Jinping I hydropower station is located in a high initial stress area，the surrounding rock is the marble and in this area behaves in obvious plasticity. After excavation，the deformation and cracking phenomena in the surrounding rock and support structures are obvious. In view of these features，a coupled damage rheology 3D model and analysis method and prediction method for incremental deformation due to crack opening are adopted for caverns stability analysis. And the computation displacement is compared with the field monitoring data. It is shown that the two results are in good agreement with each other. Furthermore，the long-term displacements of surrounding rocks are predicted and analyzed.

Emphasis is put on discussions of three basic problems in dynamic stability analysis of rock slope：(1) mechanical characteristics of fractured rock masses under dynamic loads；(2) dynamic response and safety assessment of slope；(3) safety evaluation of slope reinforcement measures(mainly anchor cables) under dynamic loads. Based on long-term engineering experiences and researches，assessment methods for dynamic stability of slopes are discussed，especially for high rock slopes under seismic and blasting loads. The strength characteristics and research emphasis for rock masses under dynamic loads are summarized and put forward. The dynamic responses of rock slope are analyzed systematically. It is pointed out that the dynamic stability of rock slopes should be assessed from three aspects，i.e. the trend of dynamic factor of safety，the dynamic fracturing and sliding of potential sliding surface，and the particle vibration velocity of key points in slopes. Finally，the security assessment of prestressed anchor cables under dynamic loads is proposed.

In light of that the surrounding rock mass of diversion tunnel group of Jinping II hydropower station lies in the condition of high geostress，two different unloading tests of marble from the diversion tunnel were carried out. In order to analyze rock strength characteristics，deformation behavior and fracture mechanism under different stress paths，the conventional triaxial compression tests of marble were also performed. The results show that：(1) Even if the stress path and initial confining pressure are different，but as long as the real-time confining pressure is the same，the peak strength is equal. (2) The peak strength increases as the initial confining pressure increases. Comparing with triaxial compression test，it decreases by 19.5% of unloading confining pressure at pre-peak，and the peak strength appears when the real-time confining pressure accounts for about 97.2% of the initial confining pressure during the post-peak test. (3) The cohesion c decreases and the internal friction angle   increases at pre-peak test，compared with the post-tests. The value of c decreases about 27.5% and   increases about 22.6% at pre-peak test，but the value of c increases about 13.7% and   decreases about 6.5% at pre-peak test. (4) From the unloading point to strain softening stage，the stress-strain curves have obvious strain platforms，which is the characteristics of the ideal plastic deformation. The strain platform increases with the confining pressure，which shows the feature of the marble from brittleness to plastic when the confining pressure increases. (5) The unloading confining pressure test at pre-peak shows that the marble expansion is limited. (6) The fracture mode is mainly the single shear fracture for the triaxial compression test and post-peak test；and the fracture mode of the pre-peak test is the splitting failure—X conjugate shear rupture—single shear fracture as the confining pressure increases. These conclusions reveal the loading and unloading mechanical properties of marble under high geostress and provide reliable theoretical reference for the numerical simulation about excavation and design for the stability analysis of deep diversion tunnels in West China.

An experimental investigation into mechanism of apparent dip slide from oblique thick bedding slope failure is performed through geotechnical centrifuge modeling test. The model is casted by mixture of gypsum，cement and barite and consists of four sets of joints. Agreements are obtained between field investigation and centrifuge test that weak layer softening and key block failure are the main reasons why Jiweishan landslide occurs. Driving blocks reach equilibrium and then start to creep crushing on key block in front as centrifugal acceleration rises. Finally，rock slope model fails instantaneously when centrifugal acceleration reaches 16.2 g. The key block fails in shear abruptly and slides in apparent dip followed by high-speed slide of driving blocks. The results of this experiment validate and reproduce the driving-blocks-and-key-blocks mode of apparent dip slide from oblique thick bedding rock slope failure proposed by previous studies.

