：Considering the disadvantage of huge calculation，preset cracks and the growth path for the traditional discrete crack model for hydraulic fracturing numerical simulation，this paper proposed a solution to simulate hydraulic fracturing using smeared crack model，and provided reference for realizing the simulation of the fracture network evolution on large scales. According to the theory of solid-fluid coupling，the stress and fluid flow control equations based on the smeared crack model were established. Hydraulic fracturing process of concrete was analyzed by both test method and numerical method based on smeared fracture model. The initiation fracture pressure in the two methods was almost the same. Both in experimental and numerical analysis，the propagation of fracture was mainly influenced by the in-situ stress，and the direction of propagation was perpendicular to the horizontal minimum in-situ stress direction. Finally，a major fracture was formed in the specimen，and ran through the whole specimen.

Strength and rheological properties of quartz-mica schist is obtained by new technology of the situ true triaxial test which can simulate complex stress state of tunnel sidewall. D-P criterion which could reflect three shear stress state is utilized to study strength parameters of quartz-mica schist under complex stress state. Under the specific condition when stress is unloaded in the direction perpendicular to the foliation plane，shear strength parameters obtained from D-P criterion are lower than shear strength parameters obtained from M-C criterion. Due to more practical stress state，true triaxial rheological parameters of D-P criterion under the condition with unloaded side pressure path can reflects the strength characteristics of rock masses of tunnel better than those under the condition with axial loaded path.

The intake slope of Huangjinping hydropower station，which cracked during excavation，was used as an example，to analyze the deformation characteristics of heavily loosened rock slope，based on its geological conditions and monitoring data. Then the crack causes of natural and cut slopes were given. At last，combined with the numerical method the effectiveness of supporting structure and the stability of the slope were evaluated. Results show that，the cracks both in the natural slope and in the cut slope are the result of structural adjustment of the rock mass due to the further loosening by excavation disturbance. However，the natural slope cracks is due to the adjustment of the whole slope mass and reflect the overall deformation and stability of the slope，while the cut slope cracks are due to the extrusion of rock blocks in a weakly supported zone and reflect local deformation and stability，i.e. the cracks are not directly related，and the slope is still in the deformation stage，no persistent slip surface is ever generated. Earlier supporting measures，mainly cable bolts，formed a reinforcing body of around 50 m thick horizontally near the slope surface，and function as a retaining wall. Supplementary cable bolts are deeper and can more effectively control the slope deformation. The slope deformation is converging gradually and its factors of safety meet the requirement of design code under all working conditions.

Clay-rich shale rock reveals greater compressibility than tight sandstone. Experiments have been conducted on Liupanshan—Yabrai shale core samples to select appropriate correlations to represent permeability as a function of effective stress. Mineralogical，mechanical properties and microscopic pore structure were analyzed by rock dynamics mechanics experiments，X-ray diffraction analysis，field emission scanning electron microscope image analysis and high pressure mercury injection to investigate stress sensitivity mechanism of shale reservoir. The results show that the exponentiation curve fit the relationship of effective stress and permeability well；The core with high clay content，low Young?s modulus present relative high stress-sensitivity and larger stress-sensitivity coefficient；shale reservoirs with nanoslot pores and throats exhibit highly stress-sensitive because of the irreversible deformation of easy-compressed throats. An increase in mesopore permeability contribution is correlated with an increase in stress sensitivity.

Impact of dynamic load on rock mass engineering is essentially a process that stress waves propagate in rock mass and interact with each other. Firstly，based on the geometric ray theory of elastic wave transmission，the component of stress wave field in rock slope is analyzed considering the effect of slope surface and top surface，when uniform planar simple harmonic P waves normally impinge from the bottom. The expression of amplified coefficient of particle vibration velocity in slope is derived by wave field superimposition. As a result，the mechanism of velocity amplification effect in homogeneous rock slope is revealed in this way. Then the key influential factors of the distribution of peak velocity are worked out. Research shows that P and SV stress waves pass the same particle have phase difference and would superimpose with each other in time delay as different transmission pathes and velocitis in slope，so the particle velocity amplification coefficient presents “rhythmical oscillation” when the slope height or frequency of incident wave exceeds a critical value according to the regularity of harmonic wave. Additionally，the critical slope height or critical frequency presents power function relationship with the elastic modulus of rock；meanwhile the relation between critical slope height and frequency or between critical frequency and slope height is negative power function.

Triaxial compression for sandstone sample under three paths，i.e. axial loading and radial constant，axial loading and radial unloading，axial constant and radial unloading are realized on WDT–1500 reactive material testing machine. The energy dissipation law in process of deformation under these stress paths and the relationships between energy and rock specimen deformation and confining pressure are analyzed comprehensively. A new method of determining rock failure point is proposed under different paths by studying on the relationship between energy and axial strain. The test results show that there are both energy dissipation and energy release under different stress paths and energy release cause failure. Especially，the energy dissipation is largest under axial loading and radial constant. The energy dissipation of sandstone under these three stress paths are mainly influenced by initial axial pressure and initial radial pressure，but the energy dissipation will obviously bring confining pressure effect in the different deformation stages.

In order to evaluate the fault disturbance effect caused by exploitation，the concept of coulomb failure stress of tectonic earthquake fault has been introduce，the dynamic model of coulomb disturbance stress changes in fault plane caused by mining disturbance is established，and characteristics criterion of disturbance effect caused by exploitation is advanced. The characteristics criterion includes stress criterion，area criterion and gradient criterion expressed by coulomb stress changes. The higher the level and gradient of coulomb disturbance stress and the greater the distribution range，the bigger the potential risk of triggering dynamic disaster. On the basis of this theory combining with numerical simulation technology，the fault disturbance effect during coal exploitation in Baodian mine is analyzed，the results of which is roughly tallying with the actual situation

The problem of rock failure is discontinuous one. The numerical results depend on meshes and computational efficiency is low when finite element method is applied to simulate the failure of rock. Standard smoothed particle hydrodynamics(SPH) method is mesh-free numerical one，which is mainly applied to model the problem of fluid. In this paper，a corrected smoothed particle hydrodynamics，in which constitutive relation of fluid is replaced by constitutive relation of elasto-brittle solid and Weibull statistical approach is used to describe the heterogeneity of the rock-like materials，is developed to simulate the failure of heterogeneous elasto-brittle rock. The corrected smoothed particle hydrodynamics overcomes the shortcomings of finite element method. The numerical results is independence of meshes and computational efficiency is high when the corrected smoothed particle hydrodynamics is applied to simulate growth and coalescence of cracks. The corrected smoothed particle hydrodynamics is helpful to understanding and predicting complex fracture processes of rock-like materials.

For the further study of acoustic emission characteristics of rock breaking under double shear loading condition，this paper will use independent developed coal rock double shear test device and PCT–2 acoustic emission system to explore the sandstone?s acoustic emission characteristics with the increase of water content. The results show that under different rates of water content the changes of the shear stress are same with the time trend. The time reaching the peak decreased when the rate of water content increased. Under the double shear loading，sandstone Hit rate-time curve and accumulative Hit number-time curve can be divided into three stages，the Hit rate peak lags behind the peak value of the shear stress and the extreme points of Hit rate increased when the rate of water content heightened. Under the double shear loading，the internal micro crack initiated and expended when the shear stress is at the 1/2 of the shear strength. At that time the sandstone is in the steady micro rupture development stage and the expending mode of the internal micro crack is mainly around the crystal and the rupture. The extension of internal micro cracks was mainly around the crystals and the last small passed through them.

The simulation of floor rock fracture evolution characteristics in deep mining is the key of research on laws and evolution mechanism of water-inrush. In order to launch the model test on emergence of water-inrush channel in deep mining floor under high water pressure，based on the similarity theory for solid-fluid coupling and the study of solid materials，a new similar material for solid-fluid coupling was developed. This material is suitable for conditions of deep mining. The measuring method for the permeability coefficient of this material was put forward. The influence law that diverse ratios affected mechanical properties of materials was concluded. The material was applied to the simulation test of water-inrush in floor，which revealed failure characteristics of similar materials and evolution characteristics of water-inrush channel in floor. Fracture developed rapidly and with higher degree affected by mining in open-off cut. This explained the greater probability of water inrush，this place is prone to result in water inrush risk. The method has some practical meaning for coal mining engineering.

Under he background of Shenhua Ordos CCS demonstration project，the Liujiagou formation and its upper caprocks as the combined caprocks was taken to research its sealing effects. The results show that the sealing efficiency of combined caprock is very significant. The existence of thin reservoirs in combined caprocks results in a lower pressure building and a higher CO2 injection rate. Therefore，combined caprock can not only effectively sequestrate the carbon dioxide but also can make full use the storage capacity of the thins reservoirs in between the multiple caprocks. The concept of combined caprock is of great significance to better the storage capacity evaluations and improve the standards of site selection.

以大理岩作为试验材料，进行了45°双预制裂纹试件的单、双轴加载和侧向卸载试验研究。利用高速摄影设备记录试件中裂纹的起裂、扩展、贯通和完全破坏过程，结合理论分析得到：(1) 3种载荷形式下试件的破坏过程可概括为4个相似的阶段；双轴加载试件的裂纹扩展形态和岩桥贯通方式与单轴加载和卸载有较大不同；卸载试件的裂纹种类和数目远比单轴加载时更多更复杂。(2) 由裂纹类型判断在单、双轴加载时，剪应力对破坏起主导作用；卸载时，尤其破坏前阶段拉应力起主导作用。(3) 定义新参数M-C有效剪应力?M-C，根据其在裂纹尖端附近的分布规律判定新裂纹起裂的危险方位和区域，对比试验过程，得到与预制裂纹夹角约为－135°和45°左右的区域为新裂纹(带)产生的危险区。(4) 加载时岩桥贯通是由剪应力引起，卸载时是由拉剪复合作用引起。

In view of the case that the slope rock mass after earthquake was frequently destroyed under the condition of rain or immersion for reservoir，typical sandstone was chosen as the research object to test under the condition of cycling loading and unloading first and circulating soaking-drying. Besides，the degradation mechanism of the sandstone was studied at length. The experiment results show that：(1) The plastic deformation and internal damage of rock were not only caused by slippage of mineral grains surface but deformation and failure of local contact in cycling loading and unloading；(2) The degradation of compressive strength and shearing strength was obvious in process of circulating soaking-drying which showed obvious time effect and heterogeneity；(3) Compared with the complete sample，the degradation speed of damage rock sample is faster，which means coupling damage effect of damage rock is obvious and can better explain why some slope after earthquake were instability under several times of cycling soaking-drying and raining.

Large-scale shaking table experiment was carried out to study the dynamic response of the front slope of tunnel entrance with weak layer has，and general conclusions were obtained through analyzing the acceleration and failure modes of front slope of tunnel entrance and tunnel lining under the horizontal and vertical excitation. The results showed that the front slope had an obvious acceleration magnified effect under the horizontal excitation and the weak layer produced a significant impact on the dynamic response of the front slope under vertical excitation；The peak acceleration of the tunnel lining at the entrance was larger than that far from the slope surface，at the entrance the maximum peak acceleration occured in the vault while that minimum occured in the invert，the forced state of the lining was complicated；With vertical acceleration excitation，the overlying soil model of the weak intercalation loosed，the soil at the toe of slope squeezed and fall-block，however the slope remained stable overall；Under the action of horizontal excitation，the soil at the toe of the front slope crushed first，and then the slope surface location along weak intercalation cracked，the overlying soil layer along weak intercalation slided，at last large-scale dilapidation and fall occured；Under the vertical and horizontal vibration force，the maximum strain amplitude occured in the 45°of the lining，the fortified length of tunnel portal section is 25 m. These conclusions can be reference for design，construction and study on the tunnel seismic study.

Rockburst is one kind of dynamic geological disasters，which seriously threatens the safety of design and construction in deep underground engineering. However，the traditional methods for predicting rockburst can only give a qualitative assessment of rockburst proneness based on the results of static quantitative calculation. It can not reasonably reflect the occurrence process of rockburst. In order to have more accurate projections for rockburst，based on the test and theoretical analysis，an intensive study on the mechanism of rockburst is carried out thereby. In essence，the study indicates that the mechanism of rockburst should be studied based on the dynamic propagation of the crack in rock mass. Then，a definition of rockburst is given from the perspective of the dynamic propagation of the crack. Finally，based on the above，a new energy criterion of rockburst—unit time relative local energy release index(URLERI) is put forward. And it is used for numerical simulation of the rockburst case for Jinping II hydropower station. The results show that there's a general agreement between simulating results and practical. And it shows that the energy criterion of rockburst is quite reasonable. The research results offered by this paper，no matter in evaluating，forecasting and preventing of the rockburst disaster in deep underground engineering，have its own significance in theory and in application.

Based on time-temperature superposition principle：a new creep equipment was designed to study the grogrids HDPE50 creep characteristic under confined load(100 kPa) and no confined load. Based on time-temperature superposition principle：the master curves were obtained from creep curves at different temperature to determine the creep reduction factor accurately. The value of C1，C2 calculated inversely by the tests data verify the rationality of the tests. The research indicate that：the effect of confined load on geogrids creep is obvious：the long time(106 h) creep value under confined load is 37% smaller than that under no confined load. The creep reduction factor calculated by time-temperature superposition creep test considered with confined load and conventional time-temperature superposition creep test RFCR1：RFCR2 is 2.4，1.8 respectively. The creep reduction factor RFCR3 calculated by the existing specifications is 1.7. Compared to the RFCR2，RFCR1 and RFCR3 will make the cost increased by 17%，25% respectively when applied to the same project design. The calculation of creep reduction factor in time-temperature superposition creep test considered with confined load is suggested to use the tensile strength under confined load：the design of project is suggested to use RFCR2.

