Precise monitoring and early warning of landslides are crucial to disaster prevention and mitigation. At present，landslide monitoring and early warning have a low success rate and a lagging early-warning time. In response to these problems，a new monitoring and early warning method was proposed based on the academic idea of “the sufficient and necessary condition for landslides is the change of Newton force”. Besides，a remote monitoring and forecasting system of Newton force for landslide geological hazards was developed. Four aspects of the system including theory，equipment，technology and engineering application were summarized in this article. First，the Newton force change law of geological catastrophes was proposed for the first time in the field of rock mechanics and a double-block mechanical model was constructed based on Newton force change measurement，forming a complete set of landslide Newton force measurement theory. Subsequently，a monitoring and early warning system and negative Possion¢s ratio(NPR) anchor cables suitable for landslide monitoring with high constant resistance，large deformation and super energy absorption characteristics, were developed. Landslide warning modes and warning levels based on Newton force measurement were proposed and an integrated landslide control technology was formed. Finally，the system was implemented at 543 monitoring points in 26 demonstration areas in China. All 16 landslide disasters within the deployment scope were successfully warned，which saved more than 100 lives and hundreds of millions of equipment and property. The scientific problem of short-term landslide prediction was successfully solved.

The landslide dams caused by landslide or avalanche debris normally have loose structure and poor stability，leading to huge breaching flood and catastrophic disaster to the downstream areas. Key processes such as stage division，cross-section and longitudinal profile evolutions，outburst flood evolution and flood routing along rivers，are discussed based on field investigations，physical modelling tests and numerical simulations. On this basis，the existing erosion equations for calculating the downward cutting and lateral spreading of landslide dams are summarized. Different from the development of artificial dams，it is found that the evolutions of the cross-section and the longitudinal direction of landslide dams are affected by the non-uniform distribution of soil materials in space and the sediment content of overflowing water. In addition，compared with other erosion relationships，the linear and hyperbolic relationships between the shear stress and the erosion resistance can better reflect the law of water-soil coupling during the failure of a landslide dam. Furthermore，five key problems are suggested for future research on landslide dam breaching，including (1) characteristics of dam breaching due to different causes，(2) effects of non-uniform distributed soil materials，(3) coupling effect of seepage and overtopping，(4) scaling effect of physical modelling tests of landslide dams，and (5) long-term impact of outburst floods on the morphology of river channels. This study provides meaningful theoretical basis for improving the prediction ability of landslide dam disaster chain and reducing the threats of dam breaching flood.

As coal mining goes deeper，the rocks are in more complex geological conditions. The strength of the surrounding rock is obviously reduced due to the action of groundwater，which seriously affects the personnel on site and the safety of production. In order to study the influence of water-rock interaction on surrounding rock properties after roadway excavation，the sandstone in a deep roadway of Wanfu Coal Mine was taken as the research object. The mineral composition，pore size and microstructure of sandstone samples were monitored by X-ray diffraction(XRD)，scanning electron microscope(SEM)，mercury intrusion(MIP) and nuclear magnetic resonance (NMR)，and the dynamic variation of the pore structure with the water content was studied. According to the mechanical test results of key water contents(0%，0.8%，1.6%，2.4% and 3.5%)，the strength softening mechanism of sandstone is discussed. The results show that the NMR T2 spectrum curve of sandstone presents a single peak characteristic. With increasing the water content，the total spectral area increases continuously，and the relaxation time corresponding to the peak shifts to the right. According to the stable stage and transformation stage of the spectral area proportion in the process，the traditional three-stage water absorption process can be further divided into four stages including rapid water absorption，uniform water absorption，pore transformation and stable water absorption，in which the pore transformation process mainly occurrs in the III stage(31–113 h). The strength of sandstone decreases non-linearly with increasing the water content，and the degree of attenuation is affected by the confining pressure. The softening degree of the strength decreases with increasing the confining pressure，and the softening coefficient of the uniaxial compressive strength is 0.372. It is believed that the expansion of clay minerals and the restriction of quartz framework are the reasons for the closure of the pores，and that the dislocation of quartz particles，the flow of pore water and the dissolution of soluble minerals will lead to the enlargement of the pores during the water absorption process. The softening mechanism at different water absorption stages is discussed. It is indicated that，in addition to the lubrication of bound water film and the decrease of the cementing capacity of clay minerals，the expansion and connectivity of the pores are also important reasons for the softening of sandstone and affect the final failure morphology of sandstone.

