock joint are closely associated with its three-dimensional topography. For a single rock joint，the roughness and waviness of its surface is of paramount importance to flow；and the flow characteristics are related not only to the topography of a single joint surface，but also to the composite topography of the upper and lower joint surfaces. Different contact condition results in different composite topography. The analysis of joint composite topography is the basis of research on flow in a single rock joint. In order to compute the three-dimensional composite topography effectively，the conditions for determining stable contact of two joint surfaces are presented；and the contact algorithm based on determinant conditions is introduced. The Visual C++ programming language is adopted to provide a procedure for three-dimensional composite topography calculation. By using the procedure，the composite topography of joint under different contact conditions can be calculated conveniently with the surface topography data derived from TJXW–3D portable rock surface topography laser scanner developed by Tongji University. Then the fresh marble tension joint is taken as an object；and different contact conditions are formed by dislocating the upper joint surface from the lower joint surface for 1，2，3，4，5 mm respectively after scanning the joint surfaces by TJXW–3D topography scanner. Based on topography data，the composite topography parameters under different contact conditions are calculated by the procedure proposed above；and the influence of different contact conditions on joint composite topography is discussed，which provides a foundation for researches on the relations between three-dimensional composite topography and the mechanical and flow properties of joint under different contact conditions.

The feedback analysis of underground powerhouse caverns excavation of large-scale hydropower stations attracts more and more attention recently. The effective feedback analysis method is very crucial to such problem. A direct solution scheme based on artificial neural network(ANN) is suggested considering that the feedback analysis is virtually a constrained optimization problem. It mainly consists of analyzing the structure numerically to build the constraints and obtaining the input parameters by ANN to fulfill the objective function. The steps of this method are also illustrated in detail，from which can find that the method is simple but universal. The ANN based feedback analysis method can avoid the deficiency of the traditional mathematical programming and improve the effectiveness and the convergence of feedback analysis. Taking the underground powerhouse caverns excavation of Xiluodu hydropower station in China for example，the fast Lagrangian analysis of continua，FLAC3D，is used to establish the ANN based feedback analysis system. The feedback analysis with the monitoring deformation data during excavation is conducted. The surrounding rock displacements obtained by feedback analysis agree with the measured displacements. The predicted deformations and stresses of caverns and the loads on the supporting structures in the next excavation are also reasonable. These not only help to evaluate the stability of the powerhouse caverns of Xiluodu hydropower station but also show that the method proposed is valid and applicable for complex monitoring feedback analysis problems；and the method may get extensive application in engineering.

Based on Maxwell curl equations，the three-dimensional finite difference time domain formula about UPML absorbing boundary of conductive medium is derived；without considering permeability，the link between simulation area and UPML absorbing boundary field is established；UPML absorbing boundary formula is used for forward simulation with different coefficients；but the area and temporary storage space are reduced and the speed is improved. Using Matlab programming to forward simulate the tunnel lining cavity and obtain the corresponding forward synthesis of three-dimensional profiles and slice maps，the three-dimension forward data visualization is achieved；and the three-dimensional map features of cavity are discussed. Through the physical model test of tunnel lining cavity，the results of numerical simulation and physical model test are similar so as to verify that the three-dimensional numerical simulation is feasibility and effectiveness. The results show that three-dimensional detection can not only determine the size，shape and location of cavity，but also understand accurate information of cavity comprehensively；it can improve the reliability and the accuracy of radar map interpretation，and the harmful level of cavity in lining can be assessed according to the distribution of defecting location and size. The study provides a reliable theoretical basis and method for automatic recognition technology of radar cavity map；and it has a great significance in tunnel detection project and tunnel quality of judicial expertise.

In order to investigate the behaviors of fluid flow through rock fractures，two kinds of artificial parallel plate fractures with different patterns of contact area distribution and one artificial rock fracture with natural fracture characteristics are designed. Flow tests on parallel plate fractures and coupled shear-flow test on artificial rock fracture as well as the related numerical simulations based on finite element method are carried out to investigate the local characteristics of flow through fractures. The results show that，despite of contact area ratio，which is the main reason，pattern of contact area distribution also affects the discharge capacity of fracture. Reynolds number plays an important role in the discharge capacity of fracture. With the increase in Reynolds number，backflow occurs around the contact area，which can decrease the discharge capacity of fracture to a certain extent. Results of numerical simulation are in good agreement with experimental tests.