To understand hydraulic fracture initiation mechanism of perforated horizontal well in shale play，the fracture initiation models of a 3D single-stage three clusters perforation and a single cluster perforation (containing natural fracture) were established by using Abaqus finite element calculation software. The effects of crustal stress，wellbore orientation，perforation parameters and natural fracture on fracture initiation pressure and location was studied. The results show that the initiation pressure of open hole perforation is far below that of the casing perforation. The fracture initiation pressure increases with the increasing of the minimum horizontal stress，but the influence degree is controlled by the ratio of vertical stress to the minimum stress. The effects of the maximum horizontal stress and vertical stress on the initiation pressure is very weak. The initiation pressure decreases roughly with the wellbore azimuth increases，when the natural fracture is presented，the initiation pressure does not show any linear law. The shear slip for natural fracture easily appears in the shear stress zone. Initiation pressure firstly decreases and then increases with the perforation azimuth increases. The change of perforation azimuth can seriously affect the fracture initiation morphology. The fracture initiation location is closely related to the minimum and maximum horizontal stress，wellbore azimuth and the cementing strength and azimuth of natural fractures. The internal perforations bear the additional stress along the wellbore direction generated by both sides of the perforations，the closure stress is increased，thus these perforations initiate more difficult，resulting in that fracture initiation sequence is from the endmost perforations to the middle perforations. When the stress difference is higher(＞7 MPa)，the additional stress interference becomes significant. To achieve a multi-fractures initiation from multi-perforations，the injection pressure needs to be improved. The change of initiation location in perforation tunnel is a competitive result between the strength of stress concentration on perforation root and the interference degree of additional stress on the distal end of perforation. Due to the great perforation cluster spacing，the effect of stress interference between perforation clusters on fracture initiation is very weak，the pressure distributions of every perforation cluster are almost identical.

Based on the prototype of Zhoushan Shenjiamen Port immersed tube tunnel，a 1∶10 scale shrinkage model test is established in longitudinal of 30 m. The test simulates the uniform distribution construction load through the water load and focuses on the formation process of sand base layer in marine environment to study the compression process and compression modulus Es of four kinds of base layer which is composed by gravel，sand，sand and gravel mixed，sand and gravel mixed with lots of silting，and the difference is compared and analyzed. The results show that，base layer construction settlement is integrally in the linear elastic stage，and the compression modulus Es of four kinds of base layer are respectively 0.67，0.80，3.26，1.85 MPa in average which have a lot to do with the base layer density. Interaction of sand and gravel during the base layer construction will greatly increase the compression modulus，which is about 4.4 times of the mixed condition without interaction in theory. The back-silting can weaken this influence and will greatly decrease the compression modulus.

Comprehensive numerical simulation of rock blasting is always a difficulty and a focus topic of blasting engineering. Based on the secondary development of LS-DYNA，smoothed particle hydrodynamics(SPH) method is implemented into the blasting damage method. Then，a method of SPH used in the near zone and FEM used in the far zone was realized. Dynamic effect of deep hole bench blasting was simulated with this method based on the Specific engineering example. Rock mass cracking and throwing reveals that SPH-FEM method could simulate the large deformation in the near zone. At the same time the comparison between blasting vibration monitoring and results demonstrate that SPH-FEM method could forecast the blasting vibration and dynamic response in far zone. Deformation and damage characteristics of different resistance line of deep hole bench blasting were compared. Research results can provide certain reference for numerical simulation of blasting and blasting crushing mechanism research.

In order to eliminate the disturbances of coal permeability and diffusion coefficient on the correctness of coupled gas flow and coal deformation model. Firstly，the geostress condition of the first mined key seam is analyzed. Secondly，a modified P-M permeability model is proposed to match the pore structure characteristics of coal seam；Finally the governing equations for the coupled gas flow and solid deformation in dry coal seams are proposed，and the Klinkenberg effect has been taken into account，at the same time the relationships of the multiphysics fields have been discussed in detail. The coupled model has been used in simulating gas migration and permeability evolution in the first mined coal seam around drainage boreholes. Numerical results indicate that the Klinkenberg effect can have a critical influence on gas pressure during the entire methane degasification period，and the influence increases with time. The evolution of permeability is controlled by two opposite effects，compressive volumetric strain and matrix shrinkage，and the resulting permeability change is controlled by the mechanism that dominates.

A method of determining the cohesion and internal friction angle of a dual-pore-fracture rock mass was improved by considering fracture connection ratio，and this method was introduced into the elasto-plastic thermo-hydro-mechanical(THM) coupling finite element method(FEM) code. Aiming at a model of hypothetical nuclear waste repository in a saturated dual-pore-fracture rock mass with a laboratory scale，the THM coupling FEM analyses were carried out for two assumed cases with orthogonal fracture sets and oblique-cross fracture sets，respectively. The results show that：compared with the axisymmetric distributions of various field quantities in the case with orthogonal fracture sets，the distributions of pore pressures and flow velocities of underground water are axisymmetric，but the distributions of stresses，fracture pressures and relative flow velocities，plastic zones in the rock mass are non-axisymmetric for the case with oblique-cross fracture sets. A large area of plastic zone occurs in the case with orthogonal fracture sets，but almost no plastic zone is produced in the case with oblique-cross fracture sets. The occurrence of fracture sets strongly influences the states of stress，plastic zone and fracture pressure in rock mass.

Fragmentation is widely applied in rock excavation，and fracture strength under blasting loads is one of the key issues in rock dynamic study. In this paper，blasting experiments with detonators and cement mortar specimens were conducted. The dynamic toughness was computed with experimental-numerical method. The loading and cracking time was determined by strain signals. The displacement field of crack tip was determined by finite element code ANSYS with 1/4 nodes element，and the loading acting on the borehole was determined according to the loading-time curve obtained from the experiments. Using displacement extrapolation method the curve of dynamic intensity factor KI(t) versus time was obtained. The dynamic toughness was determined by the dynamic intensity factor value at the crack initiation time，then a new test method of dynamic fracture toughness under blasting was proposed.

Continuously nonlinear formulas of friction angle and cohesion on the basis of Hoek-Brown criterion were proposed，and the impact of Hoek-Brown parameters on strength parameters of Mohr-Coulomb criterion and the rationality of formulas was discussed. The study shows that the material constant s has little influence compared with other Hoek-Brown constants on friction angle and cohesion. The cohesion increases with the increase of minor principal stress，while friction angle does the reverse. Through the conclusion from the contrast between strength parameters，which computed respectively by formulas in this paper and Hoek recommended equation，and the experimental results get from the triaxial tests of several rock and the in-situ shear tests of a practical project，it also indicates that equations proposed in this paper have excellent accuracy and guidance effect on the practical project application.

The upper bound finite element method is one of the commonly used methods for slope stability analysis. Since the Mohr-Coulomb shear yield criterion which is widely used overrates the tension strength，the tensile cracks cannot be get at the rear of the slope when using it for slope stability analysis. In order to solve this problem，the yield surface approximation method of the upper bound finite element method was remolded. From the viewpoint of discrete spatial orientation the plastic flow constraint equation on the discrete directions can be built easily，and by introducing the tension damage to the upper limit method，each azimuth plane was satisfied the tensile failure criteria，and then the linearized upper bound finite element method considering both tension and shear failures can be established. This method can be used to calculate the safety factor of slope and get the critical velocity field with tensile crack. A few of examples prove the effectiveness of this method.

The relationship between rock samples? deformation，strength and failure characters and temperature，confining pressure was analysed by common conventional triaxial tests of coarse sandstone after high temperature rangeing from 400 ℃～1 000 ℃. Obvious yielding plateau nearby peak strength appears when confining pressure was higher than 20 MPa after 400 ℃，but all samples have obvious peak strength points after 600 ℃. With the increase of temperature，samples have much weaker plastic characteristic and stronger brittleness. Temperature within 400 ℃ has little influence on deformation characters of samples. But with the increase of confining pressure，positive correlations with elasticity modulus，deformation modulus and ultimate strain exist when temperature exceeds 400 ℃. However，elasticity modulus，deformation modulus have negative correlations and positive relation of peak strength strain with increase of temperature. Peak strength of samples after high temperature monotonically increase with confining pressure increasing，conformed to Coulomb Rule. Comprehensive coefficient of confining pressure is 6.541. High temperature within 800 ℃ has little influence on cohesion，angle of internal friction. The cohesion decreases sharply and angle of internal friction increases slightly when temperature exceeds 1 000 ℃. High temperature within 800 ℃ has a reinforcing effect on strength of coarse sandstone and there is a positive correlation between strength and temperature when confining pressure was deducted. But when the high temperature exceeds 800 ℃，temperature has weaker influence on strength of samples，which is negative. Rupture angles in tests and theory are consistent basically，High temperature has little influence on rupture angle. Negative relation exists between confining pressure and rupture angle，which is much more remarkable than temperature.

In order to analysis the mechanical characteristic differences of coal gangue abandoned in different periods，based on the on-site gradation，the direct shear tests of consolidation coal gangue and fresh coal gangue with different moisture content are carried out. The test results indicate that different from the fresh gangue，the consolidation gangue has shown obvious bonding characteristic with the increase of moisture content. The stress-strain relationship also is gradually change into the strain hardening of high moisture content from the strain softening of low moisture content. The influence of dry density and moisture content of gangue specimen to the shear strength parameters is different to the consolidation coal gangue and to fresh coal gangue. The dry density has more significant effect to the consolidation gangue?s cohesive strength and the fresh gangue?s internal frictional angle. Compare with fresh coal gangue，the consolidation coal gangue is more sensitive to the moisture content of specimen. When the moisture content is close to saturation state，the internal friction angle of consolidation coal gangue is nearly zero and the shear strength is mainly provided by the internal cohesive force at this time. Meanwhile the reducing range of fresh coal gangue is less than 15%. The difference of shear strength characteristics is related to the fine particle composition in coal gangue. The test results in this paper can offer a basis for the stabilization calculation of coal gangue hill.

The columnar jointed rock mass is a common kind of structure rock mass in extrusive igneous rocks，and correct understanding the deformation and strength characteristics of columnar jointed rock mass under triaxial stress condition was one of the key problems that should be solved for the demonstration and design of large scale rock mass projects such as hydropower station and underground cavern excavations. Therefore，in this paper，plaster mixture was used to prepare simulated columnar jointed rock mass specimens with different dip angles ? between the direction of maximum principal stress   and column prisms. Conventional triaxial compression tests with different confining pressures are carried out on these specimens and the variations of Young?s modulus and peak compression strength with dip angle ? are obtained. From the experimental results，it is found that for seven groups of specimens under the same confining pressure，the curves of Young?s modulus and peak strength vs. dip angle ? resemble as decreasing order-shaped，that is，the Young's modulus and peak strength decrease with dip angle ? from 0°to 45°and the minimum values of Young's modulus and peak strength occur at ? = 45°，then the Young?s modulus and peak strength remain relatively constant with the increase of dip angle. Furthermore，based on the experimental results，an empirical expression is proposed to predict the Young's modulus and peak strength of columnar jointed rock mass specimens. It is found that the empirical expression can well predict the changes of Young?s modulus and peak strength with dip angle ? by comparing the theoretical curve with experimental data. Additionally，four types of typical failure modes of columnar jointed rock mass under triaxial compression condition are summarized based on test results and the failure mechanisms are also discussed.

To investigate the acoustic emission(AE) characteristics and laws of rock discontinuity under compression-shear stress，irregular serrated discontinuities with different asperity height were made of cement mortar and change laws of AE parameters and their mechanism of the discontinuities at different asperity height，shearing velocity and different normal stress are studied. Experimental results indicate that the ideal cumulative hits of discontinuity during shearing can be divided into three stages——quiet period，slow rise period and sharp growth period. It can be found that the peak energy rate increases while cumulative hits decrease with the increase of discontinuity asperity height when macroscopic shear failure occurs. With increase of shearing velocity，curves of energy rate and hit rate become higher volatility and peak energy rate，peak hit rate and cumulative energy tend to decrease. Change laws of AE parameters is not very obvious with the change of normal stress，but peak energy rate and cumulative energy tend to decrease while peak hit rate and cumulative hits increase with the increase of normal stress. Research results can provide guidance for applications of acoustic emission techniques into monitoring and prediction of the static or dynamic shear failure of in-situ rock discontinuities.

A new developed Mogi-type true triaxial test apparatus was introduced. True triaxial tests for marble with mutually overlapping platens were presented. True triaxial tests and three dimensional FE modelling study were carried out on the loading boundary effect. The results indicate that the peak value of strength increases with the ?2(intermediate principal stress). When the strength reaches its maximum value，it tends to decrease. The brittleness increases with increasing ?2. The intermediate principal stress retards the dilatancy onset. The influence of corner effect on the stress and strain distributions of rock specimen subjected to the traditional platens is apparent in true triaxial test due to stress concentration in the corner. And the strength of rock specimen subjected to the mutually overlapping platens is a bit larger than that subjected to traditional platens.

To accurately know the refreezing time and capacity of the bridge bored pile constructed in polygonal permafrost regions，two test sites were chosen. Within each site，two 15 m test piles were built. The temperature monitoring system was established in one of the two sites to record and monitor the pile refreezing process. Based on the refreezing condition，static load and dynamic load tests were performed to determine the bearing capacity of the pile. Test results indicate that the mean permafrost temperature is －1.9 ℃. The trend of temperature change within the pile in refreezing process is similar to that of the permafrost temperature change 1 m beside the pile，which indicates that the difference of temperature change is smaller than 0.1 ℃. The calculated pile capacity fits well with the testing data by introducing the refreezing pile lateral frictional parameter to modify the soil mechanical model. The capacity error obtains from static load test and dynamic load test is 3.91%，which matches the test results. This reacher provides an evidence to design and test the pile foundations in permafrost areas.

The confidence level of seepage calculations in rock mass is directly influenced by the reliability of corresponding discontinuities network models. A detailed investigation on rock mass discontinuities was launched into the well outcropped granite body in Chinese high-level radioactive waste repository candidate site in Beishan of Gansu province using new digital techniques，such as GPS(global positioning system) and GIS(geographical information system). And the three-dimensional random discontinuities network model was established after the digital statistics processing of over 10 000 discontinuities acquired in the investigation. At last，the accuracy of the model was graphically and numerically validated. The results show that compared with the traditional method，the digital measurement processing means can overcome the insufficiency of statistical sample size and precision， and can complete the detailed investigation of regional rock mass discontinuities very well. And the random model with ideal test effect is more suitable for numerically simulated calculations of mechanical properties and seepage.

