Focusing on the three key problems of how to comprehensively consider the shear resistance of anchor cables，how to quantitatively predict the service life of anchor cables and how to effectively extend the service life of anchor cables in the slope engineering，the mechanical mechanism of shear resistance of anchor cables in slopes was revealed through laboratory test，numerical simulation and theoretical analysis. Based on the three-phase deformation and failure mode，a mechanical model which can fully reflect the shear resistance effect of prestressed anchor cables was established. According to the results of in-situ exhumation and 2 160 sets of corrosion tests，including immersion，electrolytic and dry-wet cycle corrosion tests，the corrosion mechanism and evolution law of anchor cables were revealed. A three-stage service life model considering the health status of anchor cables was proposed，and the performance deterioration model and life prediction method of anchor cables were established. To solve the problem of insufficient protective measures for anchor cables，a strengthened protective structure for weak parts was invented，a special device for dynamic control of stress over the limit was developed，and a distributed stress-deformation real-time monitoring and defect detection equipment were exploited. Thus，a complete set of life extension technology including structural measures，special devices and monitoring equipment was established.

In order to effectively study the stability of mining face and roadway surrounding rock during the secondary mining period，to ensure that there will be no safety hazards in the whole process of secondary mining，and to ensure the perfect and reasonable on-site support scheme，based on the geological condition of the 50305 working face of Fa?er coal mine，the deformation of roadway surrounding rock and mining face stress during secondary mining face of 50305 working face are analyzed systematically，so as to use reasonable support measures. Through theoretical analysis，the mechanical fracture criterion of secondary mining roadway roof is studied，and the scope of the failure zone is determined in advance. Through the numerical simulation，the mining face stress during the working face mining is analyzed in detail，and the roadway stress and displacement are analyzed in detail，which provides a reference for the use of reasonable advance support measures during the secondary mining to ensure safe mining. Through the field analysis，the surface displacement and deformation of roadway and hydraulic support load during secondary mining are analyzed，and the field application effect and whether there are shortcomings are observed to provide reference for other mines. The secondary mining roadway is supported with constant resistance anchor cable，U-section steel and temporary support，and the secondary mining effect of self-formed roadway without coal pillar is good.

The deep rock mass is in a high water pressure and high geo-stress occurrence environment，the dynamic mechanical properties of rocks are deeply affected by the occurrence environment. In order to investigate the effects of the high water pressure and the high geo-stress on the dynamic mechanical properties of rock mass，based on a self-developed high water pressures and high geo-stress rock dynamic test device，impact tests are carried out on red sandstone samples under different water pressures and axial static stresss. The variation rules of the dynamic peak stress，the ultimate strain，the average strain rate and the dynamic deformation modulus of red sandstones under different water pressures are analyzed respectively. The relationship among the average strain rate，the dynamic peak stress and the ultimate strain are explored. Empirical models for the relationship between the water pressure and the peak stress，the ultimate strain，the average strain rate，and for the relationship between the ultimate strain and the average strain rate are constructed. The strength and deformation characteristics of the microstructure of rocks under the water pressure are analyzed based on sliding crack model and the influence mechanisms of the water pressure on the dynamic mechanical properties of rocks are explored. The results show that，under the same axial static stress，the peak stress of rock samples increases gradually with the increase of the water pressure，and the peak stress shows a good logarithmic function distribution with the water pressure. Besides，the average strain rate and the ultimate strain of rock samples both decrease exponentially with the increase in the water pressure. The Meniscus effect，the Stefan effect and the Newtonian internal friction effect of the water in the fractured surface of red sandstone and the external water pressure inhibit the initiation and expansion of the fissures，and thus improve the compressive strength and deformation resistance of red sandstone at dynamic loading level. The research results are beneficial to the perfection of deep rock dynamic theory and provide a theoretical basis for the safe and efficient design and construction of blasting excavation in rock mass engineering with deep high water pressure environment.