In order to study the creep properties of mica-quartz schist which belongs to thinly laminated rock in Danba hydropower station，uniaxial creep tests of mica-quartz schist specimens which the loading directions are parallel(0°)，perpendicular and 30° to schistosity planes are performed with the computer controlled triaxial creep test machine RLW–2000. Based on the test results，the creep laws of different orientations are investigated. Then，the effects of schistosity planes on creep laws of mica-quartz schist are analyzed. According to the characteristics of creep curves，the modified Nishihara model is used to identify the creep of mica-quartz schist；the parameters of modified Nishihara model are obtained by fitting the data of creep tests；and the fitting results coincide with the test data. Furthermore，the test results reveal that the long-term strength of mica-quartz schist in three loading directions is 60%–70% of uniaxial compressive strength. These studies can provide an important guidance for future study of mica-quartz schist in Danba hydropower station.

The variation in acoustic velocity along the borehole and the influence of blasting on excavation damaged zone(EDZ) are studied based on the in-situ testing results. It is found that the acoustic velocity increases gradually，then decreases gradually after a peak and tends to be stable finally. There are reinforced and weakened zones in survey area in each blasting round. Its distribution is complex and closely related to the size of EDZ and the effect of blasting. The cumulative effect of blasting rounds illustrates that the weaken zone lies in the crack area；and its damage is attributed to the effect of longitudinal wave and transverse wave. The reinforced zone lies in the stress concentration area；and its reinforcement is contributed to the tamping effect of blasting vibration and the compression of bulking force. When the distance between the borehole and the working face is up to a certain value，the blasting does not affect the shape of EDZ in spite of some slight adjustment in acoustic velocity. In other words，it does not cause the offsets of the stress concentration zone. Accordingly，the principle and time for EDZ test are proposed. Meanwhile，along the axis direction of the tunnel，the acoustic velocity tends to be stable when the testing point has a certain distance from the working face，which can provide a method to determine the blasting influence range. It is the determination of influence range that provides significant guidance for choosing the best time for the support of soft rock tunnel and the protection scope against rock burst of hard rock tunnel.

Gas adsorption/desorption may influence the coal permeability after injection of CO2 or CO2/N2 mixture into unminable coalbed for enhanced coalbed methane recovery and CO2 sequestration. The laboratory experiments under constant effective stress and different gas pressures are conducted by means of self-developed triaxial gas-seepage experimental device；and the change law of permeability of coal samples under gas pressure and adsorption is discussed. The results show as follows：(1) The permeability decreases as negative exponent with the increase in gas pressure under fixed injected gas composition conditions. (2) The change in permeability of coal samples is a function of the injected gas composition. At the same pore pressure，the permeabilities of coal samples decrease after gas adsorption. The permeability reduction is the greatest for pure CO2 followed by CH4 and N2. When injecting CO2 and N2 mixtures，as the concentration of CO2 in the injected gas increases，the permeability of the coal decreases. However，as the N2 reaches a certain proportion，the permeability of coal samples will be improved. (3) The relation curves of permeability and gas pressure in loading-unloading process of gas pressure have the hysteresis phenomenon，which may be related to the gas adsorption/desorption hysteresis phenomenon in coal. Therefore，the permeability of coal is in relation to pressure path. The results have important significance for prediction and control of reservoir permeability in the process of CO2 or flue gas injection into unminable coalbed to enhance gas recovery and CO2 sequestration.

Based on shear strength mechanism of rock joints and the selection principle and requirement of similar material，a new type of similar material with the mixture of high-strength cement，silica fume，superplasticizer，standard sand and water is developed. A large number of physico-mechanical tests are performed by using samples and rock joint models made from the new similar material. The results show that the compressive strength and elastic modulus of similar material are close to the mechanical feature of original rock；and similar material can cover low and medium-intensive rock types through adjusting the contents of different materials. The surface morphology and undulation of simulated structure surfaces made with similar material and multi-scale molds are consistent with original rock¢s surface. According to direct shear test，surface wear degree，roughness coefficient attenuation law and failure mode of original rock structural plane and simulated structural plane agree well；and the difference between test results and theoretical values is small. The similar material with the advantage of steady physico-mechanical properties，production convenience and low cost can replace natural rock joints to do different dimensional and repeated destructive rock joint tests.

