The detailed discussion on operation mechanism of concrete socket and peripheral joint with dam foundation and relationship between concrete socket and overall stability factors are carried out. The analytical results show that the symmetry of foundation and overall stability of dam increase evidently after employing large concrete socket and other reinforcing measures. By employing finite element analysis，the nonlinear effects for these dams are also given. A research on the effect of concrete socket and peripheral joint for Enguli Arch Dam，Lijiaxia Arch Dam and Jinping I Arch Dam is carried out，taking account of the change of overall stability factor，dam stress distribution and dam deformation etc.. The large sockets for high dams from the analysis are also beneficial to the design and construction of high arch dam projects.

For a long time，stability analysis methods of surrounding rocks in tunnel are unscientific and unreasonable. It still judges the stability of tunnel by the empirical criterion of displacements of tunnel perimeter or sizes of plastic zones of surrounding rocks. Displacements of tunnel perimeter are affected by elastic modulus of surrounding rocks or shape and size of tunnel，and displacements of tunnel perimeter are different at different positions. So it is difficult to get a unified displacement criterion standard. Judging the stability of surrounding of rocks by sizes of plastic zones is superior to displacement criterion. But plastic zones are affected by Poisson¢s ratio or shape and size of tunnel and size of plastic zones calculated by different softwares are different. The method is also unreliable. So the traditional empirical methods are unreasonable. The paper puts forward safety factors based on the strength reduction finite element method as the stability criterion. This criterion is based on the strict mechanical foundation，which has a universal standard and can not be affected by other factors. Taking a loess tunnel for example，the concepts of shear safety factor and tensile safety factor of a tunnel are proposed. With the reduction of c，j or c，j and tensile，plastic zones of rock mass keeping expanding，when the value of the nodal displacement or plastic strain has a big jump compared with that before failure，this means that loess tunnel reaches shear failure，and the reduction factor is just the shear safety factor. With the tensile reduction，loess tunnel reaches tensile failure when the first element of rock mass around loess tunnel free face fails in tension except for the bottom free face，and the reduction factor is just the tensile safety factor.

In order to study rock mass permeability characteristics and its mechanics and failure mechanism under high pore water pressure condition，a rock high pressure permeability testing system has been designed and produced. It can perform the test of permeability and correlative mechanics measurement studying for big size and different patterns(cylinder or square column bodies) rock mass or gravel soil under high confining pressure. The max-value of lateral pressure and permeability pressure all can be applied to 30 MPa；and the axial load can be 4 000 kN. The seepage quantity is obtained through the measurement precision of water seepage volume change quantity，which can save the test time greatly and improve the precision. On the basis of the main control devices of static servo-valve，the entry water pressure of sample can be a stable value under no computer controlled condition. The special pipeline filter and velocity adjust valve have been used to control the flow velocity in the seepage exit. When the controlled velocity equals the sample infiltration velocity，the stable water pressure can be set up，and the stable water pressure difference has been formed between the sample¢s two ends. There has the flexible computer control function，which can monitor the curve variation data and rectify the test plan at any time；and the test steps can be more satisfied than the plan demands. These systems solve the technical problem of permeability and mechanical characteristics test under high pore water pressure and low hydraulic gradient condition. Therefore，this testing system will provide a new test method for the fields such as hydropower engineering，oil and nuclear power industries，and has its significance.

The equivalent strength parameters of rock mass(composite medium) are studied from the viewpoint of energy equivalence. Based on the equivalence of the plastic complementary energy，the equivalent computational expression is derived，which shows the correlation between deformation parameters and strength parameters. The influence of the deformation parameters of medium on strength parameters and change law under different ratios of materials are studied by means of numerical examples. The results show that the equivalent method of plastic complementary energy has feasibility to determine the strength parameters of composite medium.