To study the evolution process and failure mechanism of a deep-seated toppling slope in the upper reaches of the Lancang River，base friction physical model test and universal distinct element code(UDEC) numerical simulation are carried out to simulate the instability process of a deep-seated toppling slope under the influence of valley evolution and reservoir impoundment. Displacement and velocity vector fields of the slope in different evolution stages and displacement variations of feature points are obtained by digital image correlation (DIC) and particle image velocimetry(PIV) methods. The test results show that the deep-seated toppling slope presents an accelerating deformation-decelerating creepage-traction by slope toe-integral sliding pattern，and landslide is the final outcome of toppling failure. Controlled by valley evolution，the deep-seated toppling failure experiences five stages including shear dislocation，initial bending，creep，formation of a throughgoing sliding plane and failure. Reservoir impoundment accelerates the evolution rate of toppling failure from the creep stage to the failure stage，and hence，it is suggested to adopt anti-seepage measures at the slope toe. Landslide induced by toppling mainly develops in highly toppled regions，and the formation of the scarps is an important sign for the evolution of toppling failure to enter the progressive failure stage.

Using a self-developed impact rockburst equipment，the rockburst phenomena of surrounding sandstone of elliptical caverns under true triaxial loading were reproduced. The stress acquisition system，real-time video recording system and acoustic emission(AE) system were used to investigate the sandstone rockburst failure. Specifically，the failure characteristics such as stresses，fragments，rockburst pits，velocity field and AE were discussed in detail. The results show that the process of impact rockburst of surrounding sandstone of elliptical caverns can be divided into four stages，i.e.，quiet period，small particle ejection，spalling and rockburst. Additionally，the disturbance loading makes the tangential stress of the surrounding rock increase rapidly(beyond the uniaxial compression strength)，which promotes the violent rockburst phenomenon. Furthermore，the lengths of most rockburst fragments are larger than 5 mm，and the dominant shape of the fragments is flake，which is similar to the distribution characteristics of rockburst fragments in field. Moreover，the V-shape pits are symmetrically distributed on the left and right side walls of the cavern，and their positions are perpendicular to the disturbance direction. The velocity field shows a trend of increasing and then decreasing during the both stages of spalling and rockburst，and the velocity reaches the peak at rockburst. Finally，the AE count rate is closely related to the number of loading directions，and the AE count rate and the cumulative count both increase rapidly at the rockburst stage. The main frequency band of AE gradually becomes narrow with decreasing the number of load directions，and the main frequency is mainly distributed between 100 to 200 kHz. The low-frequency(40–70 kHz)，high-frequency and ultra-high-frequency AE signals all appear at the rockburst stage，confirming the complexity of rockburst.

Compared with vertical storages，building horizontal storages in bedded salt rock deposits can avoid connecting bedded interlayers and interfaces and reduce stored oil and gas leakage risks. In this paper, the technical background and construction technique of the single-well retreating horizontal leaching method are presented, and the horizontal storage group construction schemes of single-layer star type and multi-layer staggered arrangement are presented. Based on the established multi-field coupling theory of solid-fluid-heat-mass transfer，a numerical simulation of the construction process of the single-well retreating horizontal leaching method is performed. The results show that with the help of geo-steering technology in petroleum exploration and the single-well retreating horizontal leaching method，large-scale horizontal storage groups can be built in layered salt rock deposits，greatly improving China¢s energy storage capacity. According to the multi-layer star-shaped dislocation arrangement，the net volume of a group of storages in the two-layer salt rock layer can reach more than 1.36×107 m3. To ensure the stability of the horizontal cavern and the maximum utilization of the salt rock space，in the design stage of the gas storage，the pipe string system should be arranged in the lower layer of the horizontal salt rock layer as far as possible under the premise of ensuring the reliability and airtightness of the cavern. It is also important to control the excessive upward expansion of the cavern through oil or gas injection in the leaching process. The research results can provide a technical reference for constructing domestic salt rock gas storage projects and effectively promote the construction of China¢s gas storage.