To investigate the dependence of the characteristics of rock mass fragments upon the two joint geometrical parameters，i.e. joint inclination angle and joint continuity factor，sieve tests were carried out for fragments of gypsum specimens with one set of discontinuous open joints after uniaxial compression tests. The fragments are classified into four size groups，i.e. large-sized，medium-sized，small-sized and fine，whose diameter are larger than 10 mm，5–10 mm，0.075–5 mm and smaller than 0.075 mm，respectively. The mass percentages of fragments in each size group，numbers of fragments in each size range，the specific surface area and fractal dimensions of size-mass distribution are calculated. It is found that mass percentage of large-sized fragments first decreases and then increases when the joint orientation angle increases and the minimum value appears at around 45°. On the contrary，mass percentages of other fragments，numbers of fragments in each size range，the specific surface area and the fractal dimensions first increase and then decrease when the joint orientation angle increase and the maximum values appear at around 45°，which is similar with peak strength and Young?s modulus vs. joint orientation angle. Though the peak strength and Young?s modulus decrease gradually with the increase of joint continuity factor，the variation of the above parameters of fragments vs. joint continuity factor is more complicated. In general，for specimens with joint orientation angles of 0°，15°，75°and 90°，the mass percentage of large-sized fragments is larger than that of the intact specimen while the mass percentages of other fragment groups，the numbers of fragments in each size range，the specific surface area and the fractal dimensions are smaller than those of the intact specimen. Therefore，the existences of joints in this joint orientation angle group cause more cracks and more energy dissipation. For specimens with joint orientation angles of 30°，45° and 60°，it is versus. This can be attributed to the different failure modes of the two joint orientation angle groups. Axial cleavage failure which observed in the intact specimen，combined with crushing and rotation failure in the former group，will create larger number of new fractures and continuous failure surfaces，and dissipate higher energy than the shear failure in the later group. Among all specimens，the specimen with joint orientation angle of 45° has the least number of continuous failure surfaces，which only fractures along the diagonal plane.

In-depth research and reasonable control of tunnel excavation induced ground subsidence are of great practical significance. Taking the excavation of Huguan—Mingdu section of Wuhan subway as background，based on the typical ground subsidence and monitored displacement of the tunnel cross section convergence，simplified stochastic medium theory formula is used to back analyze the displacement of typical sections. The parameters，convergence area   and   where   is the influextial angle，are obtained from the calculation. Ranges of key parameters values are given in the similar conditions. Therefore，it has some practical value in guiding the construction of Wuhan subway.

Based on the independent development of meso-shear test equipment for coal rock and PCI–2 acoustic emission detection analysis system，acoustic emission features of sandstone with different saturation degrees of 0%，50% and 100% during shearing process are studied；and the relationship between evolution law of acoustic emission signal and cracking and extension of sandstone is discussed. The results show that acoustic emission activity is associated with the whole shearing process of sandstone. The acoustic emission activity is not obvious and acoustic emission signal is comparatively small before the shear stress peak value，but after it the acoustic emission signal leaps. With the increase of water content，the shear strength reduces，and the leap point of acoustic emission signal appears in advance successively. Under different moisture states，the peak value of acoustic emission events rate always appears lag the time that the shear stress reaches its peak. With the saturation degree of 0%，the surface crack of sandstone appears after the shear stress peak and the acoustic emission activity is the most intense；the cumulative acoustic emission events at failure is the most，that is，the cumulative damage is the biggest. But with the saturation degrees of 50% and 100% the surface crack of sandstone appears before the shear stress peak，the cumulative acoustic emission events at failure is comparatively less，and the cumulative damage is smaller.

Setting reasonable segment pillar is key for ensuring successful replacement and safety production of fully mechanized caving face in extra-thick coal seam of deep shaft. Taking the determination of segment pillar width in the first mining area of Xinjulong mine as the engineering background，firstly，the side abutment pressure distribution of fully mechanized caving face in extra-thick coal seam of deep shaft was studied by using microseismic monitoring，stress monitoring and theoretical calculation，and 20 m in width of low stress zone was realized. Secondly，the width of fractured zone in side coal mass of fully mechanized caving face in extra-thick coal seam of deep shaft was determined by using engineering analogy and numerical modelling，and about 3 m in width of fractured zone was found. Finally，various elements such as resources recovery，rockburst prevention and control，secondary disaster control and roadway support were considered comprehensively，and the reasonable width of segment pillar of fully mechanized caving face in extra-thick coal seam of deep shaft was determined as 5.0–7.2 m. Furthermore，the reasonableness of the segment pillar width was verified by using observation results of surface displacement of the gob-side entry. The results can provide a reference for segment pillar setting in other mines having similar mining conditions.

