The creep rules of sandstone are obtained based on the creep test results under different confining pressures. The results show that，Burgers model can effectively describe the instantaneous elastic deformation，attenuation and steady creep deformation of sandstone，and the results fitting at the least square method demonstrate Kelvin model has optimization effect to Burgers model. According to the accelerating creep results under different confining pressures，a modified visco-plastic creep model is obtained by introducing the empirical model and combining Kelvin model for its optimization，and it reflects the accelerated creep characteristics accurately. By combining this modified model with Burgers model in series，a new nonlinear viscoelasto-plastic model can be put forward. Using the 1stOpt software to identify the new model parameters，the results are satisfactory. A comparison between the test and theoretical curves proves the validity of the proposed model.

In order to reveal the crack and destabilization evolvement laws of hard rock pillars under dynamic excavation，taking typical iron deposit as physical prototype，the large scale model experiment was carried out using VIC–3D strain measurement equipment of non-contact and in-plane and stress monitoring system and acoustic emission. The results of research indicate that multiple superimposed damages will occur in pillars during excavation of adjacent stopes in horizontal and vertical directions，the barrier pillars and central top pillar of first layer are damaged seriously and show a higher degree of degradation of mechanical properties. On the basis of the analysis of evolution characteristics of pillar damage，large deformation，instability collapse at different stages and based on the compressive arch theory，the destabilization evolution mode of pillars failure was established. Pillars are in low damage stages during the early excavation，which belongs to stable intermittent period. The increase of pillar damages leads to instability falling of barrier and top pillar，which belongs to bursting period. Pillar damages and instability were key factors causing the collapse of goaf，so the displacement，acoustic emission and stress monitoring methods should be used to monitor the severely damaged area，and effective control measures should be taken before the failure period of the pillars.

In order to study the influence of bedding angle and loading rate on the fracture toughness and energy dissipation of coal，notched semi-circular bending(NSCB) specimens were tested by using a split Hopkinson pressure bar(SHPB) system. The dynamic fracture toughness of coal specimens with various bedding angles under different loading rates were analyzed and discussed. By comparing the incident energy，absorbed energy，fracture energy and residual kinetic energy of coal samples with different bedding angles under various impact velocities，the energy dissipation law of the dynamic fracture process of coal considering the bedding direction effect is obtained. The experimental results indicate that the fracture pattern of NSCB coal samples is tensile failure and the two pieces of the broken coal sample rotate at a constant speed. The dynamic fracture toughness of coal sample is 3.52–8.64 times of the quasi-static fracture toughness. The dynamic fracture toughness increases with the increase of impact velocity，but the effect of bedding angle on dynamic fracture toughness decreases with the increase of impact velocity. The dynamic fracture energy of coal samples increases with the increase of impact velocity，but the energy utilization ratio decreases with the increase of impact velocity.

The tensile strength，deformation modulus，Poisson's ratio and other anisotropy parameters of quartz mica schist are studied by splitting test. A single rock specimen is designed to test the tensile strength of rock under different splitting surface and schistosity angle. According to the relative difference between the tensile strength and the variance value of the rock specimen after multiple rock fracturing，a method of distinguishing good and poor sandstone homogeneity is proposed. The results show that the variation of tensile strength，tensile modulus，Poisson¢s ratio and splitting surface and the schistosity angle q of the rock are as follows：The tensile strength of quartz mica schist increases linearly with the increase of q. The size effect of tensile strength decreases linearly with the increase of q. The anisotropic degree of tensile strength decreases as the height of the rock sample increases. When 0°＜q＜50°，the tensile modulus decreases with the increase of q，and the Poisson's ratio increases with the increase of q；When 50°＜q＜90°，the tensile modulus increases with the increase of q，and the Poisson¢s ratio decreases with the increase of q. The single and triaxial tests were carried out on the samples of dry and saturated states. The results show that the quartz mica schist in the dry and saturated state belongs to low anisotropy of rock mass；The elastic modulus，internal friction angle and cohesive force under dry and saturated condition increase linearly with the increase of confining pressure.

Based on fracture mechanics theory，assuming that the crack is evenly distributed in the homogeneous rock，an ideal crack element is established. The R-curve theory of rock creep fracture process is put forward based on the R-curve theory of fracture mechanics and the crack opening displacement(COD) theory. By using this curve，the whole process of rock creep fracture can be reasonably revealed and the key parameters used to describe the status change of rock creep process are obtained. According to the characteristics of this curve，the control equation for predicting the accelerating creep of rock is established. Combined with the improved Nishihara creep model，A new rock creep model is established，which can accurately predict the accelerated creep process of rock and verify the accuracy of the prediction method with rock creep test. The theoretical basis for the intensive study of rock creep also provided by this model.

To understand mechanical behaviors of joint rock with large number of non-persistent discontinuities，a new calculation of the connectivity，defined as the radio of non-persistent joint area to apparent persistent joint area，is presented based on the 3DEC discrete element software. The non-persistent joint area can be evaluated according to 3D discontinuities network through calculation of thin disk area. The apparent persistent joint area is closely related to the geometry of cutting rock mass which can be subdivided into regular and irregular shape. In the case of regular rock mass，the apparent persistent joint area is computed by simultaneous equations. For irregular rock mass，the area can be obtained using points searching approach. The proposed method is validated by two examples，and the results show that the study can achieve the numerical simulation of the mechanical behavior with respect to larger number of non-persistent jointed rock mass，and points searching approach can solve the areas of cross sections in both regular and irregular shaped rock mass efficiently. Additionally，simulation results are reliable which have good agreements with reality in two examples.

The purpose of this paper is to figure out the distribution of interfacial shear stress and how the load transfers. Based on the uniform form of shear displacement distribution curve，the formula for calculating the displacement，axial force and side resistance of infinite-length anchor bar was established. The constitutive model of double exponential curve was derived，which is essentially the same as that of Huang Minghua Model. Also，the exponential form of load-displacement curve at the top of anchor bar was deduced. The formula was further modified to apply to the finite-length anchor bar，and thus the modified formula of load and displacement distribution was obtained，by which the constitutive relation of the contact surface of the anchor can be explained with anchorage depth varies. It is noted that the modified formula avoids the limitation of the assumption that the constitutive relation at the contact surface is uniform and thus the modified formula has higher applicability. It was then verified by an engineering example. And based on this method，the whole working course for the force transferring mechanism of the anchor bar was analyzed.

Scaled model tests were carried out for a 3-lanes highway tunnel to investigate the stability of tunnel excavation nearby karst cave with internal pressure. Characteristics of tunnel convergence，steel arch internal force，surrounding rock pressure behind primary support and surrounding rock strain influenced by karst cave in different position are acquired in the process of tunnel excavation under certain cavity size and the internal pressure. The condition of no karst cave is also compared. The result shows that：the size order of tunnel vault final subsidence is vault subsidence of no cave＞vault subsidence of karst cave on vault＞vault subsidence of karst cave on side wall＞vault subsidence of karst cave on invert，the size order of tunnel side wall final horizontal convergence is convergence of karst cave on invert＞convergence of karst cave on vault＞convergence of no cave＞ convergence of karst cave on side wall. Comparing with the condition of no karst cave，the existence of adjacent karst cave increases the bending moment of steel arch，the inhomogeneity of axial force distribution and the eccentricity，which is not conducive to the stability of primary support structure. Meanwhile，the existence of karst cave locally reduces the stratum resistance and the surrounding rock pressure，increases the inhomogeneity of the strained condition of primary support. The existence of karst cave forms a certain range of stress concentration zone around the cave，greatly changes the strain distribution of surrounding rock between tunnel and karst cave， which is not conducive to the stability of surrounding rock in this zone.

