To study the deformation characteristics and mechanism of compound support steel arch，optimize the support parameters and ensure the stability of diversion tunnel，the tunnel construction in Shanxi water diversion project is simulated numerically based on the mechanical analysis of the support structure. According to the action mechanism of the compound support，the stress and deformation characteristics of steel arch during primary supporting are analyzed. Combined with field project，the pressures that surrounding rock act on steel arch，reinforcing mesh and shotcrete are calculated，and the shared ratio of pressure for every kind of support is given. The numerical calculation shows that，the compound support with steel arch，compared with conventional shotcrete support，can provide direct resistance to surrounding rocks；and the primary deformation and plastic zones of surrounding rocks can be reduced significantly. This will facilitate the formation of rock arch and increase the bearing capacity of compound support；meanwhile，the deformation and stress of the support materials can be reduced greatly. The research results provide theoretical basis for support design of the diversion tunnel for the Yellow River diversion project in the middle part of Shanxi province. This is an effective support method for fractured surrounding rocks；and they also have important reference and guiding significance for similar tunnels.

Based on the self-developed triaxial servo-controlled seepage equipment for thermal-hydro- mechanical coupling of coal containing methane，the cyclic loading test is performed on coal samples under different temperatures. The results are shown as follows：(1) The area surrounded by hysteretic curve reduces gradually with temperature increase. In a single hysteresis curve，the relation curves between principal stress difference，permeability and axial strain present X-shape. In the same cycle，the axial strain and permeability decrease gradually with temperature increase. The axial deformation increases as the number of cycles increases in same temperature condition. (2) As temperature increases，the slope of curve in loading stage increases，the cumulative deformation reduces，which means the development rate of the irreversible process has been improved. (3) In different temperature conditions，the changes of strain and permeability in loading stage are not obvious during the entire cycle. In unloading stage，the strain and permeability change significantly in the first cycle，and strain curve begins to stabilize with increase of the number of cycles. When the number of cycles is the same in different temperature conditions，the volumetric strain increases gradually and the permeability decreases with increase of temperature.

To analyze the influence of saturation period on the mechanical properties and bursting liability indices of coal mass，the bursting liability indices were tested on the specimens of coal seam #2 in Qianqiu coal mine with natural water content and saturation for 7–28 d，respectively. The results show that，under natural and saturation states，the elastic modulus，impact energy index and pre-peak accumulated energy of the coal specimens are all positively correlated with the compression strength. Water saturation of the coal specimens can decrease their compression strength，elastic modulus，impact energy index and pre-peak accumulated energy in different degrees. The saturation period of 7–10 d for the coal specimens has a significant effect on their mechanical properties and bursting liability indices；after then，the influence degree would decrease. Under natural state，the bursting liability of coal seam #2 belongs to moderate impact type(type II). After the saturation period of 7–28 d，the bursting liability index decreases obviously，and becomes weak impact type(weak type II). Therefore，it is suggested that the water should be injected about 7–10 d in advance at the coal face of Qianqiu coal mine，and the distance in front of the face should be about 30 m.

Slope stability evaluation based on strength reduction can only obtain static single safety factor. The dynamic evaluation method of slope stability is proposed based on dynamic and whole strength reduction methods in order to obtain the slope stability in the progressive failure process. At first，a series of expanded sliding surfaces are searched by using the dynamic strength reduction method(DSRM)；and then the strength parameters of the sliding surface are reduced in each reduction step. The corresponding safety factor of the slope is calculated by using whole strength reduction calculation. At last，the relationship of sliding surface propagation and the related safety factor is analyzed. Therefore，slope stability evaluation and support suggestion can be given according to the change rule of dynamic safety factors of slope. Two case studies show that sliding surface obtained by DSRM is consistent with in-situ monitoring data，reasonably reflecting the failure characteristics of slope or landslide. A series of dynamic safety factors are presented in the progressive failure process by using the advantages of DSRM and whole strength reduction method respectively. The DSRM benefits stability judgment and supporting measures suggestion of slope. Compared with the limit equilibrium method，the DSRM is more suitable for stability evaluation of the heterogeneous slopes；and it can search the potential sliding surface accurately.

