Based on the poroelastic theory and the anisotropic linear elastic mechanics，and considering the influence of fluid components in porous media and coupled thermo-hydro-mechanical(THM) function，the porothermoelastic governing equations of anisotropic porous media is established. The constitutive equations and porothermoelastic mechanical model in borehole coordinates are obtained by adopting coordinate transformation methods under the assumption that shale formation is considered transverse isotropic media. The basic methods of solving are given by superposition principle，and the strength theory of weak plane is introduced to distinguish stability of shale formation. Finally，the accuracy of the model is verified by the stress distribution around a vertical borehole and the instance analysis of well W201–H1. The result shows that the calculated stress around the vertical borehole is completely consistent between conventional model and this new model(max. error is 0.03%)，and the analysis results of wellbore stability for well W201–H1 have a good consistency with practical situations. Conversely，the calculated results using conventional model will result in a large deviation，and the accuracy and reliability of the model are verified. As time goes on，the collapse areas around the borehole are gradually broadened and deepened. The anisotropic rock strength，anisotropic rock elasticity，seepage effects and heat-transfer effects around borehole are the important reasons affecting wellbore instability in shale formations. However，anisotropic rock strength is the main mechanism of borehole instability. Thus，it¢s necessary to consider the influence of shale anisotropy and coupled THM effects on borehole stability. The research results can provide a reference for borehole stability analysis and drilling in the gas shale formations.

In order to investigate the initiation modes of hydro-fractures in horizontal wells，Laboratory hydraulic fracturing test was carried out using outcrop shelly limestone to simulate horizontal well hydraulic fracturing. The phenomena of fracture initiation and propagation around the horizontal wellbore were described and analysed by adding tracer to the fracturing fluid，analysing pumping curve，arranging AE monitoring system and splitting sample after test. Conclusions are as follows：(1) The initiation modes of hydro-fractures could be divided into three types：one transverse fracture(mode I)，transverse multi-fractures(Mode II)，transverse-longitudinal crossed fractures(Mode III). (2) Each hydro-fracture initiation mode has its certain pumping curves. Mode I had a low breakdown pressure followed by a sharp drop. Mode II had a relatively high breakdown pressure，then the pressure went up and fluctuated dramatically. Mode III also had a high breakdown pressure，but the pressure fluctuated slightly. (3) Among the specimens，the three initiation modes occurred randomly and the breakdown pressures were dispersed. (4) The AE activity could reflect the initiation and propagation of hydro-fractures and reached its peak value at the fracture initiation moment. (5) The area in which AE events concentrated was in agreement with the actual location of the hydro-fractures. AE locating results could be used to preliminary judge the distribution of hydro-fractures. (6) One transverse hydro-fracture was more likely to be formed at relatively high pumping rate，while the fracture geometry tended to be complex at relatively low pumping rate. Pumping rate is a key factor to determine the initiation mode. (7) It may be feasible to conjecture the initiation and propagation of the hydro-fractures using site fracturing pumping curves.

To establish the relationship between the scheme of coupled-crack and strength deterioration for the coal and rock mass as the target，the interaction of injection water measure and blasting measure are defined as coupled-crack，and the coupled-crack mechanism is analyzed，giving the crack propagation criterion for the implementation of coupled-crack technology. Strength deterioration analysis method of fluid-solid coupling model affected by explosion is put forward. By using numerical simulation method，we establish the models for injecting water and obtaining explosion load，axially load is applied after finishing explosion loading，the strength degradation degree of overall model at different coupled-crack schemes is analyzed. The results show that: the essence of coupled-crack is that detonation gas and shock wave formed by explosion spreads in softened coal and rock mass，coupled-crack effect is greater than the simple superposition of basting and injection water；Improve water pressure can increase the strength degradation rate of coal and rock mass，model strength has a significantly decreased with the increase of drill diameter(explosion). The relationship between the coupled-crack parameters and strength deterioration degree of f is obtained，the damage degree of coal body caused by injection water pressure of explosive consumption is quantitatively evaluated. In engineering practice，the strength of coal mass from steeply dipping extra-thick coal seam after coupled-crack is 5.48 MPa，which has a decreased by 40.07% compared with the implementation of injection water. The working face recovery rate meets the requirements of national standards for thick coal seam，which realizes the objective of improving the top coal recovery rate，providing experiment method and basis for the quantitative evaluation of coupled-crack effect.

Using independent developmental coal-rock microscopic shear testing device，the shear tests under different loading rates were carried out. An in-depth research on micro-crack propagation process and micro-crack extension space distribution was conducted by the acoustic emission technique as well as image processing technique. The result shows that the shear strength of sandstone increases with the increase of the loading rate，and presenting a linear relation. For double sheared sandstone，crack propagation and penetration on both sides are not synchronized，and the growth of micro fissure on the one side became more rapid because of the stress concentration caused by the crack damage on the other side. The formation time of penetrating main crack shortened greatly. The micro-crack initiation positions which were generally located at a point or points near the pre-shear plane extended in the vertical direction substantially. Meanwhile，the closer micro-cracks interacted with each other until penetrating to a whole crack. During the process of micro-crack propagation of sandstone，the vertical micro-cracks turned into lateral bifurcation cracks，and the micro-cracks which are perpendicular to the vertical direction stopped expansion. The failure modes are detour，pinning，holding bifurcation，induced bifurcation，hack，stop detour，hook back etc.，mainly detour and pinning.

Rock avalanche rock debris caused by rock collapse is very dangerous geological disasters. The debris flow with a sudden can achieve high speed in a very short period of time，and the rocks and detrital material move to a very far distance，the damage and effect range are very great. In order to study the different sizes of rock avalanche flow distance of migration and accumulation characteristics，we have carried out the rock avalanche physical model test of small scale with five different particle sizes of rock detritus dry unconfined particle materials. Experimental results show that under the same test conditions，rock particle size influence on sliding distance and the equivalent friction coefficient is larger. The larger the rock particle size，the greater the sliding distance and pile length，the smaller the equivalent friction coefficient. Five different rock particle sizes are similar of the accumulation form and accumulation width increases along with the increase of particle size. The measured rock particle velocity is greater than the collapse theory calculated value.

With combination of typical rockburst cases happened in deep tunnels of Jinping II hydropower station，formation mechanism and function mechanism of structural plane of slab buckling rockburst were analyzed. The research shows that slabbing failure of surrounding rock is caused by excavation unloading and the action of the tangential concentrated stress will lead to the buckling deformation of slabs towards the excavation space as well as growing strain energy stored in the slabs. When the amount of energy stored in the slabbing rock structure exceeds its energy storage limitation，or due to external disturbances，slab buckling rockburs will take place with the characteristics of crushing of slabs and ejection of rock. The gradual failure process of slabbing failure makes the structural planes be active. The existence and extension of structural planes will reduce the stability of slabbing rock structure which in turn promotes the occurrence of rockburst. The structural planes with different inclination angles play different roles in the formation of slab buckling rockburst. Slabbing specimens were made according to the architectural feature of slabbing surrounding rock and physical simulation tests of slab buckling rockburst were conducted under two different loading modes. The experiment results show that propagation of pre-existing fissures makes the specimens split into slabs，and further action of compression load cause buckling deformation of slabs towards the free face which leads to the instability destruction phenomenon of specimens characterized by crushing of slabs and ejection of rock. The research results have an important significance for  understanding and support control of slab buckling rockburst.

On the basis of damage theory，combing effective stress principle with Lemaitre¢s strain equivalence assumptions，an expression of effective stress under stress and seepage coupling condition was established. Assuming that the micro-unit strength obeys Weibull distribution，a statistical damage constitutive model considering pore water pressure was established. Comparing the test data with the results obtained from the statistical model，the new model can fit the test data well，showing the validity and feasibility of the new model. Then the relationship between pore water pressure and model parameters，damage characteristics were discussed，and it will provide good reference for safety analysis of rock engineering under stress and seepage coupling condition.

According to experimental data of joint normal cyclic loading/unloading，joint normal stiffness expressions are gained from hyperbolic function and semi-log function respectively which are used to fit joint normal stiffness-closure curves. These expressions are implemented into continuously yielding joint model and cyclic loading/unloading programs are edited by FISH language embedded within three-dimensional distinct element code(3DEC). The numerical simulation of a rock joint under normal cyclic loading/unloading is conducted. The results show that the numerical simulation method in this paper is valid and that joint normal stiffness values gained from hyperbolic function are different from semi-log function，but both of normal stress-closure curves from two functions are really close to laboratory test results and meet joint properties under normal cyclic loading/unloading. The results can finally lay a foundation for studies on the dynamic properties of rock mass，the dynamic response analysis and the assessment of stability and safety of slope in rock mass engineering.

In order to deeply study the mechanism of coal and gas outburst，and having the further awareness and understanding of coal and gas outburst from the point of view of energy. Based on the combined effects of coal and gas outburst hypothesis，using a combination of theoretical analysis and experimental methods，analyzing the coal and gas outburst of energy dissipation mechanism，obtaining the expression of elastic potential energy and gas energy. And a mechanical model describing the coal and gas was established，owing the mathematical function formula of outburst coal and its stacking location. Then the mobile power，crushing power and friction power were calculated according to the stacking states and broken situation of outburst coal. And then，the outburst conditional expression between coal and gas outburst and the physical and mechanical parameters of coal and gas，the structural parameters of tunnel were set up. Developing the instant relief symmetry breaking coal experimental setup in the high-pressure gas，analyzing the factors of coal and gas outburst，which including the mechanical properties of the coal gas pressure，ground stress. The results showed that：The compressive strength and coal consistent coefficient of outburst coal are lower than non-outburst coal. Under the effect of gas of single factor，lower gas pressure can¢t make the complete coal crushing，ground stress has a significant impact on the coal and gas outburst. The temperature will drop in the process of coal and gas outburst.

For the failure mechanism of straight joint shield tunnel lining structure under side-unloading conditions，a quasi-static test method is proposed. And a full-scale test of anti-collapse property is completed. Based on the test results and phenomena，the whole bearing process of lining structure were analyzed. The failure mode，ultimate bearing capacity and overall safety of lining structure were discussed. Through experiments and calculations：the failure of lining structure is a beam hinge mechanism，while sufficient plastic hinges appear，the ultimate bearing capacity of the structure can be estimated by virtual work theory. Using load reserve ratio as a safety indicator，the overall safety factor of lining structure under side-unloading conditions is 1.62.

For a case of circular deep-buried tunnel，cracking extent and extending length in surrounding rock masses under blasting and TBM methods are calculated，and energy dissipation during the cracking of surrounding rock masses is analyzed. In addition，based on the index of releasable strain energy，rank and position of rockbursts are determined. Results show that，compared with the quasi-static unloading of in-situ stress caused by tunnel boring machine excavation，the transient release of in-situ stress induced by blasting excavation aggravates the cracking in surrounding rock masses，and enlarges the energy dissipation during this process. This minifies the releasable strain energy after the excavation unloading and brings down the risk of time delayed rockbursts；while during the transient release of in-situ stress，influenced by high aggregation of energy，the releasable strain energy is enhanced，and the risk of immediate rockbursts is enlarged for the blasting excavation.

