Traditional rigid anchor bolts allow the deformation of surrounding rock of roadway generally below 200 mm. The rigid anchor bolts often appear tensile failure because they can?t adapt to the large deformation of surrounding rock. A type of anchor bolts with constant resistance and large deformation was therefore manufatured，which can provide the constant resistance and stable deformation. This type of anchor bolt is mainly composed of a constant resistance device and an elastic rod，which is suitable for supporting the surrounding rock in soft rock or deep roadways to effectively control the engineering disaster of rock burst etc. The anchor bolts of constant resistance and large deformation were tested with an experimental system developed in house. The experimental results show that the maximum value of the accumulated deformation of the anchor bolts with constant resistance is up to 1 000 mm. Field tests were also performed in the roadway support of a typical deep and soft rock mine with good effect.

The parallel electromagnetic responses were studied through three-dimensional numerical and physical modelling respectively. Abnormal electromagnetic responses at the planes ahead of and parallel to the tunnelling front were found，leading to the identifying of the existence of water bearing structures. Some water bearing structures being not detected by the electromagnetic responses perpendicular to tunnel front were detected by the parallel one. When large water bearing structures were very near to the tunnelling front，the paralleled electromagnetic field induced twice occurring of the back electromotive force in the fixed time windows，which can be used directly for the identification of water body in real engineering practice. These findings indicated that the parallel electromagnetic responses could be a useful method for advanced geological prediction.

Nonlinear statistical analysis of heights of zones with water transmitting fractures at three different grades of underwater mining beneath various roof rocks was conducted with the regression method and the measured data of 40 drillings. A BoxLucas1 curve between the ratio of heights of fractured to mining zones and the height of waterproof coal pillar was established，which produced smaller errors than the conventional empirical formula did. The slopes of curves for 3 types of water gradually increased and the values of types II and III were greater than that of type I，which indicated that the height of water transmitted fractured zone under water mining type I was more easily reduced by the inhibition effect of weathered and oxidized zone. The fracture of type III did not penetrate the weathered and oxidized zone as mining closing to this area and the top interfaces of water transmitted fractures of types I and II did not reach the bottom of the mud layer，which indicated that raising the upper limit of mining within a certain range was feasible. A displacement formula for tensile fracture surfaces of weathered and oxidized zone was proposed utilizing Paris?s formula of displacement and Crouch?s formula of discontinuous displacement. The calculated results show that the fractures are more easily closed due to the overlying gravity. The large plastic deformation of weathered and oxidized zone consumes the work by external forces and consumes splitting energy easily，which prevents water transmitted fractures from upward development.

The water hammer pressure and stagnation pressure during the impacting process of water-jets were analyzed based on the theories of hydrodynamics and elasticity. Radial distribution functions for the dynamic pressure in the cross-sections of water-jets during different pressure stages were derived. Numerical models for the transverse isotropic rocks under water jet impacting at different angles were developed and the influence of impact angle on the breaking of rocks was studied assuming ? = 0°，45°，90°. A number of impacting experiments on the transverse isotropic sand-stones were conducted at different impacting angles. The numerical analysis and the experiments reveal that the water hammer pressure produced broken pits on the transverse isotropic rocks and the stagnation pressure caused the initiation and development of cracks inside the rocks. The transverse cracks，inclined cracks and splitting cracks appeared accordingly when the water-jets impacting were perpendicular，inclined and parallel to the beddings of the transverse isotropic rocks.

A new type of velocity model without the velocity inversion and velocity measuring was put forward for the improvement of the traditional simplex method based on the comprehensive analysis of the traditional simplex method，the velocity models and the related errors of the microseism locating method. Numerical analysis and engineering validation on the precision of locating under the conditions of different velocity models，different iteration algorithms with velocity errors and velocity anisotropy were carried out. The results show that the new velocity model can effectively avoid the errors happened in the process of velocity inversion and measuring and avoid the problem of local minimum in traditional simplex method. In comparison with the other iterative methods, significantly higher accuracy of locating the seismic sources outside the sensor arrays is achieved，taking advantage of the easy convergence of iterations of the simplex method.

