Xinli district of Sanshandao Gold Mine is the first subsea metal mine in China. Large-scale exploitation of the mine will certainly destroy the stability of rock masses，so it is necessary to study the rock mechanics-related problems in undersea metal mines. Based on the demands of undersea mining，the mechanical parameters of ore body and rock mass，the micro-structure and permeability of clay soil in the coastal deposit are measured and analyzed. The experimental modeling system of undersea metal mining is established. The reasonable and safe thickness of the isolation roof is obtained by the experimental simulation. The numerical modeling of the undersea metal mining is carried out to testify the accuracy of the experimental simulation. Using the Orthogonal test method，the optimal structure parameters in subsea mining are obtained by constructing a objective function based on the principle to keep the stability of rock masses. By optimizing the sequence of panel mining stope of ore block，the mining sequence of the “two stope panels” is applied for the mine. By the analysis of the mining condition of the deposit，such as the properties of ore and rocks，the inclination of ore bodies，etc.，a lower settlement frame cut-and-fill stope mining method has been proposed. The results from three years in-situ mining and field monitoring show that the reasonable and safe thickness of the isolation roof，the lower settlement frame stope hierarchical level filling mining method and in-situ real-time monitoring have provided the technical foundation for the safety of seabed mining.

The lithology in fault fracture zones is complex and the pressure in roadway in these zones is variable. The deformation of surrounding rock and pressure on support structure in fault fracture zone can be grasped through the monitoring measurement of roadway. Based on the measurement，the effects of various supports and the rationality of construction scheme are evaluated. Ventilation roadway in south of Gubei coal mine in Huainan mine area passes through the fault fracture zone. In this area，the geological condition is complex. Because of the influence by tectonic movement，the geostress of surrounding rock is high and the surrounding rock of roadway is large-scale loosened rock. In order to analyze the stability and study the deformation law of surrounding rock in the periods of construction and operation，the surface displacement of surrounding rock，deep displacement，stress of anchors and cables，support pressure and the variation distribution regularity of loosened zone of surrounding rock are studied through the field measurement. The results show that：(1) The horizontal displacement of wall of roadway is larger than that of roof and spandrel；and the stress of anchor is small because of the horizontal shear force and squeeze force from fault F92. And it means that the action of anchoring is not effective. Hence，the strength of anchors and the grouting near fault F92 was reinforced. (2) From the measurement results of surface and deep displacement of surrounding rock，the floor dilates，the two walls converge and the roof sinks. It means that the floor is the weak part in the support of roadway. A revised support scheme is proposed：grouting tube at the corner of floor and rockbolts at wall corner are used to resist the shear displacement at the floor corner with concentrated stress；and the floor is reinforced by anchor and grouting to improve the shear strength of rock mass near floor. The dilation of floor is controlled effectively which means the support effect is good. (3) From the measurement result of pressure of U-shaped steel bracket，the pressure of U-shaped steel bracket from surrounding rock is about 0–0.24 MPa which is far less than the designed bearing capacity of bracket (0.4MPa). This means that the stability of roadway mainly relies on the support of anchor and grouting and the U-shaped steel bracket is used mainly for the safe protection of working face in the construction process of roadway. Based on the analysis of these measurement data，the foundation is provided for the optimization adjustment of design scheme and the information construction of roadway and the reference is provided for design and construction under the similar complicated geologic condition.

Many hydropower stations in Southwest China are located in regions with high geostresse or brittle rock masses. Deep fracture zones occur often in the sidewalls of the underground caverns. The theory and method of fracture and damage mechanics are adopted to study this phenomenon. This model can take into account area and orientation of fractured surfaces of multiple joint sets，as well as spacing and density of joints. Under the assumption of equivalent strain principle，a damage constitutive model is established based on Mohr-Coulomb criterion. The theory of fracture mechanics is applied to analyze the occurrence of secondary cracks during cavern excavation. The failure criterion for rock bridge coalescence and damage evolution equation are derived. A new subprogram for the above-mentioned damage constitutive model and damage evolution equation is developed. The program is then applied to stability analysis of an underground cavern group of a hydropower station. The results are compared with the depth of the relaxation and fracture zone in surrounding rock obtained from field monitoring. The distribution of splitting zone obtained from the proposed model is consistent with the field monitoring data. Therefore，the proposed model is validated.