The extreme-point symmetric mode decomposition method was used to denoise the acoustic emission data of marble during unloading confining pressure failure process. The characteristics of acoustic emission were analyzed. Acoustic ringing counts rate level is small and grows slowly at the initial stage and increases rapidly after the expansion point. The acoustic emission frequency trends to fluctuate. It increases suddenly before peak strength and decreases significantly near the peak strength. The fractal dimension of acoustic emission was calculated by the method of correlation dimension algorithm. The fractal dimension of acoustic emission presents a phase change during marble during unloading confining pressure failure process. It increases at the initial stage and then decreases. The fractal dimension increases sharply when the axial stress reaches to 80% of the peak strength. It decreases significantly before the peak strength. There is relation between the frequency spectrum and the fractal dimension. The sudden rise of the acoustic emission frequency and the fractal dimension are failure precursor.

The significance of study on constitutive model of rock under one-dimensional high stress and repeated impact loading was expounded. By the research methods of combination model，rock may be regarded as an elastic element and a cohesive element in series，then with a damage mass Da1 parallel，then with a damage mass Da2 in series，forming a rock combination mechanical model. Then，the constitutive model equation of rock under one-dimensional high stress and repeat impact loading was elucidated. The rock mechanical test of skarn and serpentine under one-dimensional high stress and repeated impact loading was designed. The test results show that before the peak stress，the trends of dynamic stress-strain curve is consistent，without pressure dense phase，only the elastic stage and nonlinear deformation stage. There are two phenomena after the peak stress，one is rebound phenomenon，and the other is not rebound. By comparison between the test results and the theoretical results，it is shown that there is a good coherence between theoretical stress-strain curves and experimental stress-strain curves.

In recent years，issues of rock mechanics under high temperature have been highlighted with the rapid development of nuclear waste treatment and underground coal gasification projects，which has become a focus in the rock mechanics field currently. In order to investigate the influence of temperature and sample size on the tensile strength，Brazilian splitting tensile strength tests were conducted on sandstone disc samples with five kinds of temperature levels ranging from 20 ℃ to 800 ℃ and five kinds of thickness-diameter ratios ranging from 0.5 to 1.0. Experimental results show that loading-displacement curves of sandstone discs appear remarkable brittle characteristics. And the temperature plays a leading role in the development trend of the curves，while the effect of sample size is relatively weak. With the increase of temperature，tensile strength first increases gradually and then decreases sharply，and reaches the maximum at 400 ℃. The tensile strength of sandstones under same temperature presents a linear attenuation relationship with the thickness-diameter ratio，and the corresponding experiential formula is put forward as ?t =－Aλ + B. Here，the parameter A describes the prominent level of materials affected by the size，which decreases first and then increases with the increase of temperature，and the size effect is mostly unconspicuous at 400 ℃. The parameter B is the tensile strength value of materials when the sample size is infinitesimal to the ideal plane，which first increases slowly and then decreases gradually，with the maximum value also reaches at 400 ℃.

In order to investigate the influence of moisture content on rock dynamic mechanical properties，a series uniaxial dynamic compression tests of sandstones with 4 kinds of moisture contents were carried out by split Hopkinson pressure bar(SHPB) apparatus，and corresponding dynamic stress-strain curves were obtained. Sandstone samples from 2 different coalmines were processed into a cylindrical shape with length to diameter ratio of 0.5. The test results show that，under high strain rate loading，the surface tension effect and Stefan effect of free water in cracks generate resistance force for dynamic crack propagation. Furthermore，the higher the moisture content，the larger the resistance force and the higher the dynamic uniaxial compressive strength of sandstone. By fitting analysis，it is found that the dynamic uniaxial compressive strength of sandstone increases in a power function with the moisture content. Because of the voids and micro-cracks in sandstone specimen filling with free water，the longitudinal wave velocity of sandstone also increases in a power function with the moisture content.

The shear creep curve of hard structural surface was analyzed by using generalized Kelvin model，Burgers model and six-component rheological model，respectively. The interface element in FLAC3D was improved. The shear rheological model and numerical analysis method of shear creep test of hard structural surface were put forward. The research result shows that the six-component viscoelastic shear rheological model is appropriate for analyzing the shear creep property of hard structural surface. The shear creep deformation increases with increasing slope ratio if the slope ratio is smaller than 45°，while the result will be quite on the contrary if the slope ratio is higher than 45°. In addition，the shear creep deformation will increase with increasing shear stress under fixed normal stress，and the shear creep deformation will decrease with increasing normal stress under fixed shear stress.

Joint and fracture，as the common geological defects in high-steep rock slope，can cause damage to the long-term deformation and stability of slope. In order to study the unloading rheological mechanical property of jointed and fractured rock mass，triaxial rheological tests were performed for consecutive fractured rock mass under different unloading conditions. The axial and lateral rheological characteristics of consecutive fractured rock mass present considerable anisotropy. With rheological time prolong and unloading confining pressure values increasing，the lateral rheological deformation is larger than axial rheological deformation. The rheological deformation is more fully extended and rock mass is more thoroughly disturbed under step unloading condition contrast to once unloading，while once unloading rheology more easily leads to rock mass damage through failure modes of samples. Based on test results，unloading rheological parameters of Burgers model was analyzed and the linear relations of the parameters were founded under different unloading conditions. And then，the rock mass rheological model，which can consider the effects of the different unloading paths，was established. These conclusions are very useful for theoretical research and engineering design of high-steep rock slope long-term stability.

In order to discuss the permeability and acoustic emission characteristics of fine sandstone during the deformation and failure process，a series of tests for characteristics of permeability and acoustic emission were  performed under triaxial conditions by using MTS 815 rock mechanical test system and PAC PIC–2 acoustic emission test station. The variation of permeability，the relationship between permeability and strain and the acoustic emission characteristics were studied. The results show that the permeability during the process of deformation and failure changes in accord with the stress-strain curves，and the rules under different confining pressures are similar. The permeability decreases with confining pressure increasing. The changes of permeability and lateral strain ?3 with axial strain ?1 have a good corresponding relationship. The point where ?3 increases sharply is corresponding to where permeability increases，so ?3 reflects the variation of permeability better. The acoustic emission characteristics in the whole process reflect the development of the cracks，and the acoustic emission correlates well with the stress-strain and permeability. The energy rate，one of the parameters of acoustic emission，increases with confining pressure increasing. The characteristics of acoustic emission can reveal the emergence and development of fractures in rocks，which can develop a deeper understanding of the variation of permeability during the deformation and failure process.

Cyclic loading and unloading tests with constant amplitude were designed to analyze the change rules and the correlativity between load/unload response ratio and damage variable，and the change rules of stress-strain hysteresis time，load/unload response ratio，damage variable，the corresponding peak strain of peak stress were analyzed in detail. The results show that：(1) the stress-strain hysteresis time is not a constant during the test，which is obvious larger at the initial stage of the cycle loading and unloading and the stage of approaching destruction. (2) When the rock samples are approaching destruction，the stress-strain hysteresis time，load/unload response ratio，damage variable and the corresponding peak strain of peak stress all have obvious catastrophe，which shows good correlation among the mechanical parameters，and they are closely related to stress state and damage degree of the rock. (3) Considering the effect of rock damage on degree of medium uniformity of rock in cyclic loading and unloading test，correlative equation between load/unload response ratio and damage variable is modified，the result shows that with which can make damage degree of rock clearly described by load/unload response ratio. Research results have good reference value for analyzing the relationship between load/unload response ratio and damage variable，meanwhile，the relevant test methods can provide reference for similar tests.

In order to study the static and dynamic strength and crack evolution law of concrete quantitatively by using CT numbers，the portable loading device suitable for CT scanner is used to carry out the static and dynamic uniaxial tensile tests of the cylindrical concrete specimen. Then，the fractal dimension of CT scan section is calculated by using differential box program. And on this basis，the differences of the uniaxial tensile strength feature，failure mechanism and fractal characteristics of crack of the concrete samples under static and dynamic loading were analyzed comparatively from the microscopic level. The results show that the damaged crack of concrete under static uniaxial tensile load grows slowly，the crack surface is rough and twists，and the crack around aggregate follows the weakest interface. The damaged crack of concrete under dynamic uniaxial tensile load grows quickly，the crack surface is flat，and the crack cutting aggregate follows the path which energy released fastest. The static and dynamic CT scan sections have obvious fractal characteristics. The fractal dimension develops with the crack propagation regularly. The CT scan section can well reflect the crack evolution law of the concrete material and can be used as a quantitative parameter of the crack evolution.

In order to study the recovery features of salt rock under shear damage，the incomplete shear tests of the domestic salt rock were performed. The stress-strain regularity and recovery ability under different loading ways were analyzed. The following conclusions are drawn. From the directional shear test results，it is observed that the shear strength of salt rock will not drop significantly at the initial stage，however the shear strength would drop significantly and quickly at the presence of repeated shear force from the opposite direction，which shows that the material is very sensitive to damage direction. By the comparative study of the shear tests on recovered and raw specimens，it is found that the effect of temperature on the recovery of rock salt material is very obvious. In the directional and unidirectional shear tests，stress strain curve of the damaged specimens tends to be similar to that of the original ones，which seems to indicate the relative capability of recovery for the shear damage.

The continuous pulse shock and vibration can change the occurrence of gas in coal and improve the permeability of the coal seam and enhance the efficiency of gas drainage. Deformed coal containing gas was simulated in the laboratory. With the influence of continuous pulse shock and vibration，the release of gas speed can be improved above 30%. A device which is suit for the underground coal mine and can make the instantaneous vibration energy reach to 60 kJ was designed. The field test was performed through 6 ‘downward’ radial boreholes. The results show that the speed of gas drainage increases about 56% and the effective fall time is about 54 min.

In order to study the loosening effect induced by rock mass excavation under high in-situ stress，a laboratory experimental simulation system was designed. By the rapid failure of a rock bar，the system is capable of simulating rapid unloading for jointed rock mass，thus is able to simulate the loosening effect of jointed rock mass under excavation load transient unloading(ELTU)，by which，the relationship of in-situ stress level and structural plane opening displacement can be studied. Regression analysis results show that，the opening displacement value is in positive relationship with the square value of in-situ stress. The proportion of displacement on each joint in the total displacement induced by excavation load transient unloading is dependent on the amount and location of joints.

Under a long-term geomechanical loading，creep deformation would occur in fractured rocks，accompanying with acoustic emission(AE). The laws of AE are meaningful to monitor and warning of the rock in stability. In order to look into the AE features of fractured rocks during creep shear，the direct creep shear experiment of fractured rocks induced by compressive shear and Brazilian tension was carried out under constant normal force. AE technology was used to detect the acoustic events during the creep shear. The relationship between AE energy and creep shear displacement at different loading stages is revealed. Meanwhile，the locations of the interlocks and the micro-contact fractures are also identified the laser scanned contour maps of the fractured rock surfaces by the AE events. The experiment shows that there is a signal blank phenomenon of AE events before the instability occurs. Regarding to the fractured rocks induced by Brazilian tension，the peak of AE energy mainly appears at the middle and late stages of the creep shear process，and AE energy reaches local maximum at the early stage of each loading followed with its downward trend；for the fractured rocks induced by compressive shear，AE energy valley appears at the middle stage of the creep shear process，and at each shear loading a small peak of AE energy appears at the middle stage. In addition，AE position detection shows that the micro-contact fractures mainly occur first at the central part of the interlocked surfaces. The initial micro-contact fractures present a directional character that a zonal distribution develops perpendicular to the shear direction at early loading stages.

The uniaxial compression acoustic emission tests of dry and saturated coal gangue were performed. The acoustic emission precursor laws of deformation and failure of coal gangue were researched based on the dominant-frequency and entropy changing of acoustic emission signal. The results show that drying and saturated coal gangue have two dominant-frequency bands of about 20 kHz and 30–60 kHz. The acoustic emission signal dominant-frequency of coal gangue has a mutation before the rupture of rock，and it is close to 0 and 100 kHz. The entropy of dry coal gangue concentrates in 0.5 to 2.0 without a mutation；and the entropy of saturated coal gangue concentrates in 0.0 to 0.5 and has a mutation. Acoustic emission signal entropy can evaluate the stability of coal gangue. when the entropy is greater than 1.0，it indicates the increasing of risk of the instability of coal gangue. The dominant-frequency focusing on about 0 and 100 kHz can be seen as a precursory characteristic of coal gangue rupture. Due to the saturated characteristic of the actual mining rock，as well as the complexity of its deformation and destruction，the dominant-frequency and entropy can be combined used to obtain an early warning information of coal dynamic disaster based on acoustic field parameter variation. The experimental results provide a new method and basis for research on rock damage evolution mechanism and rupture forecast，which has an important theoretical study significance for acoustic emission monitoring and early warning for the actual mining dynamic disaster of coal.

Aiming to explore the quantitative approaches on the infrared radiation temperature field evolution of rock in loading process，the factual theory，entropy theory and statistical method were employed. Three indices including characteristic roughness，entropy and variance were introduced to describe the evolution of infrared radiation temperature field in the loading process of rock. The properties and potential description of three indicators were comparatively analyzed and discussed in terms of the thermal imaging observation experiment of several hole-rock samples in loading process. The results show that：(1) Three indices can quantitatively describe the evolution and differentiation characteristics of infrared radiation temperature field in loading process of rock effectively. The indices respond variously with stress changes of rock and display anomalous IR precursor before rock failure. Additionally，the effect of quantitative expression is better than previous index AIRT. (2) There are different features for three indices. The entropy is better to describe the stage characteristics of infrared radiation in loading process of rock，and the boundary of infrared radiation changing at different stages with the increase of stress is more obvious. Meanwhile，the characteristic roughness and variance increase greatly before the rock failure and have more advantages to identify the infrared precursor of rock failure. This study would provide new way for quantitative analyzing the infrared radiation in rock loading process.

The macroscopic fracture modes and the micro-meso morphology are the important characteristics to represent rock failure mechanism. The shear failure mode is the main macro fracture mode of the granite under low and intermediate strain rates. The mesoscopic morphology was studied using scanning electron microscope(SEM) and 3D laser scanner，and the roughness of the fractured surface was quantitatively studied based on fractal theory. The research results show that with increasing strain rates，the main fracture modes change from intergranular fracture，intergranular fracture and cleavage fracture，transgranular with curved path to transgranular with straight path. Based on the research results of micro-meso fracture modes，it has been concluded that the difference of strain rates leads to the difference of energy absorption and the differences of the fracture morphology of rock，which finally leads to the rate sensitivity of rock strength.

