Considering that swelling rocks such as mudstone and sandy mudstone have the characteristics of absorbing moisture to induce swelling，this paper divided the swelling deformation process of swelling rock into two stages，namely moisture absorption and expansion，and established a moisture absorption-swelling analysis model for swelling rock，deduced the control equation of the rock mass moisture diffusion，and proposed a humidity field calculation method considering the expansion effect induced by moisture absorption. According to the analysis theory and combined with the indoor experiment，the temporal and spatial diffusion law of humidity inside the rock mass and the influence characteristics of the humidity diffusion coefficient and the adsorption expansion coefficient were obtained during the expansion process. The results show that the internal humidity diffusion of rock mass has a significant temporal and spatial law，and the development trend of humidity with time is first slow，then rapid and then gentle. At the same time point，the humidity decreases with a negative exponential trend with the increase of the distance to the humidifying surface. When the adsorption expansion coefficient is constant，the relationship between the ultimate expansion deformation and the humidity diffusion coefficient conforms to the power exponential function，and when D/  is in the(0，1)，the ultimate expansion deformation increases more obviously. When the limit expansion deformation is constant，the relationship between adsorption expansion coefficient and humidity diffusion coefficient is negative exponential，and when D/ ＞2，the humidity diffusion coefficient has little effect on the adsorption expansion coefficient.

Due to the traditional linear elastic fracture theory is no longer applicable to characterize the ductile fracture characteristics of coal and rock mass，the PPR unified potential-based cohesive crack model for mixed mode I/II fractures in mudstones and coals by using semi-circular specimen under three-point bending(SCB) tests and punch-through shear(PTS) tests to describe the I/II mixed crack propagation behavior in coal and rock mass. The experimental results show that the increase of crack tip opening displacement(CTOD) in the nonlinear damage process after load peak of the coal SCB specimen was 3.48 times that of the mudstone specimen. Meanwhile，the digital image correlation method(DIC) was used to measure the length of fracture process zone(FPZ) in the coal and mudstone specimens. The FPZ length of the coal SCB specimen was about 6.21 mm，which was 2.75 times that of the mudstone specimen. And the FPZ length of the coal SCB specimen can significantly cause a ductile fracture failure of the coal body. During the punch-through shear(PTS) experiments，the average maximum tangential displacement of PTS coal specimen is 0.055 mm，which is significantly larger than that of mudstone specimen，and the characteristics of the type II ductile fracture of PTS coal specimen are significantly higher than that of mudstone specimen. In addition，the pure mode II fracture energy of the two types of samples is higher than that of the pure mode I fracture energy，indicating that the occurrence of mode II shear fracture consumes more energy. Finally，the mixed mode I/II single-edge notched beam(SENB) through three-point bending test. And the corresponding numerical simulation were carried out for the coal and mudstone，which the numerical simulation process is based on the PPR cohesive crack model and the linear elastic fracture theory，respectively. Through a comparison with the linear elastic fracture theory，the numerical simulation results based on the PPR cohesive crack model are more in line with the experimental results. Therefore，the cohesive crack model that built in the study is suitable for characterizing the mixed mode I/II ductile fracture behavior of coal-rock mass.

预测岩石破坏或失稳是岩石力学研究的重要内容，采用非均质岩石破裂的数值模拟和岩石单轴压缩的物理试验，研究岩石单轴加载过程中试件表面测点的位移变化规律，提出岩石表面多测点的位移增量拟变异系数计算公式，分析位移增量拟变异系数与应力曲线的对应关系。研究结果表明：多测点的平均位移增量拟变异系数与岩石失稳紧密相关。在线弹性阶段及非线性塑性阶段，位移增量的拟变异系数变化平稳，趋于定值；在岩石失稳时刻，位移增量的变异系数骤增。因此，能够利用位移增量的拟变异系数变化趋势预测岩石发生失稳的时刻，或者预判岩石达到应力峰值程度。

Ultimate deformation of tunnel surrounding rock has been regarded as a critical index for evaluation of surrounding rock stability. This study attempts to work on the approach to the tunnel surrounding rock ultimate deformation. This approach relies on an assumption that the rock mass materials obey the H-B criterion，according to the mechanical characteristics of weak rocks as well as their response mechanism to excavation. Based on this assumption, the radius of loose region，generated within the surrounding rock of circle tunnels，is formulated. Next，this formulation is combined with Rabcewicz?s initial instability mode，attaining a method of computing support resistance that is required to stabilize the tunnel. Furthermore，the approach is established to calculate the ultimate deformation of tunnel surrounding rock. This established evaluation approach is validated through a comparison to numerical data provided by existing studies. Parametric analysis is also conducted，investigating the effect of rock mass properties and of tunnel geometric parameters on the ultimate deformation/strain of tunnel surrounding rock. It reflects that the tunnel surrounding rock ultimate strain has relatively high sensitivity to far-field stress，unconfined compression strength and H-B constant，while that is low in terms of intact rock Young?s modulus，Poisson?s ratio and tunnel radius.

As a kind of dense jointed rockmass with regular structure plane network，columnar jointed rockmass is with complex mechanical response processes under high stress，such as jointed plane opening，rock block rupture and rockmass structural relaxation. Based on the engineering background of the #3 diversion tunnel on the left bank of Baihetan hydropower station，time-dependent fracture process of columnar jointed rockmass under strong unloading during excavation and its mechanism were studied after with a series of synergistic observation. The synergistic observation contains microseismic monitoring，acoustic velocity test and digital borehole camera test. Results show that the period of time-dependent fracture process is more than 10 days. The number of time-dependent fractures decreases with the increasing of days after excavation. It is a logarithmic function and can be divided into three time-dependent stages：weakening period，stable period and weak period. The number of time-dependent fractures decreases with the increasing of distance from the working face，and with the increasing of depth from the side wall. The time-dependent fractures are mainly within 3 m from the side wall，the relaxation depth is about 3 m，and the visible fractures are distributed within 2.5 m. The synergistic observation results have a good spatial consistency. The excavation size and location have significant effect on the time-dependent fractures of columnar jointed rockmass. The number of time-dependent microseismic events generated by step-by-step excavation of half section is less than that of the full section. Tensile fracture is the main fracture type of columnar jointed rockmass and there are a lot of time-dependent tensile fractures beyond 30 m behind the working face. The research results can provide reference for support optimization and safe construction of dense jointed rockmass under high stress.

A novel apparatus，based on the ultrasonic-induced nucleation and solid refrigeration technology，was designed for the freezing point test of soils to solve the problems of“size effect”and“hypercooling”. The freezing temperature of NaCl solution measured by the apparatus was in good agreement with the relevant test results，which indicated that it had reliable accuracy and stable performance. On this basis，freezing point tests with different test methods and soil densities were carried out. Results shows that the soil sample could not be frozen uniformly under constant temperature condition，resulting in the different freezing state of soil samples and inducing the“size effect”. This problem can be overcome by the linear freezing mode. In order to analyze the influence of microscopic geometry characteristics of the soil sample on freezing temperature under different densities，the Fourier-Voronoi(FV) algorithm was used for the numerical reconstruction of the accumulation pattern of soil particles. The Pores and Cracks Analysis System(PCAS) was adopted to quantitatively analyze the pore characteristics of soil. It indicated that the most probable pore width had the strongest correlation with freezing temperature. The confinement effect of capillary porosity is more obvious when the dry density of soil increases and the pore between soil particles narrows，resulting that the formation of condensation nuclei is more difficult and the supercooling phenomenon is more outstanding. The ultrasonic pulse excitation can promote the random movement of water molecules，which increases the probability of condensation nucleus generation and eliminates the influence of supercooling on the freezing point test results. Therefore，the combination of the linear freezing mode and the ultrasonic excitation has a good application prospect in the freezing point test of soils.

