Model test studies based on the similarity theory was conducted to solve the safety problem of frozen rock wall in the mines driving with the freezing-blasting method. The model was constructed with a ratio of 1∶15. The degree of damage of the model was evaluated by the change of the ultrasonic velocity after blasting. Three velocity sensors were placed in the slot at the top of the model，and the sensors recorded the rock vibrating velocities of the measuring spots during each blasting process. Results show that the vibrating velocity is the largest in the radical direction，medium in the axial direction and the lowest in the tangential direction. The vibration has directional difference. The damage of frozen wall exhibits an obvious cumulative effect，and the damage factors near the blasting holes are larger than those in other places. In the vertical direction，the upper end of the model is damaged most seriously. The vibration of rock satisfies Sadovski formula with the media parameter K = 57.52 and the attenuation coefficient ? = 1.74. The largest vibrating velocity is caused by the third group detonators in the differential blasting process，and the velocity of rock vibration is very different in different directions and is the largest in the radical direction，medium in the axial direction and the lowest in the tangential direction.

In order to provide reliable data for evaluating the integrity of gas storage caverns constructed in deep salt formations(≥1 500 m)，experiments have been conducted to assess the effect of deformation on the permeability of the impure salt rock samples from Jiangsu province，China. The transient method of step-decay of Argon gas was used in conjunction with the conventional triaxial compression tests with the samples incrementally deformed and the permeability measured at the same time. The tests were performed at room temperature and at the effective confining pressures of 20 MPa in Utrecht University，Netherlands. It was found that the permeability of relatively pure salt samples decreased from 10－16 m2 to below 10－21 m2 with the increasing of differential stress(0–40 MPa)，presumably due to the crack closure and the porosity reduction. The permeability of the samples with high impurity content was 1–2 orders higher than that of the pure salt rock，which was interpreted to be due to the more effective compaction occurred in the pure salt. Using the concept of dilatancy boundary，the stress state around the spherical storage caverns in the deep subsurface is analyzed；and it is found that the stress state in the rock wall remained completely in the non-dilatant field(region of compression). It could be deduced that even under low-pressure conditions of cavern operation，dilatancy would not easily occur in the cavern walls，implying the high sealing integrity of deep storage cavern in salt rock.

In order to evaluate the stability of the foundation of new building on top of the old goaf which was not described in the present design codes，the analysis of overburden structure is carried out. The surface residual movement is firstly defined with two deformational phases. Only the second phase of the residual movement and deformation is found to cause harmful effects on the surface building. The compaction characteristics of the caving rock from boundary to the central of the old goaf is found to be different，with the border zone of voids，the central zone of collapsible rock voids and the fissures in upper rock. The regional space of two groups of the old goaf governing the surface residual and deformation are converted into the equivalent mining thickness respectively. The influence functions of the static surface residual deformation are constructed using the integral theory of probability under the influence of mining，including the influence functions of residual subsidence，the residual horizontal movement，the residual tilt deformation，the residual horizontal deformation and the residual curvature. The results of calculation using these influence functions show that the maximum residual movement and deformation of the surface occur at two border sides of the old goaf. The creep characteristics of rock are analyzed with Kelvin model and the time function of the residual subsidence coordinates constructed for the dynamic analysis of residual subsidence. It is verified that the results from the influence functions agree well with the actual observational data and the numerical simulation with FLAC3D.

The dynamic behavior of crack propagation due to the impacting of drop hammer on the defective medium of manufactured crack(inclination angle，respectively，for the 0°，30°，45°) was analyzed using the test system of digital laser dynamic caustics(DLDC). Under the action of the impact loading，the cracks started from one side of the existing crack，then extended to the whole specimen，and the path pointed to the contact point of drop hammer.   of the main crack oscillated till the occurring of the first peak. It decreased and then increased to the maximum value when the main crack began to propagate.   of the wing crack oscillated before propagation，then quickly increased to the maximum value and decreased thereafter. The velocity of the main crack decreased quickly after propagation. The main crack initiation delayed.