The digital laser dynamic caustics system(DLDC) was used to study crack initiation and propagation mechanisms near blasting source of grooved borehole with eccentric decouple charge. The effects of three grooves，i.e. triangle，circle and rectangle，on crack propagation velocity v，dynamic stress intensity factorand，and energy release rate G were investigated. Experimental results show that asymmetrical cracks were created at three grooves tips under eccentric blast loading and the main crack was located at the charge side but secondary crack at the other side. Groove geometries made more effects on crack initiation than propagation. As for main cracks，triangle groove benefited for opening mode crack initiation with the largest，v，and G but the smallest ，however，rectangle groove benefited for compressive-shear mode crack initiation with the smallest，v，and G but the largest . In crack propagation，main cracks of three grooves were mainly opening mode with similar trend in，v and G，and  is near to zero. As for secondary cracks，these from rectangle groove tip with the largest，，v and G consumed much blasting energy，which was not beneficial for main crack initiation and propagation. The results have theoretical reference significance for engineering.

The non-viscous damping is introduced into the DDA method in this article for analysing the influence of non-viscous damping on discontinuous viscoelastic structure. Firstly，the non-viscous damping is introduced into the motion equations of block system，and the difficulty of solving the differential motion equations was found. Secondly，with the relationship between force and displacement and the Newmark integration algorithm，the equivalent DDA motion equations considering non-viscous damping with the symmetrical coefficient matrix was derived. Finally，with specific examples，the block displacement response under constant force or resonant excitation was analyzed，and through comparing DDA calculated value and theoretical value，the correctness of the viscoelastic DDA solution considering non-viscous damping proposed in the article was verified. Thus，the DDA solution considering non-viscous damping is a highly effective method to deal with viscoelastic problem，and it provides a new idea for analysing the discontinuous deformation of viscoelastic structure.

In order to explore the mechanical response of a deep hydraulic tunnel in orthotropic rock mass，the analytical solutions of a non-circular tunnel under the action of the in-situ stresses and the internal water pressure，are derived. In the process，three polar coordinates are introduced and the conformal transformation method of complex function is adopted，mapping the outer region of the hole in the physical plane to the outer region of the unit circle in the image plane. Then，the stress boundary conditions on the excavation boundary are established. Finally，the stress field is obtained using the power-series method. Taking the inverted U-shaped tunnel as an example，the analytical solutions are verified by the numerical results obtained by ANSYS. The stress distributions along the boundary of a horse hoof-shaped tunnel and a circular tunnel are also analyzed. The results show that，unlike the isotropic rock mass，the stress field for an orthotropic rock mass shows obvious asymmetry. The tangential stresses along the hole boundary increase with the increase of the lateral pressure coefficients except the two corners of the horse hoof-shaped tunnel. Moreover，the internal water pressure can release the tangential stress concentration along the hole boundary，which is more obvious on the regions where the curvature is greater. But great internal pressure may also lead to tensile stress which will affect the stability of the tunnel.

The shales strength properties of anisotropic is significantly for it¢s weak planes. Strength analysis of weak plane rocks usually uses the single plane of weakness theory of Jeager J. C. However，this theory is limited for that didn¢t calculate the intermediate principal stress. This paper utilizes a method of calculating the stress in weak plane by tensor transformation rule. The analysis indicates that the shear strength model of weak plane rocks under tri-axial stress，because of single plane of weakness，the intermediate principal stress has a great influence on strength. While，the strength of weak plane rocks is determined byand. The laws of strength changing withare different from conventional models¢. With the increase of，the danger region of weak plane normal changes from symmetrical around theto symmetrical around the. The new weak plane rock strength models provide accurate prediction for weak plane in any angle.

Dynamic mechanical performance experiments are carried out for red-sandstone specimens in different low temperatures under impact loading，by using the f 100 mm split Hopkinson pressure bar(SHPB) with a low temperature compensation device. Then，the scanning electron microscope(SEM) is carried out to study its microcosmic character of failure surface，and dynamic compression failure rules of red sandstone are acquired by the quantitative processing of fracture network. The results indicate that，the peak stress of red sandstone increases with the increase of strain rate，and the peak stress increases with the decrease of temperature. The strengthening effect of strain rate and the hardening effect of low temperature are obvious. In low strain rate，the primary modes of failure surface are cementing material fracture and brittle fracture，with the low energy-consuming. In high strain rate，with the former fracture modes，the surface partially appears ductile damage，while the grade of energy-consuming is pretty high. The quantitatively analysis of fracture network come to the change rules of the pore number，the plane porosity and the pore′s shape factor. With the combination of experimental results and probability theory，the dynamic failure mechanism of frozen rock is illustrated from a new perspective. The research results have important significance to the theoretical study and engineering practice of the rock mass in cold regions.

In order to explore the interaction between different joints in the pressure-shear condition and the related failure mechanism，the shear resistance performance of double rough joints was studied by using both experimental and numerical simulation methods. The artificial joint samples were generated by pouring concrete into the PLA molds. It is proven that the JRC of the 3D-printed PLA joint surface is seriously reduced，which should be re-calculated before shear tests. The experimental results show that on account of the failure of the interlayer rock during the shear test，the overall shear strength of double rough joints is lower than that of either of the two joints，and even lower than that of the single smooth joint. Moreover，the PFC^2D numerical simulation on shear test of double rough joints shows that the stress concentration induced by the joint asperities leads to the failure of the interlayer rock，which further reduces the shear strength. In addition，the influence of joint spacing on shear strength is not so obvious.

The water-ice phase change simple algorithm was put forward based on the freeze-thaw energy stage assumption and the energy balance equation considering phase change. The THM(Thermal-Hydraulic-Mechanical) coupling simple algorithm was obtained according to series parallel of T-H-M. The combined simple algorithm was applied to FLAC^3D to reproduce indoor freeze-thaw tests and get similar results. And the experiment was extended to investigate sensitivity of various influence factors. As the convection heat transfer coefficient，freezing temperature and boundary temperature are greater，so the time of water-ice phase is shorter and the maximum freezing strain of radial direction is bigger. However，the greater porosity or water content is，the longer time of water-ice phase is. And the greater thermal expansion coefficient and freezing-throwing cycles¢ time are，the bigger maximum freezing strain of radial direction are，etc. The results have some reference significance for understanding temperature and deformation regularity and designing related experiments about rock under freezing-throwing.

For the alternatively distributed soft and hard rockmass of Jinping underground carves，the technology of image segmentation based on region growing algorithm is employed to characterize the meso-structure features of local areas of rock mass，and the method for obtaining growth parameter in algorithm is discussed. A meso-scale homogeneous mesh model corresponding to the rock sample is established by using the FLAC^3D program according to the proportional relation mapping method. On this basis，the mesoscopic probability model and elastic-brittle-plastic constitutive relation is realized for mechanical parameters of elements. Then，a mesoscopic numerical model of local region of stratified rock mass is established. And several numerical simulation schemes are used to investigate the influence of meso-inhomogeneity on rock mechanical properties. The results show that the meso-inhomogeneity of alternatively distributed soft and hard rockmass has remarkable influence on their deformation property，strength characteristic，acoustic emission law and cumulative damage process. 

In order to study the micro-mechanical properties of granite，the mineral compositions of granite and their proportion were obtained by powder X-ray diffraction experiments，also the surface morphology of granite was observed by optical microscope. Nano-indentation tests were conducted，and then，the load-displacement curves and residual indentation prints were obtained to qualitatively analyze the mechanical properties of the mineral compositions. The elastic modulus and hardness of each component were obtained by statistical analysis of indentation results. A two-step homogenization method was applied to calculate the equivalent elastic modulus and Poisson¢s ratio of the granite，which were compared with those obtained by uniaxial compression test and existing research materials respectively. Results show that：the granite is mainly composed of quartz，feldspar and biotite，which can be identified by color and morphological features. The quartz structure is compact and the mechanical properties are good，which is followed by the feldspar，but the biotite texture is very soft and its pore structure is obvious. The difference between the elastic modulus calculated by the homogenization method and that obtained from the uniaxial compression test is relatively small and the Poisson¢s ratio is in agreement with the existing data，which has important engineering significance for evaluating the mechanical properties of materials. The results of this study can help to better understand the micro-mechanical properties of granite and provide a reference for the study of macroscopic mechanical properties of rock from a microscopic view.

