Water inrush disasters are the key issues during the construction of subsea tunnels，and whether or not they are successfully treated directly influences the engineering construction. Through the analysis of water inrush cases and their occurrence conditions，three models of water inrush are established，which respectively reveal the water inrush evolution mechanisms and their essential characteristics of hydraulic fracturing，formation collapse and interface slip. Ground deformation is proposed to act as the characterization parameter of water inrush disasters. Based on the energy conservation principle，the transmission law of ground deformation is revealed，and a calculation method of layered settlement is proposed. The relationships between seabed security and ground deformation such as ground cracking and deformation as well as seabed settlement and tunnel arch settlement are established，by which water inrush disasters during construction can be predicted and evaluated in real time. A concept taking water-induced disasters as the core safety risk is proposed， and a phased process control method is proposed based on the principle of displacement distribution. In view of complex water conditions，geological guarantee techniques including detailed investigations and accurate predictions are put forward，and an evaluation method of water inrush risk level is established. Finally，a refine process controlling technology system of subsea tunnels based on ground deformation control is formed. The proposed technology system is then applied to F1 weathering trough segment of Xiang¢an subsea tunnel in Xiamen，and a precision control of millimeter level is realized，ensuring the engineering safety.

In order to simulate the influence of temperature and pore pressure on the adsorption and permeability characteristics of coal during gas drainage，the isothermal adsorption experiments and the seepage tests in the gas reduce process under different temperatures were carried out respectively by using the isothermal adsorption device and the triaxial servo-controlled seepage equipment for the thermo-fluid-solid coupling of coal containing methane. A modified dual-site L adsorption model was established，and on this basis，a coal permeability model considering the coupling effect of temperature and pore pressure was proposed. The rationality of the new permeability model was verified by test results. The results show that，under the experimental conditions，the cumulative desorption of gas increases with decreasing the gas pressure. The permeability of coal decreases first and then increases with decreasing the pore pressure under a constant temperature. With rising the temperature，the permeability of coal decreases first and then increases under a constant pore pressure. The modified dual-site L adsorption model has better fitting effect than the original model，and can well reflect the relationship between the adsorption capacity of coal and the gas pressure at different temperatures. In the process of gas desorption in coal，the contraction strain of the matrix increases with decreasing the pore pressure. The new permeability model has a good consistency with the test data and can better represent the permeability evolution law under different temperatures.

In order to reveal the three-direction mining stress variation law and the relationship between the mining stress variation and the overlying strata instability，a method for calculating the disturbance coefficient of three-direction mining stresses was proposed，and the temporal and spatial evolution characteristics of mining stresses and the process of fracture instability of overlying strata in deep stopes were studied. The transformation forms of the principal stress under different loading and unloading conditions were analyzed based on the Mohr-Coulomb strength criterion. The ratio of the maximum and minimum principal stress difference to the distance from the center of the molar stress circle to the intensity curve was proposed as the criterion for determining the intensity disturbance of three-direction mining stresses，and the disturbance coefficient of three-directions mining stresses was deduced. Based on the elastic-plastic mechanics theory，the change rules of the magnitude and direction of the three-direction mining stresses in the overlying strata along the working face advance and the working face length directions in the deep stope were analyzed using 3DEC simulation. The mining stress disturbance coefficient and disturbance intensity partition of the overlying strata in front of the working face were obtained，and the spatial-temporal evolution characteristics of mining stresses in overlying strata were revealed in deep stopes. Based on the relationship of the mining stress and the displacement of overlying strata in the process of breaking，the breaking process of roof strata were subdivided to five stages of mining stress increase，bedding separation，fracture instability，fracture instability of upper roof strata and compaction stability of overlying strata. The variation rule and action mechanism of mining vertical and horizontal stresses in the process of overlying strata breaking were revealed. The research results were applied in the mining practice with 1 000 m buried depth of coal seam，and the phenomena of frequent occurrence of mine pressure and low compressive strength were better explained.

