Large open-pit mine slopes were classified into the entire，composite-bench and single bench slopes according to their compositions and scales. The rock joints were then divided into three categories based on the joint size and the relationship with the slope at different levels：penetrating joints，non-penetrating joints and small-sized joints. The spatial locations and scales of rock joints have various influences on different types of mine slopes due to the controlling effect of rock mass structure. A graded analysis method for the stability assessment of open-pit mine slopes was suggested. The spatial locations of rock joints should match the corresponding part on the slope，and the rock joint scale should match the slope scale. According to the matching performance on the relative spatial locations and sizes，the stabilities of the entire slope，composite-bench slopes and all single bench slopes were systematically analyzed to find out the key joints and their combinations. The stabilities of the entire slope，the composite-bench slope and the single bench slope were analyzed from global and local aspects through the case study. The suggested method can give the necessary conditions for accurately evaluating the slope stabilities of large open-pit mines.

A large scale bedding landslide occurred in Xinmo village，Diexi town，Maoxian county，Sichuan at about 6∶00 pm on June 24，2017. The rock mass with the volume of 450×104 m3 destroyed the whole Xinmo village，resulted in the death of 10 people and missing of 73 people. This paper presents a comprehensive analysis on the dynamic process and failure mechanism of the landslide based on the site investigation，satellite remote-sensing(RS)，Unmanned Aerial Vehicle(UAV) photography，Ground Based Synthetic Aperture Radar (GBSAR) monitoring and other technologies. The preliminary study suggested that the rock masses of the source area were shattered and tension cracks were formed due to the shaking of the Diexi Earthquake in 1993. The shattered rock masses suffered from the subsequent strong earthquakes(such as 1976 Pingwu Earthquake and 2008 Wenchuan earthquake) and long-term effects of gravity and rainfall，which eventually resulted in the failure of the rock masses. The movement of the landslide lasted for 2 minutes in which the main landslide lasted for only 60 seconds with the runout of 2.6 km and the maximum speed of 74.6 m/s，a typical high speed and long runout landslide-debris flow. Because of the characteristics of high position and high concealment，this kind landslide is difficult to be detected with the traditional investigation methods. It is suggested that the high accuracy Earth Observation Technology(such as InSAR，LiDAR，UAV) should be promoted and applied to detect and prevent such high concealed landslides at high position in southwestern mountain areas.

Based on the testing principle of the Mogi Type rock true triaxial apparatus，the key technology that the measurement of volumetric deformation of rock，the end friction effect，the loading gap and the capture of the complete stress-strain curves are introduced in terms of the principle for designing. The test system realizes the measurement of the stress-strain curves for hard rocks under the condition of true triaxial compression with high rigidity，large loading capacity as well as fast response. The friction coefficient under different anti-friction conditions and the influence of end friction effect on rock deformation were studied. It is shown that the mixture of stearic acid and Vaseline has good anti-friction effect and is thus recommended to be used in the true triaxial experiments. Meanwhile，the end friction often results in the uneven distribution of rock deformation and the deformation modulus and strength of rock to increase.

The post peak stress-strain curves of coal are often presented curved and benched drop. The current brittleness index expressed by gradient drop of compressive stress-strain cannot distinguish the linear，curved and benched drop. A new index to characterize the brittleness of hard coal based on unsteady energy release is thus proposed to overcome the problem. The brittleness of coal is the parameter characterizing the speed of energy release under the action of minute external energy in the post-peak stage. The mechanical and geometrical models of brittleness index were established according to the energy accumulation in pre-peak stage and the energy release in post-peak stage，which were validated theoretically and experimentally subsequently. Finally，the classification of bursting liability of coal according this index is studied. The results indicated that，compared with other indexes，this index can consider the longer nonlinear elastic phase of the hard coal，the shorter plastic and post-peak benched drop characteristics and so on.