Interaction of expressway and underlying mine goafs is discussed in detail，including the response characteristics of expressway under mining，the reactivation mechanism of goafs，the numerical simulation of subsidence and deformation at different engineering conditions. Firstly，the basic developing laws of ground movement and deformation at different spatial relationships between expressway and goafs are analyzed briefly. Then，the characteristics of goafs under different mining methods，characteristics of ground deformation and failure，reactivation mechanism and stability assessing methods are analyzed. Lastly，several laws of residual subsidence and deformation characteristics under different working conditions are summarized and compared. The important effect factors are taken into account when using finite element method，such as expressway，goafs，mining characteristics，treating methods，etc. Especially，the complicated geological and mining conditions with this problem are analyzed，including different mining depths and mining thicknesses，seam inclination，multi-mining，adjacent mining，spatial relationships between different seams，etc. The results can provide reference for expressway planning，line selection and mine goafs treatment.

In order to study the vibration effect of presplit blasting，blasting vibration and sound wave tests are conducted in the foundation pit of Shidao Bay Nuclear Power Station in Shandong Province，China. Based on the change rate of sound wave velocity before and after blasting，damage depth of bedrock is determined. The attenuation law of site blasting vibration is obtained through in-situ test. The test results indicate that，under the same lithology the bedrock damage depth increases linearly with maximum charge weight per delay interval，and increases exponentially with the increase in peak particle vibration velocity. The degree of rock mass damage increases with the reduction in distance from explosion source. Presplit blasting mainly affects the upper part of rock mass. Furthermore，based on field test，the relationship between damage depth of bedrock caused by blasting and peak particle vibration velocity of rock mass 30 m away from explosion source is established；and peak particle vibration velocity is adopted as the reference parameter to be the safety control standard of presplit blasting excavation. It is shown that the controlling method effectively ensures safety of rock mass under presplit blasting excavation in foundation pit slope.

The logic and result that slope failure problem has been summed up as cusp catastrophe model research have been analyzed；and the potential sliding zone is supposed to be composed of two media only with characteristic of elasticity and with characteristics of elasticity，hardening and softening. Furthermore，it is pointed out that when slope is rigid body and potential sliding zone is composed of foregoing two media，there are not plenty of elastic energy instantaneous release and abrupt sliding mechanism in the slope failure model，which can not correspond to the action that on cusp catastrophe equilibrium curved surface there are plenty of energy release concomitant with state variable jumping from one sheet to another. The potential function of this slope failure model can not be applied to discussion of the problems about slope failure and slide，because there is only elastic parameter without residual strength parameter of section ① in it. On cusp catastrophe equilibrium curved surface，there are many basic characteristics of cusp catastrophe，such as state variable can jump upward and downward，the parameter of jumping upward lags behind that of jumping downward and system state of upper-lower sheets realize cyclically. The slope failure is irreversible，not only it can not jump backward，i.e. slope recovers original state abruptly again after its failure，but also it has no lag characteristic. Hence，cusp catastrophe can not be used as the mathematical model of slope failure prototype.

With the rapid development of mining，the large-scale equipment enters the underground coal mine. It is inevitable to excavate chamber with large cross-section in the deep，bedded and cataclastic surrounding rocks and the special problems of engineering geology will be much more obvious. Reloading chamber with large cross-section(the span is 9.9 m，the wall is 9.45 m) is constructed in bedded and cataclastic surrounding rocks in Qipanjing coal mine，which is difficult to construct and similar projects are few. According to the characteristics of surrounding rocks，the construction sequence，the failure rule of high wall and the effect of support elements are studied by the three-dimensional small model；the construction process and the spatial dynamic change of surrounding rocks are really reappeared by the three-dimensional big model. The optimized construction scheme and the reasonable staggered distance of the section construction are chosen. The theoretical analysis shows that the failure mechanisms of high walls are different；the horizontal stress release leads to the rib spalling and stripping of high wall；the concept of load-bearing wall is put forward. The study results can provide reference to the design，construction and study for similar projects.