In-situ true triaxial tests are conducted on thin-bedded marbled dolomite rock of the underground powerhouse tailwater tunnel of Wudongde hydropower station to investigate the deformation properties and strength properties of the engineering rock mass in unloading conditions. The sample is a square cylinder with 50 cm length，50 cm width and 100 cm height and contains 20–30 layers. Preloading is applied to avoid sample getting loosed in chipping process. Deformation tests are conducted under geostress level firstly and then simulating geostress variation pattern in the excavation process，the axial pressure is increased and then the lateral pressure perpendicular to bedding is step unloaded till sample failure. Some conclusions are drawn as follows：(1) Deformation is orthotropic. The ratio of the deformation modulus perpendicular to bedding to that parallel to bedding is 0.34–0.69. Beddings are opened and the lateral expansion coefficient is 0.52 while loading parallel to bedding and conversely，beddings are compacted and the lateral expansion coefficient is 0.25 while loading perpendicular to bedding. (2) There is large plastic deformation. The ratio of unloading residual deformation to loading deformation is 0.4–0.8 in the process of cyclic loading. (3) Loading deformation modulus is positively correlation with lateral compression and unloading deformation modulus perpendicular to bedding is negatively correlation with lateral compression. (4) Unloading deformation is nonlinear and the correlation between deformation modulus and unloading stress difference can be described by negative exponential function. (5) Sample failure is shear failure of bedding surface and sample volume is continuously and acceleratly expanded. (6) Mohr-Coulomb parameters of bedding surface are calculated based on shear failure mode of weak surface. Mohr-Coulomb and Drucker-Prager parameters of rockmass are calculated with presupposition that samples were homogeneous rockmass. The applicability of the parameters is analyzed.

The model test is an effective method of the study on vibration and damage characteristics of the frozen wall in the process of blasting excavation. This physical model test scheme was designed in accordance with similarity theory. The frozen model was excavated by blasting，meanwhile，recorded the vibration information of key points. The regression analysis determined the fitting formula of velocity and main frequency，as well as the relationship between the main frequency and the peak velocity. Using the predictive value of the main frequency to back calculate vibration velocity of the appointed points on the frozen wall，compared with the blasting allowable safety vibration velocity from Blasting Safety Regulation(GB 6722—2014)，The results show that the vibration regularity meet the Sadov¢s formula and the frequency meet the similarity criterion formula. Then the velocity and frequency attenuation characteristic of frozen wall is obtained. On the basis of field test results，it is feasible to evaluate rock damage based on the blasting allowable safety vibration velocity. The problem of the safety evaluation of the frozen wall after quantitative consideration of the main frequency effects was solved. The conclusions can provide some scientific references for frozen rock blasting in shaft for the similar strata.

In order to study the dynamic strength of salt rock，taking Yingcheng salt rock of Hubei province as research object，self-developed split Hopkinson pressure bar(SHPB) apparatus with triaxial confining pressure was used to study the dynamic compression property of salt rock under 5 MPa and 15 MPa confining pressure. Dynamic stress-strain curves of salt rock under different confining pressure and strain rate were obtained. Based on a unified strength-strain rate model of competition between thermoactivational mechanism and the macro-viscosity mechanism，combined with the results of SHPB test data，a formula was derived to calculate the dynamic strength of rock salt under different confining pressures，and the formula was validated by the measured data. The results show that：(1) the peak stress and ductility of salt rock presents remarkable strain rate and confining pressure effect under impact compression loading，the peak stress increases with the strain rate increases，and the confining pressure has a significant effect on peak stress and salt rock ductility；(2) the fitting effect of the formula for calculating dynamic strength of rock salt is satisfactory with minor error，the average relative error is 2.8%，the maximum relative error is 7.8%，which provide reference for the research of salt rock dynamic strength.

Johnson-Holmquist(J-H) constitutive model has been widely used to study the dynamic failure process of rock. But for the reason that J-H constitutive model contains many parameters and determining these parameters requires a lot of experiments，J-H constitutive model for describing the dynamic mechanical properties of rocks is lack of accurate and reliable model parameters. The triaxial static and dynamic rock mechanics test of the tight sandstone were carried out，and the mothed of determining J-H model parameters was discussed. The parameters and parameters range of tight sandstone from Xujiahe formation of Sichuan basin were determined. The parameters were used in the AUTODYN software to simulate the failure process of rock in split Hopkinson pressure bar(SHPB) test. The results show that the tress wave curves form test and numerical simulation are in good agreement. The average error of the dynamic stress-strain curves between simulation and test results is 14.31%，and so the accuracy of the model parameters is verified.

Uniaxial and triaxial compression mechanical tests were carried out to study the mechanical properties and constitutive relation of rock in post peak state. Based on the different stages and different failure types of rock in the uniaxial and triaxial compression mechanical tests，“segmentation constitutive model” and “damage softening statistic model in different failure types” were built. Yield point，peak point and residual strength point were used to divide the process into three stages in segmentation constitutive model，and the function of constitutive relation was founded. The failure types of rock in compression were divided into tensile failure in low confining pressure，shear failure in high confining pressure，and tensile-shear composite failure in moderate or low confining pressure in the damage softening statistic mode in different failure type，circumferential strain，shear strain and volumetric strain were chosen as damage variables to provide constitutive models，which were proved to be better in describing the relation of stress and strain of rock in the pre-peak and post-peak states，and revealing the damage development process of rock.

Frost heave force should be considered when designing a cold-region tunnel，so as to prevent frost damage. The anisotropic frost heave of surrounding rock of cold region tunnel is described. The analytical solution for the frost heave force of a cold-region tunnel is derived using the non-uniform frost heave coefficient k，in which the anisotropic frost heave expansion is considered. When k = 1，the frost heave expansion is isotropic，and the analytical solution derived in this paper is equivalent to LAI Yuanming¢s solution. Theoretical analyses and calculation analyses show that，there is no frost heave force on the circular tunnel liner if the frost heave expansion is isotropic. The example given by LAI Yuanming¢s paper presents a frost heave force，in which the elastic modulus of the frozen surrounding rock in the example is smaller than the modulus of unfrozen surrounding rock，which contradicts with the actual situation. The assumptions of the frost heave behavior in other analytical solutions are not in accordance with the actual situation，causing the overestimation of the frost heave force. The anisotropic frost heave of surrounding rock is an important reason causing the frost heave force on cold region tunnel. When the values of the surrounding rock modulus and the non-uniform frost heave coefficient are within their reasonable value ranges，the results of present solution agrees well with the actual situation. As k gets bigger，the liner would be pressed by the frost heave force，and the value of the force increases simultaneously with k. When the value of k is determined，the frost heave force is in inverse linear relationship with the elastic modulus ratio of the frozen and non-frozen surrounding rock E_II/E_III.

Currently，the in situ rock mass mechanical test technology is still in the backward status of manual loading and unloading and artificial recording. To cope with this issue，the servo control and data acquisition system for in situ rock mass mechanics test have been successfully developed. It′s operational principle，structure characteristics and key techniques are introduced. The system has such noticeable features as follows：automatic servo control and data collection during whole test process with high precision；high reliability and stable performance；simple instrument operation and convenient data processing after the experiment；application to all kinds of in situ rock mass mechanics test with prominent advantages. This system is used to carry out 6 points deformation test and 12 points direct shear test of rock mass for two-mica schists of water diversion system of Danba hydropower station in the Dadu River. It gets the whole process curves of deformation test and direct shear test of rock mass. The experiment results show that two-mica schists have significant characteristics of anisotropy. This system provides a new method for researching the deformation and strength characteristics of complicated engineering rock mass.

To evaluate the influence of swelling rock humidity-stress field on surround rock deformation and secondary stress state，firstly，based on the incremental theory，swell rock humidity stress field elastoplastic constitutive model was established. And the numerical difference scheme was deduced. Secondly，based on the FLAC^3D secondary development program module，the humidity-stress field constitutive model was coded. The algorithm flowchart and several case techniques were provided. Thirdly，the humidity stress field elastoplastic constitutive model was tested in an engineering example，by comparing its results with traditional Mohr-Coulumb model. Results showed that the humidity stress field model performed better，and visible improvement in detecting changes of surround rock deformation and secondary stress state caused by swelling force. The validation of the humidity stress field constitutive model was verified.

The deformation and failure of rock are closely relative to the change of energy in the loading process. In order to study the influences of different water chemical solutions on mechanical properties and energy mechanism of calcareous sandstone，uniaxial compression test is carried out under chemical corrosion and natural samples by WDT–1500 reactive material testing machine. The experimental results show that the water chemical solution has a significant effect on the strength and deformation characteristics of calcareous sandstone. The corrosion strength characteristics and anti deformation ability of specimens have different degrees of deterioration after the corrosion，and it has the obvious stage to time. There is the clear BDT(brittle-ductile transformation) property in the test. The corresponding portions of the strain energy of chemical corroded sandstone specimens are less than corresponding values of natural specimens. The energy stored by the form of releasable elastic strain energy percentage of the absorbed strain energy decreases，and the longer the chemical corrosion，the smaller the U^e/U. The effects of pH，concentration and composition of chemical solution on the corresponding portions of the strain energy at peak stress are significant，which shows that water chemical solution has obvious influence on the total absorbed energy U and energy storage limit. The longer the chemical corrosion，the stronger corrosion degree of the same chemical solution on sandstone specimens，and the total absorbed energy U and dissipated energy increase，but the time effect of releasable elastic strain energy is not obvious. The real-time evolution process of calcareous sandstone specimens can be divided into different stages.

Quantitative study was conducted on the GSI score chart in the Hoek-Brown criterion. A new quantitative GSI chart was established and the problem that volumetric joint count of rock mass could not be accurately determined was solved. The rock mass integrity index was used to replace the rock mass volume in order to solve the problem in proper quantitative value determination for the rock mass integrity. This chart also applied the interval number theory to indicate the uncertainty of the geological strength index，which was better in line with the actual situation of onsite value determination for the mechanical parameters of rock mass. It took into account the operability in selective acquisition of field test data and combined multiple indexes to determine the final intersection set of GSI，ensuring the reasonableness of quantitative GSI value determination and providing a theoretical basis and a transition bridge for proper acquisition of field mechanical parameters of rock mass based on indoor rock mechanics tests.

The foreboding information and quantitative description of coal and gas outburst precursors are the basis and precondition for hazard prediction. In order to research the occurrence mechanism and look for the precursors of coal and gas outburst，a laboratory investigation using microseismic system was carried out. A large-scale trials about coal and gas outburst had been set up，and the procedure was monitored by the high sensitivity microseismic system. The shaking triggering by coal instability and rupture process could be acquired by microseismic system，and the results shows that shaking signals distribution has obvious zoning characteristics in the whole process，including incubation period，emergence period and evolution period. For this purpose，the corresponding methods of hazard precursor quantitative description on the microseismic index were established. The indexes included N(number of events)，R(event rate)，E(energy) and BR(big event rate). The laboratory analysis and field measurement results show that the outburst process has obvious zoning features，and different stages have different signal features. It can be provided for the hazard prediction in advance，and be validated the occurrence mechanism further.

In order to investigate the permeability properties of low-permeability rock during the whole process of creep，a series of triaxial creep tests for monzonitic granite with different confining pressures and seepage pressures are carried out using the multi-step loading procedure. Based on the experimental results，the permeability evolution law of the low-permeability rock during the creep period was analyzed，especially under the low stress level and failure stress level. The relation between permeability and volumetric strain was also discussed. The results show that the permeability keeps steady under low stress level，while increases significantly as the stress level reaches to the failure stress. Meanwhile，the rate of permeability change has a similar law with the creep strain rate. The permeability experiences with a trend of nonlinear decreasing rate in a primary creep stage，grows linearly in a secondary creep stage，and finally exhibits an accelerated increasing rate when tertiary creep occurs.

Soil material mechanical characteristics are affected by water，which is the intrinsic factor of debris flow initiation. In order to investigate the affect and demonstrate the debris flow initiation mechanism，an apparatus  named Vane shear rheomete which was improved by the four-bladed vane and used to carry out the loading-unloading test on the fine granular soil(d≤1m m). In the test，the relationships between shear stress and strain have been checked as in 5 levels of water content. The test data reveal that the strain of soil material converge to a certain value under low water content and the test loading，and the value increases as the water content increasing. While the water content reaches a certain level (28.8% in the test，named initiation level)，the strain will diverge and eventually result in initiation. Those results mean that the debris flow initiation results from the rehology with the high water content. It is found that the rehology can be described by an improved Bingham model which was promoted. The model parameters were calculated by the test data and coherence between model and test data were checked，which shows the test and model can be used to demonstrate the debris flow initiation.

