In order to observe and measure the rock void structure characteristics under different stress conditions，a triaxial test instrument which can work with micro focus X-Ray computerized tomograph was developed. The apparatus is lightweight. It can exert triaxial pressure on the rock specimen，and carry out CT scan and permeability measurement on the specimen without unloading pressure. Besides，it can record pressure and deformation in real time. Using this device，a series of CT images during triaxial loading process for Berea sandstone were generated. Combining with the 3DMA computational package for analyzing the void structure，some quantitative microscopic geometric characteristics of Berea sandstone in different stress states，such as effective pore radii size distribution，effective throat radii size distribution，and tortuosity distribution，have been obtained. The permeability of Berea sandstone in different directions under various effective confining pressures was measured with a transient pulse technique. Combining the permeability test result with the computed result about influence of confining pressure on microscopic void structure parameters，we can see that the change of microscopic void structure is the root cause of permeability change. When increasing the effective confining pressure from 0 to 15 MPa，the permeability reduction is caused by a decrease in the population of pores with a radius of 40–100 μm，decrease in the pore and throat radius，and increase in the tortuosity in the Z direction in stressed Berea sandstone.

The folded mountains in Chinese southwest limestone mountainous areas have been undergoing long-term active geologic uplift and river erosion，leading to a“boot”-shaped morphology as steep and thick limestone strata in the upper layers，while gentle shale and mudstone strata in the lower layers. Combined with the exploitation of coal and bauxite seams，this region has become a highly hazard-prone area of large-scale stratified rock collapse in China. In this paper，the steeply inclined Jiguanling rockslide in Wulong，Chongqing is taken as an example. FLAC3D is used to simulate and analyze the progressive failure process of steeply inclined rocks induced by underground mining，i.e.，“rock bending-interbedded shearing-toppling-toe breakout-overwhelming slide”. It is considered that Jiguanling rockslide is a compound failure mode of stratified rock mass with toppling and sliding. Simulation results show that：(1) under long-term gravity the steep slope creeps along the mountain ridge，gradually producing tensile cracks；meanwhile，due to the slope situated near the anticline core areas，the stress concentration results in bending deformation of the overburden strata；(2) the long-term karstification accelerates the development and widen of slope fissures；(3) the coal mining induces stress redistribution at Jiguanling mountain ridge，stratum separation is gradually shown in the overlying rock mass，cracks are formed in the underlying rock mass，and the strength of rock mass is gradually reduced；(4) after the gradual mining，the deformation of overlying rock mass increases sharply with toppling and failure，squeezing the underlying rock mass，leading to shear failure，and finally the collapse-debris flow is formed. Thus，in the southwest limestone folded mountains，the understanding of the effect of underground mining in stratified rocks is important for disaster prevention and mitigation of large limestone mountains as well as risk zoning.

Aiming at the powered support jammed accidents are prone to take place in the working face with a raise of mining upper limit of Huainan mine area，the special overlying strata structure and its mechanism of powered support jammed are researched by using of theoretical analysis and field measurement. The corresponding mechanical models of support and surrounding-rock are established for different overlying strata structure，the loads of topsoil layer and overlying strata transfer into the key strata is deduced，the critical support working resistance is defined，and related preventive measures are put forward. The results show that: the structure type of overlying strata can be classified into six groups within four types according to filling coefficient of immediate roof，overburden key strata structure，and hydrogeology of topsoil layer on the bedrock surface. The risk of powered support jammed with single key strata structure is higher than that with multi-key strata in upper exploitation limitation-heightened working face. For the single key strata structure，when mining below the unconsolidated confined aquifer，the load on the key strata increases with the decrease of distance from the key strata to the aquifer and the increase of hydraulic pressure，so，the key stratum“voussoir beam”structure is more prone to sliding instability; while mining below the thick hardpan，the natural balance arch structure is formed in the hardpan，the sliding instability is not likely occur in the“voussoir beam”structure with the protection of arch structure.