The rockburst of granite in roadway due to tectonic stress was studied experimentally and numerically. The intrinsic links among the visible light images，the acoustic emissions(AE) and the far-infrared radiations were investigated to reveal the characteristics and mechanisms of rockburst in roadway. The proneness index of rockburst of granite was found to have moderate values from 13.84 to 18.02. The physical parameters changed suddenly and greatly just prior to the occurring of rockburst due to energy dissipation. Debris were ejected out from the two sides of the tunnel. The higher the side pressure is，the stronger the rockburst is. There are at least two temperature jumps，one is the initial temperature anomaly and the other is at omen point of rockburst. The leap of b-value and the occurrence of a quiet period of AE is the precursor of large fracturing. In virtue of the results of statistical analysis，the sensitivity to rockburst of three monitoring methods，visible image，far infrared and AE are found to be in declining order. A variety of ways of monitoring the multiple physical parameters are required to provide more accurate early warning information of rockburst on account of the complexities of internal observations with the imaging method of visible light.

Rockburst tests on specimens of large-diameter using the device developed were carried out under different loading and unloading conditions. The weight distribution and the fractal characteristics of rock fragments after rockburst，and the relationship between the rockburst intensity and the fractal characteristics were studied. The fragments from specimens of large-diameter after each test were found to have different shapes and quantities. The fragments from specimens of large-diameter have fractal characteristics. The fractal dimension of fragments from the unloading tests of low confining pressure is larger than that of high confining pressure. Accordingly，the dissipation energy required is comparatively smaller and the intensity of rockburst produced is relatively smaller. The range of rockburst decreases as the increasing of the loading rate if the confining pressure is the same. The number of fragments of large size is small if the vertical loading is small，while the fractal dimension is larger.

An elastic model of thin plate with three edges fixed and one simply supported was established as the mechanical model of high and thick strata of hard magmatic rock at working front 10416 in Yangliu coal mine，A flexural function and an analytic expression of stresses for the hard and thick strata were derived with Rayleigh-Ritz method. A formula of fracture span was obtained；and then a method of calculating the length of drawing pace of fracturing according to fracture morphology of overburden was proposed. The analysis of monitored results of microseism，supporting pressures and surface subsidence revealed the fracture process and the dynamic response of high and thick strata of hard rocks. The point of maximum deflection prior to fracturing of strata is at the location of   and  ，where a is suspension length along the strike of hard-thick strata；b is suspension length along the tendency of hard-thick strata. Fracture first happened along the dip clamper edge if a＜1.049b，along the strike clamper edge otherwise. The initial form of fracturing is “O-X” shaped，which is symmetrically along the strike but asymmetrically along the tend. Microseismicity intensified during the process of fracturing and movement of strata leading to the strong microseismicities activities to be generated and the supporting pressure and surface subsidence significantly be increased. Fracturing of high and thick strata of hard rocks causes strong dynamic response which can be analyzed and predicted by theoretical calculation and microseismic monitoring.

A modified numerical manifold method is proposed to predict crack growth of engineering materials. The first-order Taylor expansion of the displacement functions is adopted on physical patches，endowing the degrees of freedom of the physical patches with physical meanings. Enriched displacement functions used to capture stress singularity are adopted for the physical patches around the crack tip，which predicted more accurately the direction of crack propagation. Meanwhile a new algorithm for updating the physical cover system is proposed，which was more convenient and suitable for both small and large deformation problems. Numerical examples for typical linear elastic fracturing problems were presented. The results show that the predicted propagation paths are in accordance with the results obtained by others. The effectiveness and correctness of the method are thus confirmed.

To study the characteristics of deformation and permeability of coals under repeated disturbance of stresses，cyclic loading tests with different time lengths of stabilization were carried out using a servo-controlled triaxial seepage device which was developed in house. The loading and unloading stress-strain curves with different time lengths of stabilization form plastic hysteresis loops. As the time lengths of stabilization increased，the initial permeability reduced slowly but the trends of variation of the permeability remained the same. The permeability decreased with the increasing of the principal stress. The maximum axial strain of coal decreased initially and then increased as the time lengths of stabilization increased and it reached the minimum value at the time lengths of stabilization of 100 s. The minimum permeability of coal increased initially and then decreased and it reached the maximum value at the time lengths of stabilization of 100 s. The permeabilities of coals are closely related to the development of axial deformation. The variations of permeability were always lagged behind that of the volumetric strains. The lagged time lengths increased with the increasing of the time lengths of stabilization.