In order to build a more accurate and reasonable tailings constitutive model，an elasto-plastic sand model was modified based on test results. The critical state theory and state parameter were introduced into Pastor-Zienkiewicz III generalized plasticity model to describe the triaxial test results of tailings sand. Comparison between test result and model simulation shows that the generalized plasticity model can exactly reflect the influence of confining pressure on the shear strength and volume strain behavior，which the original model can not describe. Compared with Duncan-Chang model，the proposed model is capable of simulating the strain softening effect and shear dilation under low confining pressure of tailings sand. Finally，the proposed model is applied into finite element analysis of tailings dams. FE analysis results show that the horizontal and vertical displacement of tailings dam locates in middle slope and middle body respectively，which conform with the general deformation pattern of tailings dams. Research result shows that the modified generalized plasticity model can well describe the mechanical deformation properties of tailings sand and can be used for the stress-deformation analysis of tailings dam.

In seepage calculation of hydraulic engineering，there are a large number of singularity problems at turning point. It is inconvenience that the general finite element method needs to construct special singularity shape function and element property to deal with the singularity problem，which used to be ignored when the isoparametric element was widely used. In this paper，a new method by constructing a local special patch is proposed to solve this singularity problem by using numerical manifold method. Firstly，the singularity covering function is formed together by the constant term basis function and a new basis function constructed by the analytic solution at turning point. The singularity covering function is used on the star points affected by the singularity point，at the same time，the constant patch covering function is used on the other star points，and the calculation result approximates the real solution and can well reflect the strong singularity in the corner. Secondly，the discrete formula of the numerical manifold method about this kind of problem is given，and the classical regular triangle of manifold element is improved to square，as well as，the procedure of the program and the application method of the special physical patch are introduced. Thirdly，three engineering examples are

respectively confined seepage of dam foundation with impervious curtain contrast with the analystic solution，the comparison of the classical flow velocity drop test，and the confined seepage of weir with sheet pile compared with flow net which had been calculated，those show the effectiveness and correctness of the method，and provide a basis for further analysis of the effects of singularity on the structure and complex engineering. Finally，The proposed method is also applicable to other numerical analysis methods based on the partition of unity method of interpolation，and also provides an approach for those problems with continuous field and discontinuous partial derivatives.

The thermal conductivity of rock is one of the key parameters in geotechnical engineering. The thermal conductivity of rock is affected not only by rock properties，such as mineral composition and porosity，but also by the geological condition of rock，such as temperature and water saturation. To reveal the effect of temperature and water saturation on thermal conductivity of rock，the thermal conductivity of sandstone at different temperature and water saturation was measured by self-designed experimental system. The results indicate that，in the temperature range of －80 ℃–90 ℃，the thermal conductivity of sandstone decreased with the increase of temperature，and the reduced rate varies with the rock，namely grit stone maximum，fine sandstone second，and siltstone minimum. Moreover，it is found that the thermal conductivity increased with the moisture content，but its growth rate decreased with the growth of environment temperature. Finally，it is shown that the thermal conductivity of saturated sandstone increased with the temperature and there was significant mutation near 0 ℃. Meanwhile，it was revealed thatthe reason of mutation is phase transformation of pore water.

Using orthogonal experiment analysis，this paper presents a model test study on factors affecting image sharpness of tunnel lining via a mobile platform equipped with linear array camera，light of either LED or LASER，industry computer etc. Four factors are considered in this paper，which are type of light source，illumination intensity of object surface，exposure time and surface diameter. An algorithm which utilizes both the slope of the magnitude spectrum and the total spatial variation is implemented to measure the local perceived sharpness in some images acquired in the test. Significance and optimal levels of the four factors are calculated by analysis of variance. We also discuss about changing laws of image sharpness under different testing factor levels successively. The test results show that the order of principal factors affecting image sharpness are exposure time，type of light source，illumination intensity of object surface，surface diameter，among which surface diameter is an undistinguished factor. The best combination of optimal levels is LED，6 klux，90 μs. This study can show a delighted help for inspection equipment of tunnel lining defects based on CV and ML.

To explore temperature anomalies of infrared radiation in the process of loading and failure and quantify the infrared radiation characteristics of coal and rock，the variance of differential infrared image temperature(VDIIT) has been proposed as a new indicator to study the transient variation characteristics of infrared radiation temperature field. The research results indicate that sudden changes in the VDIIT of coal samples could be found at the point of failure during coal failures under uniaxial loading.The abrupt changes coincided with the sudden drops on the load-time curves of the samples and the anomalies in their infrared image sequences， indicating synchronism between them. For the rectangular coal samples， the amplitudes of VDIIT at the point of failure were about 88.3～1 905.7 times(about 700 times) the average amplitudes of VDIIT during the loading process. For cubic coal samples，the amplitudes of this indicator at the point of failure were about 16.2–448.5 times(about 130 times) its average amplitude during the loading process. The figures demonstrate that the abrupt changes at the point of failure were hugely significant. The coal samples that showed a significant abrupt change in VDIIT account for approximately 95% of the total coal samples，indicating that the abrupt change was universal among the samples. The above achievements will be useful in monitoring and forecasting the natural and engineering hazards related to rock/coal structural bursts at the point of failure，and provide basic theory to water conservation and strata control in mine.

Stress of coal and rock provides important basis for supporting design of mine，strata stress analysis，rock burst and other dynamic disasters prediction and prevention. In order to measure the stresses of coal and rock in various directions and obtain their evolution laws，stress sensors within three directions and dynamic stress monitoring system of coal and rock are developed. The chip set on the stress sensor can effectively couple with coal and rock，and the stress can be measured by the flexible deformation of sensor chip and oil pressure. By this monitoring system，the stresses of coal and rock in various directions can be monitored continuously in real time. And this system was applied to mine stress monitoring and its evolution laws analysis. The results showed that the stress distribution of surrounding roadway and it′s evolution laws，the stress relief region，the stress concentration range and degree could be gained through multi-points arrangement. According to the measured results，the normal stress distribution laws inside coal mass of the roadway were gained in three perpendicular directions，which displayed that the stress variation trend of every point coincided，but the normal stress of various directions about the same point was not synchronous. It revealed there were two stress relief and concentration regions beside the roadway. This system provides effective means and methods for directional monitoring coal and rock stress，which can be used to the analysis of mine stress，the monitoring of surrounding rock stability and early warning of rock burst and other dynamic disasters. 

The principle of dynamic interaction between surrounding rock and support is the core issue of tunnel support design. Based on the elastoplastic softening model and non-associated flow rule， the elastic-plastic analysis of deep buried circular tunnel is carried out. Then taking into account the aging characteristic of shotcrete and the process of tunnel construction，the coupling model of the interaction of primary support and surrounding rock is established. The dynamic interaction between surrounding rock and support of an analytical section at different places from the face is then obtained during tunnel excavation. Through a specific case study，the supporting effects of steel rib and lattice girder under different supporting opportunities are compared，and the effects of shotcrete hardening characteristic on the stability of surrounding rock control and the supporting structure safety are analyzed，thus the following conclusions are obtained. Lattice girder is more flexible than steel rib，which is favour of the release of surrounding rock stress and displacement，but less able to control surrounding rock deformation and more sensitive to the change of support opportunity. The development of shotcrete supporting force can be divided into four stages including slow growth，rapid growth，growth slowdown and stability，of which the distribution ratio for each stage varies with the supporting time. During the early stage of the supporting structure，the load on shotcrete can be greater than its current limit bearing capacity and leads to its failure. The selection of supporting opportunity should take the steel arch types，shotcrete hardening characteristic and tunnel advancing rate into consideration to achieve the ideal support effect under the premise of supporting safety. Dynamic interaction between primary support and surrounding rock can be forecast and the application of convergence confinement method in tunnel support design can be more accurate by the research results，thus provides a theoretical basis for the support design during tunnel construction process.

