Accurately measuring the thermophysical parameters of rocks under high temperature and high pressure is a challenging problem for the design of deep geothermal engineering and the accurate evaluation of heat recovery potential. Firstly，the thermal conductivity of Kangding granite was measured under different high temperatures and axial stress loadings，and its evolution characteristics of specific heat capacity and thermal expansion coefficient were measured under different high temperatures. Secondly，a numerical analysis model was established for the thermal storage and production process of Kangding reservoir considering thermal-hydraulic coupling based on the measured experimental data and the discrete fracture network method. Finally，the evolution law of mining temperature，pressure，and total power generation with the thermal extraction time of Kangding thermal reservoir was obtained. The results show that the thermal conductivity of Kangding granite decreases slightly with the increase of the temperature and increases slightly with the increase of the stress. Temperature can increase the sensitivity of the thermal conductivity to the stress，and can increase the thermal storage capacity and the thermal deformation of geothermal reservoir rock. According to the established model，the generated power of Kangding deep geothermal reservoir can reach 1.06 MW，and the total power generation can reach 311 million kW•h. The results are helpful to the design，construction and development prospect evaluation of Kangding deep geothermal project. 

In view of the adverse effects of the residual boundary coal pillar on the surrounding rock of the lower fully mechanized top coal caving face in the end-mining period，taking the close distance coal seams of the Yanzishan coal mine as the research background，the end-mining overburden environment of the lower coal seam is classified into four categories，namely，the gob side of boundary pillar，the solid coal side of boundary pillar，the gob and the solid coal. By establishing the rotation speed mechanical model of key blocks under abnormal loads，its rotation during the end-mining period of fully mechanized top coal caving face is divided into four stages. The critical angle，external moment and angular acceleration of each stage are solved. The angular velocity equation of the whole rotation process of the key block is obtained based on the principle of fixed axis rotation，and the influence law of the overburden load，the top-coal stopping caving distance and the main roof fracture line position on the block rotation speed is analyzed. The research shows that：(1) The influence of the overburden load on the block rotation speed is ranked as：the solid coal side of boundary coal pillar＞the gob side of boundary coal pillar＞the solid coal＞the gob. (2) The top-coal stopping caving distance can be essentially divided into three types. Type I is equivalent to the top coal without stopping，type II only reduces the rotation angle of block B without changing its rotation speed，while type III reduces the rotation angle and its angular velocity of both block B and C. (3) Compared with the main roof fracture line penetrating into the coal wall，the rotation resistance moment provided by the support structure decreases and the angular velocity of block B increases when it is located above the retracement channel，which is not conducive to the stability of the surrounding rock in the end-mining period. (4) The end-mining ground pressure control strategy of fully mechanized top coal caving face in close distance coal seams is proposed，which effectively guides the engineering practice of N0381 working face. The on-site monitoring verifies the rationality and reliability of the rotation speed mechanical model of key block under abnormal loads.

The YJW–20000S microcomputer-controlled hydraulic servo three-directional five-surface loading test system was jointly developed by Central South University and Shanghai Hualong Testing Instrument Co.，Ltd.，to expand the study on mechanical properties of large-scale rock-like materials under high stress conditions. The static and dynamical combination loading，single-face and multi-face unloading tests of large-scale rock specimens can be performed by this system to simulate the mechanical behavior of rock under complex stress conditions such as rock burst. The system?s functionality and accuracy were confirmed through true triaxial fatigue disturbance loading and unloading tests and three-directional five-surface tests on a 400 mm × 400 mm × 400 mm rock-like sample. Uniaxial compression tests on two kinds of large-scale granite specimens，viz. 400 mm × 400 mm × 400 mm and 400 mm × 400 mm × 800 mm，were carried out using this test system. The stress-strain curve characteristics，stress thresholds，size effects and end effects of large-scale granite specimens were analysed. The results show that the four stress thresholds of the large-size granite are the initial microcrack and microporous closure stress(0.37 )，crack-initiation stress(0.54 )，crack-damage stress(0.73 ) and peak strength( )，consistent with the theoretical prediction results of small-scale granite. The compressive strength value of large-scale granite specimen is smaller than the theoretical value based on the size-effect law. Additionally，the axial strain on the transverse section of the specimen?s side gradually decreases from the centre to both sides due to the end effect，and is lower than that in the middle of the specimen. The axial strain value near the side boundary surface of specimen increases with the distance from the end. The farther away from the end，the smaller the axial strain value on the longitudinal section near the centre of the sample's side. Overall，this system can provide reliable technology for in-depth research on the mechanical behavior of large-scale rock specimens under complex stress environments.