The study on the interaction of the damage and crack of brittle material under dynamic loading has great importance on the explanation of rock rupture mechanism. The dynamic method of caustics was carried out using polymethyl methacrylate(PMMA) specimens to simulate the interaction process between the crack and defects of brittle materials under dynamic loading. The dynamic crack propagation mechanism，the effects of different types of defects on the crack propagation and the interaction mechanism of crack and defects were discussed. The experimental results show that the crack arrest occurs followed by the increasing or decreasing of crack propagation velocity when there are defects near the crack path. The size of the defects and their distance from the crack path influences the arrest time. The fracture energy consumption increases when there is a circle hole near the crack path，while the multiple holes near the crack tip reduce the crack resistance of crack and the energy consumption. Other type of defects such as the surface crack and the combination of through and surface cracks influence the crack propagation velocity except the energy consumption. The symmetric cracks interact with each other during crack propagation. The minor difference between two symmetric cracks influence the crack initiation and propagation process，and lead to the asymmetric propagation of the two cracks. The crack position，crack propagation velocity，stress intensity factor and energy release rate etc.，can be obtained using the method of caustics which is a promising method for investigating the dynamic interaction between crack and defects.

As a kind of typical flaw，circular hole plays a significant role on the mechanical properties of rock. Specimens containing two circular holes were constructed and subjected to uniaxial compression based on lab experiment and two dimensional particle flow code(PFC2D). The effect of the distance between holes and the dip angle on the strength，fracture mode and crack development of rock were investigated in detail. With the increase of the dip angel，the uniaxial compressive strength of specimens decreases first then increases. The uniaxial compressive strength reaches the minimum value when the dip angle equals to 45° to 60°. When the dip angle equals to 90°，the uniaxial compressive strength of specimen increases first and then decreases with the increase of the distance between the holes，and reaches the maximum value when the distance between holes equals to 40 mm approximately. The fractures generated in the specimen can be classified into three modes，namely mode I (tensile fracture)，mode II (shear fracture) and mode III (mixed fracture). When the distance between the holes is small，with the increase of dip angle，the fracture mode between the holes changes from mode III to mode II gradually, while on the hole walls adjacent to loading part, mode I fracture occurs. However，mode II fracture always occurs on the hole walls adjacent to the side boundaries of specimen. When the dip angle equals to 90°，the interaction between two holes weakens with the increase of the distance between holes，however，the mode I fracture occurs on the hole walls adjacent to loading part and the mode II fracture occurs on the hole walls adjacent to the side boundaries all the time. The mode II fracture firstly initiates on the rock bridge between two holes，and then mode I fracture generates on the hole walls adjacent to loading part，and finally mode II fracture occurs on the hole walls adjacent to the side boundaries. Generally，the magnitude of acoustic emission (AE) from the mode I fracture is higher than that from the mode II fracture.

In the present seismic response analysis of rock slopes，the limit equilibrium method is used to analyze the static safety factor and the Newmark dynamic analysis is used to analyze the dynamic permanent displacement. Their use in engineering practice was limited due to the complexity. In this paper，the rigid body discrete element method is introduced into the evaluation of seismic stability of rock slopes. Combining the rigid body discrete element method with the strength reduction method and Newmark method，a static and dynamic stability analysis method for complex rock slopes is presented. Assuming the large stiffness for joints，the contact displacement caused by the elastic deformation of joints was limited so that the rigid discrete element method can be used to solve the static/dynamic stability of rock wedges. The rigid discrete element method does not need to assume the sliding direction and sliding mode in calculating the safety factor of the rock slope and is therefore very useful in engineering practice with the complex rock wedges. The correctness of the proposed method and the programming in the 3DEC code is demonstrated through comparisons with 4 classical static examples and 3 dynamic examples. Parameter studies confirmed that the proposed rigid discrete element method is capable of obtaining the correct trend of variation according to the changing parameters. It was found that under certain conditions the pseudo static safety factor cannot reflect correctly the extent of the earthquake response of the rock slope. In the case study，the seismic stability evaluation of K1 block based on the displacement was carried out with the rigid discrete element method. The results with the rigid discrete element method were better than those from the method of pseudo static safety factor.

A slope model with inclined soft layers intercalated was generated to simulate a slope site fornuclear waste disposal near to Longmenshan fault zone in northern Sichuan province and the centrifugal shaking table test of 50 g was carried out. The accelerations of the model under different input ground motions triggered by earthquakes were measured. The traditional Fourier spectrum and Hilbert marginal spectrum were utilized to reveal the variation of spectral characteristics of the slope in frequency domain. The experimental results show that the acceleration amplification of the intercalated soft layers was related to the peak input seismic acceleration. The acceleration amplification was weakened under the smaller peak input seismic acceleration，but was strengthened under the larger seismic ground motions. The slope has marked influence on the dynamic responses of the intercalated soft soil layers in this site. The slope caused the acceleration amplification of the intercalated layers to increase. With the increasing of peak input seismic motion，the components of acceleration response at the intercalated soft layers were changed，the higher frequencies decreased but lower components increased.