Based on the structural characteristics of bedded salt rock mass，a mesoscopic damage constitutive model is proposed by introducing the existing mesoscopic damage constitutive model and using mixture theory. The damage of Yunying bedded salt rock under triaxial compression is calculated；and the effect of confining pressure on the equivalent additional lateral stress in salt rock is analyzed. The results show that the model can describe the experimental phenomena well；and the experimental results have important significance for the underground oil/gas storage of deep salt rock and the stability analysis of underground storage in bedded salt rock mass.

By using microseismic monitoring technology，similar material simulation test and macro observation of support resistance in project site，the reasonable working resistance of hydraulic support is studied. Macro observation of support resistances shows that the support resistances under normal circumstance and abnormal circumstance(the main roof strata pressure) are 9 000–12 000 kN/frame and 13 000 kN/frame respectively. Similar material simulation test shows that the resaonable working resistances of support are 9 000–12 000 kN/frame under normal circumstance and in the case of the lower main roof pressure and the higher main roof pressure those are 13 000–15 000 kN/frame and 17 500–23 000 kN/frame respectively. Microseismic monitoring results show that the support resistance under normal circumstance is 10 971.45 kN/frame on average，and that under abnormal pressure is greater than 13 333.95 kN/frame. Hydraulic support working resistance is obtained through the similar material simulation test. Comparative study among similar material simulation experiment，field macro observation and microseismic monitoring shows that the working state of support can be divided into three categories，i.e. normal state，low roof strata pressure and high roof strata pressure.

Time scale and strength model of calcareous medium-fine sandstone of Yichang in acid environment of different pH values are studied combining several technological means，such as rock sample test，pH value variation accurate measurement and corrosion depth measurement of rock sample in immersion and so on. The concept of time scale is proposed using the amount of substance of hydrogen ion as datum quantity. Through the transformation of time scale，the long time reaction of weak acid can be simulated by the short time reaction of strong acid. Then two examples with stable acid ion supply and unstable acid ion supply are developed to verify the feasibility of this method. The porosity characteristic and multilayer phenomenon of sandstone after reaction are proposed and explained；and the relationship between corrosion depth of samples and time is established. It is also proposed that the decreasing rate of hydrogen ion concentration gets slowly with time and the increase in corrosion depth，which provides a foundation for the development of strength model. Based on the sketch of corrosion depth model of rock sample and related assumption，the relational expression of intensity change of sample and time under the action of sulphuric acid solution is deduced；and the calculated values are well in agreement with the measured data.

A series of dynamic axial tensile tests of granite are carried out by using MTS testing machine，considering the impact loads with different strain rates，different initial static loads and the variable amplitude triangular loads. The results indicate that：The tensile strength of granite increases linearly with the increase in strain rate ranging from 10－6 s－1 to 10－2 s－1. The elastic modulus of granite has no obvious change with the variation in strain rate. The peak strain has a increasing tendency with the increase in strain rate；and the ultimate strain is not sensitive to the strain rate. The ascending part of the nominal complete stress-strain curve before 40% of tensile strength under different strain rates is of linear；and then it goes into remarkable nonlinear stage，which the degree of linearity decreases with the increase in strain rate. The descending part can be divided into two segments，an inflexion point which strain is 300–400 me appears when the load decreases to 25% of tensile strength，then the deformation becomes aggravate；the strain is about 600–900 me  when the residual stress is about 10% of tensile strength. The initial static load less than 50% of tensile strength does not influence the dynamic tensile strength but be beneficial to it；the larger initial static load is harmful to the dynamic strength. The fatigue damage by the cyclic variable amplitude load leads to the descending of strength because of the cumulative damage. Residual strain increases gradually and the increase rate becomes larger and larger with the increase in cycle，which means that damage softening effect appears.