Jinping II Hydropower Station is characterisized by the four diversion tunnels which are very long and deep-buried. Two of the tunnels are excavated with open-type hard rock tunnel boring machine(TBM) which has an excavation diameter of 12.4 m，the 2nd largest of the same type in the world. The hydrogeological conditions at the tunnel site are very complicated. Three key problems might be met during tunneling，including the forecast and treatment of the groundwater，the ventilation，and the prevention of rockburst. Based on the study of a large amount of data and project case studies of the TBM development，the development of TBM over the past 50 years，its use in tunneling and the encountered problems，are summarized. Based on the research and analysis of the regional geological conditions，main engineering geological problems，and TBM construction experiences at home and abroad，the TBM type selection and tunneling method in case of rock unstability，high geostress and rockburst，water gushing，karst cavity，harmful gas，fractural zones，etc.，are studied. Construction strategies are suggested for TBM tunneling in Jinping II Hydropower Station in case of different unfavourable geological conditions；which hopefully would also benefit similar future projects.

Analysis and evaluation on optimizing design for foundation excavation of super-high arch dams is one of the most important research fields in hydraulic engineering. It is also significant for engineering and scientific study，and for proposing new design criteria of super-high arch dam or revising arch dam design standard. An evaluation criteria，design concept and flow of optimizing of design are discussed for proposing the analysis and estimation system on optimization of design for foundation interface of super-high arch dam. Based on the study progress of analysis and evaluation on optimizing design for foundation excavation of super-high arch dams，a study on optimizing design for excavated foundation surface of Xiluodu Arch Dam is presented. By employing the 3D nonlinear finite element method and 3D geomechanical model test，different excavated foundation surfaces of Xiluodu Arch Dam including feasible scheme，optimizing scheme and comparative scheme，are analyzed and evaluated respectively. The investigation results demonstrated the feasibility of using III1，and III2 typical rock mass as excavated foundation surface of Xiluodu Arch Dam. The optimizing scheme of Xiluodu Arch Dam，compared with the feasible scheme，the excavation of foundation and concrete quantities of dam will decrease about one million cubic meters；as a result，nearly RMB 700 million of investment is saved.

The deformation and failure characteristics of the surrounding rock of the high side wall of underground powerhouses of Pengshui Hydropower Station，corresponding supporting and processing scheme and the monitoring results，are described. Then dynamic feedback analysis is performed and the result is given. The result shows that the stability of high side wall is very critical when excavating large underground caverns in steeply dipped sedimentary rock strata；the deformation and stability of the surrounding rock is primarily dominated by weak structure plane and bedding plane. For the high side wall with steep dip angle and consequent rock strata，the deformation and failure mode of surrounding rock are typical sliding along the bedding plane；and for the high side wall with steep dip angle and obsequent rock strata，the deformation and collapse are caused by tension crack，break off and toppling. The results of feedback analysis based on the deformation monitoring data can provide important references to dynamic support design and information construction of the underground powerhouses.

An analogical project comparative study method for super-high arch dams is presented since simple standard design is not enough due to the complexity and large scale of super-high arch dams. The safety evaluation for super-high arch dams under design could be performed by comparative study with constructed dams. Choosing Ertan and Kolnbrein Arch Dams as analogical projects，the cracking at dam heel and the ultimate bearing capacity of Xiaowan Arch Dam are studied based on similar mesh size，same material model and same finite element software. The refined Xiaowan finite element model including the simulation of the bottom joint of dam body，terrain，faults，alteration zone，reinforcement measures and unloading zone of the foundation is adopted to evaluate the effects of these factors on the ultimate bearing capacity of the dam. The conclusions are drawn as follows：the ultimate bearing capacity of Xiaowan Arch Dam is higher than that of Kolnbrein Dam and slightly lower than that of Ertan Dam. The safety for grouting curtain in Xiaowan has a narrow safety margin under normal operation.

The research on rockburst could be traced back to the first half of the 18th century. Since then，although a great deal of scientific achievements have been published，this topic is still an outstanding problem worldwide so far. As an overall review，this paper presents first some background information relating case histories，research methodologies etc. at home and abroad. And then，the criteria and classification of rockburst commonly used at home and abroad are described. The forecast and prediction of rockburst phenomena are discussed too. After that，the rockburst control，including stress relief drilling，water injecting，anchoring etc. are overviewed. Finally，a key case history related to the rockburst phenomena occurring in the auxiliary adit of the Jinping II Hydropower Station is described emphatically. On the basis of analyzing the previous information，some practical methods for classification，prevention and mitigation of rockburst are proposed.