In order to study the seepage characteristics of loaded fractured coal，the three-dimensional fracture field used for LBM numerical simulation was reconstructed by the industrial CT and image processing technology，and the CT scanning and seepage experiments of loaded coal at different loading stages were carried out. The results show that the average error of LBM simulation results is 18.72%，which is in good agreement with the test results，indicating that the LBM simulation has good accuracy and effectiveness. The accuracy of LBM simulation results is related to the development degree of cracks in coal. The more cracks develop，the better the connectivity is and the more accurate the LBM simulation results are. The permeability of fractured coal is closely related to the compression and expansion of internal fracture field. The permeability of coal decreases continuously in the compaction stage and the elastic deformation stage while increases in the late elastic deformation stage and the yield deformation stage，and reaches the maximum in the pressure relief failure stage after the peak strength. The study results verify the feasibility of LBM numerical simulation in describing the permeability of fractured coal，and provide a reliable way for visualization research on the internal gas flow mechanism，flow law and coal seam gas extraction process of loaded fractured coal in the future.

The uniaxial compression test of granite specimens under temperature and stress cycles was carried out to reveal the mechanical properties of granite subjected to temperature and stress cycles. The results show that，with increasing the cycle number，the Young¢s modulus of the granite increases gradually while the strain corresponding to the upper stress of the samples decreases. The decrease amplitude of the upper limit strain at the upper limit stress of 85% uniaxial compressive strength is greater than that at 70% uniaxial compressive strength. Except for 600 ℃，the uniaxial compressive strength of the samples after temperature and stress cycles is greater than that at real-time temperature. Especially for 300 ℃，the strength increase rates at the upper cycle stresses corresponding to 70% and 85% uniaxial compressive strength reach 57.1% and 50.9% respectively. After temperature and stress cycles，the strength of the granite specimen changes significantly while the peak strain almost keeps invariable，which shows that studying the stability of rock from deformation rather than strength is more consistent with the actual situation. The results can provide reference to study the stability of rock engineering under the cyclic action of temperature and stress.

The impacting fragmentation of high-speed rock landslides has a great influence on the motion characteristics，and the rapid dissipation of energy and the instantaneous change of the movement performance in the process of movement lead to an expansion of the affected area. Physical modeling tests were conducted with heaves to simulate multiple consecutive impacting between landslide mass and external uneven ground surface，and different quantities of unit test blocks with different material compositions and ratios were used in the tests to investigate the influence of the particle size and the volume of the block on the kinetic characteristics of the rock landslide movement. A high-frequency camera and digital cameras were used to record the whole motion process. The test results show that the overall time of the movement increased with the decreasing particle size and the increasing volume of the block. Moreover，the accumulation time was the controlling factor of the overall movement time. It is also shown that both the average velocity of the movement process and the velocity at the exit reduced with the decreasing particle size while changed insignificantly with the volume of the block/the number of unit blocks within 1 m/s. The energy dissipation caused by impacting fragmentation accounted for a small proportion of the total potential energy，but the impacting fragmentation was an important factor of energy dissipation during rock landslide movement and controlled the motion characteristics and energy dissipation mode of the landslide body.

The sublevel caving mining often results in damage to buildings and structures，and makes them unfit for human habitation or use. Previous studies indicated that the horizontal tensile strain is the most important parameter used to assess the building damage. In this paper，a methodology based on the scattered monitoring horizontal displacement data is provided for calculating the major principal horizontal ground strain and determining the ground acceptable deformation limit. Firstly，interpolation accuracy analysis of three-dimensional scattered data is carried out to select suitable interpolation method，coordinates system of the horizontal displacement vector and the corresponding interpolation parameter and further to obtain the discrete horizontal displacement field. Subsequently，the major principal strain at any point in the continuous deformation zone is calculated approximately based on the centered difference scheme of the geometric equation in continuum mechanics theory. Finally，the ground acceptable deformation limit can be determined according to the acceptable deformation value of buildings in China. A case study in the western area of the Chengchao iron mine is presented here to illustrate the methodology. The results show that the interpolation accuracy in the continuous deformation zone by using ordinary Kriging and Radial Basis Function can be improved by representing the horizontal displacement vector μi in polar coordinates. The calculated horizontal strain at the acceptable deformation limit confirms to the law of the deformation around the mined-out areas，which verifies the reliability of the above numerical methodology. It is also revealed that the acceptable deformation angles of different representative sections at the same mining level are significantly discrepant and that the acceptable deformation angle in Chengchao iron mine should be respectively designed in four zones.