To solve the problems such as large deformation at the initial stage of excavation，large deformation of the whole section and serious destruction of U steel support caused by the dynamic pressure in the strong swelling soft rock roadway in the Beizao coal mine，the instability mechanism of low strength，strong expansion，strong water absorption softening，surrounding rock pressure，non coupling between support and surrounding rock deformation is revealed by means of microscopic physical analysis and in-situ stress test. The constant resistance bolt support method was put forward，and the support mechanism of the constant resistance anchor bolt can be supported by the high resistance，high pre tightening force，deformation and pressure release structure to support the strong swelling soft rock. Finally constant resistance supporting scheme for pressure coupling consisted of the anchor beam structure strengthening roof + constant resistance anchor reinforcing for two sides + grouting anchorage reinforcing bottom was proposed. Numerical simulation is used to compare and analyze the supporting effect. The test results show that the constant resistance pressure coupling support can greatly reduce the deformation of roadway surrounding rock and the influence range of leading dynamic pressure，the maximum deformation is 282 mm，ahead of the dynamic pressure distance is 70 m. Compared with the ordinary steel bolt and anchor beam support deformation，the deformation reduced by 64.8% and the dynamic pressure influence distance reduced by 10 m，compared with the U type steel frame shed，the deformation reduced by 54.7%，and the dynamic pressure influence range decreased by 20 m. It has good popularization and application value in similar soft rock roadway. 

Currently the studies of slope stability accounting for the spatial variability of soil properties are mainly concentrated on isotropy and transverse isotropy correlation structures. Considering the disadvantage，the influence of the rotated anisotropy correlation structure on clay slope was investigated in this paper. Based on random field theory，the rotated anisotropy random fields of soil parameters are simulated and set up using the covariance matrix decomposition method. Combining with the numerical approach，slope reliability was then explored. The results show that the rotated anisotropy correlation structure has a dual effect on slope stability in comparison to the transverse isotropy case，and the stronger effect for higher anisotropy. The mean of factor of safety obtained by stochastic analysis is less than the deterministic solution. The calculated coefficient of variation of factor of safety is less than that of undrained shear strength of clay. Three types of sliding surfaces are obtained，and the largest proportion occurring is the base sliding which is same as the deterministic results.

In order to study the blasting vibration effect influenced by charging characteristics and millisecond time，the local amplification effect of blasting vibration velocity in double-hole blasting is discussed by analyzing the characteristics of vibration wave generated by finite length cylindrical charge. Meanwhile，the particle vibration effects of rock induced by long cylindrical charging characteristics and different initiation modes are analyzed. The effects of charge length，explosive detonation velocity，charge depth，initiation mode and rock characteristics on the blasting vibration are obtained. Besides， the peak particle velocity of long cylindrical charge is fitted with the Sadov¢s formula. The results show that the magnitude and scope of the local enlargement are closely related to the millisecond time and blasting attenuation coefficient. The blasting vibration velocity would no longer increase when the charge length increases to a certain extent for the measuring point below the top of the charge. Besides，the effect of detonation velocity on blasting vibration is only limited in a certain velocity range. For the measuring point above the top of the charge，the particle velocity on the surface grows bigger with the increasing of charging buried depth. For different initiation modes，the peak particle velocity is the maximum at bottom initiation， the second is both ends initiation，and the peak particle velocity is the minimum at top initiation. When the measuring point is closer to the source，the more obvious vibration affected by the rock characteristics change. The fitted Sadov¢s formula of cylindrical charge can well indicate the peak velocity characteristic of the blasting vibration of cylindrical charge. The fitted Sadov's formula of spherical charge cannot denote the vibration characteristic of cylindrical charge.

Traditional dynamic water grouting materials have the shortcomings of water content，volume shrinkage，poor of the late hydrodynamic dispersion resistance and higher cost. Based on the demand of dynamic water grouting treatment project，we propose a two-component water grouting material(FS)，which is mainly composed of fly ash and additives，and the performance of the slurry was studied. Then，the parameters， such as final setting time，stone rate after 1 h，compressive strength and pumpability of material under the condition of the different water contents and dosage of additives were tested. Experimental results show that new dynamic water grouting material(FS) with the characteristics of rapid setting，early strength，micro expansion，high rate of stone，smaller strength is affected by water content，strong erosion resistance resisting dynamic water. And we put forward hierarchically combined grouting reinforcement technology by using material to dynamic water grouting treatment，and expound the principle and method of the technology. New grouting material(FS) and grouting technology was successful in Nanjing subway station，which verified that the materials technology was scientific and greatly reduced the management cost. it is significative to the grouting material and technical innovation.

In order to study the evolution process and failure characteristics of water inrush in Karst tunnel under， high-geostress and high hydraulic pressure，a model test system for water inrush in high-geostress and high hydraulic pressure tunnels was developed，the testing system composed of a geostress loading system，a hydraulic loading system，a multiple information monitoring system and a main box. The main features of the system can provide both high-geostress and high hydraulic pressure，the geostress loading system can provide peak pressure to 1 000 kN and hold pressure for a long time，the hydraulic loading system can provide maximum hydraulic pressure to 50 MPa and the hydraulic gradient can be controlled. In addition，the main box is an integral frame structure，high bearing strength，good tightness，visualization；the reaction frame can slide left and right，and the test space is enlarged；the all parts are connected by high strength bolts，high scalability；multiple information monitoring system can be used to collect the test data in real time. In the YK7+400–YK7+445 section of Xiema tunnel was taken as an example，the solid-fluid coupling similar materials were developed independently，the water inrush model test of karst cave in front of working face of high-geostress and high hydraulic pressure tunnels was designed，the experimental data were analyzed and summarized，the spatio-temporal change rules of stress field，displacement field and seepage field of tunnel surrounding rock under the complex geological conditions were revealed，the information of water inrush in tunnel were mastered. Test results showed that the system was stable and reliable，the research methods and results will instruct similar engineering.

The ore from chute will have negative impact on the wall of the ore pass and it is important to determine the collision position and choose the right protective method for the lifespan extension of ore pass. Based on the erosion-wearing theory，the calculation model of the damage caused by ore impact on ore pass wall is established and the method to calculate the volume loss is determined using Hertz contact theory. According to the structure of chute and ore pass，the motion model of ore is built. Taking the Huaxin limestone mine in Zuangou as an example，the damage characteristics are analyzed. The result shows：the ore will fall into the storage after three times collisions with ore pass wall. The impact area of the upper ore pass wall is small，but the damage is serious. On the contrary，the impact area of the lower ore pass wall is large，but the damage is insignificant. Considering the safety and economic reason，the classified protection measures are proposed. The results are consistent with the actual situation，which shows that the calculation method is suitable for the ore pass with flat wall and is helpful to the protection design of new ore pass.

Due to horizontal bedding existence，high horizontal stress difference or no natural fractures in unconventional reservoirs，it¢s difficult to create complex fracture network according to massive hydraulic fracturing. So a new stimulation technology based on high-energy electric impulse was investigated to promote efficient development in above formation. Firstly，an unique electric impulse experimental set-up was innovated under high voltage(25 kV). It could load three principal stresses independently to rock sample，as well as combine electric impulse with hydraulic fracturing in lab. A series of experiments were conducted with large-scale natural shale outcrops(762 mm×762 mm×914 mm) to help study fracture geometry and propagation mechanism. At the same time，more advanced impulse numerical model was established with experimental data. Then the geological and engineering factors effecting on operation distance were analyzed quantitatively. The results showed that the electric impulse could create complex fractures in different directions in shale without casing pipe damage；improving impulse energy could enlarge operation distance obviously，but the number of impulse operation should be designed in a reasonable range；Compared with the traditional hydraulic fracturing，the new operation model of the combination of electric impulse and hydraulic fracturing could be more conducive to create fracture network to improve stimulated reservoir volume. This technology will have good application prospect in oilfield development especially for unconventional reservoir.