The failure of rock slopes is significantly affected by factors such as geological structures and human activities. In order to explore the influence of structural planes on the stress change of high-steep slopes during excavation unloading，the physical model test for excavation unloading of high and steep slopes with homogeneous and structural planes was carried out based on similarity theory. The initial stress field of the model and the internal stress response law of the excavated slope were studied，and the influence of the structural plane on the stress field and its mechanism are analyzed. The results show that：(1) During the loading process，the internal stress conduction of the model is closely related to the structural plane. The phenomenon of stress isolation and stress concentration will occur when the stress passes through the structural plane. The loading stress response of the model with structural planes shows three types of change: step-increasing，fluctuating-increasing and steady-increasing. The stress conduction process can be divided into three stages：stress loading，stress adjustment and stress stabilization. (2) After the loading is completed，there is a stress loss when the stress is transmitted from the boundary to the interior of the model. The stress loss rate per unit length(1 cm) in the homogeneous model is 0.91% to 1.17%，and the internal stress loss phenomenon is more significant in the model containing structural planes. (3) During the excavation process of the slope，the internal stress of the model presents the characteristics of relatively significant stress zone(original rock stress zone，stress reduction zone，stress increase zone and high stress zone)，and the stress zone is dynamically adjusted with the advance of excavation. After the excavation is completed，the magnitude of stress reduction gradually slows down from near the excavation face to the inside of the slope. (4) The stress zone of the slope is divided according to the stress change rate before and after excavation. The existence of structural planes expands the range of stress-reduced zone，stress-increased zone and high-stress zone. The stress distribution of the slope is closely related to the spatial position of structural plane and the excavation face.

To study the mechanical properties and gas flow laws during the progressive failure of the drilled coal，the multi-functional true triaxial fluid-solid coupling test system was used to carry out true triaxial tests. The strength and failure characteristics，and permeability evolution laws of the drilled coal under different true triaxial stress paths were obtained. The results show that：(1) There are differences in the drilled coal strength for different borehole directions，among which the strength perpendicular to the bedding plane direction is the largest，followed by the strength perpendicular to the butt cleat direction，and the smallest perpendicular to face cleat direction. Both the linear Mogi-Coulomb strength criterion and the Nadai strength criterion are well fitted with the strength data of the drilled coal under different true triaxial stress paths. The Nadai strength criterion has a better fitting effect when the pre-existing cleats are obvious. (2) The permeability of the drilled coal at different deformation stages，when subjected to the true triaxial loading stress path perpendicular to cleat directions，is significantly smaller than that measured under the true triaxial loading-unloading stress paths. (3) When perpendicular to the bedding plane，the macro-fractures around the borehole are mainly tension fractures. When perpendicular to the butt cleat，there are two types of shear and tension macro-fractures generated around the borehole. When perpendicular to the face cleat，the macro-fractures around the borehole were mainly shear cracks. Besides，the number of macro-fractures，especially those accompanied by macro-fractures for drilled coal tested under the stress path of increasing maximum principal stress and decreasing intermediate and minimum principal stresses increased significantly.

The current rock failure criteria fail to fully consider the influence of engineering disturbances，leading to potential disasters. Therefore，there is an urgent need to develop a dynamic rock failure criterion considering the effect of the strain rate. Exploring the strength law of rock materials from the perspective of energy transformation in the overall failure process proves to be an effective approach. Thus，this study investigates the dynamic failure criterion based on energy theory. Drawing inspiration from the dynamic strength and overall failure laws of rock materials，a novel continuity function for the strain energy release dispersion coefficient considering the external stress environment was constructed. This function can accurately reflect the influence of the confining pressure on the energy release direction of rock materials. Additionally，the critical value Gcd，which represents the dynamic maximum energy release rate of rock material considering the strain rate effect，was established by introducing a unified dynamic uniaxial compressive strength model. Finally，the dynamic failure criterion considering the strain rate effect was proposed based on the maximum dynamic energy release rate of rock materials. The results demonstrate a good agreement between the theoretical predictions of the proposed rock dynamic strength criterion and the experimental results obtained from three different types of rock or rock-like materials. This criterion provides a better description of the nonlinear dynamic strength characteristics of rock or rock-like materials. Furthermore，the results indicate that the newly constructed energy dynamic failure criterion has a clear physical and mechanical meaning. The findings of this study have important engineering significance for studying the yield and failure characteristics of rock materials under dynamic disturbances.