Thermal cracking of rock is a very common natural phenomenon in engineering. The experiments on acoustic emission(AE) characteristics and permeability evolution of sandstone and granite were carried out at temperature ranging from room temperature(RT) to 600 ℃ by using 600 ℃ 20 MN servo-controlled rock triaxial testing machine with high temperature and high pressure (HTHP)；and it reveals the related features between thermal cracking law and induced permeability. The results show as follows：(1) There exists a thermal-cracking threshold value in the heating process from RT to 600 ℃ as a result of thermal effect. According to AE characteristics induced by rock thermal cracking，the cracking threshold temperature of granite from Pingyi，Shandong Province in China is 65 ℃ and the one of fine-grained sandstone from Yongcheng，Henan Province in China is 170 ℃，respectively. (2) The behavior of rock thermal cracking is discontinuity and multi-period from RT to 600 ℃ with temperature rising over the threshold temperature. It neither increases nor reduces monotonously in the heating process；and there exist more than two peak value areas. (3) The rock permeability appears multi-peak value area because of the multi-period of thermal cracking with temperature increasing. The relative lowering permeability lag occurs after the quietude of AE in the peak value area of permeability. But the permeability remains in a high level and it is more and more high with the increasing happening times of AE drastic period.

Deformation characteristics of surrounding rock and stress distribution of deep gob-side entry retaining，which was located in the first coal mine of Xiejiaji，the Huainan coal mining area，were analyzed by means of numerical simulation. The underground test for the deep gob-side entry retaining was introduced in detail，including the designs for primary supporting in the entry，additional enhanced supporting，and supporting beside the entry，and the monitoring data during various stages from driving，retaining to reusing. The supporting effects were evaluated through the analysis of the data of surrounding rock and backfilling body displacements and the loads along bolts and cables. The underground practice points out that the severe surrounding rock deformation in the deep gob-side entry retaining can be effectively controlled；and its stability can be kept by means of the synthetic supporting system，which consists of the high pretension and intensive bolts and cables as the primary supporting in the entry，individual props with articulated roof beam as the enhanced supporting，and paste backfilling as supporting beside the entry. On the basis of the research achievements obtained from numerical simulation and field test，the relationship between the primary supporting in the entry，additional enhanced supporting and supporting beside the entry were discussed；the great differences between deep and shallow entries on the breaking position of main roof，its rotation，and long-term creep of surrounding rock were indicated；and the supporting design criteria for the deep gob-side entry retaining were put forward. The improvement suggestions were also made in accordance with the existing problems in underground test.

Development of the study of the structure failure of mining rock and its movement are briefly reviewed；and it is found that the structure failure of mining rock and its movement not only control the strata behaviors in working face and mining roadways，but also control strata movement，ground subsidence，crack evolution and seepage in mining strata. With the deep study of the law of specific mechanical behaviors of mining rock，series of technological innovations in mining engineering are formed according to utilizing and controlling these specific mechanical behaviors；and a set of results are listed by means of engineering legend. Four innovative technologies and their developing processes，latest developments，important technological parameter indices and so on are summarized，such as the solid filling technology with waste in fully-mechanized coal mining and the quick filling technology in gob-side entry retaining with large section developed based on the law of strata movement and ground subsidence，and the technique of coal mining and gas extraction and the technique of water-preserved mining developed based on the law of crack evolution and seepage in mining strata.