The occurrence randomness of rock joints leads to generating large amounts of datum that do not belong to any dominant group in the practical datasets. This consequently causes the atypia of the data sets and the difficulty in determining dominant occurrences. In this study，A FCM-based dominant group determining method is developed，and a cut-back method is adopted to eliminate the influence of the data out of the dominant groups. Synthetic tests show that the suggested method is superior to the traditional FCM method for extracting dominant occurrences from atypical data sets. This method can not only eliminate unexpected data but also be able to obtain a high proportion of valid data and accurate dominant occurrences. Then optimal parameters for atypical data sets were obtained by comparing the performances of different distance functions with the cluster center expressions. A practical application of this method to a gold mine shows that the suggested method and the optimized parameters perform well in determining dominant rock joint groups from atypical data sets.

In order to make clear bump proneness with different strength of roof，coal and floor and whether strong roof and floor can trigger bump under static loading condition. Layered concrete specimens were prepared to simulate coal and rock of different strength. Uniaxial compression tests were conducted for concrete specimens in the MTS machine under static loading condition. Index of dynamic failure time，sound pressure level and uniaxial compression strength were used to assess the violent degree of failure which could reflect the bump proneness. The results show that coal is the crucial factor to determine the strength and bump proneness of the rock and coal system. Strong roof and floor can increase the bump proneness of weak coal，while，weak roof and floor can decrease the bump proneness of strong coal. In addition，the affect of roof and floor is closely related to the property of coal. When the coal is weak，strong floor can confine its deformation，especially with strong roof，the clamping action can increase bump proneness obviously. When the coal is strong，the affect of floor is negligible，but a stronger roof can increase the bump proneness；When both coal and floor are weak，the affect of roof is little. Under static loading condition，only strong roof and floor cannot trigger coal bump.

In recent years，microseismic monitoring has been widely used in coal mine. Based on the analysis of the distribution of microseismic events space-time and energy，the mutation of microseismic events were studied in order to determine the key layer of coal mine roof deformation and failure of the control action along the vertical direction. Based on the academic of the key layer of roof was divided two boundaries，taking Dongjiahe coal mine 517 working face as an example，the model of coal mine roof was studied along the vertical direction，And the borehole observation method was compared with the results，the conclusion as followed：The 517 working face roof rock mass is divided into six zones，including caving zone，rock zone，vertical cracks，vertical cracks，bending zone and separation zone. The fractured zone was composed with block zone and vertical cracks zone，bending subsidence zone was composed with vertical fracture zone，bending zone and separation zone. The new methods and ideas were provided for the height of divided coal mine roof.

Based on the design guide of pervious lining tunnel, this study discussed the dynamic discipline of maximum crack widths and equivalent permeability coefficient in the operating period. The influence caused by reinforcement ratio，thickness of lining and permeability of rock was investigated from the perspective of the design of the crack limitation. Then a kind of optimum design method was promoted by using multivariate statistical stepwise regression. It turns out that the increase of maximum crack widths and equivalent permeability coefficient was much larger when the rock and lining are contacted than when they were detached. In addition, the maximum crack widths were inversely proportional to the reinforcement ratio，while proportional to the logarithm of permeability of rock. As the result，it is recommended that the reduction of permeability of rock should be conducted firstly to improve the impervious capacity. Then，it is also necessary to increase the reinforcement ratio with making the augment of thickness of lining as an aided method. There is an approximate 0.02 mm decrease in maximum crack widths when existing every 0.1% increase in the reinforcement ratio. Meanwhile，the decreased of the reinforcement ratio was about 0.10 mm when the permeability coefficient of rock was reduced by 10 times.

Calculation of landslide thrust is always a key problem in reinforcing design of slopes. Currently，there is an inconsistency issue existing in Chinese technical code for building slope engineering with regard to the thrust calculation using the transfer coefficient method，which is largely caused by the inaccurate assumption about the stress state of a slope. Aiming to overcome this issue，a new method considering the vector characteristics of sliding and anti-sliding forces was proposed and adopted to calculate the residual sliding force of a local potentially sliding body. Not only the sliding force but also the sliding direction of a potentially unstable slope can be evaluated by the proposed method. Several examples were illustrated and the calculated results of the safety factor of slopes were in good agreement with the rigorous limit equilibrium method. Finally，the proposed method was applied to analyze a typical fold line slope of Zhangmu town，in the Tibet of China，and the residual sliding force calculated by the proposed method also agrees well with the result from the transfer coefficient method.

In view of the limits on existing 2D evaluation methods，twelve 3D joint roughness characteristic parameters were proposed to quantitatively evaluate the roughness of rock joints. Those 3D parameters can not only reflect shear characteristics of asperities but incorporate the anisotropy of joint surfaces. Then，using 3D laser scanning and GIS technology，it is found that the digital geometric model of joints can be successfully obtained， then all the value of 3D joint parameters can be precisely calculated. This method was first applied to analyzing the roughness of a typical rock joint surface，on which there were scarps， bulges and pits. Results shows that the area of inclines larger than 45°has a high sensitivity to shear direction. Finally，a series of direct shear tests on natural joint samples were conducted to get the empirical formula of .

The essential parts of landslide displacement prediction are the improvement of prediction accuracy and threshold computation. Based on the existed research results，an ARMA-LASSO-ELM-Copula model to predict the displacement is constructed in this research. A typical step-like landslide namely Baishuihe landslide is selected for case study in this paper. First，the ACF in ARMA model is selected to investigate the seasonal patterns of monthly precipitation and reservoir water levels. The PPMCC is also selected to analyze the data of triggering factors(e.g.，precipitation and water reservoir levels). The autocorrelation between the current value and the lagged historic values are computed. Second，all positive lagged triggering factors are selected as inputs of the prediction model. An ELM-Copula prediction model is used to predict the monthly increment displacement. The cumulative displacement can be obtained from the accumulation of the predicted increment values. Last，the best performing Copula model is selected based on the triggering factor values and predicted increment displacement. The joint distribution function is constructed to extract the optimal thresholds. Numerical results indicate the LASSO-ELM offers the better prediction accuracy in comparison with SVR，NN，ELM，and etc. The Gumbel-Hougaard Copula function can better describe the joint distribution between triggering factors and predicted displacement values. The threshold of triggering factors and the value-at-risk of displacement can be computed from the selected Copula model.

Based on the investigation on high burst proneness，high in-situ stress，F₁₆ thrust fault and conglomerate roof，the contributing factors，characteristics and mechanism of coal bursts in Yima mining area are studied. It is indicated that the high burst proneness and high in-situ stress are the major intrinsic factors to induce coal burst. The distribution of horizontal tectonic stress under the existence of F₁₆ trust fault is extremely inhomogeneous, which makes the stress concentration and energy surge in the high stress environment and the surrounding area. The roof and fault are in the unstable conditions under the influence of conglomerate roof separated by F₁₆ thrust fault. These are the main external factors to induce coal burst in Yima mining area.. Therefore，the electromagnetic radiation and support resistance could be observed as the process of increase，decrease，increase again and decrease again before the occurrence of coal bursts. The sudden decrease of indicator could be identifies as precursory information of coal bursts.

According to the practical problem that at present rock burst often occurs at heading face，analyzed on the basic theory of the rockburst hazard evaluation by electromagnetic wave CT detection，obtained the relationship between electromagnetic wave CT detection and rockburst hazard，established an evaluation model of the abnormal index BI and the gradient index GI of the absorption coefficient of electromagnetic wave in fractured coal and rock，therefore，CT evaluation technique for electromagnetic wave was established，which could define the risk zones of rockburst and the levels of danger of inside and outside supporting area of surrounding rock，and applied to field practice. Application showed that evaluation results could guide and test the effect on supporting and pressure releasing measures. The technique had a high frequency of detection(up to 32 MHz)，overcome the limitation that the traditional method could not evaluate rockburst hazard of the surrounding rock due to being difficult to detect the surrounding rock of heading face with higher precision，which was of great significance to the prevention and control of rock burst in heading face.