A new technique，a new method and a new law were put forward for the refinements and upgrading of current engineering rock mass quality classification methods，i.e. the automatic drilling process monitoring(DPM) technique，the fast and direct time-series analysis of the DPM data and the DPM based findings that the curve of the drill bit advancement depth versus the net drilling time can be easily measured and calculated and that it can be represented as a set of connected linear lines. Each linear line zone has a constant slope gradient or drilling speed and represents an intact and homogeneous rock block. The position of the curve slope gradient jump between any two connected linear zones represents a discontinuity plane. DPM can offer a new measurement method and many factual data for the refinements and upgrading. Consequently，the uniaxial compressive strengths，sizes and spatial locations of rock material blocks and the associated discontinuities in underground can be rapidly，effectively，objectively and quantitatively measured and estimated. Case studies are given to illustrate，explain and describe the new technique，the new method and the new law. The approach and its associated equations were presented to refine and upgrade the current RQD，Q，RMR and BQ methods for rock mass quality classifications. The methods for objectively and effectively measure were included and the rock strength，RQD，rock mass integrity，rock hardness and discontinuities were estimated.

A new criterion of salt dilation considering Lode angle and the total stress states on the basis of the yield criterion of triple shear energy was developed to investigate the stability for underground horizontal gas storage in bedded salt formations. The theoretical analysis of stress distribution was carried out to a salt cavern with elliptical cross-section and the state of stress along the wall of the salt cavern was discussed. The wall stabilities of salt caverns with different ratios of long-axis to short-axis and lateral pressure coefficients are estimated with the new dilation criterion. The best cavern shape for different lateral pressure coefficients and the range of pressure limits for the operation of salt cavern are thus determined. The results from the new dilation criterion are consistent well with the measured data.

The strainburst is a common type of rockburst，which frequently occurs in deep tunnels and may evoke severe threats to safe tunnelling. From the engineering viewpoint，it is essential to obtain a relatively accurate assessment on the location and the damage effect of rockburst. A comprehensive review and comparison was presented regarding the advantages and disadvantages of the proposed numerical indexes assessing the strainburst vulnerability. Based on an improvement on the theory of local energy released rate(LERR)，a novel numerical index，namely the relative energy release index(RERI)，was proposed. The establishment and the physical meaning of the method were described in detail. The rationality and applicability of RERI were studied and verified against the strainburst cases occurred in tunnels at Jinping II power station and a brittle failure case occurred in Canadian Rm415 test tunnel. RERI not only accurately indicates the potential failure location and the high risk region，but also quantifies the damage zone of rock mass excavation induced by high stresses. RERI can be utilized as a new theory and an analysis tool to assess the strainburst vulnerability and the brittle failures.

The crushing of supporting structures frequently occurs in the mining out coal pillar at the side of the upper goaf and in close distance to the working front of the shallow seams. The influence of the positions of hole-cut beneath the coal pillar was studied based on the mining practices at 4 working faces in Shigetai coal mine，Shendong mine area，China. A method of determining the cut-hole position was proposed to avoid the support crushing. As the positions of cut-hole are getting farther away from the edge of the coal pillar，the mode of the key stratum(KS) above the coal pillar varies in pushing out the coal pillar. The key stratum is stable initially，then starts to break like the cantilever. The periodic breaking occurred after the initial breaking leads to finally the occurrence of support crushing. Besides，if there is a KS in seams in close distance，this KS will affect the mode of breaking of the KS above the coal pillar. Total of 7 types in two categories of cut-hole positions were derived. The positions of cut-hole were proposed to ensure that the KS above the coal pillar would not break or its breakage would not cause the failure of supports.

The proper estimation of failure depths of mining floors is an important issue during mining above a confined aquifer. The layered rock mass of the floor is regarded as a transverse isotropic and continuous body. An analytical solution of the stresses in the transverse isotropic floor was derived considering the load distribution of seam overburden under the mining condition. The influence of the anisotropy(E1/E2，?1/?2) of deformation parameters of the transverse isotropic floor on the stress distribution was analysed. The dangerous shear plane of the transverse isotropic rock mass is found by the method of trial searching according to the calculated stress results and the Mohr-Coulomb yield criterion. The dangerous shear plane is then judged to be failure or not. The anisotropy of the elastic modulus is found to have a big effect on all kinds of stress distributions of the mining floor. The influence of the anisotropy of Poisson?s ratio on the vertical stress and shear stress is very small，but very significant on the horizontal stress. The calculated maximum failure depth and its location on the transverse isotropic floor are basically consistent with the results from the in-situ injection test due to considering the anisotropy of deformation and strength of layered rock mass.