For groundwater source heat pump system blocking mechanism study and development of sand blocking simulation test system，the gravel particles is used as porous media with the fly ash particles as the suspended solids. The relationship between relative concentration and pore volume of suspended particles is studied during the migration and deposition in gravel particles. The main conclusions are drawn as follows：(1) Under three different flow velocities，the migration and deposition of particles in gravel particles mainly experience three stages：increase，decrease sharply and stable stages of concentration. The overall trend is the same；and the main difference lies in different peak values of concentration. The greater the flow velocity is，the larger the peak value is；and vice versa. (2) The proposed permeability attenuation model of suspended particles is an effective tool to forecast test porosity decline caused by particles migration. (3) Through comparing theoretical analysis with test curve，it is found that tail effect did not appear in this test；and the test values are consistent with the theoretical ones.

Brittleness index and crack initiation stress，as the intrinsic reflection of mechanical properties for rock，reflect the heterogeneity and structural differences of rocks. Supposing that there exists a certain inevitable relationship between them，theoretical research and case study are conducted. Firstly，28 kinds of basic brittleness testing methods，based on ratio of uniaxial compressive strength to tensile strength，the whole stress-strain characteristics and hardness or soundness，are summarized. Secondly，the crack initiation mechanism for brittle rocks under uniaxial compression is studied. The method to determine crack initiation stress level is discussed by means of inflection points of crack volume strain curve；and the crack initiation stress level is defined as K. Finally，two cases are given to expose the function relationship between crack initiation stress and brittleness indices. Some conclusions are drawn as follows：(1) Based on the achievement of predecessors，by using the uniaxial compressive and tensile strengths，it is found that there exists a certain relation between crack initiation stress level and brittleness indices. (2) There are obvious function relationship between crack initiation stress level and brittleness indices B5，B6. To B5 is power function relation，and to B6 is linear function relation. The correlation coefficients are both greater than 85%，showing a strong correlation. (3) Brittleness index is redefined by crack initiation stress level，which can be obtained easily and quickly based on crack initiation stress level under uniaxial compression test. This study enriches the relationship between crack initiation stress and brittleness indices，and provides a new idea to determine the brittleness indices.

The construction technology of underground storage caverns was introduced into China a few years ago. At present，there is no extensive experience on the design and construction of groundwater curtaining system. Design principles and inter-connectivity determination method of groundwater curtaining system were investigated with reference to a case study on a pilot underground crude oil storage caverns in China. The influences of hydrogeological condition on the sealing method，arrangement method of groundwater curtaining system and inter-connectivity determination method were obtained. From field tests on the inter-connectivity of groundwater curtaining system for the pilot caverns，an improved inter-connectivity testing procedure was proposed to determine the inter-connectivity of boreholes in the curtaining system. From this study，it is found that the sealing method of underground storage caverns depends on the hydrogeological conditions of the sites；and vertical hydraulic gradient is an important parameter for the sealing property of storage caverns. For artificial sealing method，the axes of boreholes in groundwater curtaining system are suggested to be perpendicular to the orientation of dominant joints. The inter-connectivity of the boreholes could be determined using a procedure combining groundwater pressure dropdown test of single boreholes with inter-connectivity test for multiple boreholes. The distribution and variation of groundwater seepage field around the site could impose great influence on the testing results. The improved testing procedure could be employed to determine the inter-connectivity of groundwater curtaining system in different hydrogeological conditions. This study will provide an important reference for the construction of underground storage caverns with groundwater curtaining system；and provide a critical benchmark for the study of seepage behavior of jointed rock mass.