By means of model experiment，the effect of deformation joints on road tunnel resisting destruction by thrust fault stick-slip dislocation is analyzed. Considering two different cases(tunnel with and without deformation joints)，we focus on the following characteristics caused by thrust fault stick-slip dislocation：ground deformation，strain of tunnel，failure characteristics of tunnel. The results show that deformation joints make tunnel liner avoid the direct shear force. The maximum longitudinal strain at the top of the tunnel with deformation joints is 1/7 of that without deformation joints. Deformation joints significantly decrease the maximum longitudinal strain in tunnel liner，improving the distribution of longitudinal strain. Deformation joints improve the failure mode of tunnel，making the degree of damage lighter than tunnel without deformation joints obviously. Tunnel sections do not collapse，the damage focuses on area nearby the deformation joints in the range of fracture zone.

To investigate the effect of blasting load on zonal disintegration in deep rock，taking high geostress roadway in Dingji coal mine of Huainan mine area as prototype，three dimensional geomechanical model test in high axial stress and blasting excavation has been carried out by cemented sand similar material and “capacity of deep rock breakage mechanics and supporting technique model test”. Model test results show that blasting strain wave signal contains both compressive strain and tensile strain，with predominant in initial compressive strain，and it attenuates quickly with propagation distance increasing. Blasting load produces some micro-cracks on similar materials nearby the boundary of roadway with deterioration of its mechanical properties and damage to its integrity. Moreover，the stress field has also been redistributed. After overload，the radial tensile strain of surrounding rock in all three positions，vault，side wall，and floor，presents a non-monotonic change，interval distribution of peaks and troughs，with distance to model roadway increasing. Under high axial load，micro-cracks caused by blasting load propagate and connect to form a macro fractured zone. The first fracture position is surrounding rock in side wall of model roadway，next fracture position is surrounding rock in floor，then last fracture position is surrounding rock in vault. After overload，there is an obvious zonal disintegration phenomenon in model.

In the region of slab-rent structure rock mass，the representative rock blocks(i.e.，slab rupture protolith)，in which the slab rupture has occurred，were selected. To obtain the anisotropic properties for related strength parameters，the uniaxial compression tests with the loading direction vertical and parallel to slab rupture direction are performed. At the same time，the analysis of mesoscopic morphology of rupture surface is conducted using scanning electron microscope(SEM). In order to provide the theoretical basis for the rock mass slab rupture，we try to explore the potential inherent connection among the rock mass slab rupture，rock mechanical properties and its composition. The study shows that：the protolith with slab rupture has anisotropic characteristics and close relation with the direction of slab rupture；under the same magnitude of load，the load parallel to the direction of slab rupture is more likely to cause deformation and failure of potential slab-rent rock mass than the load vertical to the slab rupture direction；when the load is vertical to the direction of slab rupture，the rupture surface often shows both transgranular and intergranular fratures but the latter one dominates；when the load is parallel to the direction of slab rupture，the rupture surface is relative smooth and the area with intergranular fracture is larger than the area with transgranular fracture；the defects and damage in the slab rupture protolith are nearly parallel to the direction of slab rupture，and they are not only the foundation of slab rupture，but also be further developed due to the occurrence of slab rupture.

Existing studies on hydraulic fracturing are mainly based on macroscopic continuum method. It is difficult to reveal the microscopic mechanism of hydraulic fracturing. Taking advantage of PFC in modeling material failure and crack propagation，we developed a coupled PFC-CFD method for analyzing crack propagation in meso-level and verified by a simplified model test of a cylinder rock specimen. Then taking a tunnel project for example，we simulate the crack propagation in the process of tunnel excavation used this method and analyze the effects of the distance between the tunnel face and the high-pressure water source on the crack propagation in unsteady state seepage stage. The result shows that the coupled method is very suitable to simulate the processes of hydraulic fracturing in rock and could be applied to safety assessment in tunnel projects.

Due to the defects of simulation test device that can not precisely simulate the 3D top-coal drawing process，a self-developed 3D simulation test device for loose top-coal drawing is introduced. It is composed of test box，shield-moving and coal-drawing system，angle adjusting and monitoring system，marked particles making and locating system，box bracket and accessories. The functions of the test device are introduced as follows. The 3D test device extends the length of mining face direction compared with the 2D test device. This design can simulate the top-coal 3D drawing process precisely. By thorough design of caving shield，shield-moving and coal-drawing process can be simulated. By using angle adjusting and monitoring system，this device can simulate the inclination of coal seam both in strike and dip direction and the inclination angle is from 0° to 55°. This test device can realize the simulation of different particle sizes，caving ratios，drawing order and shield-moving speed in the condition of top-coal end loss. By locating marked particles in coal seam，the statistics of top-coal recovery and the inversion of drawing body can be realized. By using the test device，3D simulation tests for loose top-coal movement in up-dip caving condition are carried out. The top-coal recovery ratio，top-coal drawing body and the characteristic of boundary between coal and rock are obtained from tests. The test results show that the test device can simulate the top-coal drawing process precisely. It also provides a new method to study the drawing mechanism of loose top-coal in three-dimensions.

Constant amplitude cyclic loading and unloading and tiered cyclic loading and unloading have some same rules. The difference is that when complete unloaded(loading is 0 kN) and fully loaded(loading is 35 kN in the first level of fully loading) at the first three cycles the resistivity is uccessive to decrease, while at the latter two cycles increases slightly. In the process of destructiveness loading，it also exists a fast falling period at the beginning of loading. An explanation for resistivity change rule of the two process of cyclic loading at same time by using mechanism of microfissuring closure under cyclic loading is given. Experimental research shows that rock resistivity change can provide a good characterization to microfissuring development situation in rock in the process of constant amplitude cyclic loading and unloading and tiered cyclic loading and unloading.

Wave propagation across rock masses and the induced ground motion have a great influence in the design and construction of underground cavern/tunnel constructions and mining activities. When arriving at the ground surface，the waves will cause the ground motion which is threatening to the stability and safety of the ground buildings. The present investigation was concerned with the interaction between the blast wave and a natural structural plane by using a time-domain recursive method. Based on the conservation of momentum at wave fronts，two types of interaction were analyzed first，i.e. the interaction between blast wave(i.e. longitudinal wave) and a linearly elastic structural plane，the interaction between stress waves(longitudinal wave or transverse wave) and a free surface. Next，wave propagation between a single structure plane and the ground surface was analyzed. Considering the time shifting function，the wave propagation equation for every wave arrival at the ground surface was established. On the basis of the derived wave propagation equations，the mathematical expressions were deduced for ground surface vibration caused by stress waves. As the result of the wave superposition，the particle velocity on the ground surface is subsequently obtained.

In order to swelling characteristics of black shale，X-ray diffraction(XRD)，scanning electron microscope (SEM)，nitrogen adsorption test are carried out with different soaking time under the influence of water and mineral composition，microstructure，disintegration characteristics，crystal layer spacing and swelling force variation law of crystal layer on black shale are obtained. The research result shows that the trend of argillitization of black shale increases，and the illite/smectite interstratified clay minerals presents after water soaking. With the increase of saturated time，compact layer microstructure of black shale gradually changes to the irregular mass of flocculent structure，and micro-disintegration phenomenon appears. clay minerals content in black shale causes the floe hole，pore size of black shale decreases after soaking，and micro pore ratio increases；the clay minerals content of flocculation filled by 0.3–2.0 microns of micropores. Then，we specially select the interval and swelling force of (001) crystal layer among laminated structure series minerals，typically for the white mica，illite，chlorite and illite/smectite interstratified clay minerals，as calculation objects. The white mica series mineral crystal layer has the maximal interval growth as well as the swelling force of crystal layer has reach 92 kPa，an increase of 100%. The Chlorite series mineral crystal layer has the second interval growth. But the swelling force of crystal layer has an increase of 111.8%，up to 72 kPa. The Illite and illite/smectite interstratified clay minerals crystal layer has the smallest interval growth，in addition，the swelling force of crystal layer rose by 96.4%，up to 55 kPa.

The cracked chevron notched Brazilian disc(CCNBD) method，which is suggested by the International Society for Rock Mechanics(ISRM) for measuring mode-I fracture toughness of rocks，was numerically investigated by a code based on microscopic damage mechanics. Varying notch width，sample geometries，material parameters and inhomogeneity are considered，and the progressive fracture process of the CCNBD specimen was intuitively presented. Through the simulated stress distributions and acoustic emission activities，the straight- through crack assumption(STCA) was strictly assessed，which is used by traditional methods for calibrating the dimensionless stress intensity factor(SIF). Numerical results show that，crack fronts of CCNBD specimens are always curved regardless of rock heterogeneity，significantly violating the STCA. For the specimen with a more slender chevron ligament，the crack front is curved more severely. Traditional critical SIFs are found to be only 90 to 95 percent of the values that are calibrated by utilizing the simulated critical crack fronts. CCNBD samples always crack from two sides of the notch width of the chevron ligament tip，and thus the specimens with relatively smaller notch width are suggested，so that the realistic fracture route of CCNBD can align well with the ideal test principle. The numerical results call for more attention to the real fracture mechanism of the chevron notched samples. A better calibration of dimensionless SIFs should consider more realistic fracture characteristics for a better measure of fracture toughness.

To deal with the issue of stress sensitivity of cracks，a physical model with known crack parameters has been set up and then the crack closure pressure was calculated based on the effective pressure-compressional wave velocity response curve. Following this approach，the experiments were designed using controlling variable method to study the effects of the initial crack aspect ratio and crack dip on the crack closure pressure. The experimental results indicated that the closure pressure increases as the initial crack aspect ratio increases. When the uniaxial pressure is not perpendicular to the crack surface，the uniaxial pressure should be resolved，and the crack begins to close when the angle reaches Byerlee¢s critical angle，and the closure pressure becomes higher as the angle increases.

There exist some probability distributions for describing rock discontinuity，e.g.，Fisher distribution， Bingham distribution，and bivariate normal distribution. But in reality they are not suitable to represent the statistical characteristics of rock discontinuity orientation data in most cases. In such cases one should use the bivariate empirical distributions obtained for the discontinuity orientations in representing the statistical distributions of discontinuity orientations. The paper introduces the empirical bivariate distribution into the Monte Carlo simulation(MSC) of rock discontinuity orientations and develops a corresponding computer code，named as EMCSDO. EMCSDO is a freeware designed for researchers and practicing engineers，and can be easily mastered by them with little computer knowledge. Two examples with satisfactory results are presented to show the validity of the code. The second example also show if a theoretical distribution can be found to fit discontinuity orientations well，we should prefer to use the theoretical distribution to simulate the orientations based on Monte Carlo technique.

The maximum burial depth of rock mass is about 2 500 m in Jinping II hydropower station diversion line，deformation test is carried out for studying the deep rock mechanical property under the pressure of 100 MPa. The rigid bearing plate for center-hole method is employed，deformation property of deep rock mass is analyzed under the ultra-high pressure，these are relationship between deformation modulus and the burial depth，anisotropic feature，the deformation feature while the test pressure is greater and less than the initial geostress. (1) Rock mass deformation modulus is related to the burial depth，deformation modulus is remarkably improved with the increase of depth. (2) Anisotropic feature is manifested in different burial depth. (3) The rock mass is carrying on rebound test when the test pressure is less than the initial geostress，the ratio of elastic deformation to total deformation is relatively larger，elastic deformation is less when the test pressure is larger than the initial geostress. (4) The compression deformation in the depth of 0.5–1.0 m is the maximal，and the degree of damage of rock mass is more serious. Research results provide the basis for the further study of rock mass deformation property and stability analysis of deep underground cavern.