Rock deformation and failure are essentially a damaged evolution process，which includes crack closure，crack development，crack propagation and crack penetration driven by energy. The failure mechanism and complex process can preferably be analyzed from the view of energy dissipation. The conventional triaxial loading tests and acoustic emission characteristics tests on Beishan granite obtained from 550‐560 m depth were conducted to investigate the laws of strength parameter evolution and energy dissipation. Based on the stress-strain curves and acoustic emission characteristics under different confining pressures，a mathematic model describing the relationships of cohesion，internal friction angle and rock property parameters with the damage variable，namely the normalized crack volume strain －，of Beishan deep granite was established. Besides，the energy dissipation confining pressure effect equation during the process of granite fracture was established from the point of energy dissipation. Results show that：(1) the pre-peak diagram of the stress-strain curve can be divided into four different stages including crack compaction，elastic deformation，crack expansion and crack unstable growth，and the characteristic stresses at the boundary points of the stages have a linear relationship with the confining pressure，(2) with increasing the damage variable，the strength parameters c and φ of Mohr-Coulomb criterion and mi of Hoek-Brown criterion increase rapidly，then decrease slowly and finally tend to be stable，(3) there is a corresponding relationship between the AE ringing count rate and the energy cumulative number during the rock compression process，and the high frequency points of the ringing count rate are accompanied by the step growth of the energy cumulative number. The curve of the energy cumulative number can be divided into five stages such as initial stable，first rapid growth，gentle growth，second rapid growth and stable，and (4) with increasing the confining pressure，the eigenvalues of the elastic strain energy gradually increase，while the eigenvalues of the dissipated energy first change steadily，then increase by step growth and finally tend to be stable.

Heat treatment，as a potential tight gas development technique，can improve the seepage capacity of tight sandstone，while will change the rock mechanical behaviors leading to the instability of well walls. In this paper，triaxial compression experiments were carried out on the tight sandstone samples from the Xujiahe Formation in western Sichuan at room temperature and after 100 ℃‐1 200 ℃ heat treatment，and the effects of the microfabric characteristics of tight sandstone after high temperature on the mechanical properties were explored combined with DTG，XRD and SEM. The results show that with increasing the temperature，the mechanisms of microcrack initiation and propagation present clay contracts due to water lose，lamellar illite dissection，cleavage surface separation of feldspar，microcracks propagation along the intergranular and forming a network，cracking and cambium forming lamellar cracks inside the particles. In the crack damage temperature range(400 ℃‐
1 000 ℃)，the specimen is more prone to failure under external forces，and the compaction and elastic stages expand. In the ranges of room temperature ‐200 ℃，300 ℃‐1 000 ℃ and 1 100 ℃‐1 200 ℃，mineral thermal expansion，thermal induced microcrack generation and expansion，sample glazing and other physical processes dominate the change of rock mechanical properties，respectively，leading to that the compressive strength and the elastic modulus first increase，then decrease and then rise again. After heat treatment at 400 ℃，the clay minerals lose interlayer water and shrink into pongy balls，resulting in abnormally high compressive strength and elastic modulus. The dehydration of chlorite at 800 ℃ increases the brittleness of the samples and inhibits the decrease of the elastic modulus.