The axial compression and acoustic emission(AE) tests on T2b marble samples at the depth of 2 000 m show that the crack initiation strength equals 0.4–0.5 times UCS(unconfined compression strength)；and the crack damage strength approximately equal 0.8 times UCS. The results of T2b marble are similar to the results of Lac du Bonnet granite in URL(underground research laboratory)，Canada. The triaxial tests on Jinping marble show a brittle-ductile-plastic transition with increase in confining pressure. A comparison study among T2b marble，Lac du Bonnet granite and Three Gorge granite is carried out to show the difference in post peak mechanical behavior. The brittle-ductile-plastic transition of T2b marble is described by using the constitutive model based on Hoek-Brown strength criterion. The study results are applied to prediction of damage depth in excavation damage zone(EDZ) of diversion tunnels at Jinping II hydropower station.

Maji hydroelectric power station with the dam height of 290 m is a major station of Nujiang river. The geological conditions and rock mechanics environment of Maji arch dam are complex；the stress and the abutment stability are significant for engineering safety. Based on nonlinear finite element analysis and deformation reinforcement theory，three dimensional elastoplastic numerical simulation of Maji arch dam has been carried out with code TFINE. The displacements，stresses and abutment forces of dam under normal working conditions were analyzed. Then the global stability and overloading analysis of dam were made based on complementary energy norm. The dam toe and faults in foundation were analyzed based on unbalanced force. The results show that the displacements，stresses and overloading capacity of Maji arch dam meet the requirement of stability；and the current construction project for Maji dam is feasible.

Based on triaxial hydro-mechanical compressive tests and triaxial creep tests of the strongly weathered granite，a constitutive model with Mohr-Coulomb yield criterion is established to describe the elastoplastic hardening and plastic flow behavior of the weathered granite. Parameters of the mechanical model are obtained from back analysis combining Nelder-Mead algorithm and finite element method. A nonlinear creep model is established by using triaxial creep tests and relative creep parameters are obtained. On the basis，the model is imbedded into ABAQUS by writing creep subprogram. The models and parameters derived from laboratory tests are justified through field inversion analysis. Based on the developed models and the obtained parameters，long-term stability of tunnel located in F4 is studied. The numerical simulation results provide some reasonable suggestions for tunnel design and long-term operation management.

Virtual joint is adopted in the discontinuous deformation analysis(DDA)，which can provide path for block failure and fracture development. Therefore，the failure process of jointed rock mass is a progress of initiation，extending and connecting of joints inside rock mass；and attenuation of virtual joint mechanical parameters represents the strength attenuation in the process of rock failure. The attenuation law of virtual joint mechanical parameters is studied by introducing the definition of virtual joint connectivity rate；and the attenuation formula of virtual joint mechanical parameters is established. According to the phenomenon of mechanical parameters attenuation in rock failure，the strength criterion(Jennings criterion and the maximum tensile strength criterion) for intermittent jointed rock masses are studied. Programming the attenuation law of virtual joint mechanical parameters and improved strength formula of intermittent joint into DDA to simulate the fracturing process of intermittent joint. At last，the method is validated by comparing the computation results with shear test results.

Based on the results of triaxial unloading tests，the stress-strain characteristics and failure characteristics of sandstone have been discussed. The results show that the brittle characteristic of sandstone failure under unloading conditions is obvious. Compared to loading failure，unloading failure is more sudden and severe with a higher degree of rock fragmentation. Axial deformation increases continuously with decreasing confining pressure during unloading；and it increases slowly at the beginning of unloading. When the unloading reaches a certain value，deformation suddenly increases；a little change in confining pressure can cause large unloading deformation. Considering unloading degree as an important parameter，an elastic-brittle-plastic mechanical model has been established according to the characteristics of rock mass stress-strain curves under unloading conditions，which assuming that rock mass conform to Griffith criterion in unloading damage segment and Hoek-Brown criterion in unloading failure segment，unloading yield function varies linearly between Griffith and Hoek-Brown criteria.