The deformation of the right bank underground powerhouse at Wudongde hydropower station was the key issue due to its complicated geological conditions and large-scale excavation of the caverns，which seriously influenced construction schedules and personnel safety. A high-precision microseismic(MS) monitoring system was introduced to the underground caverns. The tempo-spatial evolution laws of MS events were analyzed. Combined with field construction，geological information and conventional monitoring data，the main damage characteristics of the underground powerhouse were revealed. Compared with the monitoring surface deformation data of surrounding rock mass，the seismic source parameters evolution laws were researched in the process of large deformation. An MS multiple parameters based early warning method for rock mass large deformation was proposed. The results indicated that the MS activity can sufficiently reflect the disturbing intensity of surrounding rock mass subject to the construction of the underground powerhouse. The deformation and damage was closely related to the MS propagation and evolution. Prior to the large deformation of surrounding rock mass，the MS events frequently occurred. Meanwhile，the energy index increased sharply and the apparent volume grew smoothly. In addition，the frequencies of MS signals gradually decreased. The research results will provide significant references for later excavation，supports and large deformation forecasting of the underground caverns.

In order to study damage mechanism and shock absorption joint damping technology of tunel passing through an interface of soft and hard rock in highly seismic area，the strong earthquake vibration dynamic test was carried out based on a tunnel. By analyzing formation inertia force，differential displacement，principal tensile stress，internal force and safety factor，five kinds of working conditions were comparative studied，mainly including condition A(no damping measures in hard rock)，B(no damping measures in soft rock)，C(no damping measures in junction of soft and hard rock)，D(absorbing joint only secondary lining in junction of soft and hard rock)，E(combination shock absorption measures in junction of soft and hard rock). The result show that displacement difference is significant under strong earthquake crossing interface of soft and hard rock，and the formation inertia force of soft rock is stronger than that of hard rock. The damping rate of principal stress or internal force is beyond 47% and 40% by setting shock absorbing joint only secondary lining. And the rate of maximum damping with staggered joint is increased by about 20% comparing with absorbing joint only secondary lining. The shock absorption structure of staggered joint is recommended to be used in the tunnel crossing interface of soft and hard rock in high intensity zone，namely absorbing joint in secondary lining is combined with the length of lining trolley and the shock absorption gap of initial support is set by 3 m interval. The research results have important significance to anti shock technology for traffic lifeline crossing interface of soft and hard rock in highly seismic area.

Surface subsidence induced by mining has seriously harmed pile foundation of high or railway bridge，and even causes instability and failure of the whole bridge. Based on the surface subsidence law subjected to mining and the principle of Probability Integral Method(PIM) prediction，a set of pile foundation load test system was developed，which could simulate surface subsidence induced by mining. Using this test system，four model piles located at different subsidence positions were carried out to study the bearing characteristics of existing load piles of bridge in the process of surface subsidence. Pile shaft force，side resistance and pile-soil relative displacement were obtained through the pre-set test elements. Test results show that the measured surface settlement has a good match with the calculation of PIM，which confirms the reliability of the test system to simulate mining surface subsidence. The variation of shaft force and the side resistance of four test piles are related to the location of surface subsidence curvature. The greater variation of the surface subsidence curvature，the greater change shaft force and the side resistance are. The relative displacement analysis of the pile-soil shows that the larger the surface subsidence curvature is，the larger the relative displacement of the pile-soil is，and the negative skin friction of the pile would generate，which will aggravate the pile foundation settlement and cause the upper bridge structure to produce uneven settlement，or even damage. The study results will be helpful to protect and reinforce bridge pile foundations in mining area.

In order to make a preliminary exploration of the unity of the study of soil-rock mixture under different basic materials and different scales，the electrochemical impedance spectroscopy method was used to study the soil-rock mixture composed of ideal materials. Through the macroscopical adjustment of the three materials indexes of the rock-soil mixture system of water content，soil-rock ratio，and particle size，the rules of the electrochemical impedance spectroscopy results were obtained. Based on the high-frequency extremum of the electrochemical impedance spectroscopy(EIS)，its regularity was described and further studied. Thus，a preliminary mapping was made between the electron passability at the micro-scale and the material indexes at the macro-scale. A series of concepts and tools such as coupling degree，curve of the impedance¢s extremum(CIE)，optimal point of CIE were put forward. The basic effect of water content on the structure of soil-rock mixture was obtained，and the influence of soil-rock ratio is dominated by two factors. Especially with the orderly change of the particle size，its high-frequency extremum moved along curved path. These above research results have some reference value to the study of the structural characteristics of soil-rock mixture.

There is a lack of research on the interaction between composite foundation and its retaining structure at present. To study the interaction between rigid-pile composite foundation in the vicinity of a deep excavation and its retaining structure affected by lateral excavation，two centrifuge model tests of composite foundation with lateral excavation which had the same load，same supporting structure and different replacement rates were carried out. It is analysis to the change laws with excavation of the pile axial force，the lateral frictional resistance，the pile-soil stress ratio，the vertical stress of the soil between piles，the moments of piles and the retaining structure，and their response to changes in replacement rate. The result shows that the pile axial force，pile-soil stress ratio，moments of piles and retaining structure increase with excavation，while the lateral frictional resistance and the vertical stress are less affected by excavation. The frictional resistance direction in the upper part of pile body is downward，and upward in the lower part. The position with the maximum value of retaining structure moment moves down step by step with excavation. The distance from the foundation pit determines the magnitude and the change form of pile bending moment. The pile top near foundation pit embeds cushion due to uneven settlement of piles and soil，and is constrained horizontally by cushion，which causes the negative moment in the upper part of the pile. Except that the replacement rate has little influence on the vertical stress of the soil between piles，all the above mechanical properties are decreased as the result of the increase of replacement rate，especially for the retaining structure moment，which indicates that the replacement rate of composite foundation can be increased to improve the mechanical properties of composite foundation and its support structure，and enhance the safety of lateral excavation.

The researches about primary yield and failure properties are significant foundation to establish a loading-unloading criterion for the undisturbed loess under the different stress paths. Bilinear relations between strain energy and the length of stress vector are used for determination of yield point.A series of experiments，including equal p and equal b tests and confined compression tests are conducted by using true triaxial apparatus，developed by Xi¢an University of Technology independently，and high-pressure consolidation apparatus. Applicability of determining primary yield of loess by the strain energyand three strength properties are studied. From the results of experiments，the relationships between strain energy and the length of stress vector are all parabolic. Structural yield pressures determined on the confined situation is consistent with that of bilinear logarithmic relations between specific volume and vertical stress. There is no high degree of linearization in the middle section of curves between strain energy and the length of stress vector on the condition of three dimensional stresses. The yield zones near the intersecting rangement are defined and its distributions are stripped distribution with different b-values. The failure surfaces of loess on theplane are curved-edge-triangle，which is described by lade yield criterion. The method of strain energy is applicative to analyze the primary yield and strength under the condition the confined and unconfined stresses.

Magnesium oxychloride cement(MOC) had the inherent quality of good resistance to brine corrosion and frost. The objectives of this study were to investigate the feasibility of using MOC as a stabilizing material of highway pavement structure in saline and cold area as well as the influence of mix proportion of raw materials on the unconfined compressive strength(UCS) of gravel soil solidified by MOC. The UCS and the mineral composition of specimens were analyzed，respectively. The results show that the solidified gravel soil with a larger ratio of active MgO/MgCl₂ (Mg/Cl) is mainly Mg(OH)₂ in hydrated products and has the low UCS when the brine concentration is less than 7.48%. When the brine concentration increases，3Mg(OH)₂·MgCl₂·8H₂O (P318) and 5Mg(OH)₂·MgCl₂·8H₂O(P518) appear in the solidified mixture with the decreasing of Mg/Cl. The solidified gravel soil has higher UCS when the major hydrated product is P318 rather than Mg(OH)₂，while the highest UCS is obtained when P518 appears. The greater the light-burn magnesia content，the more hydrated products and the higher UCS of solidified gravel soil. The UCS of MOC solidified gravel soil is determined by the mineral composition. The enhancement mechanisms of UCS of gravel soil solidified by MOC are attributed to the hydration of active MgO，carbonization of hydrated products，crystallization of MgCl₂·6H₂O，filling effect，mechanical compaction effect，and ion exchange effect.