The drainage of blind tube and isolation effect of waterproof board are two key scientific problems for tunnels in water-bearing stratum during construction. Analytical formula was derived based on drainage of blind tube and isolation effect of waterproof board. It involves the seepage field and water pressure ratio of support systems by considering the drainage of blind tube and isolation effect of waterproof board. The concept of blind tube hydraulic conductivity is introduced. The interactions among drain discharge，waterproof board and supporting system are obtained quantitatively. It can be applied for active control of drainage with blind pipe. The law of bearing water load of supporting system is studied under condition of different hydraulic conductivities of blind tube. In terms of Qilianshan tunnel on high-speed railway，the relationships are determined among drainage with blind pipe，external water pressure of lining and reduction factors. It could implement active drainage with blind pipe and accord with actual situation. Rational thickness and permeability coefficients of grouting reinforced region are put forward. With increasing water pressure，unfavorable position of lining transfers from arch to invert. Shearing-compression failure appears at wall-footing. Flexural failure takes place at invert as well. The ultimate bearing capacity of lining has been determined. Not only is it fit for deep tunnel in water-bearing stratum，but can be as reference for similar engineering.

This paper dealt with the dynamic strength enhancement mechanism of rock-concrete-like nonuniform brittle materials. The theoretical analysis of failure morphology of the specially designed three-point bending beam was made under different loading rates，and putted forward the root of dynamic strength enhancement as results of the combined effect of materials inhomogeneity and inertia force，and held that the static and dynamic strengths of this kind of material were related with the crack path at failure. When in static loading，the cracks of concrete growing through the thin-weak interface of the material，so that it needed minimum energy at material failure. Under the action of dynamic loading，the cracks of concrete developed along the shortest pathway in such a way that cracks can cut parts of aggregates，and the energy needed for material failure was raised correspondingly，the contribution of materials inhomogeneity to the enhancement of dynamic strength had emerged，the inertial effect remarkably increased with the increasing of loading rate. When the loading rate exceeded a critical value，the dynamic strength caused by materials inhomogeneity would not increase，thereby，only the contribution of inertial effect played a role in the dynamic strength enhancement. The theory proposed in this paper was verified by means of the specially designed quasi-static loading test and different loading rates impact test for nonuniform brittle materials three-point bending beam，and the results were basically in accordance with the theoretical assumption.

In order to deeply research the fracture law of floor aquifuge above confined water under deep mining， the new solid-fluid coupling similar material of deep aquifuge was chosen，containing paraffin and vaseline as cementing agent，river sand and calcium carbonate as aggregate，hydraulic oil as regulator based on plenty of similar material and test results. The ratio of each material in components was determined through a series of index testings，meeting the similar demand for solid-fluid coupling material；the similar material has the excellent brittleness and non-hydrophilicity characteristics after being soaked 3 days，and it could simulate floor aquifuge with different permeability. Applying the similar simulation test system with high water pressure，the change features of stress and displacement in deep floor aquifuge were analyzed，inversely gaining the crack evolution law of floor aquifuge under mining influence. The test results indicated that：(1) The mining cracks mainly appeared in the floor aquifuge below the open-off cut，middle of goaf and working face；(2) The majority of mining cracks were vertical tensile cracks，shear cracks and layer cracks；(3) The bigger of stress difference both sides of open-off cut，the fuller development of aquifuge cracks；the region between working face and fault was easy to occur floor water inrush，which presented the developed new similar material of aquifuge could be applied to study the fracture law of aquifuge，realizing the similar simulation of deep floor aquifuge.

In order to study the feature of energy dissipation of unstable failure for static coal under dynamic disturbance，the coupled loads test of static and dynamic was proceed for different saturated state coal samples by the improved split Hopkinson pressure bar(SHPB) experimental system，the feature of energy dissipation of water-saturated coal samples was analyzed in the process of impact，and the relationship between fragmentation，fractal dimension and energy density of the coal samples were obtained. The results show that the positive correlation between incident energy and energy density of three kinds of saturated state coal sample were presented. With the increase of saturated time，dissipation rate and transmissivity are gradually reduced，the transmission rate are increasing. With the increase of saturated time，the energy density of the samples is gradually reduced，and the dynamic strength is reduced，the weakening effect was presented of saturated for the strength of coal samples. Under the condition of the same energy density，the average particle size of coal sample under the natural state is greater than the saturated 3，7 days，the negatively correlated between energy density and crushing granularity were presented，both have good linear relation. The fitting curve is obviously low of energy density and fragmentation of the saturated 3 and 7 days coal sample. The water has a significant effect on crushing particle size. The fractal dimension of the coal sample is 1.67–2.25，the average fractal dimension of coal sample under natural state is less than the saturated 3 and 7 days. With the increase of energy density，the fractal dimension of coal samples is increased. The positive correlated between energy density of sample and the amplification of fractal dimension was present，and both have good linear relation.

During field scale model test of tunnel-type anchorage，the deformation of anchorage and surrounding rock are monitored by multipoint displacement meter，the strain of anchorage are monitored by strain gauge，the deformation and its history of anchorage and surrounding rock are monitored by AE. Then，3D numerical simulation of test are also performed，the analysis is focused on the deformation and stress characteristics of tunnel-type anchorage. The results show that anchorage model undergo four phases in turn：When the load is less than 5.8–7.1 MN，the deformation of anchorage model is in elastic phase. When the load is less than 19.5 MN，the deformation of tunnel-type anchorage model is in elastic-plastic phase. When the load is greater than 19.5 MN and less than 23.7 MN，the deformation of tunnel-type anchorage mode is in the yield phase. When the load is greater than 23.7 MN，the deformation of tunnel-type anchorage mode is in rheological phase. And according to the developing of the plastic zone，the potential slip surface of tunnel-type anchorage is the bottom contact surface between anchorage and the rock mass. Rock mass above the rear anchorage would be damaged due to excessive tensile stress，which can lead to instability of tunnel-type anchorage.

Impounding deformation of slope and foundation is a noteworthy problem during construction and operation periods of high arch dams. Reservoir impoundment is accompanied with various impacts，including material degradation，effective stress decreasing and buoyancy in rock masses. These phenomena are related with some engineering concerns like landslide，dam stability and reservoir-induced earthquake. However，research on mechanism of impounding effects is still limited. By extending the strength reduction method(SRM) in slope limit analysis，a modified method named stiffness and strength reduction method(SSRM) is proposed and implemented in FEM codes to simulate material degradation. Moreover，the expression of effective stress for fractured rock mass with fluid is incorporated into the Drucker-Prager criterion. Based on monitoring data of left bank slope deformation and valley width reduction of Jinping I arch dam，the above two methods are applied in the analysis of impounding influence of slope and foundation. Results show that the dam has good capability against slope deformation，with displacement and stress fields locally changed.

Support crushing disaster caused by dynamic load of main roof is a challenge in high-intensity mining face，theoretical analysis，laboratory test and in-situ monitoring were carried out for analyzing occurred conditions，mechanism and affecting factors of the dynamic impact effect. Nonideal rigid system made up of different strata provided conditions for dynamic failure of surrounding rock，fold catastrophe model of main roofs dynamic fracture was built and main roof showed dynamic fracture because its softening modulus was larger than elastic modulus. With elastic-plastic analysis of main roof，calculation formulas of dissipated plastic power，fracture surface energy and kinetic energy of the block were put forward. Two kinds of roof structures including that fracture line was ahead of mining face or located above the coal wall correctly were built. Then roof structures leading to dynamic impact effect and the impact force were obtained. Increase of advancing speed was equivalent to upgrading the cantilever beams loading speed，and thus amplifying the strain energy stored in main roof and also improving the blocks kinetic energy proportion of the total strain energy. As a result，the probability of main roofs dynamic fracture was magnified. Finally，conclusions were successfully applied into Wangzhuang coal mine and surrounding rock controlling technology and its effect were improved.

How to reasonably determine the Biot coefficient of reservoir is rather essential for wellbore stability analysis. This study tests the Biot coefficient of natural cores with different permeability through respectively Cross-plotting method，drainaging experimentation and sonic dynamic method. The results show that it is for cores with middle and high permeability(is Biot coefficient by Cross-plotting experiment，is Biot coefficient by drainage experiment， is Biot coefficient by sonic dynamic experiment)，while due to poor flowing capacity low permeability cores cannot get the Biot coefficient by the drainaging experimentation；taking the result of Cross-plotting method as the example，Biot coefficient for cores with high permeability distributes in the range of 0.90 to 1.00，that for cores with middle permeability is between 0.90 to 0.80，and that for low permeability is from 0.60 to 0.75；besides，it is recommended that under the allowed experimental conditions cores with middle or high permeability such as sandstones can obtain Biot coefficient by the drainaging method，while cores with low permeability such as shale，tight gas rocks should test Biot coefficient by the Cross-plotting method；finally，it discusses the factors from internal and external aspects on Biot coefficient. The research results will provide a good theoretical support for the analysis on the wellbore stability in deep and ultra deep wells.

In order to overcome the insufficiency of the existing double reduction factors method to determine the double safety factors and based on the assumption that the distribution of the strength parameters obeys linear attenuation，the non-proportional relationship between the reduction factor of cohesion and the reduction factor of internal friction angle is deduced. Then we introduce this relationship into conventional strength reduction FEM，and propose strength parameters non-proportional associated reduction FEM. Then strength parameters non-proportional associated reduction FEM based on field variable is realized by using finite element software ABAQUS，thus the efficiency of calculation is improved in the determination of double safety factors. In order to evaluate the slope stability，comprehensive safety factor is proposed. The safety factor is based on shear strength parameters contributing to the resistant shear force. Finally，combined with an example and the comparative analysis of the position of slip surface and the comprehensive safety factor in three kinds of different reduction ways，the rationality and reliability of the method was verified.

Along with the increased temperature of global，the temperature of South-East Tibetan has rose year by year which led to many disastrous events as glacier debris flows in the history of Nyingchi area. Therefore，the glacier debris flows located in Bome to Yigong in Ningchi as the research object was investigated and analyzed，and discovered the reducing-rate of the glacier area in studied area was about 2.93%，and the variation characteristics of glacier area related to the drainage basin of debris flow by the statistic-analysis. For this purpose，the intensity of meltwater was got by the Clapeyron-Clausius equation and thermochemical equation，and the starting characteristics of the effective diameter d10 and local shear failure of the glacial tills was studied，the relation between temperature and raining conditions was established when the debris flow out-broken，according to statistics and theoretical analysis of hydromechanics and statics，to provide certain reference for the prevention of glacier debris flow.

Due to the stress concentration of coal pillar arranged in the upper coal seam during the extraction of closed coal seam，the accumulated energy in coal pillar could induce coal bump in the mining face and roadway if the position of roadway was unreasonably arranged and designed. Based on the geological condition of No.2 coal mining in Anjialing，the physical model was established to determine the energy release in coal pillar during extraction of closed coal seam and investigate the reasonable position of mining roadway in the under coal seam. It was suggested from the physical model and field test that degree of energy release during the extraction of under coal seam was greater than that of upper coal seam. The reason was that the stress concentration of coal pillar induced by the movement of overlying rock strata was serious during the extraction of under coal seam. The physical model revealed that the reasonable distance between roadway and coal pillar was approximate greater than 8 m. The field test results obtained from roadway displacement and the geological radar suggested that the roadway was stable when the reasonable distance was greater than 8 m.