Based on the study of repeatedly appearing geological hazards such as large deformation and collapse，and the formation mechanism and influencing factors of Dujiashan tunnel through soft rock which is under construction for Guangyuan—Gansu expressway，traversing the 5•12 fault zone in meizoseismal areas，it was shown that collapses were the main deformation failure of soft rock tunnels in meizoseismal areas；and most of them happened near the tunnel faces. The low strength of surrounding rock and softening effect from groundwater on rock mass are inducements of tunnel?s deformation，and there is also a vital factor that causes the phenomena above，i. e. the effect of the massive deep shattering damaged rock mass caused by 5•12 Wenchuan earthquake and the aftershocks. At the same time，the complicated regional environment caused by insufficient similar experience in design and construction is another key factor that cannot be ignored. The research indicates that，during the construction of soft rock tunnels in meizoseismal areas，proper adjustments of reserved deformation and safety control criterion should be taken based on practical engineering site，strong supporting parameters should be adopted，the techniques connecting each link during construction should be paid attentions to，and the disasters can be effectively controlled with the adoption of micro-bench method using three steps and reserved core soil excavation.

The microseismic monitoring system is the first time to be established in underground plants of Dagangshan hydropower station in China，which is composed of detector，data acquisition instruments，control and communication system and can be controlled from internet. A lot of seismic events data are processed and different methods are used to analyze the stability of the collapse area and the whole underground plant. First，the stability of rockmass near collapse area is estimated from the spatiotemporal and energy level distribution of seismic events. Second，three methods are used to estimate the overall stability of the powerhouse，such as energy index(EI) method，cumulated apparent volume(CAV) and EI method，Schmidt number and CAV method. Third，the magnitude of seismic events near the powerhouse can be predicted by analyzing the existing monitored data；and the safety evaluation method for underground hydropower plant is set up. The results show that the seismic events are active at the lower part of the plant，but the magnitudes are small and they are a bit far away from the powerhouse. There are less microseimic events near the collapse area after reinforced by shotcrete and anchor. So the underground powerhouse of Dagangshan hydropower station is overall stable. The establishment of safety evaluation method has a good guidance to the design and construction of underground hydropower plants.

In-situ experiments of support system were carried out to investigate bolt axial force，surrounding rock pressure，steel framework stress and tunnel deformation of primary support，contact pressure and steel stress for lining. The results show that under condition of high water content gypsum breccia，the stress of primary support increases by 50 %，and the stress of lining increases by 30 % with respect to drying one. Particularly combined with drying gypsum breccia，bolts at hance were subjected to compression. Accordingly，it suggests that systematic bolts at arch should be cancelled；and only feet-lock bolt should be installed. This could reduce sealing time of primary support significantly. Nevertheless，in terms of high water content gypsum breccia，most of bolts at hance were subjected to tension. Therefore，bolt parameters should be unchanged. Framework of primary support can bear load and is of paramount to support system once it is installed. The results are not only applicable to deep tunnel in gypsum breccia stratum，but also can be as reference for similar engineering.

Energy dissipation and energy release appear evidently during the deformation and failure process of rock. In order to obtain the evolution and distribution laws of energy with stress in rock，tests on red sandstone samples under cyclic loading-unloading uniaxial compression with 4 different loading rates were carried out. The results show that：(1) The total absorbed energy，accumulated elastic energy and dissipated energy in rock samples all increase as the axial stress increases before failure，and the total absorbed energy grows fastest，followed by the elastic energy，and the dissipated energy grows slowest. (2) The elastic energy grows nonlinearly with the axial stress，and the increasing rate is small before 24% of ultimate strength，and then becomes larger gradually，but growth slows down when approaching destruction；and the dissipated energy grows slowly at first and increases substantially in the coming failure phase，with an increase of about 85%. (3) The proportion of elastic energy grows from 60% to 82% approximately in the whole loading process with the increasing rate slowing down gradually，and decreases slightly when approaching destruction；and the proportion of dissipated energy varies conversely. (4) In the quasi-static loading range，the smaller the loading rate，the greater the dissipated energy generally；and loading rate has no influence on the evolution of elastic energy basically. (5) The elastic energy density-stress curves of rock samples have no discreteness，and can reflect the inherent nature of the material itself.