Criterion and damage zone induced by excavation blasting of underground power-house were studied by field test of blasting vibration and numerical simulation. The numerical simulation software FLAC3D was adopted  with introducing damage variable D into elastoplastic constitutive model. The simplified triangular load was used as blasting load on the wall of blast hole. The blasting-induced damage zone was defined according to effective stress of rock. By revising the number of blast holes，the maximum quantity of explosive charge of single-stage priming was changed to study its relationship with blasting-induced damage zone. The results of numerical simulation show that the depth and the horizontal radius of damage zone increase with the increment of explosive charge of single-stage priming while the damage zone reduces with the increment of depth of blast hole. The maximum horizontal radius of damage zone is at the surface of the top of blast hole. According to the attenuation of particle velocity in the area near blasting source，the relationship between the maximum horizontal radius of damage zone and the critical vibration velocity for blasting-induced damage was obtained by numerical data fitting corresponding to the change in explosive charge of single-stage priming. The critical vibration velocity for blasting-induced damage was used as damage safety criterion of blasting. The study results can be used effectively in practice and have guiding significance for those similar blasting projects.

Conventional sensitivity analysis methods for slope stability are based on deterministic calculation，which can only determine the sensitivity of slope stability on individual variable，the sensitivity of slope stability on the same parameter along the different slip surfaces can not be analyzed. A new sensitivity analysis approach for slope stability is proposed based on reliability analysis method；the random field model is employed in simulating spatial variability of rock or soil property along the slip surface. The proposed approach is implemented using First Order Reliability Method(FORM) with constraint optimization approach. The sensitivity analysis results include minimum reliability index of slope，probabilistic critical slip surface and sensitivity factors along the critical slip surface. The sensitivity factors of same rock or soil property to slope stability at different positions along the slip surface can be obtained，which are always varied along the slip surface with the relative dimension of slope size and the scale of fluctuation of rock or soil property. The analysis results can play an important role in slope design and reinforcement：according to the sensitivity factors of rock or soil property along the slip surface，the reinforcement measures should be placed in the most sensitive position in order to improve the stability of the slope more effectively，which has advantages over the conventional sensitivity analysis approach.

Taking the medium-fine-grained soft rock for example，the influence of shear dilatation of rock mass on the axial force distribution of fully grouted rebar bolts is analyzed. The difference in variable rock dilatation and constant rock dilatation on rebar behavior in rock mass is investigated. In addition，the suppressing effect of rebar on shear dilatation of rock mass near excavation is discussed. For the constant shear dilatation angles，the axial forces increase with increasing shear dilatation angles；and the gradient of axial forces shows an increasing trend. However，the assumption of constant shear dilatation angle cannot describe that the shear dilatation is dependent on confining pressure and plastic deformation，leading to underestimating axial force of rebar bolts near excavation and to overestimating axial force of rebar bolts from excavation boundaries. The established shear dilatation angle model considering both confinement and plastic shear strain reveals the large tensile loading on rebar bolts at low confinement conditions；and a rapid decrease in axial forces with increasing confining pressures can be observed，which is in agreement with actual behavior of rebar bolts observed in underground openings. The rebar bolts reinforcement improves the confining pressure near excavation and suppresses the large shear dilatation of rock mass. In the underground engineering design，the rock support under low confinement conditions should be considered to effectively control the rock deformation and failure.

The brittle failure modes and mechanism of surrounding rocks should be studied and understood primarily. Furthermore，the rational evaluation of the brittle failure degree is crucial importance for stability analysis and control of surrounding rock mass in deep underground engineering. The test tunnels in Jinping II Hydropower Station are exactly constructed for these problems，the buried depth of 2 500 m is the maximum in the world. Based on the analysis of the experimental results，the engineering mechanical features of the marble T2b are studied. Then the failure modes and mechanism of the surrounding rock mass in the test tunnels are analyzed. And the range and depths of the failure zone in the test tunnels are calculated by numerical simulation method in which the constitutive model，RDM，for hard brittle marble and the FAI evaluation method are adopted. Finally，comparison between the calculated results and those revealed in the test tunnels is carried out. And the results obtained through comparison are satisfied. This study lays the solid foundation for the design of support parameters and establishment of the constructing measures in the excavation process of the diversion tunnels in this project.