The filtration effect has an important influence on the fracturing grouting diffusion process in sand. At present, there is no reasonable fracturing grouting theory fully considered the filtration effect. In this paper, the filtration effect was described by the one-dimensional filtration model. A theory model of fracturing grouting diffusion in sand was established considering the plate grouting diffusion model and the one-dimensional filtration model. Equations of grout diffusion were further derived. Compared to the model without considering filtration effects, the influence mechanisms of the filtration effects on grout diffusion were revealed. The process of fracturing grouting diffusion in sand was stimulated with ALE finite element methods dynamically. The numerical solution was consistent with the theoretical solution. The field examination of the fracturing grouting diffusion in sand was carried out. The results proved that actual length of grout veins were similar with the numerical results and theoretical calculations，which verified the rationality of the numerical model and the theoretical model.

The failure of buried HDPE pipes may occur as a result of large differential deformation caused by the localized land subsidence. The buried pipe subjected to the land subsidence is commonly analyzed using the theory of beams on Winkler elastic foundation. The theory assumes that the pipe deforms with soil and no separation is expected. However，separation of the pipe and soil may occur due to the stiffness difference and the soil arching effect triggered above the pipe when the land subsidence is developed. Therefore，it is necessary to investigate the possible “pipe-soil separation and performance of the pipe under this condition. In this study，series of large-scale model tests are conducted to investigate the mechanical responses of buried HDPE pipes by using a custom-made model box. Yangtze River sand is used as the backfill. Movable plates installed at the bottom of model box are lowered in target sequences to simulate the land subsidence. Test results show that (1) the vertical displacement of HDPE pipes and settlement trough at the soil surface are well fitted by using the modified Gaussian distribution curves. The width parameters of fitted curves for vertical displacement of HDPE pipes are smaller than those for settlement trough at the soil surface；(2) the earth pressure at the top of the HDPE pipe experiences an overall increase with lowering of bottom plates of the model box. Three-dimensional soil arching effect is observed during the test；(3) the earth pressures measured underneath the pipe reduce to zero with the lowering of the bottom plates. It is indicated that the pipe-soil separation occurs at the bottom of the pipe. It is also found that the vertical displacement and longitudinal bending moment of the HDPE pipe calculated by the theory of beams on Winkler elastic foundation are 1.1 to 9 times and 3 to 11 times those measured in this study，respectively.

The coefficients of variation V of soil strength parameters，varying in a wide range，are high and traditionally classified by experience，without taking the non-linear response reliability index β into consideration. Based on the collected 257 sets of V of fine-grained soil strength parameters，the probability distribution，characteristic parameters and confidence intervals for these data were determined. The non-linear relationship between β and V was analyzed in which the Monte Carlo Simulation method was used to calculate the slope reliability，and then a classification principle is proposed consistent with the characteristics of β. Research shows that the coefficient of variation(V_c，V_φ) of the cohesive soil can be described by lognormal distribution，and the estimated interval with 95% confidence level are V_c∈[0.05，0.73] and V_φ∈[0.05，0.47]，respectively. Analogously，the statistics for loess are subject to a normal distribution，with the confidence interval V_c∈[0.05，0.81] and V_φ∈[0.05，0.39]，respectively. The β value shows three kinds of response namely nonlinear decrease，linear decrease and micro change sequentially as the V value increases. Three types of variation of soil strength parameters，denoted by rapid changing，slow changing and stagnate changing，are proposed to describe the variation type of soil strength parameters，in which V_c≤0.35 and ＞0.35 belong to rapid and slow changing type，and V_φ≤0.20，0.20～0.35，≥0.35 are rapid，slow and stagnant changing types，respectively.

To research the strength and deformation characteristics of K₀ consolidation saturated silty clay under principal stress axis rotation conditions，a series of directional shear triaxial tests were carried out by using the GDS triaxial test system. The stress vs. strain development law and non-coaxial phenomenon of K₀ saturated silty clay under different principal stress direction angle was researched. The results show that the deformation of K₀ consolidation saturated silty clay mainly performs as the axial compression deformation and its shear strength increases with the principal stress direction angle increasing when b is smaller than 45°. The deformation performs as torsional shear deformation when b is equal to 45°. The axial deformation performs as the dilatancy deformation and the radial deformation performs as the extrusion shrinkage deformation when b is larger than 45°

And its shear strength decreases with the principal stress direction angle increasing. The maximum shear strength of soil appears at b equals to 60°but not at the pure torsion shear test which b equals to 45°. The strength envelope performs as parabola types on the  plan. Test results show that the stress vs. strain curves of K₀ consolidated silty clay obviously performs as non-coaxial phenomenon except for the pure torsional shear test. The above results provide a scientific reference to research the mechanics and constitutive relation of the K₀ consolidation saturated silty clay under the complex stress path.

It is significant to study the change rules of dynamic response on high speed railway subgrade under the condition of rainfall infiltration，which can identify the potential disease and guarantee the stability of subgrade. Therefore，the change rules are discussed through the 1∶1 large-scale model test. Research suggests the acceleration and dynamic stress of the softening condition are both reduced compared with the normal condition. The more close to the subgrade surface，the reduction is more obvious，and the reduction of the acceleration and dynamic stress are reached about 50% on the subgrade surface. In the softening condition，the dynamic stress is slightly increased because the interface effect appears between the soft and hard interface，and it is different from the attenuation rules of the acceleration. The dynamic stress propagation on subgrade appears stress diffusion phenomenon that causes the dynamic stress amplitude on the lower part of the subgrade is larger than the upper. With the increase of the excited frequency，the acceleration attenuation is increased first and then decreased in the same depth，and reaches the maximum value at 19.1 Hz. The dynamic stress is increased gradually from the surface of subgrade 0.35 m，with the similar acceleration law under 0.35 m.

Based on mass conservation equation，linear infiltration law，grout density equations and boundary conditions，a quantitative formula of infiltration coefficient l and a theoretical model of reinforcing strength were proposed for grout suspensions in sandy soil medium. Theoretical calculation of infiltration coefficient was obtained according to grout density and diffusion distance in grouting test. Then the variation law of l was analyzed and compared with the measured values of similar experiments. Through uniaxial compressive strength test，consolidation strength at different distance was studied. Then difference analysis was conducted between experimental value and theoretical value. The results show that，infiltration coefficient increases with grout time in certain conditions，and not a constant parameter in traditional studies. There is a significant negative correlation between consolidation strength and infiltration coefficient when the diffusion distance is the same. The consolidation strength deceases along grout penetration distance，and strength decreasing rate can be up to 9.2 kPa/cm. Deviation between theoretical value and experimental value is ±22%，which presents a higher coincidence degree. The results have practical value and can provide reference for construction design.

At present，the calculation method of foundation settlement in engineering mainly depends on the method in the standard. The compression modulus is used to calculate the compression settlement by the stratified sum method，and then multiplied by the empirical coefficient. The empirical coefficient is 0.2–1.4，The coefficient range is too large. In order to solve the problem，new method is proposed. The deformation modulus is proposed for the hard soil foundation instead of the compression modulus，so the empirical coefficient can be canceled. And the empirical method to determine the deformation modulus is proposed. For the saturated soft soil，it is recommended to calculate the correction coefficient based on the load level or the stability safety factor rather than by human experiments. So as to provide a simple and practical engineering settlement calculation method for engineering. Case study shows that it can effectively improve the accuracy of calculation settlement.