Impulse wave generated by semi-submerged landslides in large reservoir mostly has a low Froude number，and its impact effect and wave characteristics need to be further revealed. Taking the Wangjiashan landslide of Baihetan reservoir as an example，a large-scale three-dimensional scaled landslide-induced impulse wave(LIW) experiment with the size of 30 m×27 m×1.5 m was constructed with a geometric scale of 1∶150，following the Froude similarity criterion. Nine groups of LIW experiments with Froude number of 0.08–0.32 were carried out to study the wave regularity of wading landslide under low Froude number. The research results show that as Fr≤0.15，the drag effect caused by the underwater motion is greater than the impact effect caused by the subaerial sliding mass at the beginning of motion，and the wave appears with a small trough at first. The type of primary wave generated by the landslide with a low Froude number is mostly transition wave. In the process of wave propagation，the wave type is easily transformed from the wave type with big translation capacity to that with low or non-translation capacity. The dimensionless wave amplitude and wave attenuation rate are linear and logarithmic functions with Froude number，respectively. Wave making efficiency of wading landslide with a low Froude number is lower than that of subaerial landslide with a high Froude number. The increase of the Froude number will lead to the strongly expansion of the hazard zone of impulse wave，and the increased red warning area multiple is about 10 times that of the increase of Froude number. These new understandings revealed the concealment and hazardous of LIW in the reservoir，supporting prevention and mitigation of impulse waves in the reservoir area.

Major engineering constructions in China are frequently impacted by landslide disasters due to the complicated geological environment and major engineering construction disturbances. Therefore，it is essential to accurately understand the disaster-induced mechanisms of landslides and develop advanced prevention and control technologies. In this context，the authors present a detailed analysis of the disaster-induced mechanisms of landslides and summarizes research progress in prevention and control technologies for major landslide disasters based on their research and practical experience. The mechanisms of landslides comprise the reasons，mechanical behaviors，and landslide processes，where the reasons can be internal or external and vary depending on the type of landslide. The mechanical behavior，namely sliding mechanical mechanism，of landslides can be summarized as the shear stress on the weak surface of a slope being greater than the shear strength. The sliding evolution process of landslides can be analyzed by examining the sliding properties and development stages of landslides. The sliding mechanical mechanism and sliding evolution process constitute the landslide disaster-induced mechanism. Taking the Huangshui River giant landslide in Qinghai Province as an example，this paper analyzes the landslide mechanism，clarifies the internal and external causes of the landslide，reveals the sliding mechanical mechanism，discovers the scientific phenomenon of large-scale landslide peristaltic deformation, creep sudden deformation, and sliding sudden deformation ，and establishes the disaster-induced mechanism of“long-term shear peristaltic deformation→local shear creep sudden deformation→overall penetration fracture sliding”of large-scale landslide. To address the strong retaining problem of deep and large landslides encountered in major projects，the authors propose two kinds of landslide strong retaining technologies：fully buried multi-anchored anti-sliding pile and deep-buried low-anchored variable section anti-sliding pile. These technologies optimize the anchor cable layout on the anti-sliding piles to optimize mechanical mode of retaining structure and to reduce the pile size and anchor cable length. Additionally，to solve the problem of low disturbance and fast control of landslide dangers in major engineering projects，the author develops three kinds of landslide low disturbance retaining technologies，namely vertical steel floral tube anchor cable，oblique steel floral tube anchor cable，and trenchless anchor cable anti-sliding pile. These technologies enable rapid control of disaster dangers. The author?s research results play a leading role in the research and prevention of major landslide disaster mechanisms.