Rockbursts frequently occur during mining in magmatic intrusion areas. The mechanism of rock burst at heading roadway in thick coal seam in magmatic intrusion areas is thus studied theoretically and numerically. A formula for calculating the stress distribution in surrounding rock of the roadway was deduced based on the elastoplastic theory. The contours of stress distribution shows that the direction of maximum principal stress and the concentration area position of maximum shear stress were perpendicular to the inclination angle of coal seam. The dip angle of coal seam does not change the concentration degree of maximum principal stress and shear stress. The lateral pressure coefficient had a greater influence on the concentration of the maximum principal stress. The large hard magmatic rock roof suspending in the goaf leads to the overall increase of the stress in the large area of coal nearby，which provides the static loading for rockburst. Tunneling induces the instantaneous release of energy from the local magmatic rock，which provides the dynamic loading for rock burst. Based on the above analysis，the mechanical model of rock burst in roadway in thick coal seam in magmatic rock intrusion zone was established，the criterion of rockburst occurrence was obtained and then the mechanism of rockburst was obtained. The application of the research results guided the prevention of rock burst in practice.

In order to investigate the mechanical properties of coal after thermal treatment， two sets of anthracite samples with different aspect ratios in a box-type muffle furnace were firstly prepared and heated subsequently under temperatures from 20 ℃ to 500 ℃. The static uniaxial compression and dynamic impact tests were then conducted using the hydraulic servo testing machine and split Hopkinson pressure bar(SHPB) system respectively. The microstructure images，the porosity and the pore size distribution of typical samples were obtained using the scanning electron microscope(SEM) and mercury intrusion porosimetry(MIP). The experimental results show that the temperature range can be divided into two stages by a critical value of 300 ℃. The physical reactivity and pyrolysis play the main roles in Stages 1 and 2 respectively. The porosity of coal and the proportion of super micropores and micropores increase gradually with temperature. The bearing and anti-deformation capacities of anthracite decrease with temperature，and the tendency is more obvious in stage 2 than in Stage 1. The static and dynamic compressive strengthes at 500 ℃ are only 8.41%/16.94% of those in the natural state. The static mechanical properties are more sensitive to the temperature than the dynamic properties due to the effect of strain rate. The variations in dynamic increasing factors of the compressive strength and elastic modulus are different.

Due to the rigid platens used in Mogi type of true-triaxial test apparatus，the friction between the loading platens and samples enhances the measured strength of material. In order to quantitatively estimate the end effect，the biaxial compression tests on the red sand stone samples were conducted under different interface frictions and intermediate stress conditions. The measured strengths of samples under different interface frictions differ significantly. When the friction coefficients of interface increase from 0.12 to 0.28，the maximum stresses of samples under the same intermediate stress increase 5.5% to 43%. Several yielding criteria were used to estimate the end effect and the strain energy criterion was adopted for further analysis. An expression for end effect was established and the intermediate stress effect curves considering end effect were drawn in   coordinate. The influence of end friction on the curve?s shape was revealed to agree well with test results.

Red sandstone is widely distributed in the drawdown area of Three Gorges Reservoir，China. Understanding the mechanisms of deterioration of the tensile strength of red sandstone under cyclic wetting-drying during the operation of reservoir is therefore very important for the stability evaluation to the slopes of red sandstone. The red sandstone samples from Majiagou landslide were taken for splitting test to measure the tensile strength under water pressure and cyclic wetting-drying conditions using the test system developed in house. The system can apply the water pressure and wetting-drying cycles. Meanwhile，the tensile strength deterioration of the red sandstone in drawdown area was discussed based on the results of SEM tests，XRD tests and water absorption tests. Experimental studies show that the tensile strength of the red sandstone under water pressure and cyclic wetting-drying conditions decreases gradually with the increasing of the number of wetting-drying cycles. The decreasing rate of the tensile strength after the first wetting-drying cycle is much greater than that after the latter wetting-drying cycle. After the fourth wetting-drying cycle，the decreasing rate of the tensile strength approaches zero，indicating that the tensile strength keeps nearly constant. The tensile strength degradation of the red sandstone is a cumulative process of damages resulting from the expansion of clay minerals due to hydration during wetting process，the shrinkage of clay minerals in the period of drying process，and increasing and propagation of micro pores and cracks under water pressure. The weakening effect of cementation between detrital minerals and cements caused by the hydration of clay minerals under cyclic wetting-drying conditions plays a main role for the degradation of the tensile strength.