The objectives，conditions and methods for anti-blast effect tests of the new optimized and nonoptimized weakened composite anchorage structures are described. The only difference between the two types of structures is the length of weakened hole section. The former is optimized，while the latter is empirically determined. The experiments are characterized by low initial loads and small load increments. The experiments truly represent the whole process of chamber from deformation through failure to collapse and blockage. Experimental results show that the critical failure resistance of the former is more than 2.1 times as much as that of the latter. Under the extreme failure conditions，the large deformation dimension(arch crown lowering) and the surface spalling area of the former are only 25% and 33% that of the latter，respectively. The mechanism of weakening hole group is to form a weakened zone in the surrounding rock to turn the original two-medium system (support structure and surrounding rock) into a three-medium system(support structure，weakened zone and surrounding rock). The weakened zone will absorb a great deal of explosion energy during explosion，and transfer the crisis of the support structure at the same time.

Based on the scientific understanding of deep rock under high in-situ stress and dynamic excavation disturbance，the experiments on dynamic failure characteristics of sandstone under one-dimensional coupled static and dynamic loads were conducted with a modified split Hopkinson pressure bar(SHPB). Four cases，without axial pre-compressive stress and with three levels of axial pre-compressive stress，were designed to conduct impact tests under different strain rates. The results show that，at the same strain rate，the dynamic response of rock is influenced obviously by axial pre-compressive stress ratio. When the strain rate is a constant，the impact compressive strength first increases and then decreases as the axial static pre-stress increases；and it reaches the maximum value when the axial pre-compressive stress ratio is 0.6～0–0.7. When the axial static pre-stress is a constant，the impact compressive strength increases with an exponential function as the strain rate increases. Within a certain range of axial pre-compressive stress ratios，the incident energy will influence the dynamic impact energy response of rock specimen；and the specimen will experience three phases of absorb energy-release energy-absorb energy when the axial compressive stress ratio increases. The transformation mechanism of dynamic strength increase，rock burst and induced fracture of rock under high in-situ stress can be explained better by the above three phases. The results can also provide a theoretical guide for the deep rock engineering practice.

According to the topographical，geological features，the distribution of weak structural，shallow relaxation unloading phenomena and reinforcement program of Xiaowan high arch dam，the 3D geomechanical model is set up；and a kind of model test material called temperature analogous material whose strength varies with temperature in the process of experiment is developed to simulate the decrease of the major weak structural planes. Then，the failure test is carried out by comprehensive method which considering both overloading and strength-decreasing. Through the test，the deformation characters of dam foundation and abutment，the failure process，modes and mechanism are obtained. The safety evaluation of model experiment indicates that the strength margin coefficient is 1.2 and the overloading coefficient is 3.3–3.5；and the global factor of safety for the dam foundation and abutment is 3.96–4.20. Synthetical analysis of test data indicates that the displacement，failure status and zone of mid-upper abutment are relatively less due to the excellent reinforcement effects of concrete displacement plugs on faults and alteration zones. Based on the failure status and zone in the model test，some suggestions are proposed that the faults F11 and F10 above the elevation of 1 245 m in the right abutment and the rock above the thrust block in the left abutment should be reinforced.

Taking the Ditch-Moore #DH6 landslide in Xijiu road(S101) as typical representation，the deformation mechanism of red bed landslide at Qinghai Plateau affected by valley incision and rainfall infiltration was studied by geological analysis and geotechnical model test. In geomechanical model test，slope excavation is used to simulate the valley incision；and the technique of capillary infiltration is used to simulate the rainfall infiltration. Displacement is an important index of the test. The influence of valley incision and rainfall infiltration on slope displacement are analyzed separately；then a comprehensive analysis of two factors is made；and the roles of two weights are analyzed. The results indicate that valley incision and rainfall infiltration play important roles in the deformation of red bed landslide. The root causes of slope deformation are two strength degradation process based on special ground nature of red bed：(1) Unloading relaxation caused by valley incision(the first intensity attenuation) and the invading surface are the basis for the emergence of landslide；(2) Long-term softening of rock mass strength induced by rainwater infiltration(second intensity decay) is the direct cause of landslide development. Therefore，the mechanism of the red bed landslide is summarized as “the original landscape→valley incision→valley slope relaxation→geotechnical strength decay→rainfall infiltration→geotechnical strength decay further→overall slip”by comprehensive analysis as the representative to the Ditch-Moore #DH6 landslide.