In order to find a reasonable quantitative criteria to judge the stability of interlayer separation of complex roof in tunnels，the different stresses of structure surfaces and the distribution of interlayers to be separated were simulated and analyzed with ANSYS program to a total of 5×5 sets of orthogonal models considering 5 factors including the rock properties of the complex roof，the tunnel width，the rock thickness of complex roof，the cohesions and the internal friction angles of structure planes. The distribution of the interlayers to be separated was validated by engineering practice，and the mechanism of instability of the structural plane separation was analyzed. Using the separation range caused by the tensile stress in the middle of the structure plane to judge the stability was found to be more reasonable than using the interlayer separation size in the center of complex roof，and the threshold value of the separation range was 0.50–0.75 times of the tunnel width.

Shaking table tests were conducted to simulate the anti-seismic and damping measures on tunnel structures across faults. The fault-crossing tunnel structures with an absorbing joint，with a seismic resistant layer and without any damping measures were investigated respectively for comparisons by analyzing the seismic acceleration responses of surrounding rock，the seismic strain responses and the post-seismic destructive patterns of tunnel structures. The new type of dislocation device used in the single model box was proved to be capable to simulate the faults movement perfectly and to be able to help the shake table to exert the nonuniform seismic wave excitation. The absorbing joint reduced the strain values of tunnel structures by allowing the dislocation of the linings. The forced vibration and the seismic strains of tunnel structures due to the constraint of surrounding rock were reduced by the buffering of the seismic resistant layer. The seismic resistant layer was found to better than the absorbing joint. But the effect of these two measures were to be fully displayed，the strength of the lining concrete must be raised accordingly. The arch shoulder，the arch springing and the invert arch of the tunnel were found to be the vital parts for reinforcements.

The field investigation of the geological conditions，the physico-mechanical characteristics of the surrounding rock and the hydrological conditions of mining areas in Fenxi，together with an intensive geological detection with the method of transient electromagnetic in the typical failure zones in Xinliu coal mine was carried out. A similarity model of the failure zones was developed based on the results of the geological detection and the stress state in the pillar affected by the dynamic pressure during mining was studied. The stress state of pillar changes little and remains the initial state within a period of time in the process of longwall mining. The increase of pillar stress occurs firstly at the distance of 62.5 m ahead of the working face，while a significant accumulation appears at the pillar 12.5–25.0 m ahead of the longwall mining face. In the process of pillar extraction，the high compression stress controls the elastic core in the pillar and remains at a high level under the effect of dynamic pressure. Meanwhile，the elastic core moves forward along with the advancing of the longwall mining face and bring about the severe risks to the coal mine. Therefore，the elastic core should be destroyed by pre-unloading，so as to ensure the safety in pillar extraction.

Based on the understanding that rockburst induced by dynamic-loading is the result of structure instability of coal-rock，the experiments investigating the dynamic failure of coal-rock compound under one-dimensional static and dynamic loads were conducted using a modified split Hopkinson pressure bar(SHPB). The strength and fractal dimension of coal-rock compound were taken as the characteristic parameters and four typical levels of axial pre-compressive stresses were assigned for conducting the impact tests under different dynamic energies. The effects of dynamic and static loadings on the characteristic parameters were obtained. The results show that the coal-rock compounds with more cracks have higher resistance to the high-energy dynamic loadings and have the lower intensity of damage，which indicates that the measures of seam pressure relief would not only enhance the ability of coal-rock compound to withstand the high-energy dynamic load，but also reduce the intensity of rockburst. The structural characteristics of coal-rock not only enhances the ability of coal to withstand the high-energy dynamic load but also reduces the intensity of failure. Because of the very different time scales between the dynamic and static loadings，meanwhile，the structural characteristics weakens the effect of dynamic loading of high-energy on coal seam，and strengthens the impact of static load of high-energy.

A water inrush case upon roof bed separation of the ultra thick coal seam during the full-mechanized caving mining was analyzed. The types of water inrush in bed separation were summarized and the mechanism of formation of the hydrostatic water inrush in roof bed separation of a mining face was discussed. The possible separation locations in the studied area were calculated. The method of prevention of water inrush from roof bed separation was introduced in detail. Proposed drill holes penetrating through up to ground surface drained the water in the separation effectively. The relationships between the mining height and the water inrush from the separation，and the relevance of the mining rate and the water yield in the separation were studied.

A framework of risk management including risk identification，estimation，evaluation and control was proposed for the safety in the whole construction process of urban tunnels with large cross-sections. Taking the North Ring Road，Jiuzhou tunnel for example，the comprehensive evaluation with fuzzy method was applied to determine the set of the levels of risk factors，the set of risk evaluation and the set of membership. The risks in the whole construction process were identified，analyzed and evaluated. The risk tracking and control are achieved with the framework of risk management proposed in the whole process of construction and avoids the weakness of the scattered，dispersed，fragmented risk management mode which was used in the previous projects.