Water-rock interaction is one of the main reasons triggering engineering disasters in or on fractured rocks，and the key scientific problem is to accurately predict the spatio-temporal evolution behaviors of fractured rocks under water-rock interaction. The introduction of water into rock fractures modifies the mechanical properties of rock fractures through mechanical，physical and chemical interactions between water and rock minerals，and the basic concepts of water-rock mechanical，physical and chemical interactions in rock fractures  are firstly presented. The effects of the three types of water-rock interactions on mechanical behaviors of rock fractures are studied using theoretical and experimental methods. The physical meaning of the effective stress coefficient in a rough rock fracture is understood as the void ratio，and a new expression of effective stress coefficient only including a few common mechanical parameters is proposed. The water-rock physical interaction induces reductions in basic friction angle and asperity strength. Water-rock chemical interaction is strongly related to pH of chemical solutions. The acidic solution has the most significant weakening effect on the shear parameters of rock fractures，followed by alkaline solutions and neutral solutions. Finally，a complete form of fracture shear criterion considering water-rock interaction is proposed，and its implications in practical rock engineering is briefly discussed.

The thermal diseases generally occur in the exposed rock at the tunnel portal section in the southern region，which is the main high temperature area in China. Solar radiation transmitted to the interior of rock through near-surface fractures，and thus the thermal stress field of rock is determined by the shape and distribution of fractures. The shallow fracture surface is triangle，which is the typical shape to study the stability of fractured rock. For the multi-fractured rock at tunnel portal in high-temperature，a heat source model is established based on the triangle fracture shape，and the distribution form and variation rule of the thermal stress field are obtained by using green's function method and mirror image method. In addition，the influence of fracture shape parameters and multi-fracture interaction are analyzed. The results show that the trend of thermal stress in exposed rock is consistent with that of solar radiation. Because of the fractures，the thermal stress field in shallow rock redistributes and the stresses at the tip of fractures increase. For triangular fractures with the same depth，the greater the apex angle，the worse the thermal stability of rock. The interaction of multiple fractures leads to the superposition of the thermal stress field around the fractures. The smaller the spacing between parallel fractures and coplanar fractures，the stronger the superposition effect of the stress field. The larger the spacing，the more the stress value tends to the stress of a single fracture. For the cross fracture，the superposition effect of the stress field is strongest when the included angle is 45°. The thermal stress isolines of multi-fractured rock appear around the fractures. The thermal stress around the fractures increases significantly，and the thermal stress field presents non-uniformity.

High-precision pick-up of P-wave signals from mine microseismic signals is an important prerequisite for precise location of mine microseismic signals. Based on the time-domain characteristics of microseismic P-wave signals and the deep learning algorithm in the field of computer vision，this paper propose a picking DMSP method suitable for microseismic P-wave signals and constructs a suitable loss function. This method first builds an adaptive DAA-MINE denoises the microseismic signal in the mine，and then builds a segmentation joint picking Cut-SP to pick up the initial value and end point of the microseismic signal P wave. 3 835 groups and 959 groups of mine microseismic signal data are used as training set and test set，respectively，to train and test the model proposed in this paper. The results show that：after the DAA-MINE model denoising，the average signal-to-noise ratio is improved and more energy is retained；compared with the ER algorithm，the MER algorithm，the WFM algorithm，and the PAT-S/K algorithm，the Cut-SP model The average picking error is low，the robustness is strong，and the recognition speed is faster，and it can meets the engineering needs. The pickup model constructed this time realizes the integration of deep learning neural network and mine microseismic monitoring，and provides a new method for automatically picking up data of microseismic data in intelligent mining.

JRC is a key parameter to predict the shear strength of rock joint by using Barton?s JRC-JCS model. Although there are massive researches on methods for calculating JRC of a rock joint profile，few researches had been reported on the calculation of rock joint JRC value by considering shear direction. Herein，based on the 2D coordinate data of Barton?s ten standard profiles derived from fine digitization process，firstly the root mean square of the first derivative of the profile was calculated by consideration of shear direction. Meanwhile，forward and reverses direct shear tests were performed on artificial rock joint specimens which were of the same topography of Barton?s standard profiles. Then non-linear regression analyses were performed between JRC and  which were respectively derived from back-calculation of forward and reverses direct shear test results and 2D coordinate data of standard profiles，from which empirical logarithmic and exponential expressions were obtained for determining the JRC value of rock joint profile considering shear direction. Furthermore，the predictions of JRC values derived from the above-mentioned empirical logarithmic and exponential expressions were compared with these back-calculated from forward and reverses direct shear tests. From the comparisons，it showed that the empirical exponential expression was more suitable for calculating the JRC of rock joint profile in forward direct shear tests，while the empirical logarithmic expression was more suitable for reverse direct shear tests condition.

The“time-space”characteristics of rock bursts are difficult to predict，which severely restricts the safe and efficient output of coal resources. Starting from the mechanism of the sun-moon tidal force on the cyclic loading and unloading of the surrounding rock，the temporal and spatial distribution characteristics of typical rock burst accidents from 2001 to 2021 were calculated. The internal relationship between the sun-moon tidal force and rock burst has been clarified using theoretical analysis and data statistics. The trigger mechanism of the two time-history action modes of sun-moon tidal force on rock burst has been studied through cellular automata analysis software(CASRock). A method for optimizing rock cyclic loading and unloading stress paths based on the time window effect was proposed. The research results show that：(1) both the sun-moon tidal force and the occurrence of rock bursts have obvious regional differences. Under the cyclic loading and unloading of the sun-moon tidal force， the occurrence time of rock bursts was mainly concentrated in February and September and around the first and fifteenth days of the lunar calendar. (2) The cumulative acoustic emission quantity，equivalent plastic shear strain(Epstn)，and rock fracture degree(RFD) under the two time-history action modes of the sun-moon tidal force are all greater than conventional triaxial loading. It shows that under the action of sun and moon tidal forces，coal and rock masses are more prone to stress fall，transform from elasticity to plasticity and release more elastic energy，and it is easier to induce rock bursts. (3) Starting from the source of impact force，the two time-history action modes of sun-moon tidal force are easy to induce gravity-type rock burst and structural stress-type rock burst respectively. (4) It is revealed that the trigger mechanism of the sun-moon tidal force on rock burst is actually the result of the repeated cyclic loading and unloading of the surrounding rock. Based on the analysis of common cyclic loading and unloading stress paths，combined with the mine work system，the production period was divided into the loading phase，and the maintenance period was divided into the unloading phase. The stress path of the surrounding rock based on time effect optimization was proposed. The above research results can be better applied to rock mechanics experiments，and provide a new method for real reaction to the rock burst failure law of coal and rock samples under the action of the mining stress path.