Based on a series of triaxial cyclic loading-unloading and permeability tests，the damage evolution of granite under compressive stress condition and its impact on rock′s permeability are investigated. In this study，the conventional permeability test method is optimized by drilling two small boreholes from the sample surfaces，which allows measuring the permeability variation of rock sample with different failure modes. The testing data reveal that the damage evolution is initiated simultaneously with the appearance of microcracks，and accelerated in the failure and post-peak phases. A consistent tendency between the damage evolution and the accumulation of recorded acoustic emission(AE) events is noticed，which verifies that the initiation and propagation of the microcracks are the essential mechanism related to the degradation of mechanical behaviour of granite. The permeability is also mainly increased during the failure and post-peak phases，and its variation is found to be hysteretic compared to the damage evolution before rock failure. It means that the impact of damage evolution on permeability is limited before the coalescence of microcracks. With the increase of confining pressure，the permeability is decreased abruptly at first；and then the decreasing tendency becomes less pronounced when the confining pressure reaches a certain level. Based on the AE data，an empirical equation describing the impact of damage evolution and confining pressure on rock?s permeability is established.

In order to study the influence of water saturation on mechanical properties and energy mechanism of karst limestone，uniaxial and pseudo-triaxial compression tests are carried out under natural and saturated states by rock mechanics test equipment RMT–150B. The testing results of mechanical properties indicate that saturation has a significant effect on the strength and deformation characteristics of karst limestone；and the regression relationship between peak strength and confining pressure can be expressed by Coulomb strength criterion in principal stress. Similar softening coefficient and their reduction rate decrease with the increased confining pressure. From the perspective of energy，the energy features and energy mechanism in the process of rock failure are studied by tests；and then some conclusions are drawn as fellows：the total absorbed energy U，releasable strain energy   before peak stress and their increasing rates with axial strain under saturated condition are less than corresponding values of natural specimen. The release rate of   after peak stress declines under two states with confining pressure，especially the release rate of   for saturated specimen is larger in general. Each strain energy at peak stress increases linearly with the confining pressure；and the intrinsic reason for destroyed style difference is that the difference of dissipated energy under two states varies with confining pressure. Real-time evolution process of karst limestone specimen can be divided into different stages. As for dissipated energy，it differs slightly in compression and elastic deformation stage under two states；but in yield phase，dissipated energy of saturated rock increases faster.

Both numerical methods and single-hole packer tests are used in study of the representative elementary volume(REV) and three-dimensional(3D) permeability tensor for fractured rock masses. Based on the probability distribution functions and corresponding statistical parameters investigated in field，3D stochastic discrete fracture networks are randomly generated using the Monte Carlo method. The composite element method(CEM) is used to obtain the permeability tensor and REV of rock masses，with a large quantity of calculations concerning different sample sizes in various directions. The permeability tensor is then modified and improved by using single-hole packer test results. Finally, the proposed method is used in determining the permeability properties of dam foundation of Xiaowan hydropower station. The results show that the proposed method is feasible and reliable.

Based on the procedure to identify velocity pulse for multi-component ground motions，196 ground motions from NGA(next generation attenuation) database and Wenchuan earthquake are classified as pulse-like ground motions. Newmark decoupled method considering the nonlinear soil property is used to compare the sliding displacements of slopes caused by near-fault pulse-like and non-pulse-like ground motions. Effects of pulse characteristics and slope parameters on sliding displacement are analyzed；and the efficiency of different pulse-like ground motion parameters for predicting the displacement is also investigated. The analyses indicate that the near-fault pulse-like ground motions result in much larger displacement than non-pulse-like ground motions，especially significant effect on long-period slopes. Also，displacements induced by pulse-like ground motion commonly have shorter duration and larger sliding velocity compared with non-pulse-like ground motion. It is shown that sliding displacement characteristics caused by pulse-like ground motion are closely related to its velocity-pulse feature，and peak ground velocity is the most efficient parameter for predicting sliding displacement. The effectiveness of the equivalent wavelet pulse on representing the original pulse-like ground motions in terms of sliding displacement value is investigated. Finally，sliding displacements of slope to pulse-like ground motions is summarized in terms of a response surface.