At present，under the environment of high geo-temperature and high geostress，it is not reported that geo-temperature is considered during geostress inversion，which causes that the initial geostress field obtained by inversion is not consistent with the actual geostress field of rock masses. In order to overcome the shortcoming，a workflow of inversion for the initial geostress field of rock masses considering geo-temperature is proposed. Under the environment of high geo-temperature and high geo-stress，the initial geostress field of rock masses can be approximately composed of gravitational，tectonic and thermal stress fields. The thermal stress field of rock masses can be approximately obtained by the geothermal gradient method and the thermal-stress formula of rock masses. Superposing the thermal stress field of rock masses into the gravitational and tectonic stress fields of rock masses can obtain the initial geostress field consistent reflecting the impact of high geo-temperature. Due to that the vertical stress is calculated by the density of overlying strata without considering the thermal stress，inverting the initial geostress field of rock masses based on the stresses measured by hydraulic fracturing will cause serious errors under the environment of high geo-temperature and high geostress. At the area of the Sangzhuling tunnel，for example，the thermal stress is about 8/13 of the gravitational stress. Comparisons between the inversion results and the measuring data of Sangzhuling tunnel show that the inversion results considering geo-temperature are better than those without considering geo-temperature.

In order to clarify the propagation track and the variation rule of deflection distance of fractures during oriented perforation steering fracturing in low permeability unconventional oil and gas reservoirs，a dynamic propagation model for oriented perforation steering fracturing cracks based on microelement method was established by comprehensively considering the influences of horizontal in situ stress difference，perforation parameters，injection parameters and formation mechanical parameters. The model completes the cyclic iteration calculation between the minor step increment and the propagation deflection angle of the crack tip using a calculation program compiled by Visual Basic，and realizes the simulation of the dynamic propagation of steering fractures. The accuracy of the MEM model was verified by comparing the differences among fracture trajectories calculated by MEM model and extended finite element(XFEM) model，micro-seismic monitoring values in the fracturing field and indoor fracturing test results. Taking the tight sandstone reservoir of Shihezi Formation in Linxing block as an example，the influence mechanisms of various factors on the deflection distance of the hydraulic fracture trajectory were studied. The results show that，compared with the XFEM model，the hydraulic fracture trajectory simulated by the proposed model better matches with the micro-seismic monitoring results. The deflection distance decreases negatively logarithmically with increasing horizontal in situ stress difference while increases linearly with increasing the perforated angle，injection rate and viscosity. The perforation length has little effect on the deflection distance. The research work is significant to further understand oriented perforation steering fracturing.

：In order to describe the influence of soil anisotropy on stress-strain relationship，a non-orthogonal elastoplastic constitutive model of transversely isotropic clays is established based on the concept of the modified characteristic stress. Modelling procedures are as follows：(1) By referring to the modified stress method，the fabric tensor is introduced into the characteristic stress formula to incorporate the influence of anisotropic fabric. (2) Based on the frictional rule on the octahedral plane in the modified characteristic stress space，a transversely isotropic -strength criterion reflecting the effects of soil anisotropy and intermediate principal stress is established. (3) In the modified characteristic stress space，the inclined yield surface is adopted to describe the influence of the initial anisotropic consolidation stress condition on the yield characteristics of soil by introducing the volumetric associated hardening parameter，and (4) the incremental direction of the plastic strain of transversely isotropic clays is determined by the three-dimensional non-orthogonal plastic flow rule based on the fractional partial derivative. Only six material parameters are needed in the non-orthogonal elastoplastic model，which can be determined by conventional triaxial tests，and three model parameters are concerned in the proposed model，which can all be easily determined by the determined material parameters. The comparison between model predictions and experimental results shows that the model can reasonably capture the strength and deformation properties of transversely isotropic clays.