Since karst seepage channels may be formed by the thorough karst limestone formations，which existing on the flimsy left river bend of head area of Guandi reservoir，farther research on these formations should be carried out. The difficulties in the process of research are the development degree and the forming process mechanism of the karst formation，which directly related to the treatment of antiseepage project and the safety issues during project operation. After adopting methods of macro-geological survey，exploration，groundwater level observation，and water chemistry testing，this paper basically ascertained the geological background and features of karst development，and the karst hydrogeological conditions etc. It emphatically researched the forming process mechanism of karst，adopting seepage field numerical simulation analysis combined with engineering experience，considering reservoir leakage is less likely to happen in the future. It proposed that anti-seepage project should depend on the long-term groundwater monitoring. The groundwater level monitoring after impoundment verified pre-analysis. The reservoir did not produce leakage along the flimsy river bend area，therefore，the anti-seepage project need not to be carried out，saving billions of project investment with significant economic benefits. The case in this paper can provide reference for similar major reservoir construction. The research methods and mentality can also be instructive.

Borehole camera technology has been widely applied to various underground survey field，however，actual survey environment is often restricted by external factors and there is a difference between actual survey environment and theory survey environment，resulting in errors of the actual survey value. Therefore，according to the basic principle of borehole camera technology，we carry out the theoretical error analysis of two kinds of borehole television which may exist in the actual survey engineering and scientific research，and focuses on the systematical study when the probe is in no central of the borehole，calculating the error of fracture width，structural plane tendency，inclination and the width of structural plane on borehole wall，besides，analyzing the error influence brought by the survey speed，and giving recommendations of the survey speed. Through the above study，the conclusion can be drawn：(1) It is very small error when the probe of digital panoramic borehole camera is not in the drilling center and almost does not affect the survey accuracy and precision of the system；(2) The digital borehole camera is more accurate than axial view panoramic borehole TV；(3) The digital panoramic borehole camera system is more suitable for the investigation of structural plane；(4) The survey speed of borehole camera is suggested to be 1.5 m/min.

The force form of the surrounding rocks in underground engineering is coupled static-dynamic loads after true triaxial unloading-loading. The mechanical properties of the surrounding rock under frequent disturbance are easy to be degraded，which can induce engineering disasters such as rock burst and so on. Based on the complex stress environment of surrounding rocks，rock failure tests under the complex true triaxial pre-stressed path and local dynamic disturbance were carried out. The test results show that rock failure occurred when the amplitude of the local dynamic load was in a relatively large level，and the failure mode is splitting tensile failure. PFC3D was used to reappear the lab experiment and study the microscopic characteristics of rock failure under dynamic disturbance. When the amplitude of the local dynamic load was less than 250 kN，both shear cracks and tensile cracks were triggered and their number keep stable. When the amplitude of the local dynamic load was 300 kN，the shear cracks and the tensile cracks spread from the perturbation load position to the entire specimen. The number of tensile cracks exceeded the number of shear cracks while the rock got final failure. The results of lab test and simulation are consistent.

According to theory of unloading-loading process for rock mass and grouting migration function of parallel fracture，theoretical model is established for jointed rock grouting considering one-way coupling effect of grout and rock mass，and interaction between grout and surrounding rock during grouting are carefully studied. Results show that，grouting in jointed rock mass is companied by the process of grout pressure unloading and re-loading the fracture. After the rock mass are totally unloaded，fracture aperture will increase with grout pressure. The increment drops along with spreading distance almost linearly，with a larger drop rate for smaller fracture. The unloading area is larger than grout spreading area，and the coupling effect is more obvious for smaller fractures. Adjacent fractures influence each other，leading to the larger one open further and the smaller one tends to close. Thus，spreading distance in the small fracture is limited or cannot injected，while in large the fracture grout spreads is too far and thus of no effect. Sealing efficiency cannot be improved only increase grouting pressure. Results may provide reference to jointed rock grouting project.

In order to present an investigation into a novel technique for monitoring deep displacement and early-prediction method of landslide，the processes of the novel technology of SAA(shape acceleration array) and conventional monitoring method used to collect deep displacement of a certain landslide located in plateau mountain area were introduced. A method for calculating kinetic energy of monitoring bore was proposed. The change laws of deformation rate，acceleration as well as kinetic energy and its rate from beginning deformation to global sliding failure were analyzed and studied systematically. The early-warning method for critical landslide sliding based on kinetic energy and its rate was proposed. The results demonstrate that shape acceleration array offers a number of advantages including wide range，high stability，easy to implement remote monitoring and so on. The relationship characteristic curves of kinetic energy and its rate can be used to distinguish different stages of landslide and to predict limit time in the deformation process of landslide. The landslide warning time and evolution stages obtained from the curves of acceleration，kinetic energy and its rate are in good agreement，which indicates the feasibility and effectiveness of the proposed warning and forecasting method. According to the research，automatic early-warning of critical landslide sliding is expected to achieve.

The classification of microseismic events is one of the key technologies in microseismic monitoring. The frequency characteristics of rock fracture，blasting vibration signal in underground powerhouse are studied through S transform(ST)，the energy distribution ratio in different frequency bands were used to quantify the frequency characteristics and a model for classification of microseismic events based on the BP neural network optimized by genetic algorithm(GA) was established. Based on the monitoring data in the left bank underground powerhouse of Baihetan hydropower station，the microseismic signals were decomposed in time-frequency domain to calculate the energy distribution ratio in different frequency bands using MATLAB software. Then the feature of microseismic signal can be established，combined with the GA-BP method，the classification model was built by training 400 sets of sample data. Finally，100 sets of test data were used to verify the accuracy of GA-BP network model. The results show that the rock fracture and blasting vibration events show difference in energy distribution， the GA-BP network model presented excellent performance for identifying the two types of signals，the correct rate of identification is 98%，the research method can provide reference for the establishment of events classification model in microseismic monitoring of similar projects.

Sinusoidal curved lateral resistance method(SCLRM) is the theoretical correction for triangular method. Considering the nonlinear characteristics of soft，underwater soft plastic and composite strata that the large diameter tunnel passing through，the lateral resistance was corrected in SCLRM. The theoretical formulas of SCLRM were derived and the example was shown. Based on the free-form deformation method(FFD)，the internal force distribution for the lining structure were calculated using triangle method and SCLRM. The scope and restriction of the application of theory were expanded. The applicability of each lateral resistance method in actual complex formations was discussed. Comparing the measurement value with theoretical results for Nanjing subway line one，it is indicated that the internal force calculation of single round integral type shield tunnel by SCLRM having a definite procession and a small error range which are suitable for this engineering example design. Application of this example provided a theoretical reference of internal force maximum value for designing single round shield tunnel passing through the composite strata. It seems that SCLRM has the certain practicality for similar project design.

Xiluodu hydropower station on Jinsha River began to impound water in May 2013，and the deformation of four fractures increased significantly till the October 2013，which appeared a slope of the reservoir bank. So far，the amount of main fractures have increased from 4 to 9，with a tendency of continuous deformation and failure，which lead to a great inconvenience to local people and significantly influence on the normal operation of the hydropower station. Through site investigation and data analysis，the mechanism of its further evolution of the role of reservoir storage was proposed base on early formation mechanism study of the toppling deformation body. Due to influence of incised valley and special geological structure of the slope，nonuniform contraction-toppling deformation was occurred on the slope，which cause a toppling deformation body. Because of the impoundment of the reservoir，the toppling deformation was aggravated by the soft rockmass under the slope caused by water immersion. As a rare failure mode all over the world，a preliminary judgment was made for the stability of the toppling deformation slop by numerical simulations.

Quality of cap rock is a critical factor controlling the effective accumulation of natural gas for underground gas storages. In view of this，the brittleness evaluation model of cap rock is set up based on the complete stress-strain curves through lab tests. In combination with physical sealing method and rock mechanics method，a modified sealing evaluation method of cap rock is proposed. Based on the classification of the influence factors and the analysis of cap rock for gas storage of depleted gas reservoir，the index suitability standards of cap rock evaluation for gas storage are put forward. Then taking the analytic hierarchy process，a layer structural model of sealing evaluation is built and the importance weights of 12 influence factors are calculated. Combined with the importance weights of influence factors，a formula is developed to calculate the synthetical appropriate value of cap rock. This method is used to evaluate the suitability of Xing 9 gas reservoir and evaluation result of cap rock is consistent with the expert opinions，which shows that this method is reasonable.

To investigate the nonlinear response of deep bedded salt cavern(group) subjected to extreme loads，the numerical model considering the complete process of water solution，cyclic operation，and internal pressure runaway was established according to the geological structure of Jintan deposit. The effects of rapid unloading on the progressive failure，the volume convergence of single and double cavern，as well as the surface subsidence were calculated utilizing a new elasto-viscoplastic damage model for rock salt. The results reveal that the damage and failure region extends much deeper in the mudstone than that in the host salt. The damage and failure volume of surrounding salt induced by unloading process is 5–10 times larger than that of 10-year cyclic injection- ejection. The average volume convergence rate of salt cavern reaches 0.012%/d–0.013%/d. It is 6.0–6.5 times faster than that caused by cyclic operation. The surface subsidence presents a typical funnel curve. The influenced range of surface subsidence due to rapid unloading is about two times the maximum cavern diameters. The double cavern analysis indicates that the interaction between adjacent caverns is not obvious given the pillar width is larger than two times the maximum cavern diameters.

For the researching of the shear strength parameters of rock mass，the method proposed by this paper provides a new method and a new way. First，based on the deficiency of existing empirical formula，the mathematical relation between the geological strength index(GSI) and the basic quality index of rock mass(BQ)，the uniaxial compressive strength of saturated rock，the P-wave velocity of natural rock are established. For the rock masses uncovered by drilling，based on the results of borehole TV test，borehole ultrasonic velocity detection and laboratory core sample test，using the Hoek-Brown strength criterion，this paper puts forward a method for the estimation of rock shear strength parameters. Then this method is applied to a project under construction and the results show that the shear strength parameters of rock mass estimated by the method are close to actual values.

Based on the analysis of the occurring characteristics of rock burst and the anti-impact mechanism of bolt-net-anchor support. The anti-impact abilities of support were calculated from the perspective of the energy-absorbing property of support and energy balance theory. Taking account of the location deviation，the reliability parameterfor anti-impact supporting design was introduced to the feasibility analysis of seismic reverse calculation for supporting，and the anti-impact energies of existing support calculated with the long-term data monitored by“SOS”seismic system were analyzed and compared with real energies of rock bursts in different. Results show that strong tremors will turn into rock bursts under certain conditions. The flexible property of bolt-net-anchor support can absorb most or part of dynamic energy passed on to the anchoring zone，maintain the integrity and stability of the anchoring surrounding rock，support the internal surrounding rocks of roadway，and prevent the further failure of the surrounding rocks. This is an important factor in effective control of rock-burst. The theoretical calculation results combined withhave good comparability with actual data of rock bursts and strong tremors. The calculated anti-impact energy of existing support of previous rock bursts all have turning points with the decrease of ，and the calculated result of the strong tremor also coincides with the reality. This shows that the seismic reverse calculation method combined withis feasible.

Affected by the rainfall and the periodic scheduling of reservoir water，some of the landslides in Three Gorges Reservoir area show the obvious step-like deformation. According to the deformation characteristics of the step-like landslides，a GA-SVM model for displacement prediction based on the response analysis of inducing factors was proposed. The landslide displacement was decomposed into trend item and periodic item by the moving average method，and the trend term displacement was predicted by the polynomial function，which is controlled by geological conditions of the landslide. As the periodic displacement is controlled by the combined action of all the inducing factors，the dominant factors were selected to establish the GA-SVM model for landslide displacement prediction. The total prediction displacement was the addition of the two items. The typical step-like landslide-Bazimen landslide-was taken as an example to make a displacement prediction by the GA-SVM model. The results showed that，the response analysis of inducing factors was the essentiality of landslide displacement prediction. The GA-SVM model based on the response of inducing factors showed great prediction performance in the step-like deformation，which is an effective displacement prediction method for the step-like landslide.