The excavation of exploration tunnel at Beishan which is to be the test platform for the underground research laboratory of high-level radioactive waste was investigated in order to study the variation of internal displacement in the hard surrounding rock. An in-situ test scheme was designed and the field measuring of internal displacement in surrounding rock was carried out. The variation of the internal displacement in surrounding rock in the whole process of tunnel excavation was analyzed. The analysis of the spatial effect of tunnel face and the estimation of loss displacement was carried out with 3 typical LDP curves of Lee equation，Hoek equation and V-D equation. The research result shows that the internal displacement of surrounding rock in the whole process of blasting excavation goes through 3 stages，including the initial growth，the rapid growth and the stable convergence. The temporal curve of internal displacement in surrounding rock near the monitoring section shows the step characteristics，which is similar to the morphological characteristics of creep curve of rock in stepped loading test. The measuring points far from the side wall of tunnel is less affected by the spatial effect of the tunnel face and the displacement release in front of the tunnel face accounts for a larger proportion. The loss displacement calculated with the Hoek equation is closest to the measured value. When the measuring section was set 2 m away from the tunnel face，the loss displacement accounts for more than 50% of the total displacement.

The Central-Wan Chai Bypass(CWB) is a route to reduce the traffic congestion between the east and west of the densely populated Island metropolis. This paper is to review the performance of design and construction of the underground tunnel with trinocular cross section area of 460 m2 and a combined span of 50 m by sequential excavation method(SEM) in hard rock and adopting the new austrian tunneling method(NATM)，together with the application of NGI Q-system allowing observational approach and optimization of temporary rock support design. The trinocular tunnel also passes 20 m beneath the southern approach ramp of the Cross-Harbour tunnel(CHT). Furthermore，the comprehensive application of several engineering measures，such as the extensive instrumentation monitoring，standby dewatering/recharging system and steel weights，to reduce the risk of flotation of the existing CHT are also discussed in this paper.

In order to investigate the effect of creep behavior on the strength and deformation of rock，a number of marble samples were pretreated under different hours of creep preloading at different stress levels which contains the compaction stage，elastic stage，stable stage of crack growth，unstable crack growth and failure stage on the whole stress-strain curves. After the creep loading，the samples were reloaded under uniaxial compression to analyze the influence of creep behavior on the strength and deformation of marble. Meanwhile，a new method was proposed to divide the stages of volume strain using the volumetric strain rate. The creep at the stress levels of the compaction stage or the elastic stage enhances the mechanical performance of marble. With the creep time increases，the uniaxial strength and elastic modulus increase but Poisson’s ratio decreases. The enhanced degree of mechanical performance of creep is greater at the elastic stage than at the compaction stage. In addition，the failure of the rock samples occurs in a short time if the creep is conducted at the unstable crack growth or failure stage. The deformation process of the rock can be divided into three stages according to the dilatation rate，a stable compaction stage，an accelerated dilatation stage and a decelerated dilatation stage. After going through the creep preloading at the compaction stage or the elastic stage，the dilatation rates of marble samples decrease slightly with the increasing in creep time. On contrary，after going through the creep preloading at the stable crack growth stage，the dilatation rates increase dramatically with the creep time increases. The failure patterns of marble samples without creep preloading under uniaxial compression are mainly shear failure with a single macrocrack. With the increasing of the creep time，the failure patterns of marble samples underwent creep preloading at the compaction stage or the elastic stage were gradually transformed from shear failure to splitting failure. The failure patterns of marble samples underwent creep preloading at the stable crack growth gradually transform to the mixed mode of shear and splitting failures，accompanied by several principal cracks and numerous associated cracks.