It?s important to implement advance geological forecast for Weak zone in a long diversion tunnel construction by GPR. This paper take gravel and clay mixed dielectric constant as the research object，and study on the relative dielectric constant of shale and water mixture and its trend. Then we deduce the experience formula and the relation curve moisture content of the mixed dielectric constants. Therefore we make FDTD(Finite Difference Time Domain) forward modeling by means of two kinds of spatial distribution of weak zone，and analyze the typical imaging regularity and characteristics. So as to we may achieve the purpose of the space position in the weak zone from the measured data. Analysis results as follows：The volume ratio on the mixing soil and gravel mixture component have great influence on the dielectric constant. Meanwhile the water content reflection characteristics of electromagnetic wave are obvious and easily reform to multiple waves. In consequence we can remove interferences through the measured and FDTD forward. And we fixed formation value of moisture content and establish the 3D slice result maps. Which provide method and guidance for similar geological forecast projects.

Under the condition of safety requirement of high standard for blasting vibration，it plays an important role in tunnel blasting design that the interval time of millisecond blasting is accurately detimined in the complex urban environment. With the engineering background of Chongqing Yuzhong connecting tunnel blasting，an accurate blasting design method basing on the measured delay time is proposed，in which multi-deck customized non-electric detonator is adopted to meet the severe low-vibration control requirement in single hole cutting blasting. The identification ability on detonator’s delay recognition of instantaneous energy method in the Hilbert-Huang Transform theory is compared with EMD method. The recognition rate of EMD method is 70%～90%，about 30% higher than the instantaneous energy method. The delay time identified by the EMD method proves that actual millisecond interval is in the accuracy range of samples. On the basis of vibration wave graph and actual delay time，blasting parameters are adjusted for controlling blasting vibration accurately. Field vibrate monitor data shows that using multi-deck customized non-electric detonator can alleviate the disparity about lacked detonator delay，and single hole cutting can meet severe low vibration controlled requirement； the blasting design combined with measured detonator delay time identified by EMD method is feasible to severe vibration control. Blasting advance per attack can reach to 1.8 m under the condition of vibration velocity is less than 0.8 cm/s，and excavations of upper bench are finished by blasting twice. This design method has a certain reference value for shallow buried tunnel safety blasting operation in urban crowded buildings environment.

To investigate the diffusion mechanism of expansible polymer grouting material in fractured rock mass，a numerical approach for simulating variable density grout diffusion in two-dimensional fracture is developed based on computational fluid dynamics theory，modern fluid field calculation method and moving interface tracking technology. For this method，the numerical solution of the two-phase flow system of polymer and water is attained by using FVM for discreting its governing equations，adopting Youngs method to track the interface of the two phase fluid，and employing SIMPLE algorithm to iteratively solve discretised momentum equations，pressure and velocity correction equation. The validity of the proposed method is proved by the example of variable density fluid freely expanding in the two-dimensional rectangular slot. Then the algorithm is used for simulating the expansible grout?s diffusion in two-dimensional plate fissure，and the results show that the method can dynamically display the distribution characteristics of the flow field and the displacement effect between poymer and water，which can lay a foundation for further research on the expansible polymer grouting material’s diffusion mechanism in fractured rock mass.

Double liquid grouting mode of fast curing grouts leads to spatial uneven distribution of viscosity in diffusion region of slurry. Regarding fast curing grouts as Bingham liquid of time-dependent Behavior，in stationary water environment，diffusion process of slurry in horizontal crack is studied. Considering spatial uneven distribution of viscosity，theoretical model of grouting in horizontal crack at constant grouting rate is established. Space-time distribution equation of viscosity and pressure in diffusion region of slurry is derived，and the influence mechanism of grouting time and grouting diffusion radius on grouting pressure is obtained. Comparing with result when spatial distribution of viscosity is even，it is essential that considering spatial uneven distribution of viscosity. Predefining the spatial distribution function of viscosity in numerical model，numerical simulation of crack grouting process considering spatial uneven distribution of viscosity is realized. Comparing theoretical analysis，numerical simulation and test results，rationality of theoretical analysis and numerical simulation is verified. It is hoped that the results will be constructive to grouting parameters determination in practical engineering.