The concentrated surrounding rock stress is the fundamental force source to induce coal-rock dynamic disasters. To improve the monitoring accuracy and efficiency of the drill-cutting method，a new method to characterize the surrounding rock stress distribution characterization via borehole ultimate friction resistance is proposed based on theoretical analysis and engineering test. Firstly，the plane stress damage equation of the surrounding rock stress and drill-cutting weight is deduced，and the validity of this equation is verified by existing numerical simulation，laboratory test and engineering test results. According to the plane stress damage equation，the influence of uniformly distributed surrounding rock stress，side pressure coefficient，Young?s modulus and damage factor on drill-cutting weight is analyzed. Secondly，according to the force characteristics of the drill bit，the relationship equation between the drilling parameters and borehole ultimate friction resistance is established. Finally，the engineering test was carried out through the self-developed intelligent drill-cutting system. Combined with the test results，the relationship model between the drilling parameters and drill-cutting weight is established (DP-N model)，and the DP-N model is used to characterize the surrounding rock stress distribution characteristics of 12120 working face. The results show that：(1) The drill-cutting weight shows a linear positive correlation with the uniformly distributed surrounding rock stress and side pressure coefficient，an exponential function increasing relationship with the damage factor，and a power function decreasing relationship with the Young?s modulus. (2) The borehole ultimate friction resistance and drill-cutting weight have an obvious piecewise fitting characteristic. The drill-cutting weight on both sides of the piecewise point has the opposite characteristics with the borehole ultimate friction resistance，and is related to the dynamic changes of coal damage factor and Young?s modulus. (3) The characterization results of DP-N model are basically consistent with the characterization results of the measured drill-cutting weight，and the average deviation of DP-N model is 11.4%. The research conclusions can provide data support for monitoring and early warning of coal-rock dynamic disasters.

The drying and hardening process of the tailings cemented filler is prone to initial defects such as air bubbles，holes and micro-cracks within the filler. To study the physical and mechanical properties and damage precursor characteristics of different initial defect-filled bodies，different levels of air-entraining agents(AEA) are added to the cemented filler to simulate the initial defects in the tailings cement during the drying and hardening process. SEM，XRD mapping，uniaxial compression and acoustic emission tests are applied to the analysis. Using the cusp mutation model，the mutation warning intervals for different initial defect-filled bodies are derived from the stress-strain curves and compared with the precursor information for acoustic emission destabilisation damage. The results show that the addition of AEA can increase the bubbles，pores and porosity within the filler，leading to an increase in initial defects and a significant reduction in the number of acoustic emission signals. With the addition of AEA，the proportion of time between the compacting phase and the full process of the filling increases，the proportion of time between the elastic phase and the full process decreases，the number of large-scale cracks during damage decreases，and the disorder of internal cracks increases，transforming ductile-brittle damage into ductile damage. The mutation warning interval of AEA fillers with different content is consistent with the information on acoustic emission damage precursors，and the mutation warning interval can effectively predict the destabilization damage of tailings colluvial fillers with different initial defects，providing a reference for mine safety early-warning.

As one of the main factors that induce rock burst，hard overburden seriously threatens the safe and efficient mining of coal mines. This paper analyzes the catastrophic process of rock burst disaster of hard overburden and the key controls on the energy of the key stratum inducing rock burst，gives the determination method of the key stratum induced rock burst，and proposes the method of goaf backfilling and grouting bed separation so that weakening the catastrophic energy of the key stratum inducing rock burst. Taking the mining geological conditions of two typical coal mines under the hard overburden rock as a background，the deformation law of the key stratum induced rock burst and the evolution law of the disaster energy under different backfilling conditions are studied，the mechanisms of backfilling to weaken the disaster-causing energy effect of hard overburden rocks is revealed and the engineering design method is given. Finally，it was verified by field measurement analysis. The research results show that the energy accumulation，release and transfer caused by the deformation and rupture of the key stratum inducing rock burst formed by the hard-overlying rock are the key to inducing dynamic disasters. Goaf backfilling and grouting bed separation can effectively control the deformation of the key stratum inducing rock burst，reduce the accumulation degree and release speed of the disaster-causing energy，meanwhile，the backfilling body can absorb part of the energy and reduce the transmission efficiency of the disaster-causing energy，thereby realizing the weakness of dynamic disasters caused by hard overburden.