The surge tank at tailrace of Jinping I hydropower station is composed of two vertical cylindrical wells of large-diameter at the location of high stress and complex geological configurations with two large scale faults and multiple sets of joints. It was difficult to cavern out the domes and setup supporting structures at the top of cylindrical wells. Engineering practice and theoretical research show that the methods of excavation and the parameters of supporting are the key factors influencing the stress distribution and deformation at the crest of the dome of the tailrace surge tank. Lamprophyre veins and fault f14 were found to exist above the dome of tailrace surge tank #1 through in-situ investigations. The deformation and failure mechanisms of surrounding rock of the tailrace surge tank are studied through mechanical analysis，in-situ monitoring and 3D numerical simulation. The deformational and mechanical characteristics of the dome rocks during excavation process were studied. Some advices on the excavation and support for the tailrace surge tank are thus presented as the technical supports for its excavation and design of the support.

Based on the analysis of shear stress-displacement curve of cemented concrete-rock joint，an assumption is proposed that the shear stress of cemented concrete-rock joint is dependent on the bonding strength and the friction effect of the cohesive interface. A new model of cemented concrete-rock joint considering the bonding degradation after peak stress is therefore established. The comparison of results of back analysis using the proposed model with ones from shear tests shows that the proposed model could describe the entire process of failure of cemented concrete-rock joint. Besides，a stability analysis of the foundation of Furongjiang Bridge is carried out using the proposed model. The numerical results show that the shear stress between the skewback and the bedrock from the bridge loading is smaller than its shear strength；and the shear displacement has a very low value，which indicates a safe bridge foundation.

The lining defects of highway tunnels affect directly the life span of the lining. A geometric model of the defects of lining structures in highway tunnels was established. The detection performance and the resolution in different wavelet frequency were studied. A geoelectric model of lining on the basis of common defects was presented considering the shape and the thickness of voids，the circular and rectangular defects and the different fillings such as sand，water and air. The imaging characteristics and differences were simulated using finite difference-time domain(FDTD) method. It is found that the increase of the thickness of voids leads the imaging position of deep target to get closer to the scanning surface. The effect of the geometry of defects on the imaging features is smaller than that of fillings. The characteristics of electromagnetic wave imaging of water contained fillings are found to be more noticeable than those of air fillings and sand fillings. Water fillings absorbs the electromagnetic waves and bring about interference factors such as multiple waves from deeper targets.

A large model test system for deep mine construction was developed at China University of Mining and Technology(Beijing)，which is mainly composed of supporting frames，a system of hydraulic loading，a system of measurement and control and a system of data acquisition. The supporting frames have a main frame，a movable door shaped supporting frame at front and a support frame at rear. The thickness of models can be adjusted for 2D model test and 3D model test. The hydraulic loading system including vertical actuators(up and down)，horizontal actuators(right and left) and rear actuators，achieves loading in five directions. A constant load maintaining system is set on the equipment. The measurement and control system can accurately control the loading in real-time with a closed loop digital control system composed of a PC，a EDC220 digital controller，sensing elements and executing components. The system of data acquisition including the static and dynamic strain gauges collects the information during the simulation test on roadway construction by mechanical or blasting methods. A model test was carried out with the model test system to simulate the failure and fracture phenomena of the roadway made of gypsum block material.

A new numerical method，the numerical manifold，has been used in many fields and was seldom applied to the fracture propagation of fractured rock mass under multi-field coupling. The control equations of thermo-mechanical coupling were established considering the influence of temperature on materials and based on the linear elastic theory of thermodynamics. The method of numerical manifold with the temperature and the covering function of displacements as basic unknowns，the weighted average and the arithmetic mean as the solution algorithm of average temperature，the modified Mohr-Coulomb equation as the criterion of fracture propagation of rock mass，the physical cover as the basic element of fracture propagation，was presented for simulating coupled thermo-mechanical process and fracture propagation under coupled actions. The numerical manifold method has two kinds of covers，namely the mathematical cover and the physical cover. The mathematical cover is independent of the physical domain of the problem；and its generation will not consider the number，position and orientation of the fractures，which avoids the inconvenience of mesh generation on fractured areas during the process of fracture propagation. Therefore，the proposed method is effective for simulating the processes of coupling behavior and fracture propagation. Finally，a numerical case study was conducted with the program written with MATLAB，so as to demonstrate the feasibility and soundness of the proposed method in handling the fracture propagation and coupled problems of fractured rock mass.  