Based on the new and conventional loading procedures，the rock mechanical behaviors are simulated through using the clump parallel-bond model(CPBM) to conduct a series of numerical experiments at the specimen scale. Meanwhile，using the new developed loading procedure，the effects of loading rate and frozen period on the stress-strain response of a particle model are investigated. Furthermore，the effects of microscopic parameters on macroscopic parameters of the specimen，which is modeled by the CPBM，are studied using the dimensional analysis. Certain semi-quantification relationships between macroscopic parameters，such as the elastic modulus，Poisson′s ratio，uniaxial compressive strength(UCS) and tensile strength(TS)，and microscopic parameters of the specimen are established. The related numerical results have demonstrated that：(1) When using the conventional loading procedure，the produced stress-strain curve is incorrect；the elastic modulus，UCS and TS are overestimated；while the post-peak mechanical response of brittle rock with brittle behaviour cannot be reproduced. The failure patterns of the specimens under different loading procedures are totally different. (2) When using the new loading procedure，the CPBM can be used to reproduce a high ratio of the uniaxial compressive strength to tensile strength(UCS/TS＞10). The strength is independent on the loading rate in the quasi-static range，which is consistent with the experimental results. Meanwhile，the effect of loading rate is mainly concentrated on the post-peak range of the stress-strain curves. (3) Elastic modulus is mainly determined by the particle contact modulus and contact stiffness ratio. Poisson′s ratio is mainly determined by the contact stiffness ratio. Compared with the conventional parallel-bond model，in order to obtain the same Poisson?s ratio in the calibration，a larger value of the contact stiffness ratio should be chosen in the CPBM. The UCS and TS can be scaled by either the parallel-bond shear strength or the parallel-bond normal strength，depending on the ratio of the two quantities. The UCS is also dependent on the number of particles in one clump.

The characteristics and laws of rockburst at diversion tunnels in Jinping II hydropower station are summarized through analyzing a mass of rockburst incidents recorded during tunneling，including the law of distribution of rockburst along tunnel axis，the way of failure of rock surrounding tunnels，the distribution of rockburst incidents in tunnel cross-section，the relationship of rockburst and distance from working face，the relationship of rockburst and time after construction，the relationship between types of rockburst and the length of failure，etc. According to these laws and the relationship of the rockburst and the geologic structure，the laws of the effect of geologic structure on the mechanism of rockburst are analyzed. Rockbursts at deep tunnels in hydropower station are monitored and predicted by using microseismic monitoring technique to real-time monitor and analyze the microseismic incidents. Based on the results of microseismic monitoring of rockburst，the relationship of the temporal and spatial change rules of microseismic activity and rockburst incidents is preliminary discussed. The results of study show that there exists laws of temporal，spatial and intensity distribution of rockburst；geologic structure，construction method，construction disturbance and many other factors all have a significant effect on the behaviors of rockburst；and the geologic structure has a control function. There always be a process of gestation before rockburst，with a lot of micro-fractures emerging and microseismic energy losing(microseismic indication). Microseismic activities always occur ahead of rockburst，while the locations of them coincide with rockburst，thus the safety of construction can be guaranteed. The actual test in this project shows that it is available and reliable to predict rockburst using microseismic monitoring technique，so as to provide a new idea for prediction of rockburst and safe construction.

The hazard of Ordovician limestone karst water is the key threat of deep mining in north China type coal field，the main reason of which is the complicated hydrogeological environment. The lithology of Ordovician top，the development characteristics of karst fissure and the relative water abundance are studied in detail by means of drilling，hydrogeological tests and transient electromagnetic exploration. The relative impermeability of Ordovician top is presented. Single well pumping test and multiple well pumping test are conducted and the characteristics of seepage field of the aquifer is found out. The hydrochemical field and its evolution law are discussed deeply by the water chemical analysis. The general evolution sequence of karst water quality type during the run-off path is HCO3→HCO3•Cl→Cl. The study zone is divided into run-off partitions by hydrochemical field，which indicates that the field Ordovician limestone aquifer is located in weak flow and stagnant regions. The general principles are put forward based on the hydrogeological characteristics of field Ordovician limestone aquifer，including reasonable depth and convenient implementing，first geophysical exploration and target outlining，hydrographic system construction and monitoring detection following，upstream drilling and guiding grout，effects guaranteeing and paying attention to environmental protection. This study provides some guiding significance for preventing and controlling of Ordovician limestone karst water hazard under deep mining condition and the reform of Ordovician limestone aquifer.