Seepage deformation test methods for intercalated weak rock layer are not very matured，and there is not code for the test. Seepage deformation test and its results are presented for disturbed/undisturbed samples from faults F41 and F42 at the site of Chipwi Hydropower station planned for the upper Ayeyawdy River，mainly following the test code for soil. The results indicate that disturbed samples fails as soil flow without apparent deformation process，and the permeability differences among samples are not great. Undisturbed sample tests performed in a temporary laboratory set up at site reveal different characteristics. Main deformation is washing fine and soft mass out. Washing or local soil flow results in failure. Critical gradient is rather lower than failure gradient. Measured values are greater than that from disturbed sample tests，because undisturbed samples remain inhomogeneous internal structure and the contact status between weak layer and surrounding rock. Comparing with test results of disturbed samples，results of undisturbed samples reveal better the seepage deformation characteristics of the faults. On the basis of the test results and previous studies for other projects，test methods and the ways to apply the results are discussed. Suggestions include that integrating microscopic，meso-scopic and macroscopic study methods to reveal the seepage deformation mechanism further，taking numerical simulation to improve in-situ tests，and allowable gradient being set according to the seepage deformation process in addition to measured values with suitable safety factor corresponding to the location and harmfulness of the intercalated weak layer.

The in-situ displacement monitoring was carried out according to the geological characteristics of Daliang tunnel. The monitored result shows that tunnels deformation is charactered by high velocity，long period and large value. The maximum subsidence is 55 cm，the deformation rate run up to 1.69 cm per day. The rock masss elastic-plastic mechanics parameters are deduced by the generalized Hoek-Brown criterion based on the uniaxial and triaxial compression test result. With the rock mass considered as an elasto-plastic-rheological material which conforms to the empirical rheological model，the FEM inversion analysis was conducted based on the deformation monitored，and the rock masss rheology parameters could be got. The tunnels support design could be adjusted reasonably considering the displacement，the stress distribution and the damaged zone of the rock surrounding. According to the principle of new austrian tunnelling method，a new comprehensive support measures，which consists of enlargement of the deformation allowance，pre-grouting，bottom bolts installed，steel arch，system bolts and steel fabric installed，was adopted in Daliang tunnel which has poor rock surrounding and suffers large deformation during its excavation. It was confirmed by the fact that the tunnel was very safe after its construction.

Cofferdam break caused by slope instability of high earth no-overflow-cofferdam can make a huge loss，there is important significance to carry out risk analysis. The uncertainty of hydrological，hydraulic and mechanical parameters of filling soil-stone were comprehensively considered to establish the slope instability risk model of high earth no-overflow-cofferdam based on the safety factor. Considering the change of critical sliding surface position in each simulation，layered-LHS sampling method was used to obtain the filling soil stone random sample in order to improve the sampling efficiency. Then，K-S test principle was used to judge the distribution types of the slope safety factor，and fitting optimization index was adopted to determine the optimal probability distribution，then the calculating process of risk model was given. Finally，a large hydropower project in the Southwest of China was calculated and analyzed. The results indicate that the proposed method effectively improves the efficiency of risk calculation，and the fitting effect of probability distribution is satisfactory，so that the risk can be estimated accurately and rationally，this paper provides a new idea and method for risk analysis of slope instability of high earth no-overflow-cofferdam.

To research the risk of coal overall instability of isolated working face with irregular gobs on both sides，the isolated working face 3206 of a mine in Shandong as the engineering background was studied，and the dynamic process of roof structure in irregular gobs on both sides during the period of mining working face was analyzed in this paper. Based on the technique of microseismic monitoring with high accuracy，the amount of overburden movement angle and gangue contacting angle over the gobs was got. Meanwhile，the calculative formula of bearing pressure on isolated working face of coal and the analytic method of its instability was proposed. The results showed that stress would reach a maximum when the hanging roof structure turned to the semi-hanging roof structure over gobs，while stress would reduce when the width of gobs was large enough which indicated the gobs had came into a full-mining level. Moreover，the instability coefficient in various stages was obtained during the mining based on the geological conditions of the working face 3206. The analysis results showed that: the instability would occur quite possibly when the working face was in the process of mining. However，it could be mined safely by taking the method of drilling relief with large diameter to prevent the occurrence of rock burst. Ultimately，the correctness of this paper has been confirmed by the mining practice.

Reservoir compaction and surface subsidence caused by pore pressure depletion endanger oil and gas well integrity potentially. The theoretical methods of reservoir compaction prediction and well integrity assessment are scarce. According to the elastic theory of porous medium，the calculation formulas of reservoir compaction and surface subsidence are deduced. Based on the mechanical interaction of formation and well，the failure mechanisms of directional well are revealed and the quantitative assessment method of well integrity is proposed. Results indicate that casing buckling in production interval and casing collapse in reservoir are the main failure mechanisms. The countermeasures，including utilizing higher steel grade or heavy-wall casings and enhancing cementing quality，can improve well integrity. The research achievements provide the scientific bases of well integrity assessment and casing design for depleting oilfields.

During the excavation of the underground caverns at Houziyan hydropower station，high in-situ stress is encountered with the maximum principle stress being 36 MPa，and numerous small-scale geological discontinuities were also uncovered. As a results，the overall deformation of surrounding rock mass is comparatively large，and severe shotcrete failures，such as swelling and cracking，occurred. In order to investigate the deformation and failure mechanisms of rock mass and shotcrete，numerical simulations of caverns excavation using 3DEC code was conducted. In this numerical model a modified strain-softening constitutive model was used to simulate the unloading mechanical behaviors of brittle hard rock，and also the modeling of discontinuities having fictitious disk-like shape were specially considered. By analysis of development processes of both the stress concentration and the tensile strain in surrounding rock mass，this study suggests that the stress-dominated failures are easy to occur in the early stage of excavation due to high in-situ stress and relatively integrated surrounding rock mass，however with further excavation the discontinuities-dominated failures will progressively prevail over the stress-dominated ones because of increasing influence of discontinuities on stability of rock mass and the interaction among adjacent caverns. By analysis of displacement distribution and axial force developed in cables，this study suggests that for powerhouse cavern the significant difference between displacements on upstream sidewall and that on downstream sidewall is caused mainly by the opening and sliding of steep discontinuities which strike parallel to axial direction of powerhouse cavern.

Stress controlled failure mode is common in underground powerhouse caverns under high geostress. The relaxation zone in surrounding rock is the product of stress controlled failure mode. As one of the main external factors for rock deformation and relaxation zone，the initial geostress is the foundation of surrounding rock stability analysis. In this paper，several initial geostress field inversion methods are discussed. And a geostress field generation method is also proposed. By contrast the inversion results of this proposed method with the classical one，the proposed method is proved effective. A simulation method for relaxation zone is introduced in this paper which taking the displacement data and acoustic data both into consideration.

To study the broken energy dissipation characteristics of coalmine sandstone under impact loads，variable cross-section spilt Hopkinson pressure bar(SHPB) apparatus is adopted to conduct impact compressive test of sandstone specimens. Three loading impact pressures correspond to three loading rates. Then the energy dissipation rule of sandstone specimens is analyzed. The test results show that the proportion of absorbed energy and incident energy is relatively constant，and absorbed energy increases with the incident energy growing. There is a positive linear relation between broken energy dissipation density and incident energy. Moreover，there is a power relation between broken energy dissipation density and average strain rate，which shows a strong strain rate effect. The larger the broken energy dissipation density is，the more fierce the degree of specimen broken is. The average particle size of broken fragments is adopted to describe the degree of specimen broken quantitatively，and its value decreases with the broken energy dissipation growing. There is a logarithm relation between dynamic strength and broken energy dissipation density. The specimen absorbed energy is mainly used for damage evolution and deformation and fracture，and broken energy dissipation density can reflect the essential strength feature of sandstone specimens under external loads well.

On the basis of systematic analysis of the change rule of displacement and rainfall and their interaction relations，this article first proposes that the increment of rainfall and displacement velocity or acceleration can be respectively taken as loading dynamic parameter and displacement response parameter，so as to establish the displacement response ratio of dynamics increment evaluation parameter and its prediction model by means of elastic-plastic theory and damage mechanics. In addition，according to the quantitative relation between the damage variable parameter of damage mechanics and the displacement response ratio of dynamics increment，the dynamic displacement destabilized criterion for this kind landslide is established. Finally，taking the typical colluvial landslide induced by rainfall in the Three Gorges Reservoir Area as an example，the continuous rainfall increasing process and its displacement response characteristics are analyzed and evaluated systematically by means of the displacement response ratio of dynamics increment model and find that the values of displacement response ratio of dynamics increment have an abrupt jump just before landslide took place，which demonstrates that the abrupt jump time agrees with the destabilized time of the landslide. The research results show that the displacement response ratio of dynamics increment is an effective dynamics displacement appraisal parameter of rainfall，so it can be used in the prediction of the landslide induced by rainfall.

The basis of rock burst prevention is the identification of burst tendency. So it is very important that the identified indices are concise and rational. Based on the current analysis of burst energy indices，the time effect of both molding energy release and effectively utilized elastic energy release before coal rock peak was taken into an overall consideration. And a calculating model was set up to calculate the release speed of effectively utilized elastic energy. Also，based on the AE characteristic indices and molding energy release before the presentation of peak of recycled and unloading load，by using TYJ–500KN to control electro-hydraulic servo rock shear rheology test system recycled loading AE experiment for coal，the Section Function Calculation Formula was combined. The burst energy indexes identification experiment was carried out to confirm the reliability of the presented formula. The result shows that there is only 5.27% difference between the presentation of peak value unloading and the presentation of AE characters indices，and the two presentations prove each other. The release speed of effective elastic energy is in positive correlation with burst energy index，the uniaxial compression strength，and the effective elastic energy，but in negative correlation with time. Therefore，it is rational to identify the burst tendency by the effective elastic energy release speed.

The arch foot with an expansion section can be applied to well control deformation of large-section tunnels built in soft layers. Based on previous researches，the structure of arch foot with an expansion section is further developed，it presents a method designing an anti-slide arch foot in the tunnel. The effects of the large arch foot on the deformation of the strata are studied by theoretical study，numerical calculation and field measurement. Research results show that the anti-slide arch foot in the tunnel is able to control convergence of surrounding rocks of the tunnel effectively，as well as control settlements of vault of the tunnel. It happens mainly because the anti-slide arch foot with an expansion section is inserted into the surrounding rock，which can produce lateral resistance and prevent the arch foot from moving towards the side of tunnel near the air. Furthermore，the research results reveal that the length of the arch foot is related to classification of surrounding rocks considering mechanical behavior of arch foot subjected to forces. Under the same surrounding rocks，the length of arch foot and its ends that inserted into the soil increase nonlinearly if classification of the surrounding rock varies from III to VI.

The observation results of floor heave in the engineering practices of gob-side entry retaining show that floor heave mainly occurs between the first mining period and the second mining period. The floor heave amount is several hundred millimeters，account for 70% of convergence between roof and floor. The cause of floor heave is discussed. Concretely，the floor rockmass is broken after the first mining and then undergo post-peak creep under the action of the first and second mine-induced stress. The floor heave amount is affected by the lithology and stress environment of floor rockmass. Generally，it increases rapidly as the increase of broken degree and principle stress difference. Based on the characteristics of floor heave，the bolt method and steel pile method are proposed to control floor heave. The bolt method can reduce the floor heave amount by its anchoring force，while the steel pile method by its high deformation resistivity and stress arch. The control effect of latter is more significant. The technology of gob-side entry retaining can be further improved to increase the value of its engineering application by the research results.