Anchor cables supporting is one of the most leading measures for underground caverns，and it is fundamental to ensure the stability of surrounding rock mass. According to the practice of rock anchor cable to support side walls of underground powerhouse at Jinping I hydropower station，the design of anchor cables supporting and the statistical results on overloading of anchor cables are introduced，and the factors to cause this phenomenon as well as the measures to reduce the load are studied. The formulas to verify design proposal are also given，and the formula to compute stress of unbounded prestressed anchor cables of pressure dispersion style with more anchor heads is derived. These formulas and measures are used to verify design proposal，and evaluate safety of overloading cables.

By a standard split Hopkinson pressure bar(SHPB) dynamic test device and ZDKT–1 type transient magnetic vibration test system，the dynamic properties of coal and the characteristics of the transient magnetic nearby field in the process of coal impact damage are researched under impact velocity of 4.174–17.652 m/s. The one-dimensional stress wave theory and the signal analysis of Hilbert-Huang transform(HHT) method are used to analyze the strain signal and the transient magnetic signal，respectively. The results show that：(1) The dynamic response of coal transforms from hardening to softening within certain range of strain rate；(2) The magnetic field has varied obviously in 4 cm distance of coal sample area during coal dynamic impact process，and it shows that the duration is less than 2 s and the frequency is less than 40 Hz through the ensemble empirical mode decomposition(EEMD) analysis；(3) The characteristics of the signal curve of the transient magnetic changes in coal impact damage process is shown that the first performance straight up，then exponential decline，at the end of small oscillation；(4) The amplitudes of transient magnetic field changes in coal impact damage process rises with the impact velocity，average strain rate，the maximum strain rate and the limit value of fracture stress increasing，while it reduces with the failure strain increasing，but the data are of a larger dispersion.

The strata deformation of large section water-abundant soft rock shallow tunnel under unsymmetrical pressure passing through existing structures would be effected by several factors. This article considers the Jianfengding tunnel on the Wuhan—Guangzhou high-speed railway when electricity pylons are present on the ground surface. First，the article describes the engineering measures needed as in-situ measured data to control large strata deformation. Second，statistical and theoretical analyses comprehensively studies the relationship between strata deformation and the impact of the existing building as affected by terrain condition，attitude of stratum，tunnelling construction，tunnel cross-hole construction，ground load，and ground collapse. Third，quantitative analysis is performed on strata deformation brought about by several critical factors and based on coupled fluid-mechanical numerical computation. The main results include：(1) the strata deformation result for the attitude of the stratum is a major factor that affects the horizontal displacement and obliquity of the buildings for these large-section，water-abundant tunnels shallow-buried through soft rock under unsymmetrical pressure；(2) the additive effects on strata deformation have directional properties so that the critical factors with inverse direction can control the obliquity of the structures or buildings well；(3) the strata deformation distributes disymmetrically along the tunnel central line and the regions of greatest deformation occur at the hillside where the unsymmetrical large-span tunnel is excavated under a slope with soft-rock bedding；and (4) in a longer time，the strata deformation change with large fluctuations brought about by the tunnel excavation rapidly converges. However，the strata deformation change brought about by the attitude of the stratum shows a more persistent oscillation after tunnel excavation，and this has a lasting effect on building safety.

Crack is one of the most common and serious defects in tunnel lining. In light of the existing problems of conventional image recognition methods，an automatic crack recognition method in tunnel lining based on characteristics of local grids in images is presented. A lining image is firstly divided into local grids of 8 Pixel×8 Pixel. Cross-shaped templates are designed based on the characteristics of luminance difference and contrast difference between different directions in local grids. The pixel with minimum gray value in each grid can be recognized as one potential crack seed by template calculation. Discrete crack seeds are finally linked together to form an intact and continuous crack cluster using seed linking algorithm. During the linking process，the direction，length and width of cracks are measured automatically. The optimal parameters and threshold of the proposed algorithm are estimated using receiver operating characteristics(ROC) curves. The reliability and accuracy are validated by means of qualitative and quantitative analyses. Application cases show that the proposed method can achieve good effects of crack recognition，especially for the lining images containing minor cracks and leakage；and the reliability and recognition rate are higher than those of other conventional image recognition methods.