The maximum horizontal distance(Lmax) and apparent coefficient of friction(Hmax/Lmax) are considered as the evaluation criteria of landslide movement. In order to analyze the landslide movement，five influence factors of large-scale seismic and rainfall landslide are considered including landslide volume(V )，landslide height(H )，landslide slope gradient(a )，constraint angle of slope toe(q ) and ground type(X ). The results show that，at the landslide maximum horizontal distance(Lmax)，the landslide height H is the most important factor of rainfall landslides；and it follows by slope gradient(a )，constraint angle of slope toe(q ) and ground type(X ) in turn. When the volume is from 106 to 107 m3，the influence of ground type(X ) on the seismic landslide is larger than rainfall landslide；and the influence factors of seismic landslides are H，X，a，q in sequence. When the volume is larger than 107 m3，the landslide slope gradient a is the most important factor of seismic landslide；and it follows by landslide height(H )，constraint angle of slope toe(q ) and ground type(X ) in turn. By significant analysis，the landslide height(H) is significant influence factor of Lmax of large-scale rainfall landslide and seismic landslide with the volume from 106 to 107 m3. At landslide apparent coefficient of friction(Hmax/Lmax)，the landslide slope gradient(a) is the most important factor of seismic landslides，it follows by landslide height(H)，ground type(X) and constraint angle of slope toe(q) in turn. The influence factors of rainfall landslide with the volume from 106 to107 m3 and larger than 107 m3 are a，H，q，X and H，a，X，q respectively. The H，a，X are significant influence factors of Hmax/Lmax of seismic landslide with the volume larger than 107 m3 by significant analysis.

Considering the nonlinear deformation of soil，the Hansbo¢s formula for the non-Darcy flow is introduced to modify Terzaghi¢s one-dimensional consolidation equation；and the numerical solution analysis is performed by using the finite difference method. In order to verify its validity，the calculating solution by the present method for the case that the flow of pore water obeys Darcy¢s law is compared with the analytical solution based on the nonlinear consolidation theory proposed by Davis and Raymond. Then the effects of the non-Darcy flow parameters，the compression index of soil and the external vertical load on the consolidation process are investigated respectively. The calculating results indicate that both the pore water pressure dissipation rate and the foundation settlement rate are delayed with the increase in the ratio c of the compression index to the permeability index or the non-Darcy flow parameters m and i1，thereby they will be overestimated if the non-Darcy's characteristic of flow is not taken into account. In addition，the effect of the external vertical load on the consolidation process is related to the consolidation time and the ratio of the compression index to the permeability index.

Soil structure is the intrinsic determinant of its strength and deformation. The structural property of loess is determined by the link structural strength and the friction structural strength. On this basis，some new and reasonable structural parameters of loess are suggested based on soil dynamic strength，such as the link structural dynamic strength potential parameter mgd1，the friction structural dynamic strength potential parameter mgd2 and the structural dynamic strength potential parameter mgd. The variation laws of structural property and the structural parameters based on the dynamic strength conditions are studied with the dynamic torsional shear test of intact loess；and the impact of moisture content，consolidation pressure and dynamic shear strain on the structural property of loess are revealed. Finally，the rationality of these structural parameters based on the dynamic strength conditions is discussed.

According to the available expressions about anisotropy of soil strength，the simple elasto-perfectly plastic Tresca model is modified to allow for the strength anisotropy of soft soil under undrained condition based on the general purpose finite element software ABAQUS. Combining swipe loading method with fixed displacement ratio loading method，the bearing capacity of shallow strip foundations under combined loading is simulated through finite element numerical studies. The effect of soil strength anisotropy and vertical load level on the failure envelope of shallow strip foundations is studied. The undrained bearing capacity of shallow strip foundations under uniaxial vertical(V)，moment(M) and horizontal(H) loads is predicted and compared with available solutions. Then the VMH capacity of shallow foundations under combined loading is reported in the form of slices through the three-dimensional VMH failure envelope as planes in H-M at various levels of vertical loads. The results show that the swipe path can considerably undercut the true failure envelope for shallow foundation with the ratio of buried depth to width larger than 0.5 or subjected to three degrees of freedom combined loading. For shallow foundation with given buried ratio，the size of the failure envelope is both dependent on soil strength anisotropy and the level of vertical load，however the shape of failure envelope is only dependent on the level of vertical load but almost independent on soil strength anisotropy.

Taking the tomb pit slope at mausoleum site of Yue Kingdom in Yinshan for example，different chemical reinforcement materials are selected for the experimental study. In the laboratory test，the effect of specimens reinforced by tetraethyl orthosilicate(TEOS) shows relatively good：the appearance has the least change，the uniaxial compressive strength and water-resistance properties improve slightly；and the permeability of TEOS is better than that of others. In the field test，the TEOS is selected to reinforce rock by means of injecting，dripping and spraying. It indicates that TEOS meets the design requirements，so the TEOS can be used as one of the chemical materials for the tomb pit slope reinforcement. Now the reinforcement of the tomb pit slope is finished，the surface strength of rock slightly increases，and the case of rock fall decreases significantly.