Carbonate rocks represented by dolomite are widely distributed in southwestern China. This kind of rock mass is prone to sanding when there is water. Based on the Chengdu-Kunming double-track Jixin tunnel project，this paper adopts advanced geological forecasting，theoretical analysis，and continuous-discrete coupled numerical analysis methods to conduct an in-depth study on the tunnel face instability mechanism in sandy dolomite formations. The results of the research are as following. (1) According to the results of advanced geological forecasts，the mechanism and development process of dolomite sandy are analyzed and the objective conditions for dolomite sanding are summarized. (2) Using continuous-discrete coupled numerical simulation，the whole process of the instability of the tunnel face of the sanded dolomite tunnel was analyzed，and the displacement and failure laws of the tunnel face surrounding rock after the instability occurred were summarized. The above research provides a theoretical basis for further research on tunnels in sandy dolomite formations.

Fracture systems are always covered by accumulations，resulting in blank information on rock mass structures. Thus，the accuracy of rock mass structure analysis is tremendously decreased. This paper aims to establish a regular and complete fracture information region as well as a simple calculation method for three-dimensional(3D) fracture density，which benefit fine descriptions of rock mass structures. Specifically，this paper introduced geostatistical method to predict fractures in blank areas based on spatial geometric parameter correlations of collected fractures. Consequently，the global distribution characteristics of two-dimensional(2D) fractures in a regular region were determined. Based on the aforementioned results，3D fracture network models were established. Subsequently，conception of 3D statistical fracture density was proposed based on probability thoughts；then，density was determined based on spatial intersection trial method. Through comparison between in-situ and modeled half-trace probability density curves，rationality of fracture prediction in blank areas and 3D fracture density calculation were verified. In sum，these methods are able to obtain complete 2D fracture characteristics and significantly simplify 3D fracture network modeling procedures. Consequently，accuracy and efficiency of rock mass structure analysis can be improved.

To solve the problem of how to choose the objective function in microseismic(MS) source location for achieving better location effect，the objective function of 3 kinds of traditional location methods are analyzed，including typical MS location(TMSL) method，the time difference(TD) method and velocity difference(VD) method without pre-measuring velocity. A new objective function without pre-measuring velocity，named time method (TM)，based on joint inversion of the seismogenic time and MS source coordinates. Through the division of the number of arrival time of trigger sensors，based on the location principle of time difference，combining the expression of objective functions and the sensor array，the correlation and convergence of 4 kinds of objective functions are analyzed theoretically. The position relationship of MS source and sensor array corresponding to the existence of multiple solutions of 4 kinds of objective functions are listed in detail. Based on the comprehensive analysis of the applicability of 4 kinds of objective functions，an adaptive recognition algorithm for MS source location objective function(ARAOF) is proposed. Firstly，based on the blasting test data，the average location errors of 4 kinds of objective functions in the monitoring area are calculated. Secondly，the average location errors of 4 kinds of objective functions are compared to determine the selection order of the objective function and the objective function with the minimum average location error is selected preliminarily. Finally，according to the number，arrival time and coordinate information of trigger sensors for MS events，combining the correlation and convergence of 4 kinds of objective functions，the unstable objective function is excluded and the optimal objective function of MS events is determined. The field test of the Beiminghe iron mine in Hebei province shows that stability and location accuracy of ARAOF method is superior to TMSL method，TD method，VD method and TM method， and its average location accuracy is 34.81%，44.63%，74.7% and 27.09% higher than that of TMSL method，TD method，VD method and TM method respectively，which has important practical application value.

Based on the fact that elastic strain energy is the internal mechanism of rock failure，the internal relationship between elastic strain energy and abrupt structural failure in the process of rock deformation is firstly discussed，and it is pointed out that the strength criteria are essentially the type of strength criteria of elastic strain energy，and the fundamental reason for the poor calculation accuracy and applicability of these strength criteria is that the Poisson?s ratio of rock failure under any stress level is always regarded as 0.5. A material parameter is introduced，and the generalized strength criterion is established based on the classical strength criterion. The results show that the generalized strength criterion is a set of strength criteria with the introduced parameter as the parameter，rather than a single strength criterion，and the generalized strength criterion degenerates into the corresponding strength criterion when the introduced parameter is equal to 0.5. True triaxial test results show that the calculation accuracy of generalized strength criterion is higher and more suited to the failure mechanism of rock，but classical strength criterion has influence on the calculation accuracy of corresponding generalized strength criterion. Further discussion shows that the generalized strength criterion can directly reflect the influence of elastic modulus of rock mass，strain energy released by earthquake and supporting system on the stability of rock mass. The generalized strength criterion breaks through the assumption that the Poisson?s ratio is equal to 0.5 in the case of material failure in the classical strength criterion，which is of great significance for the accurate quantitative analysis of material failure characteristics.

When the engineering construction is carried out in the mountainous and gorge area，it is of great significance to identify unstable rock mass quickly and accurately. In the study，7 stable rock mass cases and 8 unstable rock mass cases were preset by the freezing test method，and the Laser Doppler Vibrometer is used to obtain the vibration monitoring data. Based on the support vector machine algorithm，the method of rapid identification for unstable rock mass by time domain and frequency domain dynamic index is presented. The experimental results show that the identification method based on absolute mean and mean square frequency has an accuracy rate of 100%，which is better than that based on single dynamic index. By introducing a variety of dynamic monitoring indexes，the reasonable and effective identification of unstable rock mass can be better realized. The study provides a new remote sensing technology support for the verification of unstable rock，thus can enrich the multi-source geological survey technical system integrated a full range of space-air-ground detection technologies，and provide a reference for better response to rock collapse disasters in high-risk areas such as Sichuan—Tibet Railway.

The high efficient perforation technology provides important technical support for cost reduction and efficiency increase in oil and gas development. Due to the complex distribution of stress field around the perforation holes and the absence of effective simulation methods，the initiation and propagation of hydraulic fracture for perforated fracturing are not understood clearly. This paper proposes large-scale(762 mm×762 mm×914 mm) physical experiments that simulate fracture initiation and propagation under different perforation strategies. Furthermore，a full three-dimensional numerical model based on discrete lattice method is established. Through the combination of physical experiments and numerical simulation，the geometry of fracture initiation and propagation under different perforation technologies is revealed intuitively. The results show that the fracture initiation near the wellbore is more complicated due to the effect of beddings，perforation tunnels and in situ stress field. Increasing the perforation depth obviously decreases the fracture initiation pressure and propagation pressure. Compared with spiral perforation，directional perforation significantly reduces the fracture complexity of in the near wellbore area，improves the efficiency of fluid injection for perforation holes，and decreases propagation pressure by up to 25%. Directional perforation is conducive to migration of sand-carrying fluid. Field tests on Chang 7 reservoir show that the directional perforation significantly reduces the initiation pressure by 21% and extension pressure by 14.2%，respectively，showing a good application prospect.

The current elastoplastic analytical solutions for tunnels were mostly obtained based on the loading path. However，the stress state of the hydraulic tunnel is unloading after the water filling，therefore，the solution should consider the actual stress history. According to the principle of elastic-plastic loading and unloading，the elastoplastic analytical solutions(i.e.，size of plastic zone，stress，displacement and critical water pressure) of hydraulic tunnel are derived for the whole stage from excavation to water filling，considering the advancement of the tunnel face，the interaction between surrounding rock and lining，support time and the re-plasticity of the unloading region under high water pressure. The analytical stress and displacement agree very well with the results from finite element method. Compared the proposed solutions with obtained from the loading path(the traditional solution)，it is found that the traditional solution underestimates the displacement and the size of the plastic zone.