Complex reservoir scheduling refers to the operating conditions in which the water level of the reservoir undergoes multiple rises and falls at varying rates. To study the triggering factors，evolution laws and instability mechanisms of the slope failure of the embankment on a typical accumulation body in the HD reservoir area，a centrifuge experimental system was developed to simulate the coupling effects of reservoir scheduling and rainfall. The experimental design involved a water level rise，slow water level fall，rainfall，and fast water level fall scenario. The entire experimental process was analyzed to investigate the deformation and failure mechanisms of the accumulation body slope under complex reservoir scheduling and rainfall conditions. The findings demonstrate that the slope deformation，which mostly manifests as local collapse at the slope's leading edge during the reservoir filling stage，is difficult to detect. When the reservoir water level drops sharply，the slope undergoes a staged sliding in the middle and lower parts which causes tearing cracks at the rear edge. Rainfall leads to surface erosion and overall subsidence of the slope，which exhibits traction failure symptoms. Although the rate of the second water level dip is twice that of the first，the slope deformation is mainly characterized by local traction sinking at the front edge.

To investigate the weakening mechanism of water on impact-induced rockburst，15 experiments were performed considering different water content levels on cubic sandstones. Photography and acoustic emission(AE) system were used to monitor the rockburst process. According to the photography results，impact-induced rockburst under different water content levels all experience three processes：particle ejection，debris peeling，and comprehensive rockburst. In addition，the results also show that the higher the water content level，the lower the intensity of the rockburst. This effect is reflected in the fact that the AE energy，the quality and the fractal dimension of fragment show a decreased trend with the increase in the water content level. Based on the perspective of energy and micro-crack evolution，two mechanisms are proposed to explain the weaking effects of water on rockburst intensity，including：(1) water increases the plastic deformation capacity，weakens the energy storing capacity and reduces the rockburst tendency of sandstone，resulting in a slightly intensity of rockburst，and (2) water accelerates the expansion of shear cracks，which is not conducive to the occurrence of plate cracking before rockburst，and destroys the conditions for rockburst inoculation.

Fully-grouted bolts are widely used in slope reinforcement projects，but the anchoring mechanism and evaluation method of bolt-supported concealed bedding rock slopes need to be developed and improved. In this work，a new columnar mechanical model was established according to the sliding shear failure mechanism of bolt-supported concealed bedding rock slopes. Subsequently，the stability analysis method of such slopes was proposed using the limit equilibrium approach combined with the resistance contribution of the bolts. On this basis，the effects of the bolt angle and diameter on the stability of the bolted slopes were discussed. In addition，the analytical results were compared with those calculated by the discrete element modeling(UDEC). The results show that the tensile-shear coupling of the fully-grouted bolts increases the slip resistance of the sliding body. There is an optimal bolt angle that maximizes the stability of the bolted concealed bedding rock slopes，with a value approximately equal to the friction angle of the bedding plane. The slope stability also increases with increasing the bolt diameter by a power function. The simulation and analytical results are in good agreement，thus verifying the rationality and accuracy of the proposed analysis method. The research results are of guidance for stability evaluation and treatment design of this type of slope.

To analyse the influence of rock bridge angle on the strength and failure characteristics of rock mass under different stress paths，seven kinds of double flawed sandstone samples with different were prepared，then uniaxial compression tests，single and multi-stage creep tests were carried out. Results show that the rock bridge angle has significant effect on the critical stress，but the ratio of the critical stress of the same sample is less affected by . The long-term strength of the samples is very close to the crack initiation stress ，thus the long-term strength of the rock mass can be estimated only through the conventional compression test. In terms of crack propagation，the penetration characteristics of the same samples under the four loading paths are basically the same：the rock bridge is not penetrated when the samples with ????°–??°are damaged，while the samples with  ???60°–90°show the mode of direct penetration failure of the rock bridge. It is shown that the influence of  on the crack propagation is greater than that of the stress path. In addition，some samples also show the phenomenon that the apparent crack and the internal crack propagation are not consistent. In view of this，based on the continuous medium element simulation，a crack propagation judgment method based on plastic strain was proposed，and a three-dimensional model was established for calculation. The simulation results show that they are consistent with the test results. This method is more accurate than the traditional method of judging the crack propagation through the plastic zone，and can provide some reference for the three-dimensional time-dependent propagation simulation of rock fracture.