The large geomechanical model test to investigate the failure mechanism of rockburst tunnel under the static and explosive loads was carried out with the static load simulating the initial stress field and TNT explosion simulating the rockburst. The applied vertical pressure was equal to the uniaxial compressive strength of the similar material with the coefficient of lateral pressure of 1/3. Three levels of explosive loads were applied respectively. Rockburst phenomenon occurred when the last explosive load applied. The tunnel rockburst hazard was found to be the results of the combined action of dynamic and static loads. Impact load and the existing static load were superposed suddenly，which caused the superposed force to increase significantly and to be greater than the bearing capacity of the wall rock，leading to the rock impact failure to occur. The deformation due to impact and the initial deformation due to the tunnel excavation were superposed when the impact loads applied suddenly，leading to the failure of tunnel walls when the superposition deformation was greater than allowed. The deformation and the failure areas of the surrounding rock were affected by the impact load and the initial stresses.

A large number of field observations have shown that the areas of abnormal stress during roadway excavation are also the ones where rockburst frequently occurs during coal mining. Therefore，a method of dynamic evaluation adopting the microseismic，underground sound and stress monitoring systems to monitor the dynamic information such as the vibrations and the stress signals during roadway excavation is presented to define the risk zones of rockburst and the levels of danger. The static geological data revealed during roadway excavation are added to the exploration data for the static evaluation of rockburst risk at working face. A combined method of evaluation with the dynamic and static data was established. With both the static and dynamic information from the excavation，the proposed evaluation method overcomes the limitation of traditional static evaluation and provides a more accurate basis for rockburst control before mining activities.

The homemade integrated testing system of ultrasonic wave and acoustic emission was used in the uniaxial and the cyclic loading tests on salt rock to investigate its characteristics of deformation，ultrasonic wave velocity and acoustic emission. At the initial stage of the loading tests，the velocity of ultrasonic wave of salt rock increases significantly with the reduction of crack volume，and about 0.04% of total acoustic emission(AE) events occurred. When the salt rock enters the stage of elastic compression，the volumetric strain of rock samples increases，while the crack volume remains constant；P-wave and S-wave remains stable，and the acoustic emission activity is weak with about 2.49% of all the total AE events. When the salt rock enters the phase of linear crack growth，the shear wave velocity slowly declines and the AE events become active with about 17.3% of the total acoustic emission events. The AE events increases to 76.5% of the total acoustic emission events at the phase of accelerated crack growth，with the feature of earthquake swarm. The velocities of P-wave and S-wave begin to reduce significantly. After the peak stress，salt rock produces a small number of acoustic emission events，and the velocity of ultrasonic wave declines to the lowest level. In the test of cyclic stress loading，the ultrasonic velocity and the AE activity of salt rock varies consistently with the stress condition. The velocity of ultrasonic wave increases and the AE occurs intensely in the loading process，while the velocity of ultrasonic wave decreases and the AE occurs rarely in the unloading process. Felicity effect is confirmed and the accumulated damage is obtained by comparing the change of Felicity ratio with the results of statistical calculation of AE events and stress states.

Experiments were carried out to investigate the variation of gas adsorption of coal after the treatment of hydraulic slotting and pre-draining using seven coal samples obtained from coal seam 10 of Yangliu mine. The experiment of isothermal adsorption of methane was adopted to measure the adsorption constants. The mercury injection capillary pressure(MICP) and the nitrogen gas adsorption(N2GA) were applied to obtain the variation of the pore size distribution and the specific surface area. With the increasing of the distance between the sampling locations and the slotted borehole，the adsorption constant a increases and the adsorption constant b decreases，which are consistent with the variation of the curvature of the curves of isothermal adsorption of methane. With the increase of borehole distance，the pore size distribution of coal sample varies substantially. The volumetric proportion of adsorption pore increases from 33.27% to 55.38% and the specific surface area increases from 7.254 m2/g to 9.856 m2/g. The curves of parameters(adsorption constants，volumetric proportion of adsorption pore and specific surface area) of coal within the slotting disturbance were found to be bounded and nonlinear and the curves varied gently initially，then drastically and finally gently again，obeying the Boltzmann equation. The gas adsorption of coal mass after the treatment of hydraulic slotting and pre-draining related closely to the distance from the slotting hole. The region below 1.8 m is significantly affected；the region between 1.8 and 4.5 m is transitional and the region over 4.5 m away is little influenced. Slotting disturbance leads to the decrease of the gas pressure and the increase of the effective stress，controlling the adsorption property of coal.