The mechanical properties of underground tunnel，cavern and pillar in deep high stress area are closely linked to the mechanical properties of rock after failure. Research on residual strength and post-peak mechanical properties of rock mass has very important significance for engineering design. Through cyclic loading and unloading experiments of failure rock mass，variation law of residual strength under different confining pressures(30，20，10，5 and 1 MPa) and different unloading degrees (90%，70%，30%) has been studied. The results show that the relationship between residual strength and cycle number can be fitted with the exponential function，no matter how the initial conditions are. When the confining pressure is relatively lower(≤20 MPa)，at the same confining pressure，the reduction degree of residual strength is the maximum at unloading degree of 70%，followed by unloading degree of 90%. On the other hand，the reduction degree of residual strength is the minimum at unloading degree of 30%. With the same amount of unloading degree，the lower the confining pressure is，the greater the reduction degree of residual strength is；under confining pressure of 1 MPa，the residual strength even may reduce by 73%. As confining pressure is large(＞20 MPa)，because of binding and compressive effect of the confining pressure，cyclic loading and unloading will not result in lower residual strength of rock samples.

The digital features of localized deformation of limestone are analyzed by using video images of uniaxial compression test. The original videos were record during the laboratory uniaxial compression test. The video images at loading stage were obtained by using load-time relation curves and converted into the video formats that can be recognized easily by computer. A particle image velocimetry(PIV) technique was used to compute the displacements of surface of limestone specimen in any time and in any location. The change history of tip displacement of the existing fissure was investigated；the processes of initiation and propagation of new fissures were also analyzed. The textural parameters of a single frame were selected as the digital features reflecting the deformation status of limestone. The change processes of these parameters with time were further investigated based on the grayscale histogram and grayscale co-occurrence matrix from video images. The results show that the phenomena of localized deformations of existing and new fissures are much obvious；the dividing point between stable and rapid deformation stages may be used to determinate the start point and to establish the initiate conditions for localized deformations；the textural parameters can reasonably reflect the change in the deformation status of the limestone under different loading stages and may be used to predict the initial time of localized deformations. Due to the reflection of image features on deformation/failure process of intact rocks or rock masses，the methods presented herein may provide a new research way of meso-scale mechanisms of the localized deformation and geological hazards in rock areas.

Three key issues are included in three-dimensional discontinuous deformation analysis(3D-DDA)；they are identification of block，creation and solution to motion equations of individual unit，the detection and updating of varying contacts between the units as the consequences of their motions and deformations. For these questions，three-dimensional block geometric identification algorithm was formed through the boundary operator according the concept of simplex and simplicial complex in algebraic topology. To ensure the accuracy of block identification，Euler-Poincaré formula was adopted. And simplex integration is used to obtain the analytical solution of block physical characteristics quantity. Then based on first order displacement mode，global equilibrium equations of three-dimensional discontinuous deformation analysis system was proposed in accordance with the principle of minimum potential energy. According to failure characteristics of rock mass engineering，a face-face contact model was created；on this basis，factor of safety of rock slope was calculated using strength reduction method. It is known from the example of simple wedge failure that the problem caused by assumptions of limit equilibrium method can be solved by 3D-DDA，which could calculate the correct factor of safety for wedge stability. The engineering slope example shows that，through the research on rock slope stability by 3D-DDA，rock slope failure mechanism could be understood deeply；and the location，volume，sliding direction and the corresponding support methods of critical sliding block could be easily determined. In addition，considering that DDA could accurately solve the tangential sliding force，the reasonable factor of safety could be obtained by combining strength reduction method.