With the dynamic analysis and shaking table model test，this paper focuses on the dynamic response characteristics of tunnel through fault fracture zone in longitudinal direction under seismic action. When tunnel is located on the interface of surrounding rock and fault fracture zone，the seismic internal forces and stresses of lining will increase rapidly. When the tunnel cross-section moves away from the fault fracture zone along the longitudinal direction，the seismic internal forces and stresses of lining tend to be stable gradually. The research shows when the angle between the fault and the tunnel axis is in the range of 35°–90°，the reasonable aseismic fortified length for tunnel through fault fracture zone is 3.5 times of the tunnel span. The results could provide a reference for seismic fortification of tunnel engineering.

The crater depth and crack length of granite targets impacted by different velocity projectiles were studied with experimental and numerical methods. Five experiments were carried out by gas gun. The crater diameter，maximum penetration depth，distribution of cracks on target surface and the other destructive effects were obtained from the experiments at three different impact velocities. The distribution of inner cracks was attained with the help of cutting target normally impacted by the projectile at the velocity of 654 m/s. Nonlinear dynamic software Autodyn was used to simulate the penetration destructive effects of granite target. Johnson- Holmquist shock damage constitutive model(JH–2 model) and tensile crack softening model were coupled together to simulate the compressive and shear destructive effects in high pressure region，and the damage and propagation of radial tensile cracks generated by the principal tensile stress in low pressure region. Instead of traditional elements-deleting methods in FEM，the arithmetic of SPH was used and the parameter of damage was defined to describe the failure of compression and the cracks induced by shear and tensile failure. The simulation results about crater depth and crack length are consistent with the experimental ones. Based on numerical validated model parameters，serious numerical experiments were implemented；and formulae about crater depth and crack length of granite targets under the impact of different velocity projectiles were obtained. The method and the validated material model parameters used in this paper could be referenced by relevant experiments and simulations.

A new generalized nonlinear yield criterion(GNYC) is proposed to describe the yield and failure behaviors of geomaterials，including the coupling behavior of shearing and compression，through extending the generalized nonlinear strength theory(GNST). The interpolation function between SMP criterion and generalized von Mises criterion is adopted as the yield function of the new criterion on deviatoric plane；while the closed curve function considering coupling behavior of shearing and compression is adopted as the yield function on meridian plane. As the yield function is established in the transitional stress space，the nonlinear power function is adopted as the failure curve in new yield criterion，which can be described using the proposed criterion compared to the MNLD criterion(interpolation criterion between Matsuoka-Nakai criterion and Lade-Duncan criterion). The influence of the variation of hydrostatic stress on yield behavior on deviatoric and meridian planes can also be described more reasonably by the new criterion. There are physical meanings for all parameters in the new criterion and the values of parameters can all be determined by conventional tests. The validity of the new criterion is confirmed by data from yield and failure tests of different geomaterials.

It is well-recognized that normal fault dislocation may cause severe damages to buildings and underground structures during earthquake. Understanding of deformation mechanisms of overlying soil becomes even more challenging in cemented soils with pre-existing fracture. Two groups of centrifuge tests were conducted to investigate deformation mechanism and variation of pore pressure during normal fault propagation in cemented clay. A filter paper technique was adopted to simulate the effects of a pre-existing fracture. A bending deformation mechanism was identified in cemented clay with and without the pre-existing fracture. Although the area of bending zone was reduced，the extent of damage was increased by the presence of pre-existing fracture. Observed fault ruptures could be characterized as tension cracks and shearing cracks. These ruptures provide preferential paths for dissipation of excess pore pressures generated during normal fault propagation.