The concept and method of graphics computational mechanics which integrates computational mechanics，computer graphics and modern AutoCAD technology，are proposed firstly. By making use of the mature theory，method of computer graphics and 3D modeling platform supported by modern AutoCAD technology，the rock can be cut into combination entities of a certain direction，a certain size，a certain shape and feature. The analysis of discontinuous deformation characteristics，such as main features of the graphical entities，attributes，mutual contacts，the embedded location and extent can be directly judged or calculated from the graphics. And then it can be applied to a variety of numerical methods. Compared with the existing methods，it is more intuitive，simple and reliable. Its combination with virtual reality technology will make the graphics computational mechanics a whole new area of development and greater value of its applications.

The stability of the abutment rock mass is directly related to the stability of the arch dam. The abutment of the Jinping I Arch Dam situated in the Southwest China is in a complex geological condition，whose treatment measures contain 7 layers of dense cavities. The VisualGeo 3D modeling system was adopted to establish the 3D rock mass classification geological model of the project and to establish the cavities model of the resisting rock masses reinforcement. Based on the models，simulated excavations of abutment slope and cavities reinforcement of the resisting rock masses were performed；the 3D rock mass classification geological model of reinforcement cavities was obtained，and slicing analyses of the 7 elevations was undertaken. A precise visual analysis platform was presented for the design and construction of high dam abutment treatment.

Based on the summarization of the achievements of landslide prediction at home and abroad，the in-depth study is done on their applicability and service conditions. Aiming at slope types，features，deformation traits and destroy mechanism of high steep valley slope at Jinping I Hydropower Station，and applying monitoring results，a comprehensive prediction design is suggested. In the space，according to the occurrences of unfavorable geological phenomena such as faults F5，f42–9，deep fracture SL44–1 and lamprophyre vein X，all of them can be treated as the boundary conditions for slides，potential instable blocks of slope on the left abutment are estimated which take on a wedge-shaped sliding model. In the sametime，through using three kinds of joint prediction methods such as statistic models and nonlinear models，judging from the shape of curves of deformation-time and their deformation velocities，it is found that the slope is at the state of slowly creeping to uniform deforming with a deforming velocity of 0.05 mm/d. So the comprehensive prediction models fitting for Jinping I Hydropower Station are designed and four early warning criteria are proposed so as to provide scientific evidence for the successful progress of the slope excavation.

Aiming at the insufficient theoretical study on rockburst prevention and the limited evaluation of traditional stress index in the tunneling in deep hard rock，a new method for rockburst prevention measures based on local energy release rate index is proposed. The design and construction control measures in the process of tunneling is comprehensively researched by using energy release rate index，which is analyzed in the numerical calculation using a new constitutive model reflecting the brittle failure of hard rock. First tunnel pitch and different tunneling sequences are proposed as a regional prevention measure by comparing the energy release magnitude of rock wall. Then the support opportunity and parameters of the design proposal are given based on the destress principle in the space-time evolution of the energy release. Meanwhile，the effect of the stress release hole for rockburst prevention is analyzed in the process of construction，the layout pattern of stress release hole is also optimized. At last，the prevention measures of rockburst failure for Jinping II Hydropower Station diversion tunnels are proposed. The practical results show that the proposed control measures are entirely feasible；and the method could benefit other similar projects.

Within a certain domain of rock mass，identification of all blocks cut by three-dimensional finite random or fixed discontinuities is a critical basic problem in jointed rock mass researches. Based on general method of spatial block topological identification with stochastic discontinuities cutting，the block identification of slope and cavern rock mass is studied. The main analysis procedures are given，including 3D discontinuities network simulation，analysis of intersecting lines between discontinuities and surfaces，analysis of primary loops，loops location analysis，isolated loops deleting，relative loop analysis，and closed block identification. The process of solving intersecting lines between discontinuities and surfaces of slope/cavern is discussed emphatically. Four block types，i.e. simple convex and concave，pit，torus and cavity which may occur in rock mass with discontinuities cutting are analyzed. On the basis of the different characteristics of simply connected loops and multiple connected loops，how to identify the different block types uniformly is discussed. Therefore the technique of spatial block identification of slope/cavern is accomplished. Based on these，with classic block theory combined，the technique of block progressive failure analysis of slope/cavern is achieved. Finally，cases of slopes and caverns are studied.