The theory of traditional crack strain model is mainly based on isotropic body. It has obvious limitations  to obtain the characteristic strength of layered rock mass by using this method. In order to study the characteristic strength of layered rock mass，based on the transversely isotropic theory，a transversely isotropic crack strain method is proposed to solve the characteristic strength of layered rock mass. Combined with the uniaxial compression test of chlorite schist，the deformation and failure law of chlorite schist and the characteristic strength characteristics such as closure strength，crack initiation strength，damage strength and peak strength are obtained， and the relationship between these characteristic strength and peak strength，as well as their anisotropic characteristics are analyzed. The results show that the ratio of closure strength to peak strength is in the range of 0.1–0.3，that of crack initiation strength to peak strength is in the range of 0.3–0.5，and that of damage strength to peak strength is in the range of 0.8–1.0. The closure strength，crack initiation strength，damage strength and peak strength of chlorite schist first decrease and then increase with the increase of the angle between loading direction and bedding plane. The anisotropy of crack damage strength and peak strength is between 3 and 4 with moderate anisotropy，and the crack closing strength and initiation strength is between 4 and 5，with high anisotropy.

A series of joint specimens with the same surface morphology were poured by 3D scanning and printing technology. Direct shear tests were carried out under different normal stress and shear displacement conditions. By analyzing the experimental curves and joint surface damage characteristics，the deterioration of joint surface morphology and its relationship with the weakening of shear strength during post-peak shearing were studied. It was found the three-dimensional roughness parameter based on the Grassilli?s morphology parameters can quantitatively evaluate the deterioration of the joint surface morphology. By introducing the three-dimensional roughness parameter into the JRC_JMC model，the post-peak shear strength weakening model of joints was proposed based on the variation of the JMC and three-dimensional roughness parameter during post-peak shearing. The results obtained by the proposed model agreed well with those by direct tests，which indicated that the proposed model can better characterize the shear strength weakening law of joints at the post-peak    shearing part.

In order to explore the energy release characteristics of rock fragmentation，impact compression tests with different strain rates and initial stress levels are carried out on coals by the Hopkinson pressure bar. In this paper，the elastic energy is calculated based on the dissipated energy of SHPB tests. The energy release characteristics are discussed under different confining pressures and strain rates. The effect of energy release on rock fragmentation is further investigated. The results show that：based on the energy evolution process，the dynamic stress-strain curve of coals can be divided into 5 stages under impact load. The obvious strain rate effect of coal was proved. The energy release lag effect was discovered in the process of rock failure. The elastic energy is released after the peak stress. As the strain rate increases，it is found that the elastic energy storage limit increases with quadratic polynomial and the elastic energy release stress increases linearly. The normalized value of release stress is found to increase linearly under uniaxial condition and decrease linearly under triaxial condition. With the increase of confining pressure，the strain rate dependence of release stress is weakened. The energy index W is put forward based on the release degree of elastic property. The effect of rock fragmentation can be reflected by W. The inverse relationship between W and fragmentation degree of coal rock was found. A new reference means for improving rock-breaking effect and preventing dynamic disaster are provided through W.

To better reveal the mechanism of rock fracture from the perspective of mineral meso-structure, a digital model of rock is constructed based on polarizing microscopy，computed tomography(CT) technology and digital image processing(DIP) technology，and the meso-structural characteristics of rock，such as actual mineral composition，content and spatial distribution，can be reflected through it. By comparing the results of numerical simulation experiments and physical experiments，it is found that the fracture process of the model is basically consistent with that of the real rock. The meso-fracture behavior of rock during deformation and failure, such as the initiation location, extended mode and generation mechanism of fractures in different types of mineral fractures, can be simulated. The modes of rock fracture propagation，such as transgranular and intergranular，and the types of failure，such as tensile and shear，can also be identified and quantitatively analyzed. It is found that the crack propagation mode is related to the strength of mechanical properties of mineral crystals. Specifically，the expansion mode at the strong mineral crystal is intergranular，and the expansion mode at the weak mineral crystal is intergranular and transgranular. In addition，the propagation mode of crack is also related to its mechanical mechanism. The tensile cracks，which generated in the stable development stage of micro fracture，whose propagation mode is intergranular at the strong mineral crystal，and the crack type is intergranular tensile crack. But the propagation mode at weak mineral crystal is transgranular，the crack type is intragranular tension crack. The shear cracks，which produced in the unstable fracture development stage and the post-peak failure stage，whose propagation mode at both strong and weak mineral crystals is intergranular，and the crack type is intergranular shear crack. From the perspective of crack network formation，when the distribution of strong and weak mineral crystals is relatively concentrated，a backbone crack network is formed. When the distribution of strong and weak mineral crystals is discrete，a network crack network is formed.

The landslide boundaries and their spatial shapes usually appear as irregular polygonal surfaces such as semi-circle and dustpan. However，literature review shows that inaccurate landslide point and buffer circle are commonly used as the landslide boundary for landslide susceptibility prediction(LSP)，leading to some uncertainties in the LSP results. To study the effects of different landslide boundaries on the LSP modelling，337 landslides and 10 types of environmental factors in Shangyou County of Jiangxi Province are taken as basic data. The correlations between environmental factors and landslides are built based on different landslide boundaries forms of point，buffer circle and accurate polygonal surface. Next，the multi-layer perceptron(MLP) and random forest(RF) are selected to build six kinds of LSP models，namely，Point，circle and polygon-based MLP and RF models. Finally，three methods are used to analyse the LSP uncertainties，including the ROC accuracy，difference significance analysis and distribution rules of landslide susceptibility indexs. Results show that：(1) LSP uncertainties will increase under the landslide boundaries of landslide point or buffer circle，while the accuracy and reliability of LSP results will increase under the accurate landslide polygon boundaries. (2) The uncertainty rules of LSP obtained by MLP and RF models are consistent，however，the uncertainty of RF is lower than those of MLP. (3) The LSP results of point and buffer circle based models can also reflect the spatial distribution rules of landslide probability on the whole，and can be used as a substitute scheme in the absence of accurate landslide boundaries.

Understanding the friction behavior of planar rock joints is the basis for exploring the shear mechanical properties of undulating joints and rough joints. It is also of great significance for preventing caverns from instability and slope landslides. To explore the relationship between the friction behavior and the shear rate，firstly，artificial rock joints are subjected to direct shear tests at 5 shear rates；and then，variations in shear strength，friction coefficient，shear stiffness and joint surface abrasion with shear rate are analyzed. Finally，combined with the particle discrete element method，the effect mechanism of shear rate on friction coefficient is analyzed from the perspective of contact shift. Tested results show that with the increase of shear rate，shear strength and stiffness show a decreasing trend，and the decreasing amplitude gradually weakens. Under different normal pressures，similar increasing trends of shear strength and stiffness can be observed. The friction coefficient of a joint surface and the logarithm of shear rate are negatively correlated，and the corresponding empirical model is obtained by regression. The scratch depth of a joint surface tends to decrease with the increase of shear rate. The abrasion area may be less affected by shear rate. Simulated results show that the increased shear rates shift the position of center points of the joint contacts. Therefore，the contact overlap of particles decreases，resulting in a decrease in the contact shear force. The macroscopic manifestation is a decrease in the shear strength and the friction coefficient. The increase of shear rate leads to a decrease of abrasion depth of asperities on the joint surface，which is an important effect mechanism of shear rate on the friction behavior of joints.