In order to more appropriately describe the nonlinear deformation law of the rock creep damage process and to establish a function between damage factor and time，the stress and time are used as controlling factors to re-divide the rock creep stages，and the instantaneous plastic element is introduced to improve Bingham body. Improved Bingham body，Murayama body and CYJ body are held together to describe each stage of creep respectively. Then，elastic and viscous components in the model are treated by damage theory. The one-dimensional and three-dimensional nonlinear creep damage model principal structure equations of the rock are established. By indoor triaxial compression creep graded loading and unloading tests，the evolution law for elastic and viscous element parameters(Murayama body，CYJ body) during rock creep are given. Then，obtained the cumulative development trend of the damage effect，which can be identified the process parameters. Last，the feasibility and correctness of the established model are verified by comparison. The study shows that：the hardening effect of the elastic element and the damage effect of the viscous element in the Murayama body，the dynamic evolution between the two constitutes the deformation characteristics of the isokinetic creep phase of the rock，which is manifested in the equilibrium relationship between the two inflection points of isochronous stress-strain curve. Between the viscous element and the rock's own damage，the joint action of time and stress in the CYJ body promotes the mutual superposition，further weakening the rock?s resistance to deformation，which can be verified from the damage accumulation development curve. By stress increase and time effect，the rock damage accumulation shows exponential increase，the creep process of the rock becomes the whole process of damage generation→diffusion→accumulation→release. In the model parameter identification and verification，the correlation coefficient R2 reached 0.982 with the fitted curve and the test curve，which verified the feasibility of the constructed all-time nonlinear creep damage model. A full-temporal nonlinear creep damage model for rocks，constructed by nonlinear components and damage mechanics treatment，can not only characterize the damage evolution of the whole creep process，but also accurately describe the nonlinear deformation law of the accelerated creep stage of rocks. This is new attempt to the creep model construction method.

This work aims to elaborate the mechanical properties and damage characteristics of yellow sandstone samples containing two coplanar fissures under diverse dynamic loading frequencies. To this end，multistage constant-amplitude-cyclic loading experiments were conducted on fissured sandstone，and the fatigue mechanical properties and deformation of the rock，the evolution of acoustic emission(AE) parameters during the loading process，the microstructural characteristics of the fractured surface of specimens，as well as the role of loading frequency on fatigue damage mechanism，were analyzed. The results show that：(1) The peak strength，the fatigue life，and axial strain of the specimens increase with growing frequency. (2) The strain of the specimen increases in a stepwise manner with longer time，and at the last fatigue stage，the specimen deformation rises dramatically until the specimen fails. (3) The accumulative AE ringing counts of the samples show a quadratic function increase with higher loading frequency，and the samples under high loading frequency capture more ringing counts before failure compared to those under low loading frequency. (4) The ultimate failure mode of the specimen is related to both the pre-existing flaws and the loading frequency，that is，the samples under low loading frequency conditions perform few cracks and unclear propagation path，and it is clearly observed that the cracks coalescence directly between the two inner tips of the pre-existing flaws. Samples under high frequency conditions exhibit complex failure mode，i.e.，wing cracks appear at pre-existing fissures tip，and the outer wing cracks respectively extend to the specimen ends，while the inner wing cracks gradually extend after indirect coalescence. (5) As the dynamic loading frequency climbs，the microscopic features of the fractured surface of the specimen evolves from dominant intergranular fracture，to the coexistence of intergranular fracture，transgranular fracture，and cleavage fracture，and to dominant transgranular fracture.

To investigate the effect of the unloading rate on the unloading-induced slip mechanism of shale，the slip start-up of jointed shales is triggered by stepwise-unloading confining pressure with constant axial stress using MTS815 loading system，wherein the unloading rates are 0.01，0.1，1 and 10 MPa/min respectively. The results show that：(1) The asperity altitude of the saw-cut joint decreases and the roughness increases due to slip deformation. With the increase of the unloading rate，the joint roughness coefficient(JRC) of saw-cut morphology increases by 22.68%，44.82%，38.49% and 49.89%，respectively. (2) The slip velocity increases with the elevation of the unloading rate，and the average velocity of quasi-static slip is two orders of magnitude higher than that of creep slip at the same unloading rate. The creep slip average velocities are 4.87×10－6，2.52×10－5，3.99×10－4 and 3.29×10－3 mm/s，respectively. The corresponding average quasi-static slip velocities are 7.39×10－4，5.98×10－3，2.8×10－2 and 1.2×10－1 mm/s，respectively. (3) The unloading amount of confining pressure is the smallest and the friction strengthening effect is the weakest under 0.1 MPa/min. Under 0.01 MPa/min，the friction strength of the sample is well enhanced in the long-term creep slip，and the friction strength is weakened in the dynamic slip. At the unloading rate of 1 and 10 MPa/min，the sample will slip in a short time，and the friction strength is enhanced in the dynamic slip. (4) There is a critical unloading rate between 0.1–1 MPa/min，and the unloading amount of confining pressure is the smallest when the sample slips at the critical unloading rate. It presents that the strain energy accumulated on the joint plane is smaller and the energy mainly acts on the micro-convexities to break the interlocking during the slip，so the energy released after the slip is the smallest and produces the minimum shear displacement，which is of great significance for the safety of rock mass engineering.