A comprehensive model of evaluating the prediction of rockburst was established based on the analytic hierarchy process(AHP) and the technique for order preference by similarity to ideal solution(TOPSIS). The indices of evaluation of rockburst were selected from lithological，stress and rock conditions. The criterion of rockburst level was constructed according to the critical values of evaluation indices. The weight matrix of the evaluation indices was determined objectively according to the AHP and the degree of closeness was analyzed with the TOPSIS，as such the prediction level of rockburst was determined. The results of a case study show that the predicted results of rockburst based on the evaluation model of AHP-TOPSIS are consistent with the actual measured results and agree well with the outcomes from the method of fuzzy mathematics. The proposed method considers various inducing factors of rockburst and avoids the limitation of a single criterion. The importances of various factors are compared to make the predicted results more sensible.

The key parameters in gob-side entry retaining formed by roof cutting and pressure releasing in thin coal seams at the working front 1610 in the Nantun coal mine were studied. The presplitting cutting height of roof，the presplitting cutting angle，the distance between presplitting blasting holes were determined as the key parameters based on the analysis of the stress state of roof in the process of mining. The results of numerical simulation show that，when the height of immediate roof is much higher than the height of gob and the presplitting cutting height meets the requirement of the tensile failure of immediate roof，the presplitting cutting face should deflect a certain angle towards gob in order to cut off effectively the stress transfer between the roof of gob and the roof of retaining roadway and achieve the collapsing of roof. Based on the results，the optimum distance between presplitting blasting holes was determined through field presplitting blasting test. The results have been successfully applied to an engineering project.

The metro line 1 in Hefei is in a close distance to piles of a viaduct foundation. Shield tunneling of the metro line 1 could therefore affect the safety of the piles of the viaduct. The stresses and the horizontal deformation of the piles and the ground settlements under different working conditions during the process of shield advancing were analyzed based on the mechanical principle of coupled springs for bridge-pile structures and the finite difference method. Close-distance shield tunneling with the nearest distance of only 0.63 m was found to have great effect on viaduct piles and the magnitude of the effect was closely related to the position of shield machine. The effects were superimposed upon the shield advancing of the twin tunnels in succession. As the shield was gradually close to the piles，the bending moments，the shear forces and the displacements were increased continuously. The maximum superimposed values of the bending moments，the shear forces and the horizontal displacements were 700.5 kN•m，159.6 kN and 2.39 mm respectively and were occurred when the head of the shield just passed the second row of piles and the shield tail just entered the first row of piles in the right tunnel. The space formed at the peripheral of lining segments in the rear of shield tail was found to be the main cause of the ground loss when jack pushed forward the shield machine. The flexural equation of piles was fitted by the displacements from the monitoring of piles. The bending moments and shear forces of piles in various advancing steps were thus calculated and the calculation method was verified by a case study.

The reinforcement with fully grouted bolts is widely adopted in slope engineering due to its proven efficacy and low cost. However，the bolting mechanisms for bedding rock slopes are not clear and further investigations should be performed. The bolting behaviour of fully grouted bolts in bedding rock slopes is investigated considering the geological structural characteristics of bedding rock slopes and the interactions between the bolt and the rock mass utilizing the elastic theory and structural mechanics. A new mechanical model for fully grouted bolts is then put forward. The lateral shear and axial stresses acting in the intersection of the bolt and the discontinuity are found to be activated simultaneously and that the resistance of the bolt in bedding slope is provided jointly by the axial force and the shearing resistance. A linear relationship between the anti-slide forces provided by the axial force and the lateral shear force is described. Numerical simulations with the finite element method software ABAQUS to the bolting of a bedding rock slope confirm the correctness of the proposed mechanical model.