At present，there are few studies of applicable conditions of models and evolution laws of soil arching effect. To solve this issue，a new plane strain model test apparatus is developed to discover macroscopic soil arch shape under different pile spacings and the evolution process of soil arching during the settlement of soil between the piles. Soil and piles are simplified into removable plates and rigid plates，and the pile-soil interaction is simplified into relative settlement on the pile top，which could be simulated by moving the removable plates in a precise way. Photographic survey is applied to the model test. Every 0.02 mm when the plates settle，a photo is taken. Then whole field displacements of the embankment can be measured by tracing the particles. Nine groups of piled embankment model tests with 3 different filling heights and 3 different pile spacings are carried out with the new apparatus. A couple of symmetrical triangular sliding surfaces appear initially in all the 9 tests，which is called initial triangular arch model. Following two different evolution modes for the initial triangular arch model will be revealed with further moving the removable plates：in the case of H/(s?a)＜1.8，the initial triangular arch model will turn to be triangular multi-arch model with the increased settlement of soil between piles；in the other case of H/(s?a)≥1.8，the initial triangular arch model will evolve into pagoda-shaped multi-arch model with the increased settlement of soil between piles. Key parameters of different stages of the models are summarized，which will provide reference for the next mechanical analysis in soil arching development condition.

The evaporation mechanism of Fontainebleau sand using a large-scale model chamber is studied. First，the evaporation test on a layer of water above sand surface is performed under various atmospheric conditions，validating the performance of the chamber and the calculation method of actual evaporation rate by comparing the calculated and measured cumulative evaporations. Second，the evaporation test on sand without water layer is conducted under constant atmospheric condition. Both the evolutions of atmospheric parameters and the response of soil are recorded. The evaporation mechanism of sand and its actual evaporation rate are analyzed using the recorded data. The results show that the chamber exhibits a good performance and the calculation method of actual evaporation rate is relevant. Moreover，evaporation process affects soil temperature. Two large temperature gradients are identified at soil-air interface. The relative humidity of air decreases along with the evaporation process. The effect of evaporation process on soil volumetric water content is related to evaporation duration and soil resistance. The matric suction gradients of soil at surface zone increase during evaporation.

Experimental research on intact unsaturated loess under three different natural dry densities and six different water contents is conducted by using unsaturated soil consolidation apparatus，and the effects of natural dry density and vertical stress on soil-water characteristics are analyzed. The test results show that the initial matric suction of the intact unsaturated loess water content，and the dry density has an considerable effect on soil-water characteristics. A concept of critical load of suction is proposed. Under the same dry density of the intact unsaturated loess，the critical load of suction decreases with the increasing water content. Under the same water content of the intact unsaturated loess，the critical load of suction increases with the increasing natural dry density. Under the fixed water content，the change of dry density induced by the vertical load has different effects on the suction from the change of the initial dry density. The vertical stress has little effect on soil-water characteristic curves，so the suction situation could be described by using soil-water characteristic curves under zero-load condition. Finally，the function of fitted soil-water characteristic curves is established.

This paper aims at analyzing the passive mechanical characteristics of axially loaded isolation piles under large-scale surcharge loading. Firstly，the formulation for calculating lateral additional pressure with local surcharge is deduced based on the solution of improved Boussinesq. Then according to soil movement and stress transfer approach，the rational passive load distribution of isolation piles is obtained by improving local deformation theory of plasticity considering soil arching. Finally，differential equations of elastic and plastic regions of isolated piles are established by considering the gravity second-order effect caused by lateral load and yield of soil for tri-parameter Winkler elastic foundation beam model. Combining matrix transfer method with Laplace forward and inverse transformation，the numerical solution of passive mechanical features of isolation piles is obtained. Later，the proposed approach is verified by the test data. The results indicate that the numerical and measured results are in good agreement，and the proposed approach is applicable in engineering practice.