In order to describe the mechanical behavior of geo-materials accurately and conveniently，the resistance of geotechnical materials is divided into generalized bonding force and friction force based on the failure mechanism of rock and soil shear plane. The method of combining theoretical analysis with experiment is adopted in this paper. A hyperbolic function is proposed to describe the alternative actions of the cohesive force and friction based on their out-of-sync feature. A new type of hyperbolic mechanics model is established based on the Mohr-coulomb strength theory. Physical meaning of the model parameters are discussed as well as their determination method. The critical deformation value of geotechnical material can be estimated by the proposed model. The proposed model has clear meaning and simple structure，and can describe most of the mechanical behavior characteristics of geomaterials，such as elasto-brittle，ideal elasto-plastic，elasto-plastic hardening and elasto-plastic softening material behavior characteristics，especially for the strain softening characteristics of materials after failure. Finally，the stress-deformation data obtained from shear tests on red clay and the contact surface between red clay and steel plate were used to verify the model，and the consistent results were obtained.

The implementation of the existing coal mine rock burst prevention and control measures are closely related to the pressure relief project. Based on the widely recognized rock burst energy theory，it is proposed to use different pressure relief measures to reduce the high stress concentration of rock mass in the impact danger area，effectively avoided the generation of numerous rock burst，but even when the on-site pressure relief work is sufficient，The rock burst still occurs. In addition，the prevention and control of rock burst and the roadway support themselves as a pair of contradictions，which exacerbates the complexity of the theoretical research work . In order to further to refine the rationality of pressure relief measures，the pressure relief measures are transformed from engineering scales to laboratory scale pressure relief measures. In this paper，the static load was applied by uniaxial compression，and the damage evolution law of two commonly used pressure relief methods of coal samples was obtained at the indoor scale，the consistency of the“dual energy”index is analyzed，and a collaborative early warning mechanism is constructed. The test results show that：water injection pressure relief measures can well reduce the impact tendency towards the overall coal sample，while drilling pressure relief measures to increase the impact tendency towards the coal sample，and its main purpose is to artificially guide the energy release. So it needs Determine the adaptive pressure relief measures based on the actual situation；in addition，the“calculated energy”purely through energy theory has a certain unity，and the introduction to the“monitoring energy”indexed that destroys the entire process of acoustic emission，data statistics show that the two have cross-scale consistency. Therefore，based on the above concept，the“dual energy”indexed of the failure process of the loaded coal sample is tried to be introduced into the idea of ''identifying the precursors of the failure of the loaded coal sample，and finally a collaborative early warning mechanism is formed. Among them，the water–pore–fracture coupling medium and the intact coal matrix forms/formed a relatively stable elastic body in the process of water injection and pressure relief，which is manifested by the stable storage of elastic strain energy and the slow increase in dissipated strain energy. In addition，due to the existence of high pore water pressure and water Various synergistic effects such as the lubrication of the coal matrix promote the rapid expansion of pores and cracks，and the dissipation of strain energy quickly rebounds and rises in a short time and quickly breaks. The borehole pressure relief measures all have a stress transfer effect on the loaded coal sample，and the large and small diameters show obvious differences. This puts forward requirements for reasonable drilling parameters on the engineering scale，thereby ensuring a reasonable and effective pressure relief effect.

In the field of slope engineering，especially in the slope engineering with high and steep dangerous rock mass，rockfall has become one of the main research topics in this field. At present，passive flexible protective net is widely used because of its superior performance. Taking the entrance slope of K158 Baima No.1 Tunnel on Chongqing—Huaihua railway as the research object，the service performance of the current passive protection system is evaluated under the assumption of rockfall in this area. Based on the theory of probability statistics，energy loss and collision rebound，the two-dimensional rockfall trajectory simulation software RocFall is used to simulate. Finally，according to the protection effect of all levels of protective nets，the service performance of passive protective nets is evaluated. The results show that：(1) in the case of no protective net，13.3% of the block in the #1 rockfall area may cause damage to the railway；(2) the current passive protection system has good protection effect for the #1 rockfall area with the mass less than 3 000 kg；(3) the fifth level protective net has no effect. (4) In the current passive protection system，the fourth level protection net mainly plays the role of energy dissipation，and the second and third level protection nets mainly play the role of interception. The research results can provide reference for the design and performance analysis of other rockfall protection.

Salt damage types of stone cultural relics are related to the water and salt migration controlled by microenvironmental conditions and are mainly affected by the evaporation rate on the rock surface. The sandstone from North Grotto Temple in Gansu Province and Leshan Giant Buddha in Sichuan Province were selected. The capillary rise test of Na2SO4 solution was carried out under conditions of RH = 12%，33%，59% and 76%，in order to simulate the relationship between salt damage characteristics and evaporation conditions. The capillary rise rate，evaporation rate and macroscopic surface phenomena of sandstone were monitored during capillary rise test. Conductivity test，ion content test，elastic wave velocity test，scanning electron microscopy(SEM) test and mercury intrusion porosimetry(MIP) test were performed after capillary rise test. The test results show that：after the capillary rise test，salt layer appears on the sandstone surface of North Grottoes Temple，and with the relative humidity from high to low，the thickness of salt layer gradually becomes thicker. However，with the relative humidity from high to low，the macroscopic salt damage of Leshan Giant Buddha sandstone shows crack propagation，efflorescence，granular disintegration and flaking. Elastic wave velocity test，MIP test and SEM test show that under the condition of RH = 76%，deterioration occurs inside the sandstone of the North Grottoes Temple and Leshan Giant Buddha. Under the condition of RH＜59%，there is almost no deterioration inside the two kinds of sandstone. Research results verify that the higher the evaporation rate is，the more easily the salt is carried to the surface，resulting in surface salt damage. On the contrary，the salt is more likely to be trapped inside the sandstone，resulting in internal salt damage.

In order to improve the construction technology of the pebble layer tunnel in the eastern part of Qinghai，the characteristics of the pebble layer distributed in the area were summarized. The surface displacement and the deformation of the tunnel roof during the excavation process were measured by the 1∶20 geometric model test. Combined with the monitoring data of the tunnel site，it reveals the rule that the arch top displacement is fast in the early stage and slow in the later stage during the excavation of the pebble layer tunnel. According to the unique sedimentary distribution law of the pebble strata in the eastern part of Qinghai，four types for tunnels to crossing the pebble strata are summarized，and their risk points and countermeasures are analyzed. Based on the construction experience of many projects in this area，it is put forward that the core concepts and important difficulties in the design and construction of the pebble layer tunnel are put，and the scope of application of small pipes and self-advancing anchors is given. In the end，the calculation formula of the maximum allowable settlement value of the ground surface under the limit state through the peck formula is deduced，which is convenient to improve the tunnel construction management.