Sticky rice-lime mortar has great application potential in repairation of Chinese heritage sites. The reinforcement of site soil has been certain influenced by the temperature of glutinous rice slurry. Therefore from the temperature point，the control index of making glutinous rice slurry is investigated. The aim is to save time and gain the desired glutinous rice slurry with obvious reinforcement effect.  From the aspects of hardness，longitudinal wave velocity and unconfined compressive strength，the performance of site soil reinforced by glutinous rice slurry can be superior between 75 ℃ and 80 ℃. When the concentration of glutinous rice slurry equals to 6%，the reinforced site soil has larger hardness，longitudinal wave velocity and unconfined compressive strength. Cured five days under natural environment，the hardness of sample surface basically tends to be stable. Finally，based on the viscosity，physical and chemical property of glutinous rice slurry，the test results has been explained reasonably.

 In order to evaluate the stability of clay foundation under the structural weight，wind and wave loading， an kinematic hardening elastoplastic model is modified in the framework of critical state theory，and the mechanical behaviors of saturated clay are simulated under static and cyclic loading. In the present work，the hardening rule of the existing model is modified to characterize the undrained response of saturated clay under not only static but also cyclic loading. Similar to the yield surface equation of modified Cambridge model，a new bounding surface equation is established according to the isotropic and kinematic hardening rule. The radial mapping law and moving mapping center are adopted to simulate the hysteresis of stress-strain curves，and a plastic modulus interpolation function is suggested for predicting the cyclic shakedown behavior of saturated clay under low stress levels. The validity of the modified model is verified through both the undrained monotonic and cyclic triaxial test data，and the results show that the modified model can realistically simulate the static and cyclic shakedown behaviors of saturated clay.

The deep soft soil layer of the 4th runway at Pudong Airport was studied in this paper. During preloading test，the ground settlement deformation law was analyzed and compared under two conditions，using plastic drain plate or without. It was found that during preloading，both the ground settlement and settlement rate in areas using plastic drain plate were much larger than those areas without plastic drain plate. The instantaneous settlement during preloading was both large in two conditions，which both exceeded 50% of the total settlement during whole preloading process. During the process of surcharge preloading，compared to actual loading，the state of the ground soil would appear that shallow soil was over consolidation while the deep soil was still under consolidation. Therefore，for deep multi-layer soft soil ground，residual settlement should be calculated layered and separately after unloading. The research results would have important reference significance to the design and construction of soft soil foundation treatment project.

The tensile strength of high-temperature frozen soils is an important parameter for the criterion of ice segregation. In order to research on tensile strength of high-temperature frozen soils，split tests were used to acquire the tensile strength of Tibetan frozen soils. The results showed that tensile strength increased with the decrease of temperature，however，the increasing rate decreased during 0 ℃–－0.4 ℃. The tensile strength increased linearly by the decrease of temperature during －0.4 ℃–－2.0 ℃. Moreover，fitting functions of tensile strength were obtained，which provided important parameters for the criterion of ice segregation and the application of frost heave model. The fitting functions were used to calculate frost heave，the calculated results agreed well with the experimental results.

The existing CPT and SPT correlations are mostly limited on silica sands. It is seldom to seen the correlation are based on calcareous sand. Since the calcareous sand are mostly characterized a higher crushability and compressibility，the existing correlation is not applicable. Therefore，it is necessary to extend the CPT-SPT correlation in calcareous sands. 334 group high quality data were collected from New Doha Port project in Qatar and applied to the existing correlations to compare their applicability. The comparative results indicated that the correlation with single factor, either mean diameter D₅₀ or fine content FC(%)(＜0.063 mm)is not applicable to calcareous sand，and the coefficient factors based on CPT soil type method is relatively higher，whereas the typical correlation based on soil behave type index I_c shows a good consistency in calcareous sand. Meanwhile, one correlation method based on corrective factor is proposed and the analysis result shows a better correlation coefficient. Hence one more reliable correlation based on calcareous sand can be provided in future research.  

Calcium polysulfide(CaS₅) was used to stabilize chromium-contaminated soils. Leaching test，alkaline digestion test and sequential extractions test were conducted to investigate the influence of CaS₅ dosage and curing time on stabilization properties and chromium speciation of chromium-contaminated soils treated by CaS₅. Results showed that the leaching concentration(hexavalent chromium and total chromium) and hexavalent chromium content of the soil were decreased significantly with the increased CaS₅ dosage and curing time. Leaching concentration(hexavalent chromium and total chromium) were all met the China regulatory limit (GB/T50853–2007)，when CaS₅/Cr(VI) molar ratio was 3.With CaS₅/Cr(VI) molar ratio of 5，the amount of Cr(VI) in the soil met the China Environmental Regulation for industrial reuse[Cr(VI)＜30 mg/kg]. Sequential extractions test showed that majority of acid soluble fraction of chromium was converted to reducible fraction and oxidisable fraction with CaS₅ stabilized. With curing time increased reducible fraction of chromium was converted to oxidisable fraction. The changing in stabilize properties of stabilized soil can be attributed to the change of chromium speciation.

Full-scale model tests are carried out to reveal the propagation mechanism of velocity waves of X- section pile in low strain dynamic testing. The velocity responses at various points are obtained by arranging measuring points at different locations at both pile top and pile bottom. The three-dimensional effect and high frequency interference of X-section pile in low strain testing are researched. The results show that the velocity responses in the direction of concave arc are similar with those in the direction of convex edge. The three- dimensional effects of incident waves on pile top are obvious；however，the reflection waves from pile bottom are almost the same. The arrival time of incident waves is increased with the increase of the distance from the pile center，while the time difference between incident and reflection waves is decreased. The high frequency interferences at the location of 0.4R to 0.5R from pile center are unobvious，while they are more significant at the edge of pile section. There are two kinds of high frequency interference waves in velocity waves of X-section pile in low strain testing.

The mixed soil of precast pile with extrusion method is a new technique for soft foundation treatment. A single pile is pressed with the mixed soil in a soil extruding pile machine and then maintained. A total of 17 single piles of different recipes were designed and extruded under the optimal water content of soil. These piles were measured for unconfined compressive strength and water stability after 28 days. According to the test results，we found laws including：(1) The strength of the sample increased with the cement incorporation ratio when no or little lime was mixed，but decreased after an increase when adopting a relatively high lime incorporation ratio. (2) The strength of the sample increased with the lime incorporation ratio when no or little cement was mixed，but increased at 3% point after a decrease under a condition of comparable high cement incorporation ratio(4%，6%). (3) The water stability test showed that the water stability of the sample reached a good state with a 2% or 4% cement incorporation ratio. The strength maintenance coefficient increased with the increasing lime mixing ratio. The strength of different samples decreased fast in a 10-day or 20-day immersion but then tended to be stable after that. Based on the results mentioned above，the best formula for the pile of mixed soil was selected as cement 2% + lime 7%. This formula can provide support for the popularization and application of mixed soil of precast pile with extrusion method.

The employment of coefficient of subgrade reaction is limited to the reaction of ground surface in the homogeneous elastic half-space，not demonstrating the influence of soil stratification，extensity and anisotropy against the coefficient of subgrade reaction，and would cause a large calculation error and complicated post processing in engineering treatment. This paper carried out analysis of foundation beam deformation with reference to elastic stratification theory and compared with the solution of Winkler foundation model，then proposed the expression of subgrade reaction coefficient when taking limited compressible soil layers and special characters of stratification of the soil into account. This paper tested the validity and feasibility of the proposed method in combination with some examples. What¢s more，the design charts of correction factors in the expression of subgrade reaction coefficient are provided in terms of different distribution of elastic modulus and thickness of soil layers. For a specific case，the soil is first considered as homogeneous limited compressible foundation，and calculated kH with k∞ and the total soil thickness H，and finally got k by kH and the specific stratification of the soil.