The stability of arch dam and slope of hydropower stations is a hot issue that many scholars pay attention to. The stability of the Xiluodu hydropower station is studied by combining numerical simulation and micro-seismic monitoring technology. The variation law of the stress and displacement of arch dam and slope under different water levels is analyzed. The relationship between the stability of arch dam and slope and the water level is explored. The distribution characteristics of slope micro-seismic events and micro-fracture types are studied. The relationship between high stress and micro-seismic events is revealed. The results show that：(1) The stress and displacement of arch dam and slope are positively correlated with the water level. The stress and displacement of the arch dam at the same elevation gradually increase from the downstream surface to the upstream surface，and there are high stress accumulation areas and large deformation areas in the dam toe area. (2) The micro-seismic activity of the slope increases gradually with the water level. The micro-fracture of deep rock mass of slope is mainly tensile failure type，accompanied by a large number of mixed type and a small part of shear type. (3) The high stress area of the slope is consistent with the micro-seismic event gathering area in time and space，and the high stress of the slope is the internal driving force of the micro-seismic event. (4) The 580 m water level is the sensitive characteristic water level of Xiluodu hydropower station. The research results have guiding significance for the safe and stable operation of the Xiluodu hydropower station，which also have certain reference value for the stability study of the similar hydropower stations and slopes.

The adsorption-desorption-diffusion-seepage characteristics of CH4/N2 are important indicators to measure the gas extraction capacity and N2 injection on gas displacement effect. In order to study the adsorption-desorption-diffusion-seepage law of CH4/N2 and the deformation characteristics of coal in the whole process of the experiment，the adsorption-desorption-seepage experiments of CH4/N2 were carried out. The timeliness characteristics of gas adsorption-desorption-seepage and coal deformation were analyzed. The influence of gas volume fraction on gas adsorption-desorption-seepage and coal deformation was clarified. The quantitative relationship between gas adsorption-desorption-seepage capacity and coal deformation were clarified. The space-time characteristics and anisotropic characteristics of coal deformation were discussed. A coal strain model for the whole process of CH4/N2 adsorption-desorption-seepage experiment was established. The results showed that under the same injection pressure of gas，the adsorption capacity/desorption capacity of pure N2 was the least，and the equilibrium time of adsorption/desorption was the shortest. As the increase of CH4 volume fraction in the mixture，the gas adsorption capacity/desorption capacity increased，and the adsorption/desorption equilibrium time prolonged. The adsorption capacity/desorption capacity of pure CH4 was the largest，and the equilibrium time of adsorption/desorption was the longest. The seepage capacity of pure N2 was the largest. As the volume fraction of CH4 in the mixed gas increased，the gas seepage capacity decreased，and the seepage capacity of pure CH4 was the least. The coal deformation produced by adsorption-desorption-seepage of CH4/N2 has timeliness，spatiality and anisotropy. The diffusion coefficients of CH4 and N2 in column coal had linear and quadratic function with pore partial pressure. The axial/circumferential adsorption strain and desorption strain of coal had a primary and quadratic function relationship with the gas volume fraction. The coal axial and circumferential of seepage strains had linear and cubic functions relationship with the gas volume fraction. The axial/circumferential strain of coal had a quadratic，primary，quadratic function relationship with the adsorption capacity，desorption capacity and seepage capacity，respectively. The coal stress in the process of gas adsorption-desorption-seepage covered the expansion stress of adsorbed gas to coal matrix，the compression stress of free gas to coal matrix，and the expansion stress of free gas to coal microporous fracture. Considering the three kinds of deformation effects by two state gases，a coal strain model in the whole process of CH4/N2 adsorption-desorption-seepage experiment was established.

Granite and other crystalline rocks exhibit heterogeneous properties such as discontinuity and anisotropy due to the microstructure such as mineral shape，mineral orientation and mineral composition. However，existing numerical methods are not able to quantitatively study the influence of mineral grain shape and orientation. In this paper，in order to investigate the influence of inhomogeneities such as shape and orientation of mineral grains on rock properties，the grain texture model(GTM) based on the particle discrete element method is proposed，GTM can investigate the influence of mineral grain shape and orientation and study the evolution of intra- and inter-grain crack of minerals by generating a random irregular shaped Cluster representing real mineral grains. By comparing with the results of experimental tests，the GTM can mimic the macroscopic mechanical properties and failure mode of LdB granite under different mechanical conditions with good agreement after the calibration of micro-parameters. By modeling GTM with various grain aspect ratios and rotation angles to investigate the influence of mineral grain shape and orientation，it is found that the change of grain shape and orientation will lead to the change of intra- and inter-grain contact ratios and orientations，which in turn affects the macroscopic mechanical properties and failure mode of the rock. The GTM can study the mechanical properties and failure mechanism of rocks more comprehensively from the perspective of microstructure of rocks，which provides an effective method to reveal the influence of heterogeneous properties on the macroscopic mechanical properties and intra- and inter-grain crack propagation.