Approach of determining shear strength of rock mass at present is briefly reviewed. Taking Maerdang hydropower station located in the upstream of the Yellow River for example，the relationship between shear strength and BQ rating is built up on the basis of rock mass classification，suggested shear strength by codes and in-situ large scale shearing test；and the relationship between BQ rating and GSI is also created according to field survey and measurement. Based on these，shear strength of rock mass at in-situ test point is estimated by Hoek-Brown criterion. The result shows that rock mass shear strength derived from this paper?s method is coincident with practical situation；while equivalent fraction coefficient from Hoek-Brown criterion is lower than test value and cohesion force is far greater than that from shearing test. It is shown by error analysis that the difference between experiment values and estimated ones is mostly induced by the span of minimum principal stress used in Hoek-Brown criterion. For this situation，some cautions and corresponding resolve methods while using Hoek-Brown criterion are reminded.

There are coupled thermo-hydro-mechanical processes in the thermal recovery producing and their analysis models and methods are insufficient at present. According to development characteristics of heavy oil reservoir，the “two boxes” analytical methods in the reservoir heat and mass transfer processes are proposed. “Black box” analytical method as a general analytical method rules out internal heat and mass transmission in reservoir porous media，and includes energy transfer process between reservoirs and outside and energy change within the system. “White box” analytical method as a fine analytical method contains “black method” and it also studies energy conversion process system among internal parts. On this basis，numerical simulation and analysis by CMG software are carried out and the judgment criterion of finding vapor condensation area and its front finger during thermal recovery is proposed. This research gives basic theories for further research of flow characteristics in heavy oil thermal recovery injection process and improvement of the oil and gas recovery during tertiary recovery.

In order to research the hydro-mechano-chemical process in fractured rock，we designed three different kinds of experimental conditions，changing the osmotic pressure and the chemical solution for injection. During these three tests，we measured the seepage discharge，ion concentration and the pH value for observing the seepage properties in fractured rock. Through analyzing the test data and the summary about the characteristics of fractured rocks under different factors，a kind of relationship between the aperture variance ratio and the ion concentration of seepage was established. The test results indicate that：the seepage discharge and the fracture opening all decrease with time，and reach stable state eventually；the improvement of seepage pressure results in the increase of discharge through fractured rocks，correspondingly，the aperture enlarged which the permeability properties of those fractured rocks increased；carbonated with acidic coming through limestone can produce chemical reaction to accelerate the erosion and dissolution of the limestone，resulting in the increase of the aperture. Through analyzing the relationship among the seepage discharge，ion concentration and the pH value with time，we described the evolution of pressure dissolution，free-face solution，chemical dissolution，furthermore revealing the seepage properties of the rock fracture under coupled hydro-mechano-chemical process.

The fast Lagrangian analysis of continua in three dimensions(FLAC3D) was adopted based on nonlinear finite element analysis，to develop three-dimensional elastoplastic numerical simulation of Wudongde arch dam. Nine possible sliding blocks were determined through the altitude of discrete fracture inside the arch dam rock mass. The calculation method of the experiment was to apply the finite element stress value to the sliding face through interpolation，discount sliding face shearing strength based on the altitude of discrete fracture inside the sliding face，and compute the factor of safety through 3D vector sum method. The results indicate that the stress and displacement distributions are basically symmetrical to the river valley. However，affected by the faults F15，f42 and the K25 karst system，there is a slightly larger area affected in right abutment than that in left abutment. The results also show that the nine sliding blocks have high margin of safety under normal impounding level；temperature rise load causes the stability reduction of a majority of wedge blocks，while temperature drop load mainly affects the stability of right abutment negatively. Under the seismic load，the stabilities of all the wedge blocks reduce largely with an average reduction of 30% and the maximum reduction of 53.9%. However，the global abutments rock mass can still remain stable under such situation.