The structure and function of self-developed coal rock shear-flow coupling test device in great detail were presented. This device system consists of five parts：the servo control system，the source of fluid loading system，shear box and its sealing system，control and data acquisition system and the 3D scanning system for coal rock section. Among them，the self-developed shear sealing system can realize a good seal under high-performance and comprehensive experimental condition. The servo loading system can offer constant normal(shear) load，constant normal(shear) displacement loading mode，different loading rates and different displacement rates mode. And through control and data acquisition system，it can realize real-time monitoring of the whole process as well. For the source of fluid loading system，it can provide hydraulic pressure or air pressure up to 5 MPa and maintain stability. Using displacement sensor and deformation sensor to monitor the shear deformation of specimen and normal deformation can ensure the completeness of shear-flow coupling test under high precision. The 3D scanning system for coal rock section is used to collect the information of coal rock section，to further study the characteristics of failure section and coupling mechanisms of seepage. The test results of intact sandstone by this device show that the self-developed shear-flow coupling device can meet the expected functional requirement. It can ensure a stable test process and high accuracy of test data. It can be both used to study the hydraulic performance of joint rock mass and explore the landslide mechanism of rock slope，and perform the experimental study for the internal failure process of coal rock under the influences of original rock stress and mining dynamic pressure and the coupling mechanism of the permeability of coal gas.

Referencing the expression of the Ottsosen strength criterion for concrete，a simple three-dimensional Hoek-Brown(HB) criterion is proposed to overcome the shortcomings of the HB criterion，where the influence of the intermediate principal stress on rock failure is not taken into account. The mathematical deduction of three different expressions of the proposed strength criterion is made. Besides，the convex and smoothness of the failure envelope surface is proved. A non-linear multiple regression technique is adopted to obtain the best fitting material parameters，and Poly-axial test data for eight different rocks was used to verify the proposed criterion. In addition，a comparison of determination of coefficient for three different expressions of the proposed strength criterion is made. Further，a comparison of the new criterion with three existing ones is also made. The new 3D HB criterion is easier，robust and convenient to set up elasto-plastic constitutive models in future.

Theoretical analysis，numerical simulation and statistical analysis are applied to study the relationship between coal-gas outburst and astro-tidal-triggering based on the Mohr-Coulomb criterion and Newton's second law from the astro-tidal-triggering influence on geological disasters. Results show that there is a certain correlation between coal-gas outburst and astro-tidal-triggering and the tidal force plays a certain role in promoting the coal-gas outburst. Coal-gas outburst and astro-tidal-triggering both exhibit a periodicity in time and regional difference in space. Coal-gas outburst occurs at high frequencies under the strongest tidal force，while it occurs at low frequencies under the role of the weakest tidal force. Numerical simulation results verified the correctness of the tidal force?s role in promoting the coal-gas outburst. A new research direction is provided to further understand the mechanism of coal and gas outburst.

In general，the problem of rock mechanics is the mechanical behavior of fractured rock-mass in the engineering scale，especially the strength distribution，deformation character and failure evolution of fractured rock-mass under loading. In this paper，the study of failure evolution process and differences between intact coal and fractured coal rock-mass with single fracture and multiple fractures，according to the distribution of max-amplitude of acoustic emission under uniaxial loading，is based on specimens of fractured coal rock-mass obtained by pre-loading on intact coal. The study results are as follows：the value of   can describe the distribution regularity of max-amplitude of AE during the failure evolution process under loading，and the value increases with increasing block to the expansion of fractures in specimen；the value of   decreases with increasing loading under different stress level and increase with increasing fracture under the same stress level；it can be considered as the precursor of specimen?s failure when the decrease of   value becomes flat according to the regularity of   value in intact coal and fractured coal rock-mass during the failure evolution process，and that can provide a test basis for the application of AE technology of monitoring and prediction in situ.

In order to study the effects of joint location and size on comprehensive shear strength of rock mass，cement mortar is selected as model material and specimens were prepared with prefabricated joints of the same size at different locations and with joints of various sizes at the same location，and shear tests were conducted under various normal stress of 3 different joints undulating angles. Experimental results indicate that shear strength increases with the increase of normal stress when the location and size of the joint are definite，and when the joint is located in the middle of the specimen，the shear strength and cohesion are the lowest，while largest when the joint is located at the back and fall in between them when located in the front of the specimen，but change law of the internal friction angle with different joint location is not obvious. When the joint location is definite，the longer the joint the lower the shear strength and cohesion. Moreover，shear strength of joint decreases linearly with increase of joint length. Effects of joint location and size on comprehensive shear strength of rock mass may be decided by both the strength parameters of joint and rock bridge and damage degradation of rock bridge. Position of joint should be considered when shear strength of in-situ jointed rock mass is estimated.

After earthquake，intensive parameters of fractured rock including initial elastic modulus were changed，and its mechanical properties were affected in this process. Based on the Rock Mechanics Testing System(MTS)，samples were made with different pre-existing fissures in aspect of fracture angel，spacing and connectivity. In order to simulate the influence of earthquake wave，dynamic load was applied with a certain frequency and amplitude before the uniaxial compression tests. Based on macroscopic statistical damage model，in consideration of the coupling action of initial damage caused by dynamic load and damage caused by static load，getting the damage threshold by least energy consumption principle，the modified damage evolution constitutive equation of fractured rock sample was established，which can correctly describe the stress-strain relationship before peak strength. Through the analysis of relationship between damage variable evolution and characteristic of structure plane，it was indicated that fracture characteristic parameters do not affect the macroscopic constitutive relationship. With the increase of fracture angle，the initial and critical damage variables both increase with an outstanding damage accumulation process. With the increase of connectivity，the initial and critical damage variables both increase. With the increase of fracture spacing，fracture coalescence and failure level become higher，and the initial damage variables are essentially unchanged，while the critical damage variables decrease.

Considering the connectivity rate and spacing of fractures，volume fractions of pore matrix and fracture material in a representative element volume，a method of determining the cohesion   and internal friction angle   which vary with direction in a dual porosity medium was suggested，and the equations established for calculating the values of   and   were proved to be reasonable. Introducing the method solving   and   values into the elasto-plastic finite element method(FEM) code，the computations were carried out for a change obviously，the plastic zones accelerate development，and the distributions of displacements，stresses and plastic zones change from symmetric ones to asymmetric ones，as well as the anisotropy of surrounding rock mass displays more significantly；but with the increase of fracture spacing，the dynamic state of surrounding is just the reverse of what in the case of increasing fracture connectivity rate.

Differences existed in dynamic and static elastic parameters. In order to obtain the transformation functions between dynamic and static elastic parameters，experiments were done under reservoir conditions，which had important practical significance for fracturing in reservoirs. Rock mechanical properties of tight sandstones under reservoir conditions(including formation temperature and pressure) in Sulige gas field were obtained using the AutoLab 1500 machine made by the New England Research Company. The results demonstrated that dynamic Young?s modulus was greater than the static Young?s modulus，and there was a liner relationship between them in the same core samples under the same experimental conditions. The dynamic Poisson?s ratio was higher than the static Poisson?s ratio，but there was no obvious relationship between them. The compressional velocity and shear velocity would both increase when confining pressure increases or temperature decreases in one core sample. The dynamic Young?s modulus of one core sample would increase when confining pressure increases or temperature decreases. However，the static Young?s modulus of one core sample would increase when confining pressure increases or temperature increases. The dynamic Poisson?s ratio of one core sample would decrease but the static one would increase when confining pressure increases. The dynamic Poisson?s ratio of one core sample would decrease but the static one would decrease obviously when temperature increases. The mechanism for this phenomenon was analyzed，and the transformation functions between the dynamic and static elastic parameters under different temperature or pressure were obtained. Basic parameters were offered for rock mechanical property researches under reservoir conditions in tight sandstones in Sulige gas field，which provide foundation for the development of oil layer fracturing program.

The construction load causes extra deformation and bending moment on nearby buried municipal pipelines，even damage. Simplified theory for longitudinal response of municipal pipeline under construction load is given，based on the Winkler subgrade model and consideration for the mechanical property of joints of discontinuous pipelines. The effects of extra stress and soil displacement are considered respectively from different mechanism，and soil-pipeline interaction parameters are revised. The rationality of the method is verified by comparisons with model tests and finite element method. Then the parametric study is conducted to investigate the influence of soil elastic modulus and the joint stiffness on the behavior of pipeline due to nearby construction load. The research provides theoretical support for the long-term maintenance of municipal pipelines.

The disturbance factor in the generalized Hoek-Brown(HB) criterion (2002 edition)，which is different from selection of a fixed value employed in the existing analysis for underground excavations in HB rock mass，is taken to be progressively decreased from the excavation surface to the elastic-plastic interface. By employing a non-linear non-associated flow rule，it can give a formulation of the critical internal pressure，the radius of plastic zone， stress and displacement，whose values can be determined by numerical integration techniques. The analysis model in this paper is the description of strain-softening in plastic zone for the progressive disturbance of the heavily jointed rock masses，which is triggered by blast damage and stress relaxation due to excavation. The calculation results of an example indicate that the present analysis model can also obtain analytical solutions of elastic-perfectly plastic and elastic-brittle-plastic models by means of different treatment for D，which provides a reference of theoretical solution for testing the degree of progressive disturbance near the excavation surface in practical project.

The traditional characteristic line method takes the preliminary lining as elastic component. But infact so the deformation of preliminary lining in practical tunnel engineering is much bigger than elastic deformation and the preliminary lining would be in the plastic state. Preliminary lining is considered as elastic-plastic materials to correct the traditional characteristic line method and numerical limit analysis is conducted to work out the safety factor of tunnel surrounding rock. Thus the corrected characteristic curve of surrounding rock and the pressure on the surrounding rock and preliminary lining can be obtained through strict mechanic calculation. The corrected characteristic line method through numerical limit analysis based on FEM strength reduction can solve the problem of design and calculation of tunnel engineering quantitatively，which provides theoretical basis and calculation method for the tunnel design.

In order to access the information of fractural images accurately and comprehensively，the image processing based on partial differential equation is introduced. After discussing the theory of active contour without edges model，a modified C-V model based on the technique of image enhancement is processed in order to overcome the drawback of the C-V model. High quality binary images as well as effective characteristic parameters of coal with meso-cracks are obtained using the modified C-V model and quantitative disposal. It?s the foundation of the continued investigation，for instance the calculation of seepage and the damage of coal. The results showed that，for low contrast ratio and inhomogeneous gray meso-cracks images，the modified conventional C-V model is better than the C-V model in obtaining the image segmentation and the quantitative information which can be used for computing the permeability and damage factor.

To reduce the destruction damage of conventional blasting on reserved rock，a new blasting method，namely，directional pressure relief vibration isolation blasting，is proposed and its technical principles are introduced. The test results of hopkinson bar，ultra-dynamic，dynamic caustics，dynamic photoelasticity，level one light gas gun and other tests results show that：this method would make explosion pressure reduced by 30% to 60% on the isolation material side；blasting vibration peak decreased by 32% to 67%；detonation wave would be blocked 46.95% and sound velocity reduced 13.48% on the isolation material side. The primary shear stress of the free surface side is 3.5 times of that on the isolation material side；stress intensity factors are 1 to 2.12 times of that on isolation material side. Engineering practices show that it brings a large number of energy together in free surface，geting a good blasting effect，meanwhile it can reduce the cost of the open pit slope excavation and overexcavation in drifting.

Development of model similitude material for geophysical fields is the key to the success of geophysical detection model test. According to the similar problem of the seismic wave field，electromagnetic field and the direct current field，a comprehensive model similitude material for multiple geophysical fields is developed by multiple geophysical fields similarity theorem and orthogonal experiment. It is composed of silty clay，gravel and cement. Silty clay and gravel are used as aggregated，and cement is used as the cementing agent. The velocity range of this material is about 236～1 260 m/s and the resistivity range is about 27.2～342.8 Ω•m. The influent factors order of specimens wave velocity is compactness，moisture content，cement/clay and gravel/clay，that of specimen resistivity is moisture content，compactness，gravel/clay，cement/clay according to the results of the orthogonal experiment. And the compactness and moisture content is the two prominent influence factors for velocity and resistivity of the comprehensive similitude material. Finally，a large scale physical model packing test of multiple geophysical fields is conducted，and the similitude material proportioning for the concrete model test is obtained. Strong reflection interface of TRT(tunnel reflection tomography) offset and low resistivity anomaly of inversion image are obtained. The response characteristics in model test are similar to response characteristics in field. The detection result is consistent with actual location in model test，which indicates that the similitude material could meet comprehensive model test for the multiple geophysical fields.

More and more cross tunnels are facing complicated geological conditions and significant disturbance of surrounding rock，and it is quite necessity to research reasonable construction methods for tunnels. Based on the project of Zoumagang highway tunnel passing through upon Guangdong Yuegang water supply tunnel. Firstly，the construction method was numerically simulated for safety and construction sequences have been suggested according to vibrate speed control criterion for DWSS tunnel. Meanwhile，the ground pressure of surrounding rockmass of primary tunnel support and section convergence of existing tunnel were monitored. The field measurements show that at the intersection of two tunnels，the surrounding rock pressures of excavating tunnel achieved stability in 10 days basically. And the maximum ground pressure was 0.2 MPa and appeared at the hance of the tunnel and then decreased to a stable value slowly. The convergence and concrete strain of the water supply tunnel were relatively little. The research results showed that this construction method was safe and reliable. The achievements from the research work will benefit work can provide reference for similar projects.