In recent years，the technique of composite ground presents a trend from using a single column type to the combined use of multiple types of columns. This paper takes the combined composite ground improved by prefabricated vertical drains(PVDs) in combination with impervious columns as the research object. In view of the different arrangements of piles，different unit selection methods are employed. Accordingly，three analytical models for consolidation of the combined composite ground are proposed，including the outward flow model(Model A)，the inward flow model(Model B) and the outward-inward bidirectional flow model(Model C). Then a unified solution for the three models is derived. Based on this，detailed solutions are further obtained for instantaneous loading，linear loading，multi-staged instantaneous loading and multi-staged linear loading. Finally，the consolidation behavior of the combined composite foundation is analyzed by a series of the parametrical analysis. The results show that the present solutions are able to consider comprehensively the effects of the well resistance and smear effect of the PVDs，as well as disturbance effect of the constructions of the impervious columns，compared to the previous studies. Moreover，the Model C is more universal to cover all the cases of regular layout patterns of the PVDs and the impervious columns. A smaller well resistance of the PVDs，or a denser layout of the PVDs and the impervious columns，or a higher compression modulus of the impervious columns，will lead to a faster consolidation of the combined composite ground.

Nanjing Heyan Road cross-river tunnel is constructed with a super-large-diameter slurry shield (excavation diameter 15.07 m)，which needs to pass through the Nanjing Baguazhou embankment. With this project as the background，the finite element analysis software is employed to establish a three-dimensional numerical model of the super-large shield tunnel crossing the Yangtze River embankment. Taking into account construction factors such as soil excavation，slurry support，segment lining，grouting behind the lining，and ground loss，a detailed numerical simulation of the construction process is carried out. The numerical solution is compared with the monitoring data to verify the rationality of the model，and then to study the variation of the embankment settlement when the slurry shield passes through the embankment，and analyze the influence of different grouting pressures on the embankment settlement. At last，this paper summarizes the settlement control measures of the slurry shield passing through the embankment from seven aspects. The measured maximum settlement of the embankment is 21.7 mm，which is controlled within 0.5% of the height of the embankment，and a good control effect has been achieved，which can provide a reference for similar projects.

In order to study the effects of freeze-thaw cycles on the volume changes and mechanical properties of clay-gravel mixtures，the freeze-thaw test was carried out on clay-gravel mixtures，and it was concluded that the sample volume will shrink when frozen，and the sample height shrinkage is less than the diameter shrinkage. When the number of freeze-thaw cycles exceeds 5 times，the sample volume tends to be stable. Besides，a series of unconsolidated and undrained triaxial tests were conducted with the different numbers of freeze-thaw cycles under various confining pressures，and the stress-strain behavior，failure strength，elastic modulus，cohesion and angle of internal friction were analyzed. The testing results show that the mechanical properties of clay-gravel mixtures are affected considerably，but the shape of the stress-strain curve doesn?t be influenced by the freeze-thaw cycles. After the first freeze-thaw cycle，the failure strength of the sample decreased sharply，and when the number of freeze-thaw cycles exceeds 2 times，the failure strength of the sample shows a trend of slowly decreasing first and then increasing slowly as the number of freeze-thaw cycles increases. The elastic modulus under various confining pressures decreases first and then increases with the increase of the number of freeze-thaw cycles，and the samples will get a minimum elastic modulus after 4–6 freeze-thaw cycles. The cohesion decreases first and then increases slowly as the number of freeze-thaw cycles increases，but the angle of internal friction is almost unaffected by freeze-thaw cycles. It is suggested that the strength parameter after 6 freeze-thaw cycles can be used as design parameters for engineering design of clay-gravel mixtures in seasonally frozen regions.

Foundation bottom consolidation of loess tunnel has become a common means to prevent tunnel diseases. Based on Fujiayao #1 tunnel，combined with the actual situation of the tunnel bottom reinforcement with jet grouting piles，the force and deformation characteristics of the tunnel under the conditions of excavation and immersion are analyzed by indoor model test method. The results show that during the tunnel excavation period，the foundation pile-soil stress ratio is about 1.1–1.2. After penetration，the pile-soil stress ratio at the foot of the wall is about 1.4，and the bearing capacity of the reinforced pile at the foot of the wall is effectively brought into play. Under flooding conditions，as the saturated water front moves to the positions of each measuring point，the radial pressure and tangential stress of the surrounding rock at each measuring point increase to a certain extent. After the saturated front is moved to the bottom of the pile，the load-bearing capacity of the tunnel base is weakened，the overall sinking phenomenon appears，and the radial pressure and tangential stress of the surrounding rock at each measurement point are reduced. When the saturated water front moves to the bottom of the tunnel，the base pressure on the bottom of the tunnel is the largest，and the pile-soil stress ratio also reaches the maximum，about 1.1 to 1.9. When the saturated water front moves to the bottom of the pile，the tunnel undergoes rapid settlement，and the lateral deformation along the bottom of the tunnel is obvious，which easily causes the middle of the invert to bulge，and in severe cases，the invert is bulged and damaged.

Based on large-scale triaxial test and PFC3D-FLAC3D coupling analysis method，flexible servo triaxial loading models，which restore the actual shape of some large-size stones are established. The deformation and failure characteristics of soil-rock mixture(SRM) specimens and the development law of shear plane and contact force chain are studied. The numerical simulation results show that the triaxial shear process of SRM can be divided into two stages：axial compaction and lateral bulging. The axial compaction stage decreases with the increase of confining pressure，while the radial deformation increases with the increase of confining pressure. The friction angle of SRM increases with the increase of the gravel content，while the change trend of the cohesion is opposite. The impact of rock content on the friction angle and cohesion is about 10%，and rocks mainly enhance the structural of the SRM. X-shaped shear bands are formed in the middle of the sample during failure and lateral displacement mainly occurs in the middle，while the upper and lower ends have tapered elastic areas and vertical displacement mainly occurs. When the axial strain is less than 5%，the coordination number increases with the increase of the axial strain，and the porosity decreases with the increase of the axial strain while the change low is opposite when the axial strain is greater than 5%. With the increase of axial strain，the force chain gradually concentrates to the area with more rocks，and the axial force is mainly provided by the contact between rocks. The normal contact force of particles mainly provides the axial force，while the horizontal force is mainly composed of tangential bonding and friction.

As a new kind of widening structure with smaller occupied area，lower cost of ground treatment and less requirement for fill，the pile-supported reinforced-earth wall(PSRW) has been used to widen the four-lane expressway. By means of centrifugal model test，both the PSRW and the geosynthetic-reinforced pile-supported embankment(GRPS) are used respectively to widen the existing subgrades that with or without piles. A total of 4 cases are selected and both the external deformation and internal stress characteristics after widening are obtained. The test results demonstrate that the PSRW has better stability than the GRPS when used for subgrade widening，because the GRPS widen subgrade built on the original subsoil without consolidation directly without slope cutting. Widening by PSRW can reduce the surface settlement of the subgrade effectively. When the existing subgrade with piles is widened by GRPS，the effect of widened subgrade on the piles at the central axis of subgrade is far greater than that of widened by PSRW，while the axial force of piles is slightly less.