Based on laboratory model test with 1∶10 geometric similarity factor，stacked inner lining has been taken to reinforce the structure with axial cracks on the top lining. With test data，we conclude the failure mechanism of reinforced lining under loose pressure，by analyzing its lateral deformation，development of main cracks，short-term stiffness of lining apex and final failure mode. In addition，we also quantitively study the influence of crack depth on the ultimate bearing capacity. It is important to note that the cracked tunnel works under loose load and the rock resistance coefficient is 10 MPa/m. The results show as follows：(1) the process of failure can be divided into three stages，namely，specimen crack stage，“arch crack-penetrated arch crack”，penetrated arch crack-specimen fail. (2) The main cracks in on the vault and haunch，the overall failure mode is brittle failure. (3) There exist linear relationship between existed crack depth and crack moment，short term stiffness，ultimate load.

Flexural toppling failure is one of the most common types of failure in layered counter-tilt slope. The limit equilibrium method is still the most common approach in the toppling failure study at present. Firstly，Based on the cantilever beam limit equilibrium model proposed by Aydan，the toppling failure limit equilibrium equation considering the influence of block top shape，damaged step height and slope toe triangle block is established. Secondly，depending on the block stability state and failure mode，blocks above the basal plane are divided into three zones that stable zone，toppling zone and sliding zone. In addition，the boundary condition is deduced. Thirdly，based on limit equilibrium equation，the calculation method of failure basal plane for flexural toppling failure in layered counter-tilt slope is proposed and a special computer code is developed. Finally，two case studies are used for practical verification of the proposed approach as well as the parametric study is conducted. The analytical results show that the angle between the failure basal plane and the plane normal to the discontinuities nearly increases linearly with the slope cut angle while decreases with the strata thickness. The results also indicate that slope failure mode gradually transforms from toppling failure to toppling-slipping failure with the increase of slope cut angle. In addition，the steeper the slope natural angle and the larger the scope of the destruction zone.

Rock burst and large deformation coordination controlling is a common problem of thick coal seam in deep mines. The mechanism of rock burst and large deformation coordination controlling in thick coal seam of deep shaft was studied through field monitoring and theoretical analysis，and the mechanical model of gob-side entry lateral roof secondary fracture was set up. Following results were obtained：(1) In the condition of Xinjulong coal mine，the pre-relief borehole with diameter of 120 mm，depth of 25 m and spacing of 1 m was implemented，the effective pressure-relief protection area width is 10–15 m. (2) The mechanism of gob-side entry large deformation of thick coal seam in deep shaft is mainly caused by secondary breakage of roof and rotation induced by intensively venting the pulverized coal，and verified by theory. (3) The mechanism of rock burst and large deformation coordination controlling in thick coal seam of deep shaft is to determine the reasonable pressure-relief parameters. By intensively venting pulverized coal to release the expansion deformation of surrounding rock，the pressure of roadway surrounding rock is also decreased. Meanwhile，the damage level of surrounding rock structure is reduced. Field practice shows that by optimizing the parameters of supporting technology and pressure-relief，the problem of large deformation of gob-side entry can be resolved to a certain extent. The results can provide some references for rock burst and large deformation coordination controlling in thick coal seam of deep shaft.

Setting reasonable partition pillar is a key to ensuring safe mining of working face heading the goaf in thick seam of deep shaft. Taking determining the width of partition pillar close to 7108 goaf heading mining of LW7110 in Tianchen Mine as the engineering background，the mechanism of the goaf heading mining inducing rock burst and the reasonable width of partition pillar were studied through theoretical analysis，numerical modeling and field monitoring. The following conclusions were obtained. (1) The evolution process of overlying strata spatial structure during LW7110 mining heading the goaf is described as “the fixed S-shaped，the moving S-shaped，the connected S-shaped，the C-shaped and the U-shaped”，and the evolution process of partition pillar stress is described as “the fixed abutment pressure，the moving abutment pressure，the stress superposition and the stress concentration”. (2) The mechanism of rock burst induced by the goaf heading mining is described as the vertical stresses in the partition pillar reaches impact stress condition because of stress concentration. (3) Under the premise of implementing stress relief around the pillar，the reasonable width of partition pillar close to 7108 goaf heading mining is 65 m. Furthermore，the reasonableness of the partition pillar width was verified with a good result. The results can provide a reference for prevention of rock burst induced by mining engineering.

How to complement effectively ground control has been an important and difficult issue in multiple fully-mechanized longwall mining for closed distance coal seams. Patterns of abutment pressure distribution，characteristics of hydraulic support force and condition under mined gob with longwall retreat mining should be synthetically investigated in order to prevent roof accidents such as rib spalling，roof fall and hydraulic support damage. Taking the No.5 coal seam and No.4 coal seam of Panbei mine as the background，the characteristics abutment pressure and the plastic zone in front of coal wall were deduced from theoretical formula. The mining-induced stress development，peak value and its location were obtained in front and background of No.12124 longwall panel under mined gob using FLAC3D to simulate surrounding rock mechanical characteristics. The characteristics of working resistance，maximum resistance and distribution of hydraulic support had been observed and obtained. Researches results show that abutment pressure evolution superposition mechanism has been revealed under closed distance and mine gob in thick coal seam and large dip angle with fully mechanized longwall mining. Based on comprehensively analyzing，ground control countermeasures have been put forward to increase working resistance，to push roof metal-mesh，and to enhance face guard with individual prop. And effective applications were obtained.

The purpose of this paper is to predict the radius of plastic zone for a high pressure gas well during well testing. Firstly，the plastic radius equation is given for idealized elastoplastic model considering of varying pressure. Secondly，it drew a comparison between the pressure distributions for the two kinds of flow models，and pointed out that the flow model including the gas acceleration term has a more steepening pressure curve near the wellbore. Then，it analyzed the radius of the plastic zone for the two kinds of flow models，and pointed out that the flow model including the gas acceleration term has a larger radius of plastic zone for the same factors. Finally，influencing factors such as bottomhole pressure，permeability，borehole diameter，gas acceleration，property of rock and in-situ stress on the radius of the plastic zone were analyzed，and summarized the influencing rules.

According to special supporting requirements in swelling，extremely soft rock roadway，for the purpose of developing shed support with high-strength，relying on moment analysis of structural mechanics，we analyzed the supports moment distribution under different lateral pressure coefficient. And we also analyzed moment distribution in 5 improved structures of different height in bottom arch，original support with floor beam，original support with roof beam，original support with floor and roof beams，original support with floor，roof beams and other ribs. The results showed that under different lateral pressure coefficient，top and bottom arch demonstrated larger moment and were the main weak plane when support destructed. There was greater impact on strength of bottom arch as height of bottom arch increasing. Based on original support，strength of bottom arch was enhanced obviously when floor beam added，but little effect on top arch and strength of top arch was enhanced obviously when roof beam added，but little effect on bottom arch. Strength of top and bottom arch were enhanced obviously when roof and floor beams added，and the strength coefficient of top and bottom arch was improved to 3.51 and 2.715 when the roof beam closed to top and floor beam closed to bottom. Based on roof and floor beams，braces added in top and bottom arch further，the strength coefficient of top and bottom arch was improved to 3.719 and 2.889 under combination structure of “V” in vault and “” in dome. Consider the economic benefits and the impact of construction on site，we gained the ideal support structure with roof beam closed to top and floor beam closed to bottom.

Soil is a complex granular medium and its strength and deformation characteristics behave strong particle size effect. On the basis of the physical effects of cohesion and friction generated by the interactions between soil particles at different scales，a soil cell element that can describe the internal material information and particle characteristics of soil was constructed by dividing particle size into different scales to investigate the influence of soil particles at different scales on the macro-scale mechanical properties of soil. According to the mechanical responses of soil at various scales，the notion of coordinated micro-cracks was introduced，and a multi-scale and hierarchical soil cell element model was proposed to establish the conversion relationship of the displacement and stress between different scales. Therefore，the microscopic soil mechanics was promoted from qualitative analysis to quantitative calculation. Moreover，various soil samples with a variety particle combinations were prepared for a series of direct shear tests to study the particle size effect of soil. Meanwhile，microscopic parameters of the model such as the strain gradient and intrinsic length scale were quantitatively studied. The results show that：The yield stress of soil increases with an increase in the volume fraction of the reinforcement particles. When the volume fraction of the reinforcement particles is low(≤0.125)，the yield stress of soil increases with a decrease in the reinforcement particle size whereas when the volume fraction of these particles is high(≥0.177)，the yield stress of soil increases with an increase in the reinforcement particle size. The action of the reinforcement particles that causes the strain gradient and coordinated micro-cracks of soil to appear at the matrix joined with the reinforcement particles is the microscopic physical mechanism of the particle size effect of soil. The yield stress of soil calculated by the soil cell element model is in good agreement with that of the test result.

In order to study the impacts of anisotropy of compacted loess on strength and deformation behavior，a series tests with fixed principal stress direction were carried out on compacted loess with a hollow cylinder apparatus. The impacts of intermediate principal stress coefficient b and principal stress orientation angle α on strength and deformation of compacted loess were emphatically discussed. Test results revealed that when α increased the strength of compacted loess decreased first and increased when ＞60°. Tangent modulus of generalized shear stress-strain curves of different intermediate principal stress coefficient decrease with principal stress orientation angle increase from 0°to 30°，and increase with principal stress direction when ＞60°. The peak of generalized shear stress was used as the failure criterion of compacted loess according to the generalized shear-strain curves. The generalized shear stress at the generalized shear strain of 15% can be taken as the failure criterion when peak generalized shear stress did not appear. The impact of intermediate principal stress coefficient on strength is mainly manifested in the strength of b = 0.5 are lower than b = 0.0 for different principal stress directions.

Under the groundwater environment that is rich in sulfate and chloride ions，solidified/stabilized heavy metal contaminated soils may suffer secondary pollution and resulting in the deterioration of solidification effectiveness. Thus，the strength and microstructure characteristics of cement solidified/stabilized lead contaminated soils under the secondary pollution by sodium chloride solution were studied. A systemic experiment program was performed on the cement solidified/stabilized Pb2+ contaminated soil. Test results show that the unconfined compressive strength of solidified soils decreased and compressibility increased with the increased in concentration of sodium chloride solution. The strength reached minimum and compressibility reached maximum when specimens soaked for 7 days. After soaking for more than 7 days，with the immersion time increased，the strength enhanced and the compressibility decreased. The results of triaxial compression test show that the stress-strain curves of solidified soils can be divided into three different sections：elastic deformation stage，plastic yielding stage and failure stage. Scanning electron microscopy(SEM) results indicate that erosion of sodium chloride solution leaded to porosity increased and loose structure of the solidified soils. Particles of the sample that soaked 28 and 90 days arranged more compactly and steadily than that soaked 7 days.

Consists of sandstone and mudstone，the red-bed slopes in the east of Sichuan province belong to high geological hazard-prone areas. The soft layer(especially muddy layer) in the slopes was prone to be softened by water with the reduce of its mechanical strength，which favors the development of potential sliding surface. With the aim of revealing the change law of microstructure and mechanical properties of samples，a series of experiments of the sampled undisturbed soil from landslide sliding zone under the saturated condition were carried out. The result shows that after saturating the internal structure of tested soil became loose，meanwhile the way of connection of soil particles changed from plane-plane to plane-edge，edge-edge. Both cohesion and internal friction angle variations follow an exponent curve and tend to be stable after soaking 10 days. According to this result，the softening effects on slope stability were analyzed by the limit equilibrium method. The calculation result shows that slope stability coefficient is reduced with the softening of soil of sliding surface. Some slopes may eventually tend to be unstable even though without the static water pressure from the rear crack of slope and uplift pressure from sliding surface. Therefore，the dramatical decrease of soil strength due to softening and saturating is considered as the important cause of slope failure in red bed regions. The research conclusion can provide an important basis to understand genetic mechanism of landslides and control hazards in Sichuan red bed area.