Over the past six years after“5•12”Wenchuan earthquake，we have carried out engineering geological surveying，acoustic detection，coring-drilling，electron microscope scanning and other works to the Daguangbao landslide，which is the largest landslide induced by Wenchuan earthquake. Studies showed that the sliding zone of this landslide occurred in dolomite intraformational disturbed zone which was located in the third section of Denying group of Sinian system(Zd3). Comprehensive studies reveal the macroscopic characteristics of the fragmentation rock of slide bed as follows：the rock presents sandy soil within the 0–1 m depth below sliding surface，which the sand content occupy more than 60%；1m below the sliding surface，the average rock acoustic velocity is range in 2 500–3 000 m/s，in addition the integrity index of the rock tends to 0.15–0.77. On the whole，the damage degree of the rock mass generally decrease with the depth increase of slip bed，but under the same depth those increase with the elevation increasing，except the local difference broken. On the other hand，microscopic study reveals that the compression-shear crystal of rock mass of slip zone is fold and torsional fracture with lots of transgranular crack，which shows parts crystal loose and intergranular connection loss. Study reveals the significance of engineering geology as follows：(1) Property of the rock mass in sliding zone mainly controlled by argillaceous graniphyric dolomite of intraformational extrusion dislocation，which the composition of this layer is complicate with the high degree of weathering，joint development and poor integrity；(2) Under “5•12”Wenchuan earthquake，the rock mass of slide zone generated strong shear failure (tensile and compressive shear failure) and wing crack extend，which caused sharp drop of the rock shear strength index and the integrity coefficient，thus deterioration of the rock mass. Furthermore，the rolling and rubbing action of thick sliding body afther starting further promote frictional resistance reducing in the sliding zone rock mass. In summary，the fragmentation of rock mass damage of Daguangbao sliding zone is a dynamicly progressive evolution process of rock internal defects under seismic load，the lithology and rock structural characteristics of slide zone are the main intrinsic factors，earthquake loads are its key external incentives.

Rockfall hazard has a greater threat on the construction workers，equipment and structures during the engineering construction process，so that it?s important to understanding the motion characteristics and the impact force of rockfall. Based on the kinematic principles of rigid material，a calculation method is presented to simulate the motion characteristics of rockfall. The reasonable of the presented method is validated by comparison analysis of theoretical values and numerical results，and the motion parameters of rockfall are used to compute its impact force on structures. On the basis of considering the self-rotation of rockfall，a computational method for determination of impact force is presented base on impulse theorem，and the difficult problem for determining of the impact time is solved by use of elastic mechanics. The presented method is adopted to determine the motion characteristic parameters and impact force of the rockfall hazard at the natural slope of Changheba Hydropower Station. Simulated results show that，during the movement process of rockfall，the maximum jumping height is 25 m，the maximum translational velocity and rotational speed are 57 m/s and 350 rad/s，respectively；and influenced by the terrain condition. Combined with the motion parameters of rockfall and theoretical model for impact force，the impact force of rockfall effect on structure at different locations are determined，the calculation results have a great reference value to the location selection of structures and the hazard mitigation and prevention of rockfall.

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Currently，existing geostress measurement methods are not suitable for salt-gypsum formation，while it needs geostress data to do drilling design for ensuring drilling safety in salt-gypsum formation. To alleviate this problem，geostress of rock salt-gypsum for the first time by DRA-Kaiser method is measured. It indicates that combining DRA and Kaiser method could increase the credibility of test data. When the stress-strain difference curve displays inflection point，and stress-acoustic emission intensity curve has significantly increased point，the stress which corresponds to axial compression is the stress that rock suffered. It avoids displaying several Kaiser points in previous Kaiser effect experiments.

As underground resources exploitation goes deeper and deeper，how to effectively control the floor heave becomes a key problem in roadway support. Considering the surrounding rock damage serious and difficult to support of Liuzhuang coal mine in Xinji，combined with the geological environment characteristics of refrigeration cavern of Liuzhuang coal mine，a large number of in-situ and laboratory tests were done including geostress measurement，true triaxial rheological test，physico-mechanical properties of roadway surrounding rock and rock mineral composition analysis. The research results show that floor heave of this roadway is mainly caused by the flowing deformation of the weak wall rock under the influence of high horizontal tectonic stress. Optimized support design is carried out for this roadway based on analysis above，proposing the floor heave control strategy of compressible steel arch and foam concrete combined with pre-stressed anchor cable. The rationality of the scheme is verified by means of numerical simulation.

The stochastic approximation method under different distance measures is implemented in clustering of joint orientation data and the performance of different validity indices is investigated by case study. The clustering results indicate that the Euclidean，arc-length and sine-squared distance measures are all proved to be suitable for clustering analysis. But the performance of validity indices is found to be different under different distance measures. The index CH works only under arc-length distance measure. The index I is effective under Euclidean and sine-squared distance measures，while the indices DB and XB are found to be applicable under all three measures. The difference between validity index and objective function in determining the best clustering results is also studied. Only under sine-squared distance measure，the index I and the objective function give the same clustering results. Thereby the combination of sine-squared distance and I index is proposed to be the best solution to clustering of orientation data. The in situ data of Beishan deep rock mass are then successfully classified with the above combination scheme.

A semi-analytical solution for dynamic stress concentration factors(DSCF) of underground lined cavity in half-space for incident plane SH waves is presented using wave functions expansion method combined with boundary discrete method. The cavity is with circular inner wall and arbitrary-shape outer wall of the lining. The Monte Carlo method is also used to randomly generate 30 samples of variation coefficient of 0.05 for outer-wall shape of lining，and the effect of outer-wall shape variation of lining on DSCF peak values are studied by statistical analysis. It is shown that，the outer-wall shape variation of lining has significant effect on the inner-wall DSCF peak values，with larger effect for flexible lining than stiff lining. The maxima of DSCF peak values for flexible and stiff lining are increased by 178.15% and 31.98%，respectively，compared with the case of a completely circular linings. The variation coefficients of DSCF peal values for flexible and stiff lining can be up to 9.84 and 2.57 times of those of outer-wall radius of the lining.

Due to the section form of the high filling channels has a great influence on the additional stress of filling body and foundation. A mechanism that the real additional stress below the theoretical value of each soil layer at the center line of high filling channel?s filling body was uncovered through the ANSYS FEM，after a calculation model with a variable section form was established. The additional stress correction coefficient of the filling body and additional stress ratio of the foundation in the high filling channels were proposed. The effects of the filling body?s slope ratio and high aspect ratio to its additional stress correction coefficient and the slope ratio，high aspect ratio and relative depth to the foundation?s additional stress ratio were both clarified. And a calculation method for the additional stress of the filling body and the foundation of the high filling channels was established accordingly. The study result shows that，it could easily and accurately calculated out the additional stress of each filled soil and the additional stress of different depths in the foundation at the center line of the channels by the calculation method，which only needed to know the slope ratio，top width， filling height，and specific weight of the filling body. And it has an important guiding significance to calculate the settlement process for the high filling channels in the North Water Transfer Project.

A statistical damage numerical model was employed to investigate the fracture mechanism of underground openings under triaxial stress state. A three-dimensional tunnel model was established by considering rock heterogeneity described by Weibull distribution. The strength reduction method was introduced into the numerical model to achieve progressive failure of surround rock mass by decreased rock strength gradually. The fracture patterns and safety factors of the underground openings in different stress fields were also obtained quantitatively. Failure patterns under different lateral pressure ratios and axial stresses were analyzed by varying the lateral pressure ratios of the maximum principal stress to the minimum principal stress. The influence of intermediate principal stress on the opening stability, and the stress condition of zonal disintegration phenomena were discussed. The results showed that the failure behavior of the surrounding rock mass was complicated due to the various triaxial stress states. Both lateral pressure ratio and axial stress had significant influences on the tunnel failure patterns. When the direction of tunnel axis is parallel to the maximum principal stress，the zonal disintegration of underground openings appeared because of large axial stress，and the ruptured zone resulted in tensile strain concentration. The numerical model can obtain the fracture patterns and evaluate the tunnel stability，which will be much helpful for revealing nonlinear deformation and failure behavior of rock tunnels in tunnelling engineering.

Due to the uncertainty subway construction and complexity structure of bridge, safety risks on new subway crossing to existing bridge construction are significantly increased. For solving this security problem, safety risk assessment and control system including detection before construction，assessment before construction，dynamic control under construction，assessment and restoration after construction is proposed. Then possible risk is recognized. Control indexes and control standards under construction, especially the maximum differential settlement of existing bridge are put forward. Based on the application of grouting and active lifting measures, under the guarantee of information method，the security of existing bridge in the whole process is realized. According to the analysis of the data after construction，the necessary assessment and restoration after construction should be adopted. The achievement is applied in Line 6 Beijing Subway construction crossing to the garden bridge. According to the results analysis, the desired control goal has been achieved so that the existing bridge safely operation will has been realized during the whole construction.

Considering the disaster caused by leakage during tunnel construction and operation，finite difference method which takes the stress and pore pressure coupled effect into account is employed to study the influence on surrounding soils and parallel tunnel from different leakage positions. The disaster model of one place of stream-like leakage occurring on unit area of tunnel is established. The analysis shows that different leakage positions have different influence on surrounding soils. With the development of leakage，the lower leakage position causes wider vertical displacement field and deeper horizontal displacement field. The existence of parallel tunnel leads to the dissymmetric deformation and larger curvature distortion of the ground surface. Besides，different leakage positions can cause very different displacement modes of the parallel tunnel. Displacement of parallel tunnel could be larger than the leaky tunnel itself. Finally，influence zones of leakage positions are divided according to the impact of leakage on the leaky tunnel and the parallel tunnel. The research indicates that efficient and pertinent countermeasures according to the different leakage positions are necessary.

For the variety pore shape，the multi-scale pore space and the complex pore distribution in carbonate，The characteristics of the pore and hole structure can?t be obtained with the velocity of primary wave，which is the result along the path of the maximum wave impedance. Based on the wave theory and finite difference method，Numerical simulation of ultrasonic transmission has been achieved. And the relation between attenuation factor and the pore shape，size，distribution and density has been studied. According to the study，the conclusion is as follows：(1) Attenuation factor was significantly influence the pore shape，pore size，pore distribution and pore density. And the effect of pore density on the attenuation factor is the most significant. And the pore shape and distribution have less influence on attenuation factor. (2) Whether in the vertical direction or parallel to the propagation direction，pore size have significant influence on the attenuation. And the pore size which perpendicular to the direction of propagation have more influence. (3) For certain frequency vibration source，there is the critical pore size. If the pore size is bigger than the critical size，the changes of pore size cannot be analyzed by the attenuation coefficient. (4) The relationship between attenuation coefficient and pore size，porosity with different pore shapes was expressed as power function with better correlation.

To control the surface subsidence and minimize the negative influence from shield tunneling to surrounding environment，a DBN-based，parameters optimization method in shield tunneling was proposed according to the deficiency of the existing method and was applied to a shield tunnel in Wuhan，China. Firstly the main construction parameters were selected to optimize as node variables and the network structure was built. Then discretizing rules were set to divide the nodes states and measured data were discredited for parameter learning to get the complete DBN optimization model. After model validation with engineering measured data applied this model to parameters optimization. The results show that this model can reflect the inner link between the surface subsidence and shield construction parameters. Based on this model the optimal setting-range of each construction parameters can be determined and within the range construction parameters can be adjusted and optimized real-timely，which is helpful to reduce surface subsidence；This method is valuable in practice

For improve drilling and blasting excavation efficiency of vertical shaft hard rock section，design a large diameter cavity in center of same deep of two section parallel cut blasting. According to theoretical calculation and practical experience choose cut blasting parameters，circle diameter of the first section cut hole is 1 700 mm and it?s hole space is 850 mm，the second section cut hole circle diameter is 2 500 mm with hole space 650 mm. Finite element software LS-DYNA is used for blasting stress field of first section cut blasting numerical simulation analysis and blasting parameters rationality verification. The numerical simulation results show that large diameter cavity in center can improve stress peak value and extend action time，stress wave of rock around large diameter cavity is 2.2 times than the value of rock without cavity. At the same time，numerical simulation show stress wave superposition and reflection，guiding phenomena during large diameter cavity of parallel cut. Then deep-hole blasting field research for vertical shaft hard rock section is done，obtained good effect of average utilization rate 91.7%，lumpiness uniform in rock stability coefficient f = 12–17.

To deal with the problems associated with rock bolt materials in the coal mines，the complete support technology using prestressed steel bars，including steel bar material，locking device，component，anchoring method，machinery and procedure，was developed，based on numerical models，laboratory and field tests；according to laboratory tests，the yield strength of steel bars is not less than 1 140 MPa，the tensile strength is not less than 1 270 MPa，the extension ratio is more than 15%，the impacting absorbing energy is not less than 30 J，and the plates and locking devices compatible with the steel bar strength are developed. Numerical models are used to analyze the distribution characteristics of the stress field caused by steel bars，as well as the main affecting factors，under high prestressed conditions，the magnitude of the stress field caused by steel bars are big，the scope of compressive stress is widely spread，and the active support performance of steel bars is obvious. Field support trials using prestressed steel bars were carried out in the water-discharging roadway of Zhangcun coal mine，Luan coalfield，the displacements of roadways are moderate，no roof separation is shown，the pre-tensioned force is 100–120 kN，the force of steel bars is stable and not affected by the roadway development，and the support performance is good. The cost of using steel bars is less than that of using high strength rock bolts by 29.5%，the spacing of steel bars is big，the installation of pre-tensioned force is fast，the speed of roadway development can be improved to some extent，and this support technology is deserved to be promoted.

To solve surrounding rock control problem in super-high roadway，the ultrahigh segment(section size is 5.25 m×8 m) of No. 5201 main transport roadway in Wujiagou mine was selected as research object. Response characteristic of coal side un-stable triangle block was analyzed by UDEC and balance arch theory. The results showed that：(1) Coal side force state is like unconfined uniaxial compression，the failure form is triangle block shear slip，whose angle is 45°－?/2 in the direction for lateral wall. (2) The vertical stress and the horizontal stress difference increases gradually in deep part，which constitutes main force source of un-stable triangle block slip. (3) Subsidence curve and horizontal displacement curve in coal side both have obvious inflections，which transfers to outside gradually with roadway height increasing. (4) Maximum width and roof pressure of un-stable triangle block add with roadway height increasing，stability gradually drops. It proves that：(1) High performance，high pre-stress bolt could enhance surrounding rock characteristics，decrease roof pressure and keep integrity of un-stable triangle block，and with middle and lower bolt in coal side pass through the shear slip face，also could resist shear and slip of un-stable triangle block. (2) Diagonal cable beam structure could be anchored in the shoulder and floor stable area out the caving arch，develope advantage of high strength，increases friction of un-stable triangle block. Based on this，the support technology of high strength and high pre-stressing bolt net bar and sides diagonal cable beam is proposed. During the period of driving influence，roof-to-floor relative convergent velocity is 4.1 mm/d，both sides maximal relative convergent velocity of sides is 4 mm/d，roof-to-floor relative convergence is 104 mm，both sides relative convergence is 150mm，the total roof separation was 3.5 mm，roadway self-stable period after it was dig out for 10 days，integrity of un-stable triangle block is well and slip sign is not obvious.