Compared with the general columnar jointed basalt，the one at Baihetan Hydropower Station on the Jinsha River has significant characteristics as follows：undulating and irregular columnar joints，irregular and incomplete cutting columniation，microfissures enriched in the inner of columniation，gently dipping structural surface developed comparatively in basaltic mass，poor integrity but still intermittent mosaic structure in basaltic mass. Based on the engineering geological investigation and field experiments，the essential character and the deformation mechanism under different experimental conditions of loading on columnar basalt at Baihetan Hydropower Station are systematically analysed. Columnar joint，microfissure and gently dipping structural surface are the three fundamental factors which lead to the small deformation modulus of basaltic mass. The wide disparities in the horizontal and vertical direction of columnar jointed basalt¢s deformation modulus at Baihetan are determined by the structural surface and stress condition. Since columnar joints and microfissures are hard structural surface，they are closed under confining stress，but relaxed under unloading. Columnar basaltic mass maintains large deformation modulus in confining state.

Kela 2 gas reservoir is the largest dry gas reservoir so far discovered in China. It has such features as high pressure and pressure coefficient，and gas reservoirs with a pressure coefficient of over 2.0 are not commonly found. The abnormal high-pressure gas reservoirs are quite different in characteristics and performance during the process of depletion exploitation. During the depletion exploitation，the formation pressure depletes slowly；but the effective stress to the rock grain increases. The effective stress may cause rock to deform，resulting in the elastic or plastic deformation；and this deformation makes the rock physical property parameters such as porosity and permeability become quite sensitive to effective stress. Therefore，it is necessary to know the property of stress sensitivity for this abnormal high-pressure reservoir. The testing chart and method being used to study the property of stress sensitivity are designed. By means of testing porosity and permeability of sand rock core sample of Kela 2 gas reservoir under different effective stresses，the reduction property of porosity and permeability is obtained. The results demonstrate that the rock permeability behaves in an exponential manner with the effective stress variation，and the lower initial permeability would lead to the stronger stress sensibility；the same variation has been found for the porosity，but the magnitude of the effective stress sensibility of porosity is lower than that for permeability. The complete stress-strain curve is obtained through triaxial high temperature and high pressure rock deformation- seepage test. The characteristic of permanence plastic deformation with the dropping of the formation pressure can be quantitatively described；this is the reason of the stress sensibility of reservoir physical property. These results offer a very important base and guide for researching and designing the production performance of an abnormal high-pressure gas reservoir.

A composite element algorithm for temperature field of discontinuous rock masses is implemented based on the principle of composite element method(CEM) and the implicit expression of unsteady temperature field. The remarkable feature of the algorithm is that each composite element has the possibility of containing arbitrary discontinuities segments such as faults and joints. And the mesh generation of the rock structures with discontinuities requiring explicit treatment in the calculation will not be restricted by the number，position and orientation of the discontinuities. In the phase of preliminary study，assuming the influence of heat convection and radiation in rock are ignored；the thermal conductivity equations of rock sub-elements and discontinuity are deduced for the composite element model containing one joint. Consequently the fundamental equations set of composite element algorithm for discontinuous rock masses temperature field is derived. And then the algorithm is incorporated into the conventional finite element analysis program. Finite element method and composite element method are applied respectively to simulate the varying process of temperature field when hot water flows along a single fracture in rock masses. The computation results of the two methods agree with each other very well. It shows the validity and robustness of the composite element algorithm for temperature field of discontinuous rock masses. But the corresponding post-process program needs more improvement to describe a fine contour of temperature field. Thereby the algorithm will provide one more way in the research of multi-fields coupling of deep rock masses.

The criteria for evaluation of compaction quality and the mechanical properties of over coarse-grained soil are not clearly. These problems hindered its farther project application. At present，test section method is often adopted to determine parameters of important filling construction and well effect is obtained. In order to adapt the needs of project development，the compaction mechanism and the influence of different construction technological parameters such as grain composition，water content，construction machinery，filling thickness and compaction times etc. are discussed by the field roller compaction test depending on a embankment project of S325 highway in Henan Province. On the basis of the test，the optimal technological parameters and quality control specification of the given project are found by contrast tests for which various detection methods such as compaction settlement，watering method and flexure are adopted. And field compaction quality control method of over coarse-grained soil is put forward，namely，differential settlement is given priority but construction technological parameters must be considered at the same time. The method may insure filling quality effectively and quicken construction progress. And it also can provide scientific data，standards for the quality control，quality check，quality evaluation of the projects for which over coarse-grained soil is adopted as filling material. It has significant applicable value.