The segmentation of lining crack image and characteristic extraction are the key points for the automatic crack detection. Based on theenormoustest of the collected images，the digital image processinganalysis is optimized，and some algorithms are improved. For the image segmentation，this paper proposes a newbinaryzation algorithm combining Prewitt operator with Otsu threshold. The binary image processed by the new algorithm，combined with mathematical morphology，can result in the one with more complete fracture zone and less interference regions.For characteristic extraction，area，perimeter，compactness，rectangle degree，Feret’s occupy rate，and the mean width are defined as the morphological characteristics.The real application results showthat the integtated algorithm can achieve better image segmentation，and it is more suitable for crack image with complex background. The characteristics extracted fromdifferent regions in the imagecan form a representative information base andlay a foundation for automatic identification of cracks.

Due to the limitation of Modified Cam-clay model，which can?t depict overconsolidated or structured clay，the concept of super-subloading surface was introduced to describe the destruction of Boom clay. According to the characterization of yield surface of Boom clay，the super-subloading surface model was modified based on energe dissipation. Adopting the closest point projection method(CPPM)，the UMAT subroutine of the developed model is implemented in FEM code ABAQUS. With the developed model and Modified Cam-clay model，numerical simulations of undrained triaxial compression tests on Boom clay under different confining pressure was performed. The simulated results with two different models were compared with the test results. It was shown that the developed model can depict the destruction process of Boom clay during shearing and the peak strength of overconsolidated clay was decreased compared with conventional super-sub loading surface model.

Based on a series of creep tests with MTS815 rock mechanics test system and the acoustic emission(AE) monitoring system，the creep behavior of the Beishan granite is experimentally studied. A special attention is paid on the influence of temperature and stress level on the creep behavior and cracking process. The experiment data revealed that the creep process can be divided into three stages：the transient creep，the steady creep，and the accelerated creep. The rock failure is essentially related to the intensive accumulation and coalescence of microcracks during the accelerated creep stage. A consistent tendency between AE cumulative counts and volumetric creep strain is noticed. The variation of recorded AE events is found to be more sensitive to the occurrence of rock failure than the volumetric deformation. Under same confining pressure，it is indicated that the increase of temperature and stress level has quite limited affect on the total deformation before rock failure，while it may accelerate the cracking process，and consequently reduces the time to failure. The Beishan granite failed at a similar axial strain under the same confining pressure，of about 0.34%，0.54% and 0.71% under confining pressures of 2MPa，10MPa and 30MPa respectively.

Some site condition of Chinese strong-motion stations is still unknown，which greatly restricts the effective application of strong-motion records. We proposed a site classification scheme based on strong-motion data from Japanese KiK-net stations according to Chinese Code for Seismic Design of Building(GB50011-2010)，and calculated the Chinese mean site classification curves using the spectral ratio method from 279 stations of KiK-net. Then an empirical method for Chinese site classification was proposed based on the range of predominant period，peak value of spectral ratio and the spectral shape. Compared with the borehole information of stations in Chinese Sichuan Province，the classified result shows that this method is independent of different regions. Finally，we were able to classify Chinese 113 strong-motion stations from the records during 2007 to 2011.