In order to study how the splitting tensile strength of layered rock is influenced by varied moisture contents，samples of layered sandstone with five different moisture contents were used in the splitting tensile strength test along the weak stratification plane. The tensile strength of layered sandstone decreases fast initially and slowly then as the moisture content increases. When the saturation degree is lower than 80%，the tensile strength is reduced significantly. With the increasing of saturation，the parameters of height and texture of the fractured rock surface increase fast initially and slow then. Besides, there is a good linear correlation between the tensile strength of rock and the microstructure parameter of splitting surface. The total energy absorbed by the sample and the elastic strain energy in the loading process decrease gradually as the moisture content increases. The ratio of elastic strain energy to total energy decreases while the dissipated energy ratio goes up. The weak bedding plane is not only the weak surface of layered rock structure，but also the main absorption space and migration channels for moisture. The mechanical property of weak bedding surface and the distribution of pore water vary with the increasing of moisture contents and the crack propagation is changed in the in-situ loading process，which directly influences the proportion of the elastic strain energy and dissipation during the loading process. In conclusion，the influence of water content on the tensile strength of rock is a progressive process of microscopic structure changing to the macroscopic degradation of mechanical properties.

针对被动柔性防护网在实际工程中承受累计冲击的现状，开展标称能级为1 500 kJ的防护网结构足尺落石试验，在无修复状态下进行连续累加冲击；基于LS-DYNA的显式算法，对试验进行全过程模拟；进而采用数值分析开展标称能级为750，3 000和5 000 kJ系统的累计冲击模拟。结合试验与数值仿真研究累计冲击作用下，结构的传力机制、变形特征、耗能分布。结果表明：中跨已成功拦截1 500 kJ落石冲击的被动柔性防护网，仍具有继续承受左跨750 kJ、右跨750 kJ和中跨1 500 kJ共4次连续冲击能力。系统的冲击力学行为具有明显的三阶段特征，随着累计冲击的开展，系统的主要耗能由第二阶段转换为第三阶段；减压环的耗能比例降低，网片的耗能比例提高；结合各工况的性能曲线，建立系统的能量储备系数与各阶段能量比例的相关计算公式，采用该公式可对系统的能量储备进行预估，研究结果为被动柔性防护网结构的设计提供理论基础。

A method based on the extended finite element(EFM) was proposed to overcome the problem in modeling the multi-field coupling in permafrost engineering which has the characteristics of moving interface of phase transition and changing material zones. A theory capturing various couplings among the liquid transport within the pores，the force interaction between the soil skeleton and crystal ice，the energy jump during the phase-changing between ice and water was used. The governing equations for solving the primary field variables such as temperature，liquid pressure and solid displacement were derived and an analysis platform 3GEXFEM was developed. The validation of the program was accomplished by means of the numerical simulation to an experiment published by Fukuda. The results of the simulation of the temperature field，moisture distribution and heave agreed well with the experimental results. In addition，the moisture-heat-stress coupling of frozen soil during freezing process was solved under different environmental conditions such as overburden pressure，temperature gradient，temperature change mode and cooling rate, showing that 3GEXFEM program are well adapted for practical engineering.

The incompatibility between the bentonite and inorganic solutions has adverse impact on the impermeability of the filter cakes and backfills in soil-bentonite slurry walls. To improve the hydraulic performance of bentonite were backfills exposed to inorganic solutions，the Polyanionic Cellulose(PAC) and sodium activated bentonite were directly blended to produce a polymer-amended bentonite termed as PB. The Calcium Chloride(CaCl2) solutions were selected as the test solutions，and the hydraulic conductivities of the bentonite filter cakes to distilled water(kw) and to concentrated CaCl2 solutions(kc) were measured through modified filtrate loss tests under various applied pressures. The results indicate that the kc of PB filter cake increases with the increase in CaCl2 concentrations，whereas the filtrate loss volumes(V) of PB specimens remains less than the standard limits(25 mL). The hydraulic conductivity of PB is lower than that of CB in the range of CaCl2 concentration used in the study. The water contents(w) of both filter cakes decrease with the increasing of CaCl2 concentration for a given average effective pressure，which results in the decreasing in the void ratio of filter cakes and increasing in the kc of both filter cakes. The increasing of average effective pressure can partially counteract the adverse effect on kc caused by the increasing of CaCl2 concentration. The hydraulic conductivity ratio(kc/kw) of the PB filter cake is less than 10 when the CaCl2 concentration is no more than 60 mM，illustrating that the kc of PB filter cake has no significant increasing. Therefore，mixing PAC with bentonite can improve the hydraulic performance effectively.