In order to ensure the safety of underground mining operations，the“three tests and one model”multi-directional rock damage mechanism research method was proposed. The results show that：(1) In the dry-acid erosion environment，the damage rate of the rock mass changes from a slow response at the early stage to an increased response in the middle and late stages. The damage response is gradually exhausted at the late stage and basically proportional to the hydrogen ion concentration index. (2) After the impact，the peak stress and elastic modulus of the rock mass decrease with the increase of the number of dry-acid erosion，and the overall damage shows the softening phenomenon. The damage deterioration of the rock mass increases in the late erosion period. (3) Under uniaxial compression，the elastic potential energy of the rock increases with the increase of axial load，and its energy growth rate is not obvious. The ratio of elastic potential energy to the total energy is the smallest at the axial load of about 80 kN. In the early three stages，the ratio of plastic dissipation energy to the total energy becomes smaller. The percentage of plastic dissipation energy tends to increase in the later plastic phase，i.e.，near damage failure. (4) Assuming that the rock strength of white sandstone follows the Weibull distribution，a statistical damage constitutive model of rock that can better reflect the residual strength of white sandstone is constructed. The accuracy of the model is effectively verified by the results of uniaxial compression tests. This research results greatly improve the safety of deep rock mining and provide a new idea for damage research of underground rock mining operations.

As the coal resource exploitation gradually goes deeper，large-energy mine tremors occur frequently in several mines in Shandong and Inner Mongolia，which seriously restrict the productivity and effectiveness of mining activities. The focal mechanism analysis of seisms is the precondition for early warning and prevention and control of strong mine tremors induced by coal seam extraction. This paper provides an in-depth analysis of 27 strong mine tremors that occurred during the mining process of panel 63upper06 in Dongtan coal mine. The fast Fourier transform (FFT) method is employed to process the seismic waveforms of strong mine tremors by using field monitoring and theoretical analysis. The corner frequency and low-frequency displacement amplitude are obtained by fitting the Savage source spectrum model. The internal relationship between the source parameters of strong mine tremors is analysed，as well as the scale and occurrence of source rupture are calculated effectively. Based on the moment tensor inversion and occurrence of source rupture，the focal mechanism solutions of strong mine tremors are determined in Dongtan coal mine. The results show that the focal mechanism of these strong mine tremors is dominated by shear failure，followed by mixed shear failure. The overlying thick and hard rock strata above the coal seam are fractured and faulted along the advancing direction of the working face and the transverse direction of the adjacent goaf，respectively. We believe the two forming types of strong seisms cross each other and promote each other. The violent movement and instantaneous fracture of the overlying thick and hard rock strata caused by coal seam mining are the main reason for the frequent occurrence of strong mine seismic events.

In order to study the relationship between the shear bearing capacity of the rock-concrete interface and the mechanical properties of rock and concrete，the irregular joint specimens of fine-grained sandstone，silty-grained marble，granite and coarse-grained marble were prepared by using a splitting method，the rock joint morphological parameters were obtained by a three-dimensional topography scanner，and then the rock-concrete interface specimens were made by pouring concrete on the rock joint surface. Finally，direct shear tests were carried out on rock-concrete interface specimens under different normal stresses by using the RDS–200 rock joint shear test system. The results show that the peak shear strength of rock-concrete interface and concrete joint increases with the increase in normal stress，and the former always increases faster than the latter under the same normal stress；the average peak shear strength of the rock-concrete interface has a good exponential correlation with the average pre-peak shear stiffness of rock-concrete interface. With the increase of the difference between the elastic modulus of rock and concrete，the internal friction angle of the rock-concrete interface decreases linearly，the cohesion of the rock-concrete interface increases linearly，and the peak shear bearing mode of the rock-concrete interface gradually changes from the friction bearing mode to the combined bearing mode of friction and cohesion. Therefore，an empirical formula of the peak shear strength of the rock-concrete interface in the form of Mohr-Coulomb criterion is proposed. Based on the power relationship between the concrete wall sharing coefficient in the rock-concrete interface compressive strength and the basic friction angle of rock joint，a new method for determining the rock-concrete interface compressive strength JCSab is proposed，and an empirical formula of peak shear strength of rock-concrete interface in the form of JRC-JCS model is established. Through the comparison and verification between the calculated values and the test values of the peak shear strength of the rock-concrete interface，it is found that the two newly proposed empirical formulas can better predict the peak shear strength of the rock-concrete interface，and the parameters are easy to obtain，which can provide a reference for the estimation of the peak shear strength of the rock-concrete interface in engineering practice.