To reveal the stress-contraction pattern of loess in shearing，undisturbed specimens were obtained from the backwall of a typical landslide in Heifangtai. Three series of triaxial tests were carried out，including isotropically consolidated undrained tests and isotropically consolidated drained tests for saturated loess，and constant water content tests for unsaturated loess. The stress-strain relationship and the critical state strength of the loess are explored. The state parameter and the contractive/dilative behavior of the loess are investigated. The stress-contraction/dilation rules of the loess are studied based on classical dilatancy equations. The findings are as below： firstly，the saturated soil shows a unique critical state line which could represent the major stress level corresponding to the thickness of Heifangtai loess，while the unsaturated soil at 94 to 100 kPa suction shows a roughly parallel critical state line. Secondly，the loess commonly demonstrates a tendency of contraction or contractive deformation， but can also shows a tendency of dilation or dilative deformation which is affected by its initial void ratio and intial stress level. Thirdly，the undisturbed loess can be depicted by the soil state parameter，and can also demonstrate the phase transformation behavior from contraction to dilation. Fourthly，the contractive behavior of the loess can be generally reflected by the dilatancy equation in the Cam-clay model.

For structures constructed onto pile foundations，according to embedded condition of raft，pile foundation could be distinguished into high and low raft pattern. In many practical engineering，Due to post stage settlement of unconsolidated clay or backfilled soil after construction，or other cases such as soil rheology and seismic field subsidence，all of these may lead to a separation of raft from clay surface，i.e. from original design state which raft was embedded into clay to a new state of high raft pile foundation. For static condition，this kind of separation may disadvantageously result in negative skin friction force along piles，and in turn to reduce vertical bearing capacity of piles. However，during seismic shaking condition，this study，by conducting centrifuge shaking table experiments and ABAQUS simulation on both cases，indicates that pile will undergo a higher maximum bending moment and a much larger active depth under high raft case than those of low raft case. This suggests that embedding condition plays an important role in seismic response of pile-raft foundation，it will become more disadvantageous when raft embedding condition changes from low raft case to high raft case，and should be taken into enough account on practical engineering design.

A series of undrained tests were carried out on Hangzhou soft clay with a hollow cylinder apparatu，and the elastic parameters were obtained at first，on the basis of which the non-coaxial development behavior of soft clay was studied as well as the influence of intermediate principal stress parameter，elastic strains，intermediate principal stress parameter，deviatoric stress and induced anisotropy on non-coaxiality. The results show that the non-coaxiality of soft clay is similar to that of sand，but they are far from identical. Regardless of intact soft clay or remodeled soft clay，the non-coaxial angle fluctuates with the increase of angle of principal stress，of which the cycle period is 90°. The non-coaxial angle basically decreases with the increase of intermediate principal stress parameter. The elastic strains have a significant effect on the angle of non-coaxiality at the beginning of loading，and it will overestimate the non-coaxiality of soft clay if not considering the elastic strains. The deviatoric stress has certain effect on the angle of non-coaxial as well as its development trend，and the larger the deviatoric stress is，the smaller the angle of non-coaxiality is. As to the test of remodeled soft clay，it shows that the non-coaxiality is not only entirely determined by the inherent anisotropy，the induced anisotropy also has a great impact.

In order to discuss the torsional behavior of single pile in nonhomogeneous single-layer subsoil，based on the balance principle，the shear displacement method and power function distribution model of the subsoil shear modulus，the load-deformation control equation for the pile shaft and surrounding subsoil under pure torsional load was first set up，in which the non-zero subsoil shear modulus at the ground surface (on the contrary，zero value was assumed by almost all available other methods) and the nonlinear limit friction resistance along the pile-soil interface were considered as well. Then，elastic，elastic-plastic and plastic analytical solutions for the inner forces (torque) and deformation (torsion angle) of the pile shaft under various bearing states were deduced respectively. Based on the obtained solutions，a parameter analysis was carried out to find out the influencing factors and rules for torsional piles. The results show that，the non-zero subsoil shear modulus factor of ?g at the ground surface will influence the transmission efficiency of torque along the pile shaft. Furthermore，pile head stiffness will gradually decrease with the plastic zone development depth in the subsoil. When the plastic zone reaches a depth of 0.3 times of pile length，the pile head stiffness will reduce by 60%，i.e.，plastic failure in the surface soil layers plays a leading role for the decreasing of pile head stiffness. Therefore，reinforcing the surface subsoil is an effective way to improve the performance of torsional piles in practice.   