The Wugushan No.1 tunnel of Taijiao railway was monitored and the deformation characteristics of the surrounding rock of the weak interlayer tunnel were analyzed. Converting the mean values and standard deviations of mechanical response results of the surrounding rock and the support on multisection into the ECULID distance from the origin point on a two-dimension plane as evaluation indexes，the influence of the reinforcement parameters on the mechanical response of the surrounding rock and the support was analyzed by orthogonal experiments. Based on fuzzy decision theory，by using the ECULID distance between the simulated result of each group and the global optimal value of the multiple evaluation index as the comprehensive evaluation index，a reinforcement parameter design method was proposed. The mechanical response of the surrounding rock and the support of No.1 tunnel without grouting and with grouting using the optimal reinforcement parameter combination were respectively studied. The results demonstrate that the crown settlement of the tunnel has the characteristics of long duration，fast settlement and large final settlement. Grouting reinforcement can reduce about 70% to 80% of the crown settlement，shorten the stability time of the surrounding rock and effectively restrain the development of the surrounding rock displacement. Cohesive and shear strength have the most significant influence on the excavation response of the weak interlayer tunnel. In the non-grouting tunnel，a large bending moment and a non-negligible torque are produced at the intersection of the weak interlayer and the excavation section，and the concentrated stress occurs at the arch foot of the initial support，which makes the excavation stability of the tunnel is difficult to be guaranteed. No.1 tunnel was reinforced by grouting utilizing the reinforcement design method proposed in this paper，showing that the surrounding rock loose area is narrowed，the section torque is reduced to be negligible and the stress concentration of the initial support is positively improved.

Horizontal well segmented multi-cluster fracturing technology is a core technical means for the development of shale gas reservoirs. For truly simulating the multi-cluster fracturing progress to reveal the propagation law and mutual interference mechanism of multiple fractures within the segments，a physical simulation experiment system for the initiation and propagation of multi-cluster hydraulic fractures was developed based on an existing large triaxial hydraulic fracturing experiment system，by designing a multi-channel fracturing wellbore and composite wrapped layered artificial specimens and equipping a multi-cluster shunt and monitoring system and a strain monitoring system. The advantages and innovations of the test system include that：(1) a number of independent fracture positions can be set in the multi-channel fracturing wellbore to guarantee the sufficient fracture propagation at each perforation cluster，(2) composite wrapped layered artificial fracturing cube samples with a side length of 500 mm can be prepared by considering the maximum allowable sample size of the testing machine，the maximum fracture propagation path，the stress interference between fractures，the pressure maintenance after fracture initiation and propagation，the influence of bedding and other factors，(3) the multi-cluster shunt and monitoring system can monitor the instantaneous flow rate，the pressure and the cumulative injection volume of each cluster channel in real time，which is helpful to understand the flow competition and allocation mechanism，(4) the strain monitoring system can monitor and record the deformation characteristics of the rock mass around each perforation cluster and fracture propagation path in real time during the fracturing process，which could be used for explaining the propagation behavior of hydraulic fractures，and (5) the system can not only simulate the initiation and propagation of multiple clusters of fractures，but also imitate the ball-sealer in-stage diversion technology and re-fracturing after the initial fracturing by selectively shutting a number of channels with sufficient fluid intake. A true triaxial multi-cluster fracturing test was carried out to verify the effectiveness of the system. The test results show that the breakdown pressure of the subsequent perforation clusters gradually increases while the corresponding stimulated area decreases. The developed experiment system provides a new method for the study of multi-cluster fracturing，which can promote the in-depth study of the initiation and propagation of multi-cluster hydraulic fractures and the stress interference mechanism between the fractures.

The internal structure of oil shale，as a sedimentary rock with obvious anisotropy，will change complexly in the process of pyrolysis with water vapor as heat carrier fluid. In order to study the influence of the steam temperature on the permeability and anisotropy of oil shale，a reaction device of oil pyrolysis by water vapor injection was designed. The permeability test of oil shale samples in parallel and vertical directions was carried out，and the permeability anisotropy coefficient was calculated. At the same time，the permeability of oil shale under different heating modes was compared. The results show that the permeability of oil shale in the direction vertical to the bedding is small with a maximum of 10－2 mD，and increases 2 933 times when the pyrolysis temperature increases from 314 ℃ to 382 ℃. The order of the permeability in the direction parallel to the bedding is much larger than that in the vertical direction. When the pyrolysis temperature increases from 382 ℃ to 555 ℃，the parallel permeability also increases significantly. It is also indicated that，when the pyrolysis temperature is 314 ℃，the permeability anisotropy coefficient reaches the maximum，and that，in the process of the pyrolysis temperature increasing from 382 ℃ to 555 ℃，the permeability anisotropy coefficient is small and basically increases slowly. The difference of the permeability of oil shale between steam heating and direct retorting is mainly reflected in the direction parallel to the bedding，and the permeability of oil shale in the direction parallel to the bedding after high-temperature water vapor treatment increases more significantly than that after direct retorting when the pyrolysis temperature increases from 314 ℃ to 382 ℃.