Various interface elements are successfully applied in traditional finite element method(FEM) to model discontinuities，in which Goodman element is the most representative one. The paper discusses the feasibility of introducing Goodman element to model geological discontinuities in meshless method in full length，and points out the problems existing in some current studies. The Goodman element is presented in the framework of FEM；the displacement mode of Goodman element is designed to be compatible with the finite element along the common boundary between finite element and Goodman element. But，in the meshless method，the displacement mode of Goodman element generally is not compatible with the meshless displacement mode which is based on a number of discrete nodes，the number，however，cannot be known beforehand. The key to solve this problem is that the stiffness matrix of the Goodman element must be computed through numerical integration，then the computed matrix but not the analytical stiffness matrix in the traditional FEM is added to the general matrix of the system when the contribution of the Goodman element to the general stiffness matrix is considered. So，discontinuities can be represented by Goodman element in analytical model in implicit or explicit mode. In the framework of the natural element method(NEM)，the implementation scheme of the Goodman element，implicitly and explicitly respectively，is addressed in detail for illustration of the idea. The presented method is general and suitable for all existing meshless methods.

Jinping II Hydropower Station is a large-scale national key project located in a high geostress area. Thus，it is significant to study the deformation and strength properties of jointed rock mass in this area. Marble specimens containing natural joints were prepared from rock mass of the auxiliary tunnels. A series of compression tests on the jointed specimens were carried out by a MTS 815.03 triaxial testing machine for rock mechanics. In the tests，the angle q between the joint plane and the major principal stress ranged from 29.3° to 56.0°；the confining pressure ranged from 5 to 40 MPa. The results show that：(1) failure modes of the specimens can be classified into two types，one is shearing-failure across the joint plane and the other is sliding-failure along the joint plane；the failure mode mainly depends on the angle q，which is not affected by the magnitude of confining pressure；(2) deformation behavior of the specimens mainly depends on the angle q and is affected by magnitude of confining pressure；(3) it is evident that all the axial equivalent deformation modulus are less than the Young¢s modulus of intact rock；and (4) failure strength of the shear-failure specimens is equal to that of intact rock；failure strength of the sliding-failure specimens is significantly decreased compared with that of intact rock，the discrepancy is mainly affected by strength difference of the joints contained.

At present，the rigid-body limit equilibrium method adopted in the design of crane beam on rock wall can not reflect the actual mechanical behavior of crane. Finite element method is a broadly used effective approach to the analysis of crane beam on rock wall. The authors will focus on a few key technical problems，and complete a series of relevant research work. According to mechanical behavior of crane beam on rock wall，the relevant mechanical model and estimation formula of safety are established；some factors influencing on the results of finite element method are also studied，such as the mesh size，model range，length of anchor-bolts sleeve，classes of surrounding rocks，in-situ stresses etc.；and the double effect of excavation release stress in construction period and wheel pressure in working period are studied too. The main achievement has been quoted by Design Criterion of Crane Beam on Rock Wall for Underground Powerhouse(draft) and explanation items.

Shanghai Yangtze Tunnel is the largest diameter and longest once-driving distance shield tunnel in the world until now. The average covering soil is 9.0 m，and the shallowest covering soil is only 6.8 m. In order to control the floating of segment during large diameter shield driving under high water head and shallow covering soil，a single-liquid synchronous grouting process is adopted. The construction process of Shanghai Yangtze Tunnel east line river-crossing part is numerically simulated with a 3D elastoplastic coupled anisotropic seepage and stress model which could consider the soil permeability varying with volumetric strain. Combining with the measured data，the change laws of tunnel segment¢s rising displacement and the pore water pressure outside the segment during tunnelling are revealed；and the pore water pressure distribution outside the segments and above the crown when the deformation has been stable are studied. Moreover the influences of groundwater seepage on surface settlement and segment internal forces under different water depths are analyzed. The results show that the current single-liquid synchronous grouting material and technology can effectively control the floating of segment；the ratio of pore water pressure outside the segment to hydrostatic pressure increases with the depth when the segment deformation has been stable；and the action of groundwater improves the segment¢s forced state；but the negative impaction of high pore water pressure caused by the high water level on the segment force should be paid more attention to.