The key block theory assumes that the rock masses are crossed over completely by structural planes，which is in conflicting with the fact that the lengths of traces of structural planes are finite，leading to the overestimation of the number of key blocks and the underestimation of the safety factor in calculations. The edge lengths of key blocks and the actual lengths of traces were thus computed according to the stereo-analytical method of block theory. The key block probability was redefined as absolute key block probability，relative key block probability and non-key block probability according to the probability theory of traces of structural planes. Calculations on the example of an equilateral triangular pyramid showed that when the ratio of length of trace to edge was larger than 100，the absolute key block probability was nearly 1.0 and structural planes could be considered to cross through rock mass in this case. If the ratio of length of trace to edge was equal to 1.5，the relative key block probability reached 0.75 and if the ratio of length of trace to edge was greater than 7.5，the non-key block probability was close to 0. The safety factor of the underground cavern at Bulungl-Gongur hydropower station was 3.145 according to the stability analysis of key block theory and was 4.591–5.233 based on the absolute key block probability，increased 46.0%–66.4%.

When the finite element method is used to simulate the instability of saturated sand，an elastoplastic constitutive model which can accurately reflect the plastic volumetric response of the sand is needed. An implicit algorithm of integration for the state-dependent sand model is derived. Two types of numerical errors occurred during the calculation process；and an appropriate numerical treatment is presented. Loose sand specimens under plane strain and undrained conditions are analyzed. The numerical results demonstrate differences of the static liquefaction phenomenon between rapid and slow loading cases. Another numerical example concerning the man-made slope of loose sand on seabed is analyzed with the negative work of second-order as the criterion of instability. The numerical results demonstrate the rationality of the criterion and reliability of the numerical algorithm.

In mesoscopic level，the soil-rock mixture is treated as a two-phase composite of rock and soil in two dimensional case. Convex polygons are used to represent the rocks and empty space the soil contents. The convex polygons are randomly scattered in simulated region in the numerical simulation. A rhombus was randomly generated and was randomly transformed into a convex polygon according to the parametric expression of rhombus. The convex polygons of different sizes are randomly assigned into the area of simulation in accordance with a certain distribution functions until the terminating conditions are satisfied. If the distances between a newly generated convex polygon and other polygons the generated previously are not zero；the new generated convex polygon is then adjusted accordingly to simulate the real physical condition of the soil-rock mixture. As such，a soil-rock mixture with the rock content of 72.01% in terms of area ratio is generated within the square of 30 cm in length；and the particle diameter is in the range of 1–8 cm. Finite element mesh of the soil-rock mixture is generated；and a numerical analysis is carried out to simulate a mechanical loading test. The stress concentrations on the interfaces between soil contents and rock particles are observed from the simulated results stress nephograms，which agreed with those in real situations.

In order to study the effects of freezing-thawing cycles on the mechanical properties of silty sand from Qinghai-Tibet，triaxial tests were conducted with the different numbers of freezing-thawing cycles at different freezing temperatures under various confining pressures. The stress-strain behavior，the static strength，the elastic modulus，the cohesion and the angle of internal friction were measured for unfrozen samples as well as thawed ones. The testing results show that the mechanical properties of studied soil are affected considerably by the numbers of freezing-thawing cycles. The freezing temperature has little influence and showing no obvious regularity. The method of significance analysis is used to analyze the influence level of the number of freezing-thawing cycles，the freezing temperature，the confining pressure and the interactions between them. The results of significance analysis show that both the values of confining pressure and the numbers of freezing-thawing cycles had significant influence on the mechanical properties；while the influence of the freezing temperature is weak. The interactions between the confining pressure and the number of freeze-thaw cycles and the one between the freezing temperature and the number of freeze-thaw cycles both affected the mechanical properties of silty sand significantly，so as to suggest that the method of significance analysis may be used to study the influence of different factors on the properties of frozen soils.

The strain controlled dynamic triaxial tests to measure the dynamic moduli and the damping ratios were conducted on intact marine samples from sea area at Daishan，in Zhoushan Archipelago. The experimental results show that the hysteresis curves of Zhoushan Daishan marine sediments are not completely closed loops and are strain softening. The values of dynamic modulus and damping ratio under certain strain amplitude fluctuate around constant values respectively which are designated as the representative values of the dynamic moduli and damping ratios under the corresponding strain amplitude. As such，relationships between dynamic moduli and strain amplitude and between damping ratio and strain amplitude under different confining pressures are established，which converge asymptotically. Hardin-Drnevich(H-D) model is modified to fit the experimental data. Meanwhile，the resonant column tests are conducted to measure the elastic moduli of the marine sediments under wave loading. The results from two tests show that the marine sediments from Daishan are sensitive to the confining pressure.