In order to solve the serious deformation and difficult support problems for the gob-side entry retaining in the working face front section，taking the transport entry in LW2901 working face of Juji coal mine as the field project，the surrounding rock stability control of the gob-side entry retaining in the front section of the working face by anchor-cable strengthened technology was investigated through theoretical analysis，numerical simulation and field measurement. By establishing the mechanical structure models for the gob-side entry retaining roof with the consideration of roof cutting or not，the equations of the support strength and the subsidence of the roof were derived. The results show that，compared to the roof without cutting，the subsidence and the support strength of the cutting roof reduce 46.4% and 40.4% respectively，which proves that gob-side entry retaining is an effective entry surrounding rock control way. The surrounding rock damage characteristics under different strengthened support schemes were simulated by the software of FLAC3D，and the reasonable design scheme was determined as “4–   3–3–3–4”cyclic arrangement of reinforcing anchor cables along the direction of the entry. With increasing the number of the strengthened anchors，the stress and deformation of the surrounding rock gradually decrease and the decrease rate shows a decreasing trend. The in-site monitoring results show that the maximum values of the roof subsidence，the floor heaving and the coal wall deformation are 451 mm，550 mm and 507 mm，respectively. The successful practice of the anchor-cable strengthened support technology of the gob-side entry retaining with roof cutting and pressure releasing in the front section of the working face provides a useful reference for the surrounding rock control under similar conditions.

The regional landslide susceptibility assessment is the basis of landslide hazards and risk assessments. However，how to scientifically select landslide conditioning factors is still a weak part of the previous researches. 1022 identified landslides induced by the Jiuzhaigou earthquake in the Jiuzhaigou National Geopark on August 8，2017 were taken as the sample dataset. A total of 16 landslide causative factors including seismic，topographic，geological，hydrological parameters and human engineering activities were selected. Based on the collinearity test of these continuous conditioning factors，the logistic regression(LR) model was used to generate 30 landslide assessment models by combining different covariates under the slope units，and then the 10-fold cross-validation and receiver operating characteristics(ROC) curve were adopted to assess success rate and prediction accuracy of the models in R statistic software. The results show that the LR model has good applicability in the earthquake-induced landslides(EQILs) susceptibility assessment for the study area，and EQILs are mainly controlled and affected by seismic and topographic parameters. Once hydrological conditions and human engineering activities are excluded out，the performance of the models decreases within a small range. Moreover，compared to the traditional data sampling methods，the cross-validation approach can effectively reduce selection bias and prediction variance，and can better test the robustness of the models. This research may enrich the theoretical research content of EQILs regional assessment and provide references for rapid post-earthquake assessment and disaster prevention and mitigation for the Jiuzhaigou area.

Theory and experiments show that the general twin-shear stress criterion can represent the shear strength of soil and rock more accurately than the conventional Mohr-Coulomb criterion. However，there is no constitutive model based on the general twin-shear stress criterion in the existing large-scale finite element software. The smoothed function proposed by Gudehus-Argyr is essentially a corner model of the general twin-shear stress criterion for removing the sharp edges of the Mohr-Coulomb criterion. On the basis of studying the corner model，a plastic potential function was established，and the expressions of all flow vectors were deduced. In line with the complete implicit backward Euler integration algorithm，the corresponding user material subroutine UMAT was programed using the Fortran language in ABAQUS. The UMAT was applied in numerically modeling the conventional triaxial compression test，the uniaxial tension test and true axial test as well as in analyzing the stability of an embankment，and the modeling results were compared with those by the embedded Mohr-Coulomb model in ABAQUS. It is shown that the numerical implementation approach of the corner model is completely correct and reliable，and is beneficial to the practical application of the general twin- shear stress criterion to overcome the conservative flaw that the conventional Mohr-Coulomb model is prone to.