To get the acoustic emission(AE) characteristics of deep monzogranite and altered minerals in Lingnan gold mine during the whole failure process of loading，uniaxial compression tests were carried out using GAW–2000 microcomputer controlled electro-hydraulic servo rigidity pressure testing machine，and the acoustic emission signal was received by AE21C acoustic emission testing system. The experiment results were shown the failure and acoustic emission characteristics of the two deep rocks. Then，based on indoor rock mechanics test and on site investigation，the rock burst proneness for different rock samples in nineteenth level were determined according to the linear elastic energy criterion. Finally，the results were compared with the acoustic emission data and site actual situation，which revealed accumulating counts of acoustic emission energy for medium rock burst tendency was 15 times higher than low rock burst tendency. Therefore， accumulating counts got from indoor acoustic emission testing technology had a reference value in quickly determine the rock burst proneness， and could be used in field prediction.

In recent years，with the global temperatures rising，the frequency of debris flow breakout events has increased，which includes glacial-rainfall type debris flow disasters in Tibet region. This paper will set the glacial- rainfall debris flow gully in Nyingchi of Tibet area as the research object，by observing the vary characteristics of water levels，pore water pressure in the starting process for the first time to get the relationship and its starting characteristics by water levels，pore water pressure，the slope，and the thickness of accumulation. By similar physical experiments，relationship of the experimental parameters among flow rate，flow depth，velocity and the slope，thickness of debris flow accumulation，the vary relationship of water level and pore water pressure are analyzed，according to the time relationship of the water level，pore water pressure under different test conditions，we could define the glacial-rainfall type debris flow starting process，which consists of early stage of saturated phase，starting phase and accumulation stage. The experimental results of flow depth，velocity are consistent with the field observation results of typical glacial debris flow in the study area，which are obtained by ratio of similitude provides the reference for the glacial-rainfall type debris flow study in research area.

During construction of bedded salt cavern，the handing interlayer collapses periodically as the size of salt cavern expands. Meanwhile，gypsum interlayer has varying degree of weakening when soaked in brine with different temperature and different concentration. It can cause the pipeline to break and fracture. Moreover it has a dramatic impact on the shape and speed of construction of salt cavern. The problem is the research background of mechanism of interlayer's collapse. Based on the theory of annular plate, a mechanical model for the analysis of the gypsum interlayer's collapse is established. Besides, the non-bucking failure and bucking failure of annular plate are analyzed in this paper. Finally, the concept of periodic caving pace and the flowchart of calculating is proposed. The flowchart is applied to measure to the failure characteristics of gypsum interlayer. Through the theory and simulation analysis and example demonstration，it was showed that the periodic caving pace decrease gradually with the increasing area of salt cavern. Periodic caving times was affected by temperature and concentration of brine. The caving pace of gypsum interlayer which not be soaked in brine was reduced to 8.50 m from 12.00 m and collapsed three times. However, the caving pace of gypsum interlayer which be soaked in hot brine (70 ℃) was reduced to 1.98 m from 4.05 m and collapsed seven times. Periodic caving times increased with the increase of temperature and concentration of brine.

A larger similar physical model experiment system for floor high water inrush in deep mining is developed to solve special problems in deep rock mining，such as the high in-situ stress，the high ground temperature，the high hydraulic pressure and the dynamic disturbance，and it also provide information on landslide evolution law and the evolution process of inrush water channel under the conditions solid fluid coupling of rock. The mainly parts of this design are test bench system，servo loading system，hydraulic control system and computer information collection system. Its maximum three-dimensional size is 1 200 mm×800 mm×1 600 mm. The horizontal and vertical pressures of this experiment system are realized by closed circuit servo-loading devices with the maximum charge of 300 kN，the actuator?s maximum stroke are 200 and 400 mm respectively and the displacement sensor reached to 30 mm；the maximum water pressure reached to 1.5 MPa is realized by servo-regulator system；96 fiber optic sensors are set on the hole at the water tank to detect changes of water pressure and flow. Has been overcome problems of low visibility and degree of automation、pressure weakly of previous test system，this simulated experiment system shows characteristics of diversity、reliability and the whole process. Therefore，with the advantages of small，high precision and simple operation，this system suitable to solve problems such as the physical simulation of floor water invasion，solid-fluid coupling of rock in deep mining and so on.

Comparison of point cloud data in different stages is a problem to be solved in slope deformation monitoring by 3D terrestrial laser scanning technology. Through the improvement of Hausdorff distance algorithm，direct precise comparison algorithm based on octree structure is presented. By this means，automatic comparison of multiple point cloud data in deformation region is achieved，reducing manual intervention and improving the efficiency of point cloud data processing. 3D visual laser point cloud data processing and analysis software LPCP is developed on the basis of block management/storage method by octree structure and the theory mentioned above. Application in the deformation monitoring and analysis of Yanjiagou landslide shows that，the caculated deformation region and displacement by this method is accurate in verified with the fixed point monitoring data，DEM analysis results and laser point cloud data of typical section. Moreover，the algorithm is efficient. The method can be extended to a variety of precise deformation analysis，broadening the application area in deformation monitoring greatly for laser scanning technology.

In order to study the deformation features of deep thick unconsolidated layer caused by de-watering，the calculation model of fiber Bragg grating(FBG) sensor–Adhesive–Packaging material-borehole sealing material- unconsolidated layer strain transfer system was established. Based on the strain transferring analysis of FBG sensors and the unconsolidated layer，it was found that the formulae deduced in previous researches were not suitable for the strain calculation of the unconsolidated layer monitoring. A new mathematical model of strain transferring of the unconsolidated layer and FBG sensors was proposed，and the factors affecting the strain transferring of the unconsolidated layer were analyzed. The higher strain transfer ratio can be obtained when sealing material elastic modulus was in the range of 8–15 GPa. In a coal mine，24 FBG sensors were installed in the 12 unconsolidated layers，the settlement and deformation monitoring results of the unconsolidated layer with the depth of 92.40–148.69 m were calculated using the new mathematical model proposed in this paper. Field practice indicated that high stress concentration region of the mine was located at the unconsolidated layer with depth of 97.56–104.33 m and 141.94–144.88 m，which was in well accordance with the actual case and the results obtained from other monitoring methods. Study of Fiber Bragg Grating strain transferring theory has important practical significance to promote the development of optical fiber sensing technology and its application.

Through defining central sliding surface to determine the direction of shear on slip surface ，and considering the shear potential energy of slip surface，a three-dimensional stability analytical method is put forward for the homogeneous slope with arbitrary sliding surface based on the principle of minimum potential energy. Firstly，taking the sliding body as a whole，the three-dimensional potential energy functions is established. The sliding body virtual displacement can be determined by using the principle of minimum potential energy. Secondly，the normal force and the limit sliding resistance on slip surface is determined based on the relationship between force and displacement. Then the safety factor can be obtained on the basis of its definition model. Compared with the classic examples，it indicates that：the safety factors are in good agreement with that of the three-dimensional limit equilibrium methods；the shear potential energy of slip surface has some influence on the safety factor. Finally，the application of engineering example shows that the method has good practical value.In a word，the method is no need to partition strips and iterate，so the process of this method is simple and easy to use in practical engineering projects.

How to precisely predict the ground subsidence induced by metro station construction becomes the key problem in urban underground engineering. A NARXNN time series prediction model is proposed due to the single linearity of traditional time series prediction model and its static limitation caused by ignorance of construction factor. In order to take the process of metro station construction into consideration nonlinearly and dynamically，construction impact factors，as a part of external inputs，are applied in this model that itself has delay unit and feedback architecture. Based on the NARXNN time series prediction model，the prediction results of ground subsidence induced by the Beihaibei station of Beijing metro line 6 construction show that：(1) Compared with traditional ARMA time series prediction model，NARXNN time series prediction model has a better adaptability and precision. (2) The NARXNN time series prediction model has a precise trend forecast at breakpoints of the settlement-time curve. (3) Multiple construction impact factors or subdividing each group of construction impact factors can be used to improve forecasting precision in using NARXNN time series prediction model.

We tested basic physical characteristics of the outcrop samples with developed beddings from the Lower Silurian Longmaxi in Southeast Chongqing. Based on these tests，we carried out the research of shale mechanical characteristics under the different bedding angle conditions. Our tests indicate that the uniaxial compressive strength of shale increases linearly with the increase of the bedding angle of the samples. The extending direction of failure surface is consistent with the bedding angle when the angle is between 0°–45°. While the angel ranges from 60° to 90°，only a partial consistency between the crack distribution and angle of bedding was reached. Rock will produce the splitting failure because of the inconformity between the main failure surface extension and the angle of bedding. The tensile strength of samples range from 2.872 0 MPa to 10.490 0 MPa，and the stiffness 556.62–1 842.98 MPa，which shows wide dispersion. when the angle between core drilling direction and layers changes the mechanical properties of shale vary greatly.，we should take into account the anisotropic of mechanical characteristics during the designs of drilling and fracturing of shale gas.

Taking II82 district in Luling coal mine as the engineering background，the dynamic evolution rule of floor stress，the stress characteristics and displacement distribution of the floor roadway were analyzed by similar material simulation test and numerical simulation. The results show that the floor stress distribution has obvious cyclical fluctuations. The fluctuation range in first mining is the greatest，and the degree of the concentration and unloading of the floor stress and the normal distance from coal seam showed a negative correlation relation. Considering the characteristics of developed rock fracture and large range of loose circle，this paper，based on double-layer bolting-mesh-shotcrete support and combined with grouting anchor bolt reinforcing and hollow grouting anchor cable reinforcing methods，proposed that mobilizing the bearing capacity of surrounding rock can make the support system and surrounding rock as a whole to bear. The field test shows that this support scheme can effectively control the stability of roadway，the roadway was stable after one month and the amount of floor heave is less than 100 mm.

Determination of the reasonable width of pillars between roadways is the key for ensuring safety production of large mining height face with double roadways layout. Taking the double tunneling pillar between haulage gate and gas drainage roadway of 204 large mining height face in the second panel of Tingnan Coal Mine as the engineering background，firstly，the failure regularity of pillar between roadways under the effect of double tunneling and two times mining was systematically studied by using the method of field stress monitoring. A 3 m wide of fractured zone near the gob was found，and a 18 m wide low stress zone was realized. The distribution curve of stress in pillar between roadways after the first mining was asymmetric. After the second mining，distribution curve of stress in pillar between roadways was like a asymmetric “saddle”and the cumulative broken at the edge of pillar was more than 9 m. at the same time，the division of pillar between roadways was given after the two times mining，and the reasonable width of pillar between roadways was determined preliminarily to be   5.2—13.0 m. Secondly，the stress evolution law，the elastic-plastic region variation，and the roadways deformation law of 5 different coal pillar that width of 4 m，6 m，8 m，10 m and 12 m were studied by numerical simulation. Various elements such as safety production and resources recovery were considered comprehensively. The reasonable width of double tunneling pillar between roadways in large mining height face was 10m. Finally，the reasonableness of the pillar width was verified by engineering practice. The results can provide a reference for the setting of pillar between roadways with similar mining conditions.

On the basis of an improved joint model containing joint spacing，the influence of joint spacing，joint angle and confining pressure on rock mass stress-strain curve，strength have been carried out. The results show that：(1) When joint spacing increases to a certain extent，the rock mass strength is equal to the rock strength，and when joint spacing decreases to a certain extent，the rock mass strength is equal to the ubiquitous joint strength. (2) Joint spacing has a great influence on the three stages of the rock mass stress-strain curve：the elastic deformation，yield strength and residual strength are all increased with the increase of joint spacing. (3) If the confining pressure is increased，the rock mass degradation characteristics induced by joint is abate，and the joint spacing which reach the rock strength or ubiquitous joint strength，decreases with the increased confining pressure. (4) When a joint plane angle is less than   or greater than  ，the rock mass would not crack along the joint plane，and even if the joint spacing is changed，the strength would not change under this angle. When the joint plane angle is greater than   and smaller than  ，the rock mass would crack along the joint plane，and with the increase of joint spacing，the rock mass strength would increase. (5) The first type of columnar joints can be consider as ubiquitous joint model，but the second or third type of columnar jointed rock mass can't be considered as ubiquitous joint model due to their larger joint spacing. The columnar jointed model containing joint spacing proposed by this paper is more applicable for the columnar jointed rock mass.

TBM is known for its quick driving，but the normal driving will be affected under the unfavorable geological condition because of the limitation of equipment and the supporting capacity. TBM faces the risk of lock and even shutdown. The general depth of Jinping II diversion tunnel is more than 1 500 m，and the geological condition is very complex. When TBM driving in unfavorable geological period of Baishan group，due to the low strength of broken surrounding rock，and the poor steady ability，the risk of TBM  driving need to be evaluated. First the initial mechanical parameters of rock mass were studied by excavation response of field surrounding rock. Then，comparing the displacement of different quality of rock mass and the thrust needed for TBM driving，it was found that the required thrust in the unfavorable geological condition has exceeded the provide maximum thrust，and that the displacement is also hard to limit in the range of TBM expansion. The surrounding rock has been damaged in gripper compression，and cannot provide enough thrust to ensure TBM driving. The pilot tunnel was proposed，and the calculation results show that the pilot tunnel can relieve deformation to avoid lock. Other support optimization designs and coping strategies were presented. The research results can provide good reference for similar engineerings. 

In order to study the damage evolution rule of long-term performance of pre-stressed anchor structure，accelerated corrosion tests and material property tests of pre-stressed anchor bar are conducted in corrosion environment indoors. Based on test results，the influence laws of various factors such as corrosion pH，corrosion time，stress level，oxygen level，etc. on the corrosion appearance，corrosion weight per unit length and loss of mechanical properties of pre-stressed anchor bar are analyzed. The study results show that these influencing factors are closely related to the degree of corrosion and damage of pre-stressed tendons anchor. The influence law can be drawn as follows：(1) The longer the corrosion lasts，the more serious the degree of corrosion of pre-stressed anchor bar is. (2) The anchor bar corrodes significantly after acidic liquid immersion，and the smaller the corrosion pH is，the more serious the degree of corrosion of anchor bar is. While corrosion of anchor bar is not obvious after alkaline liquid immersion. (3) In strongly corrosive conditions，the higher the stress level is，the more serious the degree of corrosion of anchor bar is. 4) Under the conditions of weak corrosion，the extent of corrosion of anchor bar is closely related to oxygen level，and the anchor bar corrodes lightly in the environment with insufficient oxygen.