Unloading stress path resulted from underground rock mass excavation is completely different from loading stress path，for which results in difference from that of rock mass strength，deformation property and failure mechanism. The surrounding rock mass of diversion tunnel group of Jinping II Hydropower Station lies in the condition of high geostresses. Aiming at this characteristics，four various stress paths are chosen as test schemes corresponding as the uniaxial loading and unloading test，triaxial compressive test，pre-peaking and post-peaking unloading the confining pressure test under high stress conditions are carried out on the marble specimens from the diversion tunnel #3. The complete stress-strain curve，deformation properties，failure characteristics and change rule of major mechanical parameters are obtained under respective stress path. Some instructive conclusions are drawn from above experimental research as follows：(1) the turning rings for axial repeated unloading vary with gradual higher stress level in terms of area and the unloading stress at yielding stage takes the greatest effect on deformation；(2) the triaxial compressive tests performed under different confining pressures discover that strain softening attribute of marble begins to transferred to ideal plasticity when confining pressure reaches above the value of 40 MPa；so it can be considered as the transition point of brittleness and ductility；(3) by compared with the strength criteria equations under different stress paths，and regular peaking strength parameters，under the same initial stress conditions，the changed magnitude of stress required for rock failure is comparably less than that of triaxial compressive process，which reveals that marble sample is more prone to be subject to failure under unloading stress path；the pre-peaking confining stress unloading path strength are the most sensitive to confining pressure；(4) in terms of deformation property and failure characteristics of marble，its brittleness is constrained by plastic deformation；plastic deformation under post-peaking unloading path is greater than that of pre-peaking；and it has absorbed considerably elastic deformational energy after reaching peaking strength；therefore，post-peaking failure has no outburst property under this stress path；the rock failure mode transforms from tensile failure to the combination of tensile and shear failure；and (5) according to the results of SEM test performed on fractures of marble specimens in case of loading and unloading paths，fracture analysis of marble specimens under different stress paths validates the microcosmic tension and shear failure mechanisms. In conclusion，the above research reveals the differences in mechanical properties of Jinping marble under loading and unloading paths，and it can offer valuable references in solving underground rock engineering problems.

The mechanical parameters and boundary conditions of landslide often change with time during the process of construction. Traditional quantitative assessing methods of landslide stability，such as limit equilibrium method，finite element method etc.，are pretty difficult to simulate the dynamic mechanical behavior of landslide during the process of construction at the present time，so it cannot achieve the real-time quantitative assessment for landslide stability. A real-time quantitative assessing method of landslide stability in period of constriction is proposed. The new method based on deformation monitoring at depth of landslide may avoid the errors caused by the no determinacy of calculating models，mechanical parameters and boundary conditions etc. According to the respective relationship of the accumulated deformation of sliding surface and slip mass，by calculating the value of Si and Sf，the real-time quantitative assessing the stability of sliding surface from below to above in the progress of construction is conducted. The failure criterion is the peak value of relative deformation. According to the criterion，the symbol of landside instability is the failure of sliding zone which is marked by the destroy of sliding zone¢s hanging wall. When Si = 1 or Sf = 0，the landside is complete stability；when Si = 0 or Sf = 1，the landslide is eventual failure. Different destructive correspond a value between 0 and 1. Moreover，it shows that the method is easy to use and very efficient in application.

Triaxial creep test was carried out on marble samples from Jinping Hydropower Station under the condition of step unloading lateral stress and constant axial stress. The test process is introduced and the differences between axial and lateral creep properties are investigated. At the same time，the effect of stress state on the rheological properties of the marble is discussed；and the analysis shows that deviatoric stress is the main factor that affects creep deformation. By applying the Burgurs model as theoretical model to fit the processed creep curves，the parameters of the three-dimensional constitutive model are obtained directly. Based on comparison between the lateral and axial creep properties of the marble，obvious difference is found in the creep deformation law in the two directions；thus，it is unreasonable to propose a constitutive relation only based on the axial deformation. It is recommended that overall deformation property of the rock samples should be considered while proposing a three-dimensional constitutive model for marble from Jinping Hydropower Station.