To obtain the distribution of rock mechanical parameters，a rock indentation equipment was developed based on the digital control three-dimensional platform，and a parameter acquisition method based on this equipment was proposed. The correction formula of the load-displacement curve for the testing machine was established by integrating different indentation tests with the refined three-dimensional numerical simulation and considering the effect of the test procedure and frame stiffness. Then，a large number of numerical simulations and parameter sensitivity analysis for this equipment were conducted，and the classical Oliver-Pharr formula was improved to precisely determine the elastic parameter of rocks. The results indicated that there was a great difference between the estimated elastic modulus by the classical Oliver-Pharr formula and measured values. The proposed improved Oliver-Pharr formula gave a better performance in predictions of the elastic modulus for three types of rocks，with relative errors of 5.83%(granite)，5.14%(marble) and 10.79%(sandstone)，respectively. Moreover，the plastic parameter of rocks was determined based on the indentation test by establishing the relationship between the cohesive and the plastic region area(S) and the difference between the unloading stiffness and the secant stiffness of the loading phase(Kp)，respectively. Compared the results with the measured cohesion by the experimental test，we found that the formula of stiffness difference based on the M-C model gave a better performance in estimating the cohesion of rocks，with relative errors of 17.81%(marble) and 21.93%(sandstone)，respectively. Moreover，the discussion was conducted in terms of the acquisition of the spatial parameter fields of rocks and rock damage based on the testing device. The results of this research presented an efficient approach to obtain rock mechanical parameters fields and provided support for the parameter selection of the refined numerical simulation in rock mechanics.

To quantitatively analyze the grain size effect of the compression characteristics of granites under loading，a three-dimensional grain-based model based on particle flow code is used to restore the internal structure of granites. The whole force chain network of the sample is divided into multiple levels. The value，number and orientation distribution of force chains in intragranular structures and intergranular structures are quantitatively explored. The grain size effect on uniaxial compressive strength，micro-cracking behavior，load-bearing capacity and fracture resistance of various structures is quantized in force chain point of view. The results show that when the number of contacts is basically unchanged，the decrease in the general force chain(GF) number and the increase in the microcrack number have a good correlation. The orientation distributions of various GFs are relatively uniform. The overall level of the force chain network increases with the increase of RG. The main orientation distribution of the high-strength force chain(HF) is consistent with the loading direction and is orthogonal to that of cracks. The number of HF can well characterize the macroscopic mechanical properties of the sample. The load-bearing capacity of intact minerals and intergranular structures increases with the increase of RG，and the variation range is proportional to the micro-tension strength of internal contacts. The number of HF required to produce a single crack in intact mineral structures increases as RG increases，that is，the fracture resistance increases，but the fracture resistance of intergranular structures do not change significantly versus RG.