The combination of statistic secondary stress field and dynamic disturbance induced by blasting excavation is the major cause of internal damage of rock mass. The static secondary stress field was calculated for a circle tunnel. Then based on the up-layer excavation of city-gate section diversion tunnel of Xiluodu hydropower station，dynamic analysis was conducted. The damage area induced by the combination of static secondary stress field and dynamic disturbance was calculated. During this process，a comparison was made for different material models，based on regression analysis of calculated blasting vibration values and monitored data in field. Result calculated with kinetic-hardening model complies better with the monitored data. As the in-situ stress field increases，the damage area induced by the combination of static and dynamic effect. However，with in-situ stress transient unloading considered，the volume of damaged rock mass is largely increased. Therefore，the transient process of in-situ stress unloading should be considered in blasting excavation of deep underground tunnels. Besides reducing step length or total charge in one delay，prolong the unloading process for in-situ stress is also a measure applicable for controlling rock mass damage.

Forewarning of rock burst induced by shock bump is a worldwide problem. Long-term spot monitoring and study on the mechanism of monitoring and forewarning shows that the sudden decrease of stress in the stope monitoring area is a precursor to this kind of rock burst. We can obtain the mechanism of spot forewaring based on the stress drop in coal and rock mass before shock bump occurred by analyzing the inner relationship between fracture characteristics of the key stratum triggering shock bump and variation laws of stress in coal and rock mass. The mechanism is that advanced abutment pressure evolves from single peak to double peaks before and after the tensile fracture of the overlying key stratum，and stress drop occurs in the coal and rock mass beneath the fracture position of the key stratum. After that about a few minutes，the strong dynamic load induced by rock beam rotation and fracture leads to rock mass destruction and shock bump in the below loading area. According to the drop value of spot stress and its variation range，the damage extent and influence scope of shock bump can be determined，and thus spot control measures can be adopted timely. Combined with predicting breaking span of the key stratum before mining，tracking rock fracture height by high-precision microseismic monitoring technology can estimate the danger area where shock bump will happen. This whole prediction method will enhance the time-effectiveness and accuracy of spot forecast. The phenomena and critical data revealed in this paper provide a direct and effective approach to the spot forewarning for rock burst induced by shock bump.

The improved triaxial gas permeable apparatus device was employed to conduct a series of experiments for sample of mixture with different sand ratios，dry densities and water contents in order to study the law of gas permeability of GMZ bentonite-sand mixture buffer/backfill materials. The result shows that within the range of experimental condition，the gas permeability coefficient of bentonite-sand mixture(including pure bentonite) is between 3.9×10−4–2.1×10−2 cm/s. Gas flow of bentonite-sand mixture materials can be expressed by Darcy law，but higher gas pressure gradient has certain influence to figure of gas permeability coefficient，and sand ratio，dry density and water content have effect on gas permeability of mixture respectively. The gas permeability ratio of mixture increases exponentially with the increase of sand ratio，while decreases exponentially with the increase of dry density and water content. The gas permeability coefficient formulas of mixture under different conditions were set up within the range of experimental research，which coincide well with the experimental result. A set of experimental data can provide scientific basis for the construction of HLW(high-level radioactive waste) geological disposal in China.

Using PFC3D，the influence of intermediate principal stress on strength and deformation of granular materials was studied and microcosmic mechanism was probed using statistical method. Simulating results show that shearing resistance angle，axial peak stress and the corresponding axial strain firstly increase and subsequently decrease with the increase of intermediate principal stress ratio b. The strain in the intermediate principal stress direction is tensile train and becomes compressive strain with the increase of b，while volumetric strain transitions from shear contraction to shear dilatancy. Simulating results agree very well with Lade-Duncan criterion. In microscopic level，b affects the distribution of contact forces. As b increases，the increase effects in intermediate principal direction are more prominent for lower b values and strength has an initial increase. When b approaches 1，the decrease effects in minor principal direction are more prominent and lead to a lower strength.

Rock and soil aggregates(RSA) has the properties of strong heterogeneity，heterogeneity，discontinuity and environment dependent. Based on the nonlinear property of RSA，the mesoscopic structure characteristics of RSA was analyzed by fractal geometry theory. Remodeling process of RSA samples was explicated，stress-strain relationship under uniaxial compression test and characteristic strength value of RSA samples were mainly discussed. Results show that：(1) As an important index to mechanical characteristics for RSA，stone content is closely associated with RSA granularity fractal dimension and meeting power function relationship. (2) According to uniaxial compression test，the pre-peak stress-strain curve of RSA is divided into four parts：contact consolidation stage，elastic stage，crack stable propagation stage and crack unstable propagation stage. (3) With the increase of stone content，uniaxial compressive strength reaches to maximum when stone content is 50%，axial strain is increasing with stone content，the radial deformation of earth-rock aggregate is more sensitive；(4) Analogy the mechanical properties of brittle rock and concrete，cracking initiation stress of soil-rock TB crack is predicted and stress value is calculated using LSR method，relationship of crack initiation stress，volume dilatation stress and peak stress are analyzed. The mesoscopic structure of RSA has hierarchy and similarity. Fractal geometry theory is a good method to study mesoscopic mechanics characteristics of RSA，which provides theoretical inference to study the mesoscopic structure and mechanical property for RSA.

Based on the in-situ monitoring data and compression tests，the modified filed deformation analysis(FDA) was introduced to deeply discuss the formation mechanism of the post-construction settlement components and predict the long-term settlement of the high-filled embankment on the background of Luliang airport over deep loess foundation. The results were verified by the settlement values and settlement rate curves based on Mikasa consolidation theory and Voigt-Kelvin viscoelastic model. The results show that the primary consolidation settlement of foundation is about 74% of the total post-construction settlement，and the rest of that is the creep settlement of the foundation and the high-fill body. This approach mentioned above is roughly consistent with the actual engineering，and could offer some valuable guidance to the design of loess-high filled and the post-construction settlement prediction analysis of engineering.

Based on the viewpoint of traditional modulus softening method and hyperbolic constitutive model，a formula of permanent deformation changing with time was established. Compared with results of dynamic triaxial test，it was found that the formula was impossibly used for the silty sand which was easily liquefied. On this basis，a rheological term was introduced into the stress equilibrium equation，by which the character of silty sand permanent deformation could be described properly. At the meantime，the way of calculating related parameters in the equations was also introduced. Plugging these parameters into the equilibrium equation，it showed that the numerical calculating results were highly identical with the test results. Although some problems needing for further studies，a new idea in studying the permanent strain was provided.

The process of flowing soil in cohesionless soil was stimulated in laboratory tests to study the change rule among parameters such as permeability coefficient，hydraulic gradient and seepage discharge during seepage deformation. The cyclic process of preferential flow formation and development was analyzed in the process of seepage failure. Comparative tests were conducted to study the anti-permeability strength of soil after a period of consolidation. Results show that there is a period of steady fluid flow under low hydraulic gradient，during which the preferential flow has not formed and the permeability coefficient is a constant. The preferential flow induced by seepage is spatially variable in cohesionless soils. In the cycle of preferential flow formation，development，disappear and reformulation，the tiny seepage deformation happens all the time. In the broken area of flowing soils，the hydraulic screening changed the soil structures and reduced the anti-permeability strength.

It is difficult for fine unclassified tailings to be settled and thickened. The concentration of paste directly determines its quality，such as fluidity，bleeding and stability，and is the direct reflection of property of paste. In order to find the reasonable concentration of paste in the engineering application，concentration range was analyzed from the view of bleeding rate，rheology，paste new definition and dynamic compaction by theoretical analysis，laboratory tests and similar simulation test. The method and conclusions were applied to a copper and molybdenum mine，and then the concentration of paste was determined：67%–71% when considering bleeding rate；69.3%–70.9% when considering bleeding rate and saturation rate；70.68% when considering rheology；67.41%–70.73% when considering dynamic compaction when rotational speed was 0.05–0.10 r/min. Then，conclusion can be reached that the recommended concentration range of fine unclassified tailings paste of this mine is 67%–71% with an average of 69%.

Based on the basic equations for unsaturated porous media，the transient response of an unsaturated semi-infinite porous medium saturated with water and oil was studied. The integral solutions for the one-dimensional transient response of an unsaturated semi-infinite porous medium with two types of nonhomogeneous boundary conditions were developed. Using the sine and cosine transforms，the basic equations were first transformed into a set of ordinary differential equations. Then，the state-space method was employed to solve these equations and the analytical solution in the transform domain was obtained. Finally，the integral solutions were obtained by using the inverse sine and cosine transforms. The integrands of the integral solutions were real functions，which had great advantages on the numerical calculations. Numerical examples were provided to verify the validity of the proposed solutions and investigated the dynamic behavior of unsaturated porous media，and it was verified that three types of compressional waves exists in unsaturated porous media that contained two immiscible fluids.

Soil-cement mixture includes cement treated soil and cement stabilized soil. A series of unconfined compressive strength tests of soil-cement mixture specimens after various curing periods were carried out on two typical soils samples with different water contents，in order to analyze the variation of porosity，saturation，and strength of soil-cement mixtures. The test results show that porosity of soil-cement mixtures is depended on the initial water content，the degree of compaction and hydration product output. Saturation decreases with the increase of cement content and curing time. There is a power function relationship between strength and cement content in term of the cement content between 5% and 20%. The strength of soil-cement mixtures grows linearly with the logarithm of curing time. A unique power function relationship well adapts unconfined compressive strength of soil-cement mixtures with a comprehensive parameter，which represents the effect of cement content，curing time and porosity. Test data from the literatures also demonstrate the effectiveness of the proposed comprehensive parameter to represent the strength characterization of soil-cement mixtures.

The complicated mass and momentum transfer problems in the porous regions，especially at the interface between porous and open fluid regions were analyzed. By taking the Brinkman viscous dissipation term and Forchheimer nonlinear inertia term into account，a new and more general nondimensionalized governing equation was proposed. It was noticed that in the previous literature an analytical solution cannot be obtained freely，and a limitation equation for the given physical parameters had to be proposed，which believed that previous models need to deal with an infinite large number. In this paper，a method that the porous region can be divided into two regions，core region and near boundary region was proposed. Taking the Poiseuille flow model with one open fluid layer in the center and two porous layers aside as an example，the basic flow by solving the difference equation using the Runge-Kutta-Gill method was obtained，which was validated by comparing with those of previous literature. The results show that under the condition of constant Darcy number Da and porosity ?，there is less effect on the basic flow pattern by varying Reynolds number Re alone，while changing the Da or ? has a great influence.

A slurry infiltration apparatus was developed to study the laws of filter cake forming during slurry shield construction in high permeability and complex strata. The laboratory test was aimed at finding the influence of slurry properties and materials on filter cake forming process，during which the uniform design was used. Results show that the slurry proportion is the primary factors influencing the filter cake quality. Larger pores in gravel sand can be filled by the cementation sets after the hydration of bentonite particles. And in medium-coarse sand and gravel sand，the appropriate slurry proportion is between 1.20 and 1.25，slurry material is suitable to choose both bentonite and clay which is compound by new pulp and original pulp. According to the slurry management during construction，slurry proportion is set by 1.20–1.25 and the usage of bentonite is 3–5 kg every 1 m3 of new pulp. Feedback shows that the proportion of the original pulp is stable in the corresponding range，which is to say the filter cake is forming well and the excavation face is stable.

Lateral bearing capacity of pile was influenced by deformation characteristics of pile surrounding soil obviously. However，the deformation characteristics of pile body could be obtained，while the deformation characteristics of pile surrounding soil was hardly be obtained by using conventional testing methods. Therefore，one model test system using transparent soil and PIV(particle image velocimetry) technique was developed. The whole system contains a lateral loading system and an optical measurement system(including an optical platform，a CCD(charge-coupled device) camera and a linear laser，etc). The deformation characteristics of pile surrounding soil under lateral load were non-intrusively measured. Based on multi-slice soil displacement fields，a three-dimensional displacement field was obtained，and model test results were comparative analyzed with those of numerical simulation results. The test results show that the load- displacement curve of the pile under the lateral load was shown as steep drop type，which is similar with the bearing characteristics of laterally loaded pile embedded in typical dense sand. It also shows that rigid rotation destruction was happened in this test condition，and its rigid rotation point is nearly on 78% pile embedded length.

First of all，based on fast or slow-pouring of concrete and its bearing capacity analysis，quickly pour concrete generate upper limit of bearing capacity of pile foundation was argued under the same other conditions. Because of actual speed of the pouring of concrete for the construction is between the fast and slow of definition，its bearing capacity is somewhere between the two limits. Secondly，for fast pouring concrete，there is distribute pressure at soil-pile edge surface of flowing concrete. After solidification and upon reaching the design strength of bearing characteristics，the pressure value is directly related to the size of the normal distribution and this is used to define the boundary conditions of displacement and stress and deducing solving methods of this paper. Last，the theoretical solution is tested and verified by the measured data from a pile engineering. The research shows that computational results of the solutions coincide with the measured data.

Shear strength of unsaturated sandy and clay residual soils were conducted by consolidated-drained shearing method using the conventional strain controlled direct shear apparatus. Results show that the shear strength of two kinds of residual soils decreases with increase of water content. The initial water content has effect on both cohesion and frictional angle of sandy clayey soils. The relationships between cohesion，frictional angle and water content of sandy clayey soils are quadratic and power respectively. While the initial water content has negligible effect on friction angle of clay. The considerable influence of increasing water content on shear strength of residual clay is decreasing the cohesion. The variation of cohesion with water content can be described by an exponential relationship. On the basis of variation of shear strength indexes with water content，two new strength formulas of unsaturated sandy clayey and clay were established without suction component and were demonstrated by further tests. Comparisons of the calculated and measured shear strength show that the accuracy of the prediction is higher under high vertical stress. Two strength formulas can provide the good estimation of shear strength of unsaturated residual soils in Xiamen for engineering application.