More and more crossing projections will appear with the further development and utilization of urban limited underground resources. In order to discuss the mutual influence between underground structure and above structure seismic responses，a tunnel-soil-adjacent frame structure computation model was established and the key influence factors on system seismic responses were studied systematically，which include：tunnel depth and radius，the character of layered soil，the ratio of frame height to width，the distance between frame structure and tunnel center，the characteristics of input seismic waves. The computation results show that：(1) The existence of tunnel almost have no influence on system natural frequencies，while frame structure has a significant influence on system frequency character. (2) The main influence of tunnel on frame structure is come from tunnel radius because the bigger tunnel size can break the propagation of seismic wave and some degree of shock absorption can be achieved. (3) The influence of frame structure on tunnel seismic response is insignificant because the frame structure considered in the paper is too light；(4) The characteristics of input seismic waves have a significant influence on system seismic response because the frequency contents and frequencies of frame structure itself. (5) System seismic responses were influenced greatly under multi-layer soil and one-layer soil because soil stiffness was changed under different soil models. The research results can provide references for preliminary determine the mutual influence on their seismic responses qualitatively.

Model specimens of slabbing failure were made by using high-strength gypsum and pre-stressed bolt model were made by aluminum bar，the reinforced effect of bolt on the model specimens is studied under the condition of one lateral side restraint uniaxial loading test. The results show that：the peak strength，residual strength and elastic modulus of reinforced specimens increase at different degree，the lateral deformation after peak strength decrease dramatically， the effect is more obvious with the increase of pre-stress of bolt；different with the bulcking failure of slabs and ejection of slices of the unstability destruction phenomenon of unreinforced specimens， the reinforced specimens remains better integrated with local breakage and fall off of slab；the change of the axial stress of bolt during the deformation of specimens can be divided into three stages：the linear slow growth stage，nonlinear growth stage and sharp rising stage，the change rule of the axial stress of bolt reflect its working mechanism and the deformation characteristics of the specimens. The anchoring mechanisms are analyzed：the applying of pre-stressed bolt not only effectively weaken the concentration effect of stress near crack tip，playing the role of restraining the propagation of pre-existing fissures but also significantly restrict the bulcking deformation of slabs by reinforcing the splitting rock slabs into a whole，playing the role of improving the critical buckling load values of the slabbing specimens. At last，based on the results and perceive of the experiments，a“timely supporting，regional control and key area reinforcement”anchor spray support control strategy is put forward against to the control of slabbing surrounding rock.

Several important stress thresholds，termed as the crack closure stress，the crack initiation stress，the crack damage stress and the peak stress，can be identified from the progressive failure process of brittle rocks. The crack closure stress and its relationship with the stress-induced microcrack damage were studied. Firstly，various methods that have been proposed for identifying the crack closure stress were reviewed，and a new method，called as axial strain response(ASR) method，was proposed. An attractive feature of the proposed method is that it does not require subjective interpretation from the user and can be easily programmed. Secondly，the method was verified using the test data from uniaxial and triaxial compression tests. The crack closure stress determined from the ASR method was comparable with that from other methods in unconfined and confined conditions，which validated the proposed ASR method. Finally，the crack closure stress was used to evaluate the stress-induced microcrack damage of three types of rock from Forsmark and Oskarshamn sites，Sweden. By correlating the crack closure stress with the sampling depth，it was found that the crack closure stresses varied with the sampling depth. At the shallow depth，the crack closure stress increases roughly linearly with depth increasing. However，at greater depth，the crack closure stress is more or less constant. A linear relationship between the crack closure stress and the difference of in-situ stress was also observed，indicating that the magnitude of the difference of in-situ stress may be a key factor that dictated the amount of stress-induced microcracks in the rock.