The Borehole Shear Test(BST) provides direct determination of friction angle and cohesion of soils in-situ. In recent years，BST has been gradually used to in-situ shear test for soil investigations in China. In order to reveal the deformation and strength characteristics of remolded loess by BST，the normal displacement and shear displacement observation system are added to modify the traditional BST apparatus，the model test device for BST is designed，and the influence law of shear strength parameters test results caused by the initial normal stress，normal stress increments，consolidation time and testing procedures are discussed. On this basis，the method of adjusting the test control parameters according to the shear characteristics of the tested soil layer is proposed，which can be used to guide the in-situ BSTs of loess foundation treated by cushion method and compaction method. The test results show that the normal displacement curve includes initial deformation section，quasi elastic deformation section and plastic deformation section；The shear displacement curve includes quasi elastic increasing section，plastic deformation section and shear failure section；The normal pressure applied should be controlled in the range of quasi elastic deformation section；There is no significant difference of the shear strength parameters which measured by the multi-stage testing(MT) and single-stage testing(ST)，and the measured cohesion by MT is 2.3–3.5 kPa smaller than ST，and the measured internal friction angle by MT is 0.8°–2.4° larger than ST.

A series of suction balance，equal suction drainage consolidation and equal suction and equal b-value shear tests were carried out on intact expansive soil by using unsaturated soil true triaxial apparatus to investigate the effect of intermediate principal stress and matric suction on the strength and deformation characteristics of intact expansive soil. The swelling and shrinking characteristics，yield characteristics and strength change characteristics of intact expansive soil were studied. The results show that the intact expansive soil shows an elasto-plastic volumetric strain in the process of wetting and drying，and yield suction is equal to 71 kPa. When  0 kPa≤s≤37 kPa，the expansive soil exhibits elastic swelling，when 37 kPa＜s≤71 kPa，the expansive soil exhibits elastic shrinkage，when s＞71 kPa，the expansive soil exhibits plastic shrinkage，indicating the existence of the Suction-Increase(SI) yield locus in the drying path of the expansive soil elastoplastic model. The isotropic compressive yield stress increases with an increase in suction，which verifies the existence of Loading Collapse(LC) yield locus in the elastoplastic model of expansive soil. As the suction increases，the dilatancy of the intact expansive soil increases. The dilatancy is not only closely related to the net confining pressure and suction，but also affected by the intermediate principal stress，and the dilatancy is weaker as the intermediate principal stress is larger. The cohesion increases nonlinearly with an increase in suction at different b values，and when the suction is constant，the cohesion increases with an increase in intermediate principal stress. For a given b value，the internal friction angles of expansive soils with different suctions have little difference，and the internal friction angle decreases with an increase in the intermediate principal stress. While，the suction friction angle increases nonlinearly with an increase in intermediate principal stress.

Based on the small strain model，the random field theory is combined with the finite analysis method to study the influence of the spatial variability of stiffness parameters on the surface and retaining wall deformation induced by braced excavation. A series of isotropy random field models of clay stiffness are generated by Covariance Matrix Decomposition method. With Monte-Carlo framework，the paper analyzes the influence of coefficients of variation and scales of fluctuation on the surface settlement and retaining wall deflection. The results show that the spatial variability of stiffness parameters in clay has an important influence on surface settlement and retaining wall deflection. The surface settlement and the maximum deformation ratio are the most dispersed when the scales of fluctuation is close to the excavation size while similar conclusion has not been drawn in retaining wall deflection. Compared with the corresponding deterministic results，the mean values of maximum surface settlement and maximum retaining wall deflection show different results in the stochastic analysis because of the dominant effect of low stiffness. With the help of probability statistics method，the paper studies the possibility of surface settlement and retaining wall deflection exceeding the monitoring control values，which can provide a reference for the safety warning for the maximum deformation induced by braced excavation before construction.

To investigate the impact of gauge length on the tensile mechanical indices of roots，Elymus nutans was selected as the tested objects due to its narrow variation in its diameter. After that，tension test was conducted on
the roots with its gauge length of 20，40 and 80 mm，and meanwhile tensile resistance，tensile strength，tensile strain and tensile modulus of the roots as well as its diameter were also measured. Built on these results，one-way analysis of variance(One-way ANOVA) was conducted to investigate the impact of gauge length on the tensile mechanical indices of roots，in which gauge length was taken as the independent variable and other indices as tensile resistance，tensile strength，tensile strain and tensile modulus were taken as dependent variables. And then Normal distribution，Lognormal distribution and Weibull distribution were introduced to describe the distribution of these indices. The results show that tensile resistance，tensile strength and tensile strain exhibit a decreasing trend with gauge length decreasing，while tensile modulus exhibits an opposite trend，gauge length exerts no impact on the relation between root diameter and its tensile mechanical indices. Normal distribution，Lognormal distribution and Weibull distribution could be used to describe the distribution of the tensile mechanical indices for E. nutans. The optimal distribution for both root diameter and its tensile modulus is normal distribution，and the optimal distribution for tensile resistance is Weibull distribution，indicating that the optimal for these indices is independent on gauge length，whereas the optimal distribution for tensile strength is Normal or Weibull distribution，and the optimal distribution for tensile strain is Lognormal or Weibull distribution，indicating that the optimal distribution for the two indices(tensile strength and tensile strain) are dependent on gauge length. Negative correlations between tensile resistance，tensile strength，tensile strain，and gauge length was discovered，whereas a positive correlation between tensile modulus and gauge length was found. This finding can be used to widen and deepen the theory of slope protection by vegetation，and meanwhile this conclusion has a theoretical significance and practical value in preventing soil erosion，shallow landslide and other geological hazards in areas suffering from severe soil erosion and shallow landslides.

In order to deeply analyze the characteristics of kinematic interaction(KI) and inertial interaction(II) in seismic-soil-pile-superstructure-interaction(SSPSI)，a test model with end-bearing single pile，medium-hard clay and superstructure(variable mass) is designed and studied by shaking table test. Firstly，the motion of pile cap under different test conditions is discussed，and then the contribution of kinematic interaction and inertial interaction at the upper surface of pile cap is qualitatively explained by comparing the amplification coefficient of peak acceleration. Finally，the contribution of kinematic interaction and inertial interaction under different test conditions is further explained quantitatively by defining and calculating the coherence function ratio R. The analysis results show that the pile cap mainly moves horizontally along the vibration direction，and the contribution of rotation of the pile cap to the bending moment of the pile head is very small，which can be ignored. When there is no superstructure，or the weight of superstructure is small(37.5%  and below，  is the characteristic value of pile vertical bearing capacity) whereas the amplitude of ground motion is small(0.1 g and below)，the kinematic interaction is dominant. When the weight of superstructure is small(37.5%  and below)，but the amplitude of ground motion is large(0.2 g)，or the weight of superstructure is large(75%  and above)，the inertial interaction is dominant. Therefore，when the superstructure in SSPSI is heavy，the inertial interaction has a great impact on the horizontal bearing capacity of pile foundation，and attention should be paid to the influence of vibration characteristics of superstructure in the seismic design of pile foundation for this kind of structure.