Crack is the key factor of structures for the normal operation. A superposed element method(SEM) is proposed for crack analysis. Firstly，the structure containing cracks is divided into two independent meshes. One is the global mesh without cracks，and the other is the local mesh of the crack together with its adjacent zone. Then，the global mesh and the local mesh are superposed together；the finite element format is adopted for the local mesh. Outside of the coverage of the local mesh，the finite element format is adopted for the complete elements；and the numerical manifold technology is adopted for the incomplete elements on the basis of the global mesh. Finally，in order to couple with the global mesh，the penalty stiffness coefficients are adopted at the boundary of local mesh. The case studies show that the preprocessing of the SEM is quite simple，and its calculation precision is relatively high. The proposed method is suitable for the dynamic simulation of crack propagation process.

Using the self-developed small-scale model flume，combined with the controllable intensity artificial rainfall simulator，the experiment of debris flow induced by artificial rainfall is carried out to study the influence of water content on the sandy soil flow starting process. Based on landslide type debris flow starting process，precise measuring instrument matrix suction is used to measure variation relation of soil cohesion with water content，and pore water pressure gauge is used to measure the performance of pore water pressure during rainfall process. Using software GeoDog，the sandy soil displacement field is analyzed before it turns to debris flow；and the relation of water-soil interaction on the slippery fracture is confirmed. By researching the macro damage state and the slippery fracture position of different initial water contents sandy soil，the influence of water content on the sandy soil flow starting process is revealed.

Based on the trial functions of displacement and excess pore water pressure satisfying the boundary conditions and the semi-analytical numerical technique，a semi-analytical numerical scheme of finite layer method for solving three-dimensional Biot?s consolidation of the anisotropic and layered soil with compressible constituents is presented. Moreover，by means of the orthogonality of the trigonometric functions series，the weighted residual equations are decoupled into several independence ones associated with different series modes. Based on a computer program developed for solving this problem，several numerical examples are given. The validity of the presented method is verified through a comparison between the numerical results and the classical solutions. Meanwhile，the influences of anisotropy of permeability，compressibility of pore fluid，transverse isotropy and characteristics of layered soil on the behaviors of three-dimensional Biot?s consolidation are demonstrated.

Model test is a necessary scientific method which is used in the research on bearing performance of pile foundation. The differences of bearing capability of piles using different piling techniques are significantly studied through designing model test and analyzing test data，and the influence of unloading effect caused by cavities drilling to bearing mechanism of bored piles，as well as the mechanical and settlement property of piles，are also discussed by comparative analysis. The study indicates that：Q-S curves of test piles appear steep drop type；the bearing capacity of jacked pile is the most prominent of all，but less obvious in pre-buried pile and bored piles in steep performance. The load transfer performance of test piles will be affected by different construction methods，and the load transfer capability of jacked pile in the depth direction is worse than that of pre-buried pile and bored piles due to the difference between compacting effect and unloading effect. The skin frictions of four piles are intensified in certain depth，and the strengthened position of jacked pile is slightly higher than that of bored piles and pre-buried pile，which is caused by the fact that compacting effect makes skin friction increase. Otherwise，unloading effect caused by cavities drilling of bored piles and the backout of film wrapped around pre-buried pile weakens skin friction to a certain extent. The extremum exertion and extreme points location of skin friction of piles are highly influenced by different piling techniques. Skin friction and tip resistance do not display in identical time and do not achieve maximum at the same time；and the proportion of tip resistance in total working load varies with upper load.

Analytical expressions for the active earth pressure ratio and active earth pressure are derived，against on a rigid retaining wall from clayey backfill undergoing horizontal translation，considering the soil arching effects and the influence of soil-wall friction angle，wall adhesion and cohesion of backfill. The results show that the active earth pressure ratio and active earth pressure are related to soil-wall friction angle，depth of the point and the internal friction angle，cohesion，unit weight of the backfill. The theoretical comparisons between the analytical expressions proposed for active earth pressure ratio and active earth pressure and the existing classical theory，the previous research results show great agreement with each other，so as to verity the correctness of the results in this paper.

Based on the theory of analogy between thermal and hydraulic problems，using the superposition of potential function in hydraulics，this paper proved the existing analytical solutions of temperature field for the single-piped，single-row-piped and double-row-piped frozen soil walls. Further by using the coefficient of coverage，an analytical solution of three-row-piped frozen temperature field was also worked out. Comparison of the analytical solution with the numerical thermal analysis shows that the analytical solution is precise enough and will afford some new thoughts in working out the analytical solution of multi-row-piped frozen temperature field，as well as some reasonable guidance in three-row pipe freezing projects.