In urban environment，the existing underground structures could exert a barrier effect on groundwater seepage and soil movement. According to current research results，this barrier effect would either aggravate or diminish the ground settlement，while the specific characteristics of ground deformation is associated with the types and spatial distribution of the underground structures. In this paper，laboratory-scale model tests were conducted to investigate the mechanism of dewatering-induced deformations when a foundation pit is adjacent to a pre-existing metro station. With installing deformation and stress sensors in the physical model of pit-strata-station，the variations of groundwater level outside the pit，ground surface settlements，wall deflections and lateral pressure on both sides of the enclosure wall were monitored in real time during dewatering. All the monitored results were compared with those from another model test without a subway station outside the pit under the same pumping conditions；based on the comparison，the impact mechanism of the barrier effect incurred by metro station on the dewatering-induced foundation pit deformation is revealed. Results show that as to the case with metro station outside the pit，the same dewatering operation as the case without metro station would induce smaller water yield of the pit，smaller enclosure wall deflection but greater ground surface settlement and greater groundwater drawdown on both sides of the enclosure wall. In foundation pit design，engineers could consider reducing the number of pumping wells to achieve the same pumping effect，and should evaluate the barrier effect of adjacent underground structures on foundation pit deformation to provide a more reasonable supporting scheme.

The pile-soil stress ratio of the composite foundation reinforced by piles and solidification layer under embankment load was studied. The friction resistance of pile was supposed to be constant in the solidification layer and linearly increased with depth in the soft layer，considering the impacted of the relative displacement of pile and soil. Based on the load-transfer method，the force on the discretization of the soil and piles were analyzed. The analytical expression of the pile-soil stress ratio of the composite foundations was derived，taking the compatibility equation of deformation into consideration. The influence factors of the pile-soil stress ratio such as the solidification layer，the modulus and thickness influence were studied. The result show that set solidification layer on deep soft soil foundation using the suitable dosage of curing agent can decrease the pile-soil stress ratio，increase the bearing capacity of soil between piles and the composite foundation. The increase amplitude is not obvious while the elasticity modulus of the solidification layer larger than 50 MPa，so the dosage of curing agent should be in the suitable range. The pile-soil stress ratio increase with the increasing thickness of the solidification layer，but the choose of the thickness should in the right range from a economy perspective.

To investigate the coupled problem of one-dimensional nonlinear consolidation and heat conduction in saturated clay，the governing equations for nonlinear consolidation and heat conduction are derived considering the effects of temperature change on the physical and mechanical properties of clay，and a corresponding coupled model is established. This model can consider the interaction between nonlinear consolidation process and heat conduction process. Later，the finite difference method is adopted to solve the proposed coupled model，and the rationality of the model is effectively verified by comparing it with the calculation results of COMSOL software and other analytical solutions. Based on the presented coupled model，an example is used to analyze the influences of temperature increment ΔT，pre-consolidation pressure pcR and linear loading time ta on the consolidation behaviors. The results show that the temperature change has comprehensive effects on the nonlinear consolidation process，the increase of ΔT generally accelerates the dissipation rate of excess pore-water pressure，and also increases the settlement rate and final settlement. The dissipation rate of excess pore-water pressure in saturated clay increases with an increasing pcR，while the settlement decreases with an increasing pcR. The increase of ta reduces the maximum excess pore-water pressure generated in saturated clay，and also slows down the consolidation rate. In addition，it is observed that the consolidation degree Us defined by settlement is less than the consolidation degree Up defined by pore pressure during the consolidation process.