The use of geocell on slope to resist erosion is a green，economical and efficient protection method. Aiming at the problems of quantitative evaluation and engineering application of geocell reinforced slope，an analysis model of slope erosion under rainfall condition is established，and compared with existing geocell  reinforced slope erosion test. Considering the interaction between the geocell and the slope soil，the study focuses on three working conditions：bare slope，laying only the geocell and planting grass in the geocell，and the erosion prevention mechanism of geocell reinforced slope is revealed. The effects of rainfall intensity，rainfall duration，slope gradient，slope length，geocell size and grass planting conditions on runoff and soil loss of geocell reinforced slope are comprehensively studied，and the parameter sensitivity analysis is carried out based on the anti-scouring effect of geocell reinforced slope. The research results show that the geocell can reduce the amount of soil loss by 20%–40%，and can effectively play a role in preventing the slope erosion. After combining with the function of plants，the amount of soil loss can be reduced by more than 90%. Among the parameters，rainfall conditions and geocell size have a significant impact on the anti-scouring effect of the slope，while the slope parameters have a relatively small impact. The study can provide reference for the optimization design of slope reinforced by geocell.

High pressure jet grouting piles are widely used in the foundation stabilization and anti-seepage engineering of buildings in China，while traditional detection methods cannot achieve effective and real-time measurement of pile diameters. Based on the electromagnetic induction effect，the electromagnetic induction signal response characteristics of the model piles under different conditions of pile diameter，detection orientation，detection depth and additional easy magnet volume were investigated by physical simulation tests，and further analyzed and tested by linear regression method. The test results indicate that the decay rate of electromagnetic induction intensity decreases with the increase of the diameter of the model pile uniformly doped with easy magnetic material；the detection orientation and detection depth do not affect the electromagnetic induction signal response of the model pile；the additional easy magnet reduces the pile resistivity and enhances the electromagnetic induction effect；the orientation of the pile anomaly can be identified by signal response characteristics of different detection channels.

Geological hazards such as earthquakes and landslides are often encountered in bridge construction. Therefore，a 1∶100 similar ratio shaking table test is carried out to simulate the dynamic response characteristics of pier structure in the area where the bridge structure is passing through the landslide. Under the premise of satisfying the similar law，the seismic waves with different acceleration amplitudes are input as the basement excitation.Additionally，the three dynamic response parameters of acceleration, strain and earth pressure at the bridge piers are monitored. By analyzing the dynamic response of acceleration，strain and earth pressure at the bridge pier，the following conclusions are obtained：(1) The peak strain at the measuring point at the pier shows that the peak strain at the measuring point on the slope path is the smallest. Furthermore，different locations of the same pier are affected by seismic waves，which shows that the vibration response of the upper end is more intense，showing that the vibration response of the upper end is more intense. (2) The magnitudes of acceleration and peak earth pressure at the bridge piers are positively correlated with the intensity of the loaded seismic waves. (3) The correlation coefficients of acceleration and strain peaks at both the front and rear piers are greater than 0.8，with very strong correlation. This indicates that the selection of pier spacing in the model test meets the bridge design requirements and can provide a reference for bridge engineering construction. (4) According to the strain conversion at the pier，the pier will have a certain creep deformation under the action of seismic wave. The top deformation of the pier is the largest and the bottom deformation is the smallest. In practical engineering，the use of seismic materials should be selected in combination with this feature. (5) The filtering effect of the sliding zone material is stronger than that of the sliding body and bedrock material，which is reflected by the weaker vibration response of the measurement points located in the slip zone.

The unsaturated wetting deformation induced by rainfall infiltration is one of the leading sources of post-construction deformation of earth-rockfill dams，which significantly impacts the stress and deformation behavior of structures. In this study，a modified triaxial apparatus equipped with a micro-hole water distributor was newly developed to simulate the unsaturated infiltration process of rainfall in complex triaxial stress states. Then，the apparatus was used to test the unsaturated wetting deformation behavior of a rockfill material from the Nuozhadu high earth-rockfill dam，under different stress and saturation conditions. The evolution of unsaturated wetting deformation at different stages was investigated. Results show that the wetting deformation of the rockfill material mainly occurs at a relatively low water content. Generally，the unsaturated wetting deformation that exhibits similar features to the saturated wetting deformation can be characterized by the generalized-load model. The unsaturated wetting strain of rockfill material can be divided into two components，i.e.，the instantaneous wetting strain and the wet-state creep strain. The former possesses the characteristics of parallelism，and the latter exhibits features similar to those of general dry-state creep deformation.

Many achievements of electroosmotic drainage technology have been made in soft soil foundation reinforcement. Low-permeability dense clay was not well reinforced by conventional drainage consolidation method. In order to solve the problem，a low permeability dense clay sample of an open pit coal mine was selected. The electroosmotic drainage test was carried out on undisturbed soil and remolded clay samples in the laboratory. The results show that the electroosmotic drainage was divided into initial drainage stage，stable drainage stage，and later drainage stage. In practical engineering，the sharp decrease of current can be used as the end sign of electroosmotic drainage to avoid increasing energy consumption in the later drainage stage. During the reinforcement of low-permeability dense undisturbed clay by electroosmotic drainage method，the water content decreased by 13.4 % on average, the bearing capacity increased by 1.34 times on average，and the shear strength increased by 1.85 times on average. In addition，under the same conditions，the plate electrode layout has a better reinforcement effect on soil，but the electrode parallel dislocation layout is more suitable for practical engineering.

To calculate the pile foundation?s horizontal bearing capacity by the replacement hard shell method，a formula was established for calculating the horizontal resistance parameters according to the shear strength index of the foundation soil. The layered soft after the foundation is treated with the replacement hard shell method. The influence of the horizontal bearing capacity of the pile is revealed by the analytical calculation formula for the horizontal bearing capacity of the pile is derived. Under the conditions of embeddedness，the influence of the thickness and the shear strength index of the replacement hard shell layer on the increase of the horizontal bearing capacity of the pile was discussed and analyzed. The results revealed that the greater the internal friction angle of the hard shell soil and the thicker the thickness，and the greater the increase in the horizontal bearing capacity of the pile and the smaller the horizontal displacement of the pile top. Finally，a case of a pile foundation project in Zhejiang Province was studied，it indicated when the replacement thickness of the hard shell layer is 2–3 m(pile diameter 0.8 m)，the increase in bearing capacity basically reaches the maximum value and the horizontal bearing capacity of the pile foundation is increased by 7 to 15 times. However，the horizontal displacement of the pile top is reduced by 85% to 95%，as well as the maximum bending moment of the pile body is reduced by about half. This study could provide a reference tool for similar engineering applications.

To make the resource utilization of sludge，the layered reinforcement of sludge is conducted by consolidation-solidification composite technology to treat the sludge in the test site. During the test，the shallow sludge is reinforced by the solidification technology to forms a overlying crust. For the deep sludge，the vacuum preloading technology is used to reinforce it so as to improve the bearing capacity of the underlying stratum. Field test results show that the solidified agent has obvious solidified effect on the shallow sludge. When the solidified agent content is 2%–8%，the characteristic value of bearing capacity of overlying crust in shallow solidified sludge is 117–200 kPa. The deformation modulus of solidified sludge is between 8.5–14.59 MPa. The sludge after layered reinforcement can be described by a two-layer foundation model. For the two-layered foundation，the overlying crust has a certain stress diffusion effect. The stress diffusion angle of the shallow solidified sludge is between 8.28°–20.57°，which can effectively reduce the additional stress of the soft underlying stratum and the characteristic value of bearing capacity of the two-layered foundation can reach 80–170 kPa.