Weakly cemented soft rock is widely distributed in the western region of China. Under this condition，when there is thick conglomerate with relatively high strength above the coal seam，the fracture of conglomerate layer has a significant impact on the overall ground pressure. In order to solve the difficult problem of strong ground pressure control，a research method of in-site monitoring，theoretical analysis，similar material simulation and numerical simulation was adopted. The main control driving role of thick gravel rock is revealed，and a mining pressure control technology for weakly cemented soft rock is proposed and applied on site. The results show that：(1) there is a gradual trend of“slight→severe→slight”ground pressure manifestation in the initial mining stage. Combined with the occurrence characteristics of overburden，the thick conglomerate layer above the stope is the main control layer of strong ground pressure manifestation. (2) The structural mechanics model of “transferring rock beam +conglomerate plate”of overburden is established，which reveals that the overburden characteristics of the stope driven by the fracture of the conglomerate layer：“basic roof→conglomerate layer→rock stratum above the conglomerate layer”progressive linkage instability in space，“large-small cycle periodicity”of the basic roof in time，and“instantaneous”instability characteristics of the rock stratum above the conglomerate layer. (3) Based on the analysis of influencing factors of strong ground pressure，the location coefficient of conglomerate fracture “ζ” is proposed It is used to describe the degree of transition from the broken position of conglomerate layer to the goaf. The smaller the overburden breaking coefficient is，the closer the corresponding broken position of overburden is to the goaf，and the weaker the rock pressure appearance is. (4) The key technology of strong ground pressure control is proposed，which is optimized by the setting load of hydraulic support and the mining speed of the working face. Through numerical simulation and field practice，the initial support force and the mining speed are optimized to 31.8 MPa and 8 m/d，and the field application effect is obvious.

Aiming at the problem of the low utilization of blasting energy due to that the burst gap cannot expand well in the direction of the coal seam during the blasting increasing permeability of high gas low permeability coal seam，the experimental study of the composite effect of control hole and directional control blasting is carried out. According to the propagation law of explosion stress wave，the mechanical model of explosion stress wave propagation under the auxiliary action of control hole is established. The four groups of control holes with different apertures after blasting are compared and analyzed with the crack initiation and stress development law of one group without control holes，and the propagation law of bursting cracks and the amount of increase of stress peak are obtained. The self-built blasting test platform is used to carry out blasting similarity simulation test. The results show that in terms of crack propagation，when the control hole diameter is too small，the control hole has a weak effect on crack guidance，and the crack parallel to the coal seam between the blasting hole and the control hole is not obvious. With the increase of the aperture，the control hole's effect on the crack orientation is strengthened，a straight connecting burst crack is formed between the two holes，and the orientation effect is more obvious. In terms of stress，the stress peak on the blasting side of the control hole increases with the augment of the aperture，and the maximum percentage of increase is 40.4%. On the back of blasting side of the control hole，the stress peak increases first and then decreases as the aperture increases，that is，the surrounding stress field will have a maximum stress field as the aperture increases. The research results are applied to the directional controlled blasting of high gas and low permeability coal seams，which can effectively improve the blasting energy utilization rate and permeability of coal seam.

In order to accurately predict the penetration grouting radius in coarse-grained soil，a method for identificating geometrical characteristics of microscale particle and resconstructing mesosceale grouting channels based on the geometrical characteristic of stacked particles was put forward. And combining these two methods and the largescale grouting diffusion model，a multiscale penetration grouting radius prediction model was established. First，based on the mesoscale CT sectional images of geomaterials and employing the geometric characteristics identification method(GIM)，the ellipticity，roughness，long-axis inclination and size of the stacked particles were identified. Then，employing the grouting channel reconstruction method(GRM)，the penetration channel model was reconstructed according to the obtained parameters，porosity and gradation. According to the reconstructed model，the mesoscale penetration diffusion model with statistical significance was obtained using the multi-field coupled finite element method(FEM) and Monte Carlo method(MC). Coupling the mesoscale penetration diffusion model and the largescale grouting diffusion model according to the seepage field results in the multiscale prediction model of penetration diffusion radius. Compared to the existing experimental results，the rationality of the prediction model is verified(the error is less than 10%). Finally，based on the proposed method，this paper systematically studied the influences of ellipticity，roughness，particle size，porosity，long-axis inclination，time-varying factor and average slurry viscosity on grouting diffusion radius. The affecting relationship in reducing order is：particle size，average slurry viscosity，long axis inclination，time-varying factor，porosity，ellipticity and roughness，and the Pearson coefficient is 0.5，－0.374，－0.238，－0.188，0.161，－0.036，－0.019，respectively. Through the analysis of the grouting diffusion process，it is found that the influence mechanism of the geometric characteristics of the stacked particles on grouting diffusion mainly includes the“pore-throat constraint”，“inertia resistance”，“channel width”and“fluid-solid interface”effect.