A series of scaled model tests were conducted to study the influence of the net distance between adjacent pile caps and embankment fill properties on the soil arching effect of geosynthetic reinforced and pile supported embankment. The influences of fill cohesion and the distance of adjacent pile caps on soil arching effect and the variation with the surcharge on the top of embankment were analyzed. The results show that：(1) Cohesion makes the soil arching effect stronger，soil pressure on the pile caps becomes larger，while soil pressure between pile caps becomes smaller. Comparing to fill without cohesion，for embankment constructed by fill with cohesion，pile efficacy increases，the settlements of subsoil between pile caps and on the surface of the embankment become smaller under the same load. (2) The arching conditions would be independent of fill cohesion，the height of soil arching is 1.0–1.5 times of the net distance of adjacent pile caps. (3) The greater the distance between adjacent pile caps，the weaker the arching effects，and the smaller the pile efficacy. (4) No matter what fill is or how the distance of adjacent pile caps changes，soil pressure on the pile cap edge is bigger than that over the pile cap center.

Complex geologic conditions like fault，extrusion zone，development of deep crack，heavy unloading of rock of Jinping I arch dam have contribute the foundation treatment to be the key part of the whole project. As regular cement grouting can not solve problems like strength of weak rock，deformation，penetration completely，so cement chemical compound grouting was studied systematically combining with the development of new material technology in recent decades. The method of cement grouting firstly，then chemical compound next was proved to improve the strength and anti-permeability of weak rock effectively and greatly. Based on the various field tests，cement chemical compound grouting has successfully applied to the treatments of the weak parts of dam foundation in important area，result in significant increase of their sonic speeds，deformation modules，anti-seepage abilities，integrities and stiffness. According to the feedback analysis of dam structure during the third impoundment stage，cement chemical compound grouting has been successfully applied in the Jinping I arch dam foundation treatment，and solved one of the critical technical problems of high arch dam construction.

Currently，soil models have been widely adopted to represent the waste behavior in numerical analysis for landfills. Although some aspects of waste behavior are similar to soils，a number of unique characteristics of municipal solid waste(e.g. consist of large number of compressible solid) cannot be accounted for by existing soil models. This paper aims to propose a constitutive model which can reflect the behavior of municipal solid waste more properly so that it can be applied in numerical analysis and serve for the landfill operation. On the basis of the modified Cam-clay model，a constitutive model for municipal solid waste(MSW) considering the deformation of compressible sold was established. The MSW can be divided into two parts：one part includes the incompressible solid particles and the voids，and the other parties the compressible solid particles. In detail，assume that the stress-strain behavior of the first part which includes the incompressible solid particles and the voids is elastic-plastic while the deformation of the other part which is large and irreversible is assumed to be plastic deformation. The proposed model is based on the modified Cam-clay model and the parameters in the model have clear physical meanings. It is found that the model can properly reflect the stress-strain behavior of MSW by comparing the numerical calculation results using the model with indoor triaxial drained test results of the municipal solid waste. As a result，the accuracy and rationality of the model is confirmed.

Used as a modified material，the waste tire granulated rubber was expected to enhance the effectiveness of liner system in landfill and extend the utilization of the waste. The internal strength and interface shear strength tests of waste tire ground rubber and clay mixtures were conducted and the effect of ground rubber on strength properties was studied. The shear strength of the mixtures increases slightly as rubber mixing content increases，and the unconfined compressive strength can meet the requirement in the specification. When the rubber mixing content is 15%，the interface strength of geomembrane/mixtures is higher than that of geomembrane/Kaolin clay. However at the normal stress of 400 kPa，there are stress drop for the interface of geomembrane/mixtures，which results in the lower residual strength. At low normal stresses，the interface strength of GCL/mixtures is slightly lower than that of GCL/Kaolin clay，which is opposite at high normal stresses. The interface strength is lower than the internal strength of the soil. Overall，the effects of the two rubber particle size in this study are not significant，and there are not adverse effects of the waste tire ground rubber on the internal and the interface shear strength.

Based on equivalent continuum media model，the fractured soil located on the slope surface can be regarded as dual-porosity media，including the crack network and the pores of soil matrix，and the degree of fissure and the average fissure width as the introducing variables were taken. According to the capillary theory and the pore-size distribution，an effective method was summarized which can evaluate equivalent bi-modal unsaturated soil property functions for fractured soil. Then this method was applied to analyze an engineering practice on how the crack network affects the seepage field under rainfall infiltration condition. The results show that the crack network provides a priority channel for rainfall infiltration，and the perched water table is formed within the slope typically 1–2 m deep.

Loess is a kind of special structural soil. The structure can be described by a quantitative parameter called structural index. At present，qualitative relationships between structural and physical indices have been studied a lot，but seldom for quantitative relationships. In order to study the quantitative relationship between the structural and physical indexes of loess，a series of uniaxial compressive strength tests of undisturbed，remoulded and saturated loess specimens sampled from seven different fields were carried out respectively under different water contents，and the corresponding structural indices under different water contents were calculated. Furthermore，the quantitative relationships between structural index and water content were analyzed by the methods of data fitting，the comparison of fitting curves and the test verification. It is shown that the linear fitting curve converted from power function fits the laboratory results much better than exponential and power functions. The empirical formula of the quantitative relationships between structural index and water content are obtained. And the magnitude of structural index in engineering would change from the dry structural index to the saturated structural index. Thereby，a comprehensive physical index Z was proposed to calculate the dry structural index and empirical formula for the quantitative relationships between the dry structural index and physical indices was presented. These quantitative relationships would be beneficial for the application of structural index to practical engineering.

In order to study how the surface feature of reinforced geomembrane affects the reinforced geomembrane and geotextile interface shear strength，the fractal dimension D was calculated by cubic covering method and fractal geometry theory. Basing on the direct shear test，the correlation between the fractal dimension D and the shear strength of different reinforced geomembrane was gotten. It shows that the interface shear strength increases with the increase of fractal dimension D strengthen，so that fractal dimension could measure reinforced geomembrane and geotextile interface shear strength. And then，after revising the JRC-JCS model combined with inosculation ratio-JMC and experience factor ，the connection between the joint roughness coefficient(JRC) and the fractal dimension D was worked out with the shearing text，on the basis of which the experiential estimative equation of reinforced geomembrane and geotextile interface was derived. Finally，the calculation results were carried out with the experiential estimative equation，the comparison between the calculation results and the shear test results was conducted. Form the comparison，it shows that calculation results fit in with the test results，and the calculation accuracy and the achieved reliability of the equation can meet the requirements of engineering estimate.

Based on neural network method，the influence of gravel-soil gradation on permeability coefficient was studied. Obtaining 92 groups seepage test data of gravel-soil，a neural network was trained and tested. Based on this neural network，permeability coefficient of gravel-soil was predicted and compared by full gradation(d10–dmax，all particle size) and a few gradation character respectively. Then mean impact value method was used to analyze the influence of each particle size on the permeability coefficient，and the degree of influence was given. At last，the reliability of the above analysis was verified by a set of laboratory test. The following conclusions were obtained：the permeability coefficient of gravel-soil predicted by full grade can be more accurate，while with great uncertainty by one or a few gradation character. There are limitations in the application of current empirical formulas. d10 is the key grain，which is different from coarse particle soli generally with d20 the key particle size. Coefficient permeability of gravel-soil decreases with the increase of dmax，coarse particles play an important role in the control of permeability coefficient. d50 is the boundary particle size，increasing the particle size below or above d50，the permeability coefficient will increase or decrease correspondingly.

Extended foundation of Baihetan high arch dam is considered as an important form of reinforcement to adapt to the unfavorable geological condition of the left bank foundation，the evaluation method research of its reinforcement effect is not yet fully definite. Three-dimensional numerical model was built，coupling with elaborate simulation of the foundation structure，and the reinforcement effect analysis of extended foundations conducted through elasto-plastic finite element method，during which an evaluation method was proposed based on deformation reinforcement theory. The result shows that extended foundation can help to increase the integral rigidity of dam body，improve the symmetry of the left and right arch abutments deformation and the stress state of rock mass near the base surface. The unbalanced force and plastic complementary energy(PCE) were taken to quantize the reinforcement effect. During the overloading process，the unbalanced forces of dam faces，dam toe and dam heel，area of dam surface yield zone were reduced by extended foundation，while the PCEs of different statistical parts consequently decrease as well. Thus，the stabilities of these critical region of arch dam engineering were promoted by it. The research focusing on the extended foundation proves the necessity of this reinforcement measure，and will be useful to understanding its reinforcement mechanism，which is also expected to have a vital significance for design and practice of high arch dam engineering.

Base on indoor model experiments of mouth-closed step cross-section and constant cross-section pipe piles performed in foundation pit，the load transfer characteristics of both kinds of mouth-closed pipe piles were studied by comparing horizontal load-settlement curves，horizontal critical load and bending moment distribution of piles. Results of test show that horizontal load-settlement curves change slowly of both kinds of piles. Horizontal bearing capacities of step cross-section pipe piles are higher than constant cross-section pipe piles and there are close relation to average diameters of both kinds pipe piles. Horizontal critical bearing capacity per unit volume has increased by different degrees with improvement of segmentally cross-section ratio. Moreover，to step cross-section pipe piles，there are two bending moment extreme on pile and bending moment extreme on small diameter pipe has declined with the improvement of segmentally cross-section ratio. Finally，it is very obvious that step cross-section pipe pile is more reasonable than constant cross-section pipe pile in bearing characteristics because the bending moment has been improved greatly on small diameter pipes.

To overcome the disadvantages such as poor corrosion resistance，volume shrinkage at later stage and etc. of traditional slurry，a new type of alkali-activated geopolymer two-shot grouting material is put forward. Through laboratory test，the influence rule of volume fraction of sodium silicate and powder proportion on initial/final setting time，uniaxial compressive strength，erosion resistance and dry shrinkage is analyzed. Through field test，the feasibility and effect of the grouting material are studied. The results show that gel time of alkali-activated geopolymer grouting material can be controlled between a few seconds and a few minutes. Under specified conditions，when the volume fraction of sodium silicate is 20% or mass ratio of slag to metakaolin is 1∶2，the induration can have the highest compressive strength. In acid solution，strength loss of induration of cement slurry is 50%，but strength loss of induration of alkali-activated geopolymer grouting material is only 20%. Alkali-activated geopolymer grouting materials drying shrinkage rate gradually decreases with the increase of the content of metakaolin. However，when the content of metakaolin is more than 30%，the influence of metakaolin on the volume shrinkage rate of the induration significantly weakens. Alkali-activated geopolymer two-shot grouting material makes full use of industrial waste，its proportion can be adjusted according to the engineering requirement，and its various performances can meet the requirements of grouting treatment.

The influences of fiber length(3–18 mm)，fiber content(0.1%–0.3%) and confining pressure(30– 300 kPa) on strength characteristics of polypropylene fiber reinforced aeolian sandy soil(FRASS) were investigated via unconsolidated-undrained triaxial compression tests. Fibers included in FRASS were randomly distributed. Test results show that failure strength and residual strength of FRASS are substantially enhanced with increasing fiber length，fiber content and confining pressure under given test schedule. The increase in fiber length or fiber content results in a significant increment in cohesion，but a negligible increment in internal friction angle. As fiber length increases，a transition from strain softening to strain hardening is observed for FRASS，while the ductility appears to be unchanged. As fiber content increases，FRASS with fiber length of 3 mm maintains strain softening state and its ductility almost has no change，on the contrary，FRASS with fiber length of 9 mm，as well as 18 mm，presents a transition behavior from strain softening to strain hardening and ductility deserves a remarkable increment. As confining pressure increases，the ductility and the degree of strain hardening of FRASS increase. Failure strength-confining pressure relationship of FRASS exhibits bilinear behavior with bilinearity break occurring at critical confining pressure. At confining pressures less than the critical，the reinforcing effect of fiber inclusion is more pronounced in increasing internal friction angle. At confining pressures higher than the critical，the reinforcing effect of fiber inclusion is more pronounced in the enhancement of cohesion.