In order to predict the rockburst intensity efficiently，the main control factors of rockburst including the values of in-situ stresses  ，the compressive strength  ，the tensile strength  of rock and the elastic energy index of rock Wet were considered，and three factors  ， and Wet were defined as the original criterion indices for rockburst intensity prediction in the proposed model. The concept lattice was used as the reduction tool to get the maximum reductions. A comparison between the reduced concept lattice and the reduction of discernible matrix in the traditional dominance rough sets was made. Then rough sets were applied to establish the prediction model of rockburst intensity，and then preferences decision rules were generated. The quality of classification was 100% and the model was applied to predict the rockburst intensity in some projects in China. The prediction results using rough sets based on the reduced concept lattice agree well with the actual situation and those methods using three control factors. The model reduced the required control factors and improved the efficiency of prediction.

The impacts of moisture content，dry density，temperature and other factors on the electric resistivity of phosphate tailings are studied using the method of two-phase electrode. Modified triaxial apparatus is used to conduct triaxial tests on the specimen of phosphate tailings to obtain the stress-strain curves and the changes of electric resistivity synchronously. Then stress-strain-electric resistivity curve and the relationships between the electric resistivity and the cohesion and internal friction angle are obtained. Results show that the electric resistivity of phosphate tailings decreases with the increase of water content，temperature and dry density. The initial electric resistivity correlated negatively with the shear strength，the cohesion and the internal friction angle. During the triaxial compression process，the electric resistivity of phosphate tailings increases initially and then decreases with the growing of strain.

The homemade triaxial servo-controlled seepage equipment was used to investigate the coal containing methane under the coupled action of thermo-fluid-solid. The gaseous loading-unloading tests under the different confining pressures and axial compressions were carried out to explore the process of the coal deformation and gas migration at different seam depths. During the loading process，the strain of coal decreases linearly with increasing gas pressures，while during the unloading process，the strain of coal increased with the decreasing of gas pressures. With the axial compression and the confining pressure increasing，the variations of the strain of coal under unit gas pressure reduce. As the gas pressure increases in the loading process，the permeability of coal decreases firstly then increases，which exhibits a V-shape. The permeability of coal has a turning point at the pressure about 1.2 MPa，which indicates that the expansion degree of coal porosity and the thickness of adsorption layer depends on the adsorption or the dominance of effective stress. As the gas pressure decreases during the unloading process，the permeability of coal decreases firstly then increases due to the effective stress or the effective stress dominance. With the effective stress increases，the permeability of coal decreases firstly then increases. The change of permeability caused by the effective stress is a logarithmic or exponential function in the different intervals. The gas pressure shows a typical of two-stage characteristics. The permeability and the volumetric strain are closely related to each other，indicating that the effective stress，the expansion due to absorption as well as the matrix shrinkage all affect the internal structures of coal.

A new iteration method with the softening constitutive model is proposed to overcome the shortcomings of the existing method of strength reduction in FEM that every computational process started from the zero stress state. In the new method，the strength reduction factor to bring slope into the limit equilibrium state after all the external loads applied was increased gradually. The method directly simulated the process of strength reduction. During the process of the yielding surface shrinking，the stresses at each Gauss' point reached the equilibrium state through stress drop and plastic flow. Two examples are given to prove the effectiveness of the method.

The stress coefficient ?θ/?c，the brittleness coefficient ?c/?t and the elastic energy index Wet were selected as the evaluation indices，and two classification criteria were chosen for normalization of the rockburst indices. A normal distribution function was selected to construct the membership functions. MATLAB programming was adopted for the back analysis of index weights. A standardized fuzzy comprehensive evaluation model based on the weighted back analysis was established. The model is theoretically sounder and solves the problems of over subjectivity of weights and the unrealistic membership functions existed in the traditional models. 46 sets of rockburst data at home and abroad were selected as the samples for weighted back analysis，and three engineering cases were used to compare the effects of application of different classification criteria and weights. Results show that the prediction model based on back analysis weights is better than the one based on subjective weights. Results from applying different classification criteria are inconsistent with each other，so that further investigation is required.