The influence of membrane penetration is the key to determine the reliability of test results of gravel soils. Influencing factors and laws，and calculation methods of membrane penetration are still very controversial，which is the bottleneck of current theoretical research and engineering application of gravelly soils. By using the two-scale method and the large-scale triaxial apparatus，the penetration volumes of 11 kinds of graded gravelly soils were measured and analyzed with different membrane thicknesses，and two key indexes，the penetration volume of membrane per unit area and the elastic volumetric strain of soil skeleton，were obtained. Influencing laws of main factors were analyzed，and a new calculation method for the penetration volume of membrane in wide-graded gravel soil samples was established and verified in many aspects. The results show that the two-scale method is applicable and reliable for large-scale triaxial test of gravelly soils，and that the influence of grading condition on the membrane penetration cannot be fully described by single characteristic particle size such as  and . The influence of the membrane thickness varies with the size of soil particles and can be ignored when  is greater than 2.5 times the membrane thickness. It is also revealed that，under isotropic consolidation condition，the gravel soil in unloading stage is not always isotropic and hence，the calculation models of the penetration volume based on isotropy assumption are not suitable for wide-graded gravelly soils. The membrane penetration volume in wide-graded gravel soils can be calculated by the developed model with three factors of ， and . The new model and calculation formula are simple in form and obviously superior to the existing model formulas in accuracy and applicability.

In view of the characteristics of natural structural saturated clays such as large porosity，high strength and certain cementation，the UH model of over-consolidated soils was expanded into a three-dimensional structural model related to state variables. The left endpoint of the yield surface in the p-q space was shifted to the left of the origin，so that the cementing characteristics of a certain extent of stretching could be considered. The evolution equation of cementing strength parameters was proposed. By introducing a state parameter χ and deducing it’s expression，the yield surface equation was corrected so that the dilatancy equation can describe the strength characteristics of the variable phase stress ratio of the body changing from shear to dilatancy. The concept of structural stress ratio parameter R* was proposed and used to modify the uniform hardening parameter. By using the transformation stress method based on t criterion，a generalized model of stress representation was proposed，which can describe the true triaxial stress-strain relationship. The comparison between test and prediction results shows that the proposed model has strong applicability.

Under the action of seismic load，pile group is subjected to the joint action of cap and soil，and the bending moment of pile body of different pile types will change obviously，especially under the condition of saturated sand. In order to study these problems，the seismic dynamic response tests of vertical and batter pile groups in saturated sand were carried out by ZJU400 geotechnical centrifuge of Zhejiang University. The spectral components of the saturated sand and the pile cap were analyzed in detail through the method of spectrum analysis and then，the distribution of the bending moment of the piles were discussed in detail. The results show that，under seismic loading，the characteristic frequency of the saturated sand decreases obviously after liquefaction. With increasing the vibration intensity，the characteristic frequency of the pile cap of the batter pile reduces while the characteristic frequency of the pile cap of the vertical pile keeps at 0–2 Hz without significant change. Under different vibration intensities，the influence of different frequencies on the bending moment envelope of the vertical and batter pile groups is different. The influence of the frequency of 0–2 Hz on the bending moment of the piles is most obvious except for the case of 0.05 g where the influence of 0–2 Hz is less than that of 2–5 Hz. At the same time，with increasing the vibration intensity，the position of the peak bending moment of the straight group piles in the buried depth range of the soil moves down. In practice，it is suggested to appropriately increase the bending rigidity of the pile near the position where the bending moment is larger.

Moisture content is an important factor affecting the disintegration characteristics of granite residual soil，and transient infiltration is an important reason for initial disintegration. In order to better understand the unsaturated effective stress state of granite residual soil under transient infiltration in the initial stage of disintegration，the unsaturated effective stress in the disintegration process was approximately simulated by mathematical morphological method. The disintegration tests on different water content samples were carried out，and the unsaturated effective stress under different saturations was calculated by 18-lattice method based on the Pore Algorithm(PM) method. The approximate simulation of initial disintegration process was performed in combination with transient infiltration method，and the disintegration mechanism was analyzed from the perspective of unsaturated effective stress. The experimental results show that the disintegration curve of granite residual soil has significant two-stage characteristics and presents a“S”shape in the initial stage of disintegration. The initial disintegration rate increases with decreasing the water content. The simulation results show that the gas inside the sample can not be exhausted in time during the transient infiltration stage，resulting in that the pore pressure inside the sample increases rapidly and tends to be stable in a certain range，and that the synthetic unsaturated force between particles rapidly decays to zero and the decay rate is faster with a lower initial saturation. If the initial saturation is low enough，the synthetic unsaturated force will suddenly become negative at the moment of infiltration，that is，a tensile stress occurs inside the soil. If the tensile stress is greater than the strength between soil particles，the microscopic structure of the soil will be destroyed，which corresponds to the initial disintegration failure.