To reveal the strength and deformation characteristics of sandy gravel material covering the dam foundation in Suwalong hydropower station affected by the intermediate principal stress ratio and the stress level，a series of large-scale true triaxial tests were performed，combined with a special friction-reduction technique. The stress，strength and dilation were then analyzed under the framework of generalized deviatoric stress and mean effective stress. The internal friction angle was found to increase with the rising of intermediate principal stress ratio，but decrease with the stress level. Among three classical strength criteria，Lade-Duncan criterion shows the best fitting to the tested results，despite of the underestimation at higher level of b values. With the increasing of b value，the slope of the stress path reduces. Meanwhile，the peak strength increases with the decreasing of the stress ratio q/p (q is deviatoric stress，p is mean effective stress)，indicating that the mobilized strength reduces at unit mean effective stress. The angle of dilation decreases with the increasing of stress level and intermediate principal stress.

In order to solve the problems of draining and supporting for deep foundation pit in soft soil area，a new type of supporting structure with vertical sheet drains and self-drilling tire tandem anchors was put forward，and the working mechanism was studied in detail. The bearing capacity of the self-drilling tire tandem anchor under pore ware pressure was derived based on the cylindrical cavity expansion theory. The effect of prefabricated vertical sheet drain were analyzed and its influence on the uplift capacity of self-drilling tire tandem anchor was discussed with the finite element software ADINA. The bearing capacity value from simulation was compared with the theoretical one. The results show that the vertical sheet drains have a good dewatering effect，which can dissipate the pore pressure in the soil quickly and effectively. The axial force of anchors and the horizontal displacement of frame columns are significantly reduced with the prefabricated vertical sheet drains. The excessive pore water pressure caused by tire expansion can be dissipated immediately with the prefabricated vertical sheet drains. Furthermore，with the dissipation of pore water pressure，the displacement and strain of the soil along the axial direction are reduced，and the uplift capacity of anchors are improved. The theoretical uplift capacity is basically accordance with that from simulation，which proves the correctness of bearing capacity formula.

The in-situ solidification and stabilization(S/S) technique using SPC was implemented to remediate a heavy metal contaminated site nearby a Pb-Zn smelter in Gansu，China. Several series of tests were conducted to examine the water content，soil pH，metal leachability，metal speciation and penetration resistance of untreated soils and stabilized soils. The influence of binder contents on these physical，chemical and mechanical characteristics，as well as the fixation mechanisms of Pb，Zn and Cd by SPC were also investigated. The results show that in-situ S/S using SPC reduces significantly the water contents but raises the pH values of contaminated soils. The leached Pb，Zn and Cd concentrations decrease. The metal leachability satisfies the corresponding criteria for solid waste. The large percentages of Pb，Zn and Cd are transferred from the exchangeable fraction to residual fraction after in-situ S/S using SPC. The penetration resistance of stabilized soil increased with the increasing in the SPC content.

A pedestrian underpass in Nanjing was constructed using pipe jacking method，which traverses both the existing metro tunnels and an urban main road in short distance. In order to ensure the safety of the tunnels and the road，a 3D FEM model was established before construction to simulate the whole construction process and to predict the possible deformation of tunnels and ground settlement. Based on the simulation results，the targeted measures to reduce the deformation were put forward，and a reasonable field monitoring scheme of tunnels and ground surface deformation was proposed. The monitored items included the vertical displacement，horizontal displacement，diameter convergence of tunnel and the ground settlement. The variation of tunnel and ground deformation was analyzed based on the observed data and three different stages that tunnel and ground surface experienced during construction were proposed. The results indicate that the vertical displacements of tunnel are mainly manifested as heaving induced by the unloading in the underpass. The influence of excavation of working shafts on the vertical displacement of tunnels is almost negligible. In the whole construction process，the vertical displacement of tunnel mainly experiences an initial settlement stage，a quick heaving stage and a steady heaving stage. The ground settlement goes through a heaving enhancing stage，a heaving weakening stage and an absolute settlement stage. In the same monitoring section，the maximum ground settlement occurs on the central line of underpass，and the settlement decreases away from the central line. The slight under-excavation method applied in the construction is effective in reducing the ultimate tunnel heaving and ground settlement.