The mode of pit-in-pit is becoming more and more common in foundation pit projects，however，it has not been systematically studied. Its uncertainty in position and shape，on one hand，raises the bar in design and construction，on the other hand，makes the surrounding strata deformation much more complicated. Based on the hypothesis of theoretical excavation line and function mass，the mechanism of difference in surrounding strata deformation was proposed. A prognoses method on curve and the maximum value of ground subsidence which is suitable for Beijing area was put forward combining the theory of ground loss with empirical equations. And on this basis，the reasonableness and adaptability of prognoses method by comparing with numerical simulation method and the empirical method were analyzed. Moreover，conclusion of ground settlement which is sensitive to excavation depth the most was also presented. The research findings can guide the design and construction of similar engineering in Beijing and other areas，and has a great significance in preventing engineering accidents and avoiding wasting resources，which can also be provided as reference material for precise control of impact made by pit-in-pit excavation on surrounding environment.

The mechanism of effects for isolation piles on reducing displacements of soil and tunnel below the ground surface needed to be studied. Field measurements were carried out in a deep excavation project in Tianjin，which adopted the isolation piles to protect the adjacent existing tunnel. The deformations of the diaphragm wall，soil outside the excavation，isolation piles and the tunnel were obtained and analyzed. Based on the measured data，a parametric study of isolation piles using finite element method considering the small strain of soil was conducted to investigate the horizontal displacements of the tunnel and the soil below the ground surface adjacent to a deep excavation. It was shown that isolation piles had both effects of isolation and drag on the tunnel adjacent to the deep excavation. The deformation of adjacent tunnel from deep excavation can be increased when the drag effect was more remarkable. The buried isolation pile could be used to minimize the effect of drag and the horizontal displacement of tunnel. Moreover，the isolation piles had higher efficiency in reducing the tunnel displacement when the piles were located closer to the tunnel.

With the development of informationization and requirement of the deep excavation，it is important to develop a strong information management system for the foundation pit engineering. Based on the analysis of the pre-existing foundation pit information system，a new digital foundation pit system was provided. And using the object-oriented language，database technique and 3D visualization technique，a digital foundation pit had been developed in this paper. Through this system，the engineering geological conditions of the engineering area，monitoring points and foundation structures could be queried and managed dynamically in 3D space. Also the monitoring data can be queried visually in sheet or curves，and according the previous monitoring data the developing trend in the future can be predicated conveniently. As an example，the system has been used in the excavation of the foundation pit of the Tianjin cultural centre. According to the analysis of the system，some results have been obtained on the deformation rules of the diaphragm retaining walls during the excavation process. According to the comparison between the predicting and the monitoring results，the prediction method in the system is well. The idea of the digital foundation pit system and the corresponding software developed in this paper，which is very useful for the development of the information construction of the deep excavation and other geotechnical engineering.

Concrete gravity pier with bored pile foundation are widely used in high speed railway bridge in China. According to the main structural characteristics of high speed railway bridge，the characteristics of seismic response were introduced. Due to the larger transverse rigidity of pier shafts and larger cross-section resistance，seismic action of high speed railway bridge pile foundation is also bigger，so it is difficult to achieve capacity design based on intensity control. By comparing the different requirements of seismic performance for pile foundation from AASHTO(LRFD)，Eurocode 8，bridge manual of transit New Zealand and seismic design standards and explanations for railway structures of Japan，it is necessary that the pile foundation of high speed railway bridge should transform from capacity design to performance-based seismic design. The ideal of multiple seismic fortifications should be adopted for pile foundation according to the importance of bridges，and plastic energy dissipation of foundation soil should be reasonably used in order to reduce horizontal earthquake action of bridge piers. The latest research progress of the nonlinear static calculation model of pile foundation under strong earthquake was introduced，and reasonable simulation method for the nonlinearity of foundation soil was summarized.

Threshold gradients and large deformation of thick soft soil may have been realized by researchers. However，the theory of large strain consolidation of soft clay with threshold gradient has rarely been reported. Supposing the constant coefficient of volume compressibility and the square relationship between coefficient of permeability and void ratio，the governing equation and solution conditions of large strain consolidation of soft clay with threshold gradient are developed in Lagrangian coordinates，in which excess pore water pressure serves as a variable. Finite difference method is adopted to obtain the solution for the problem of moving boundary which is induced by threshold gradients，and the reliability of numerical results is verified by comparing the numerical solutions under tiny threshold gradient(10－5) with analytical solutions in case of Darcy?s flow law. Thus，an effective method is provided to solve the problem of moving boundary. Finally，the influence of dimensionless variable R on consolidation behavior and the difference of consolidation behavior between large-strain and small-strain assumptions are analyzed，and the results show that the value of dimensionless variable R influences the final flow front location，the moving rate of flow front location and the dissipation rate of excess pore water pressure. The larger the value of R is，the slower the moving rate of flow front location is，and the slower the dissipation rate of excess pore water pressure is. The larger the value of R is，the larger the residual excess pore water pressure is, and the less the final settlement of soil layer is. The dissipation rate of excess pore water pressure with large-strain assumption is faster than that with small-strain assumption；furthermore，the residual excess pore water pressure with large-strain assumption is less than that with small-strain assumption. This consolidation behavior results in that the final settlement of foundation with large-strain assumption is larger than that with small-strain assumption.

Research on the subgrade accumulated deformation has a significant meaning to the dynamic stability analysis in traffic engineering. By analyzing the results of the cyclic dynamic triaxial tests，whether in the drained or undrained conditions，for both saturated normally consolidated and overconsolidated clay，the pore water pressure and accumulated plastic strain are considered to have a certain relationship. Through improving the Terzaghi-Nicolson consolidation formula and studying the relationship between the pore water pressure and the accumulated plastic strain，a new accumulated plastic strain nonlinear predicting model for the saturated clay is proposed. The model can predict not only the variety of the pore water pressure in the clay，but also can predict the development of the soil accumulated plastic strain. The model validation shows that the developed model can well reflect the developments and changes of the saturated clay pore water pressure and accumulated plastic strain.

Rock and soil aggregate(RSA) is a kind of multiphase and multi-component material and its composition and internal structure characteristic is very complex. The damage process of RSA is a complex structure change process. CT tests and numerical simulation method are used to study the deformation and cracking characteristics of RSA，and it is point that cracking failure is a unique characteristic for RSA which differs from other geology bode. The primary reason cracking is the elastic mismatch between rock blocks and soil. The essence for RSA failure is a process including crack initiation，propagation，interlocking and coalescence. In this paper，some conclusions can be drawn as follows：(1) The RSA deformation features analysis based on CT tests show that the mean CT value for specimen，rock block inclusions and its adjacent soil region decease with the increase of loading，and the change is more sensitive for block inclusions. (2) The numerical simulation results show that the failure process of RSA go through with crack initiation，slow-cracking，fast cracking and coalescence. Interface between rock blocks and soil is the weakest part of RSA. The difference sliding unloading result in the crack initiation，then cracks propagate to soil along block boundary and cracks are influenced by rock blocks. The local development of crack and interlocking leading to formation of shear line with X character or wedge shape. (3) Failure of RSA is a progressive process which can be divided into three levels——rock-soil interface cracking，soil cracking and rock cracking.

The concept of dynamic prospecting is presented aiming at emergency slope reinforcement. Based on the target of dynamic prospecting，the steel sheet pile is chosen to be used to emergency slope reinforcement. Combined with three pressing methods of U-shaped steel sheet pile，the pressing curves of each construction method are collected. And the pressing curves are on the quantification analysis. A series of quantitative parameters are defined. The internal relationship between the pressing curves and the strength of layers is analyzed. The empirical formulae for the piling data of three construction methods and strength characteristic value of layers are fitted or derived，which are verified by project examples. The results show that pile pressing curves present different changes in the interface of layers，which can be used to judge the location of interfaces. Pile pressing curves in different layers present different characteristics，and the empirical formulae can be used to predict the strength of layers. Therefore，it is feasible for“dynamic investigation”to utilize the corresponding relationships between the characteristics of the pile pressing curves and strength of layers.

The soil-rock aggregate(SRA) is composed of soil and rock block and the mechanical characteristics of SRA are closely related to features of rock block. A combination method of experiment research and numerical simulation has been used to study the mechanical properties of SRA. The polygonal rock block generation module was developed using the FISH language. Through laboratory experiments，the relation between macro- and meso-properties was studied. The shape factor m is proposed to quantify the psephicity of rock block. The PFC model of SRA was established to analyze the effects of rock block features(such as rock block content，rock block strength and rock block shape) on mechanical characteristics of SRA. The micro reason for enhancing strength performance of the SRA which contains a certain amount of rock block was studied. The change tendency of SRA strength parameters affected by factors was revealed. The simulation results indicate that the shear strength of SRA increases with the increase of rock block content and rock block strength. When the rock block content is less than 40%，the mechanical characteristics of SRA are dominated by soil. The internal friction angle increases and the cohesion decreases linearly with the increase of rock block content. With the increase of the shape factor m the shear strength of SRA decreases，and the internal friction angle and cohesion decreases. The stress distribution is uneven in SRA. The rock blocks，which generate skeleton，bear the majority of the load.

The consolid system is a chemical reinforcement reagent that has been succesfully used worldwide to improve the engineering properties of soils. However，few studies address the application of the consolid system in the Huangtu Plateau(China). Here we tested the the consolid reagent for the improvement of loess soils form Qingyang and Lanzhou，thus to evaluate the feasibility of Consolid system applied in loess region of China.  Laboratory tests conducted include Atterberg limits tests，compaction tests，unconfined compression tests，swelling tests and the drying shrinkage tests in diverse mixed ratio of the consolid system to bulk solid. The results implied that，with the increasing proportion of Consolid system in the mixture，the liquid limit，plastic limit，plasticity index，optimum moisture content，compressive strength and anti-disintegration property increased. While the maximum dry density and the swelling percentage decreased. The liner drying shrinkage percentage decreased followed by increased. The optimum proportion of Consolid system added into loess soils is suggested to be 2%～2.5%，which made the comparable effect to the 5% modified cement or 5% modified lime，with respect to requirement of engineering construction in loess area of China.

Crushing of the slag from Qincun Reservoir and the gravel-cobble from Yuxi Reservoir was studied by large-scale direct shear tests，and discarding parameters were introduced to investigate laws of breakage development from stratification planes of fractions and granular soil as a whole respectively. The results show that the relationship between discarding ratio Rk and nominal stress ? is linear for different fractions of the tested coarse-grained soils with ? varying in the research range. And difference of crushing of the two tested soils，which is mainly reflected in the grains from larger fractions，tends to disappear as grain size decreases. For coarse-grained soil as a whole，when ? varies in the range of 0–300 kPa，the breakage degrees of two soils are rather close. However，once ? varies in the range of 300–1 200 kPa，crushing of slags from Qincun Reservoir is more significant than gravel-cobble from Yuxi Reservoir. Besides，breakages of the two coarse-grained soils tend to be more remarkable as  increases.

By analyzing the horizontal static load test results of bored piles in certain area，experimental research on application effects for bored piles with pile lateral friction and tip resistance grouting technique are studied. The results show that：(1) The characteristic value，critical value and ultimate limit value of horizontal bearing capacity of bored piles depend mainly on the pile-soil interaction force. (2) By compared with test results of single pile，the critical load with grouting technique is increased by 25% and the ultimate value is increased by 14.3%. (3) The coefficient of pile lateral soil resistance coefficient of single pile with grouting technique is increased by 57%. (4) Compared with the calculated results for two piles cap，the value of horizontal critical load for two piles cap with grouting technique is increased by 33.7%. (5) Based on the relationship between a variety of soil deformation modulus and its m values，a linear equation about deformation modulus and m value is proposed and the expression of grouting soil composite compression modulus is deduced. The calculation method about m value of grouting soil is proposed. Tests and calculation demonstrate that by adopting grouting technique with pile lateral friction and tip resistance，the value of horizontal capacity of bored piles can be improved significantly.

Freeze-thaw has a great influence on strength characteristics of soil. In this paper，a series of freeze-thaw test on silty clay from the Tibetan Plateau are carried out. Then the soil samples after different runs of freeze-thaw test are used to conduct uniaxial compressive strength tests，scanning electron microscope (SEM) test and mercury intrusion porosimetry(MIP) tests. Results indicated that the uniaxial compressive strength decrease with the increase of freeze-thaw cycles and then keep stable until 30 times of freeze-thaw cycles. Microscopic pore structure parameters including plane porosity，the proportion of four kinds of pore and fractal dimension of pore experience fluctuant adjustment stage and dynamic balance stage during the freeze-thaw cycles. There is a negative correlation between the uniaxial compressive strength and plane porosity. The pore size distribution has changed after few freeze-thaw cycles，and both the pore size and pore density increase during the cycles. During the freeze-thaw cycles，some connected pores and cracks develop in the soil samples. These pore and crack changed the grain skeleton and particle characteristics of the soil，leading to changes in the soil structure and mechanical system. And consequently，the strength of the soil sample decreases. Comparison and combination between SEM tests and MIP tests make the study of soil micro-structure more accurate and effective.

When the earth pressure balance shield machine(EPBM) advances through in soft ground，it is essential to optimize the driving parameters so that the surface settlement induced by tunneling meets the requirement of deformation. The EPBM driving parameters including advance speed，ground surface settlement were measured from a greenfield site of the shield tunneling section between Jianguo road station and Tianjin railway station of metro line 2. Based on the field measured data，a 3D finite element model was established to analyze the tunneling impact on the surrounding soil. The numerical results agreed well with the measure data of the greenfield site and thus the model was verified. Furthermore，the sensitivity analysis of the ground settlement to the parameters was conducted under the normal construction condition. Fault tree basic events were derived from the key driving parameters during tunneling and then the quantitative risk analysis was performed. The results showed that the value of the key driving parameters varied with the shield advance speed. The parameters were also related with each other. Moreover，the risk factors were ordered based on the sensitivity and risk of the ground settlement，under the condition that the normal advance speed was approximately 30 mm/min. Therefore，the ground settlement induced by tunneling could be fine controlled according to the order of the risk factors.