The rock strength gradually degraded with time and stress if applied load exceeds a certain yield stress level in creep process；and this damage law could be quantified with the reduction in the basic mechanical parameters of rock，i.e. elastic modulus E，cohesion c and internal friction angle j. Based on the creep experiments of mudstone obtained from Qinyuan coal mine in Baoji under conditions of eight different stress levels and three different times，the variations of mechanical parameters E，c and j were measured in the process of mudstone creep by using single specimen method. Then，the coupling functions，that the mechanical parameters E，c and j decayed exponentially with increases in stress level，long-time strength and time，were established through test data. Moreover，the mudstone common expression of damage law of mechanical parameters was obtained by analyzing the characteristics of coefficients in coupling functions，in which the parameters had clear physical meanings and simple testing methods. This study could provide the foundation for further establishment of non-stationary rheological constitutive model.

At present，the combined support method of long anchor cable and bolt shotcrete mesh is widely used in deep soft surrounding rock，but it is very deficient in understanding on bearing behavior of the combined supporting structure；and it still lacks quantitative analytical formulae especially for bearing capacities of primary supporting and secondary supporting. In allusion to the united supporting characteristics of anchor，spray net and cable of deep wall rock，the mechanical model of overlap arch bearing body were put forward based on rock mechanics theory，which are composed with the main compression arch(bolt supporting) and the secondary compression arch(intensive cable supporting). By means of elastoplastic theory，neutral point theory of bolt and force transferring mechanism of cable，strength equations of the bearing body of primary supporting and second supporting were deduced. Community composed of wall rock and supporting structure is regarded as an equivalent coupling surrounding rock；and relation equations of rock mechanics parameters of surrounding rock with release displacements(yield displacements) were obtained from the method of elastoplastic mechanics. Computational results of engineering indicate that the peak intensity and bearing capability of rock mass were enhanced obviously for the breaking cavity of Jinchuan Mine III after the support of overlap arch；the limit bearing capacity   of equivalent coupling surrounding rock can reach 513.34 kN；the value of   can reach 47.54º and the value of   can reach 1.37 MPa. Monitoring data also show that deformations of surrounding rock supported by overlap arch bearing body trend to be stable，convergence rate of which is less than 0.1 mm/d.

With the development of large-scale hydropower projects and the underground space constructions，the rock stress measurement and the influence of stress on engineering rock masses and constructions attract more and more attentions. Based on in-situ stress measurement of Huangdeng dam，the elastic moduli are obtained from the core confining pressure test，the interior compression modulus test and bearing plate test；and the elastic moduli are different. Therefore，the phenomena of difference are analyzed according to rock damage mechanics and rock mass properties under high confining pressures. Besides，stress relief process of measurement is analyzed based on unloading rock mass properties；and the effect of expansion on stress measurement is determined. The results show that with the increase in confining pressure，the elastic modulus of rock mass may grow positively mainly due to the compression of rock fractures；unloading rock mass may appear the phenomenon of serious expansion with the mechanical vibration. Considering the above analyses，a selecting principle of elastic modulus in aperture deformation method in in-situ stress measurement is proposed；and it would offer a reference to other similar projects.

The seepage process in porous media is significantly influenced by water content and drying/wetting history that the material has experienced. Based on the continuum theory of porous media and an internal state variable-based model of capillary hysteresis，a two-phase flow model of porous media is created and implemented into the U-DYSAC2 finite element code. Comparing with the experimental data，the results show that the proposed model can be reliably and efficiently used to simulate the unsaturated seepage problems of porous media under complex conditions. The new procedure is used to analyze the seepage processes in a soil slope subjected to drying/wetting cycles. The results show that the effect of capillary hysteresis on unsaturated seepage process is significant；and the hydraulic state of soil is not only related to the current value of water content or matric suction，but also depends on the drying/wetting history that the soil has experienced. In particular，it is shown that if the main drying soil-water characteristic curve is adopted in the analysis，the matric suction of soil will be over-predicted；hence the shear strength of soil and the factor of safety of slope stability can be over-estimated based on the traditional methods of stability analysis. Therefore，it is necessary to take into account the effect of capillary hysteresis in modelling unsaturated seepage problems.