The determination of yield function，plastic potential function，hardening law and corresponding hardening parameter is essential when establishing elasto-plastic constitutive model for soils. Consequently，the establishment the calculation formula of hardening parameter is particularly important. In this paper，through the comparison of the stress-strain relationship and strength behavior of normal and over consolidated soils，the construction of the unified hardening equation considering the influence of initial state is presented. Then，based on the mechanism analysis of strength behavior of over consolidated soils under complex stress paths，the strength potential MY which can consider the joint effects of initial state and loading process is introduced. Additionally，the unified hardening equation for soils under complex stress paths is obtained through replacing the Mf with MY in the original unified hardening equation. Finally，the significance of the novel unified hardening equation to the establishment of constitutive model for soils is verified by comparing with the experimental results under various stress paths.

To study the shear characteristics of residual soil derived from granite under dynamic loading，a series of horizontal cyclic shear tests were conducted under different moisture contents(13%，17%，21% and 25%)，vertical stresses(50，75 and 100 kPa)，shear amplitudes(1，3，6 and 9 mm)，and shear frequencies(0.1，0.5，1 and 2 Hz). The variations of shear stress and vertical displacement of the residual soil during the cyclic shear process were investigated，and the changes in the microstructure of the residual soil were analyzed using scanning electron microscopy to reveal the shear failure mechanisms of soils with different moisture contents. The experimental results showed that the peak shear strength and residual shear strength of the residual soil increased first and then decreased with increasing moisture content during the cyclic shear process. Higher moisture content and vertical stress resulted in greater final vertical displacement of the soil and more significant volumetric strain. When the shear amplitude was equal to or greater than 3 mm，the soil exhibited cyclic shear softening，and the degree of softening increased with larger amplitudes. For moisture contents of 13%，17% and 21%，the average peak shear stress of the soil initially increased and then decreased with increasing shear frequency. However，for a moisture content of 25%，the average peak shear stress of the soil increased with increasing shear frequency.

When air-booster vacuum preloading method is used to reinforce soft dredger fill，the reinforcement effect will be affected by air injection pressure and air injection time. Indoor model tests with different combinations of injection pressure and injection time were used to investigate the effect of the air injection loading path on the reinforcement of soft dredger fill. Four air injection loading paths were considered：constant pressure-constant time，constant pressure-variable time，variable pressure-constant time and variable pressure-variable time. The test results show that the reinforcement effect of air-booster vacuum preloading method is always better than that of conventional vacuum preloading method. And when the air injection loading path of variable pressure-variable time is adopted，the soil reinforcement effect is the best. Compared with the air injection loading path of constant pressure-constant time，the air injection loading path of variable pressure-variable time can lead to an increase in soil surface settlement by 9.25%，an increase in drainage by 9.35%，a decrease in average water content by 13.91% and an increase in average vane-shear strength by 20.59%. The gradual increase of air injection pressure and air injection time can effectively prevent the accumulation of clay particles to the prefabricated vertical drains(PVDs)，and increase the number of soil pores between PVDs and the booster board. The permeability of soil and the reinforcement effect of deep soil can be improved by using the loading path of variable pressure-variable time.

Clay rock is a common engineering rock mass. Its water-softening and expansion properties are an internal predisposition to geological disasters such as landslides and bank collapses. To understand the water-induced deterioration of mechanical parameters and the propagation of cracks in the process drying-wetting cycles，laboratory test and numerical simulation were carried on. Firstly，a humidity stress transient analysis method based on the water head is proposed. Secondly，a humidity-relative cohesive element was developed. Then，the main parameters are calibrated based on the experimental data. Finally，three loading expansion examples and drying-wetting slake samples of clay rock are simulated by FDEM. The study shows that：(1) the clay rock shows the water-softening property in the process of water-induced expansion. The uniaxial compression strength and elastic modulus of saturated samples are 22% and 25% of dry samples. Therefore，the decrease in strength and rigidity cannot be neglected in the expansive analysis of soft rock. (2) The water-induced expansion of clay rock lags behind the water-softening in history. When the normal pressure is larger than the expansive stress，the confined clay rock always appears in the compression recovery phenomenon. (3) The propagation and coalescence of crack is the main factor inducing slake of clay rock during the drying-wetting cycles. The external crack is easy coalescence and fragment was generated，while the internal crack also causes irreversible damage to the sample. In this study，a new numerical method of shrinkage-expansion analysis is proposed，which plays a guiding role in the engineering calculation in slope，tunnel，and reservoir banks in swelling rock areas.