Fracture toughness of rock is one of the most important factors for evaluating the fracability of shale reservoir quantitatively. Based on straight seam grooving Brazilian disc test(SNBD)，fourteen shale pieces taken from Longmaxi Formation have been tested to measure fracture toughness of both type I and II. And by using the above results，combining with the logging data where the cores locate，the paper makes a regression of the shale fracture toughness with the data of density，acoustic time and GR logging. Comparing previous prediction model based on tensile strength，a direct relationship between fracture toughness and geophysical logging data was established in this paper. According to the prediction model，fracture toughness of organic-rich shale is proportional to the density and interval transit time of rock，while inversely proportional to its shale content. The more total organic carbon(TOC) or clay mineral is， the smaller fracture toughness is，it is more easily to extend forward after crack initiation. The results indicate that the fracture toughness of predication model has a pretty good correlation with that measured by SNBD. This paper can provide important theoretical basis for engineering design process to identify“Sweet Spots”.

Thermal expansion and thermal conductivity instruments were used to measure the coefficients of thermal expansion(CTE) and thermal conductivity(TC) of Fushun oil shale in directions vertical and parallel to bedding. Experimental results were adopted in the simulation of thermal cracking based on the orthotropic assumption and one-way physical coupling. The CTE vertical to bedding was 1.69 times as much as that parallel to bedding，while the TC parallel to bedding was 1.83 times larger than that vertical to bedding direction. With the temperature increasing，the TC descended linearly while CTE fluctuated. KI varied when hydraulic fracturing dip changed，and KI reached the maximum when the dip was zero. The concept called the local effect during the thermal conducting was put forward to reflect the temperature distribution near the fractured area.

Frost heaving pressure in rock mass undergoes a process of initiation，development and dissipation under the freezing-thawing condition，which results in the fatigue degradation of the physical and mechanical properties of rock. The freezing-thawing damage model and the damage evaluation method are the key problems for the rock mass in cold regions. There are many evaluation indexes of freezing-thawing damage including the porosity，the longitudinal wave velocity and the elastic modulus. The frost heaving pressure was considered to be equivalent to the triaxial tensile stress for frozen rock mass. A freezing-thawing fatigue damage model was established based on the equivalent triaxial tensile stress. The equation describing the freezing-thawing damage variation has the same expression but the different physical meaning with that obtained under repeated uniaxial tensile stress. A new unified damage variable depending on the p-wave velocity and the porosity was deduced based on the definition of the dynamic modulus of elasticity. The damage variable includes the effect of dual physical parameters，and is a better prediction index for the uniaxial compressive strength under different freeze-thaw cycles. The loss of 40% of dynamic elastic modulus was defined as the damage threshold. With the damage threshold，the maximum failure freeze-thaw cycle was determined. The freezing-thawing damage model was solved in combination with the unified damage variable. Finally，the validity and applicability of the freezing-thawing fatigue damage model were illustrated through two examples.

In order to apply two-scale coupled approach for solid phase to saturated soil，a scheme coupling fluid and discrete-continuous solids is established. For fluid-phase，based on the ALE(arbitrary Lagrangian Eulerian) description which is convenient to control moving boundaries and meshes，unified fluid dynamic equations are established. Besides，the fluid-solid interaction terms which exhibit unified forms and pick up fluid-solid interaction forces in the discrete and continuous domains respectively，are incorporated in these fluid equations. Then based on the Characteristic-based split algorithm，the split of the developed fluid dynamic equations is performed to obtain the proper forms suitable for a standard Galerkin-type discretization procedure. Finally，this proposed method is applied to simulation of underground structure buried in liquefiable soil under seismic excitation，which demonstrates that this scheme incorporates discrete-continuous solids and unified fluid dynamic equations can effectively depict non-continuous contacts between particles and the underground structure，decrease the number of particles for simulation，and take into account moving boundaries for fluid-phase caused by underground structure as well.