When a shield tunnel passes through a gas-bearing formation，the presence of shallow gas will affect the normal construction of the subway. Relying on an actual project of a shield tunneling through gas-bearing strata，a theoretical calculation formula for soil deformation caused by shield construction in gas-bearing formations was proposed for the first time by equalizing the soil deformation after deflation to the local uniform settlement and considering construction factors including soil squeezing effect，soil softening，grouting pressure and soil loss. The research shows that the theoretical calculation results are in good agreement with the measured data，and can better reflect the characteristics of surface deformation caused by shield tunneling in gas-bearing formations. Comparison with the surface deformation characteristics of saturated soil layers indicates that the matrix suction in the gas-bearing formations caused by the residual gas respectively increases the uplift deformation of the soil in front of the shield and the settlement deformation behind the shield tail by about 30% and 20%. When the gas-bearing layer is thick，the air-bearing soil friction in front of the shield excavation is relatively large. In the theoretical calculation and analysis，the cutter head thrust correction coefficient or the interface friction angle can be appropriately increased.

Aiming at the status that some one-dimensional large strain consolidation analytical solutions fail to fully consider the non-linear compression and permeability characteristics of soft soils，in this paper，data analysis of large numbers of laboratory compressibility and permeability tests was conducted， showing that there are good linear relationships between the void ratio with the effective stress and the permeability coefficient in the bi-logarithmic coordinate system，and the variation ranges of parameters for the bi-logarithmic model were also provided. The nonlinear compressibility and permeability model in the bi-logarithmic coordinate system can not only effectively describe the nonlinear consolidation characteristics of soft soils under the condition of small strain，but also reliably reflect the compression and permeability characteristics of soft soils under the condition of large strain. Based on the nonlinear compressibility and permeability model in the bi-logarithmic coordinate system，a one-dimensional nonlinear large-strain consolidation model for thin soft soil layer was developed in the Lagrangian coordinate system by considering the excess pore pressure as a variable. Besides，the analytical solutions for the nonlinear large-strain consolidation model under three conditions were derived，respectively. Then，the reliability of the analytical theory was verified by comparing with laboratory test results and finite difference solutions. Finally，the differences in consolidation behaviors between large and small strain consolidation theories under different strain conditions were discussed. It is found that，when the soil strain is about 15%，the deviation from the excess pore pressure between large and small strain consolidation theories can reach 15%，indicating that it¢s rather necessary to use large strain consolidation theory to calculate consolidation when the corresponding soil strain reaches or larger than 15%.

In the process of shield tunnelling，once the permeability of conditioned soils is too high，it is easy to cause water spewing. Therefore，it is very important to predict the permeability of foam-conditioned soils. In this paper，a theoretical calculation model of the permeability coefficient of foam-conditioned soils was proposed based on the modified equivalent gradation method. Combined with the results of large permeability tests，the prediction accuracy and application range of the developed method were compared with the effective permeation channel method. The results show that the predicted permeability coefficients of the two methods are distributed in the same magnitude with the measured values. The predicted values by the effective permeation channel method are closer to the measured values，and the predicted values by the modified equivalent gradation method are larger than the measured values. On the whole，the predicted values by the modified equivalent gradation method maintain the same growth and reduce trend with the measured values，even for coarse-grained soils. Due to that the modified equivalent gradation method does not consider the conditioning states of foam-conditioned soils，it is applicable to a wider range of soil particle size and easy to be popularized in practical engineering applications.

The excavation of shield tunnels usually causes non-uniform settlement，which shows a general law that the farther away from the excavation surface，the smaller the settlement. The non-uniform settlement causes shear stress in the soil，rotates the principal stress axis of the soil and hence，changes the stress state of the soil. Based on the results of early indoor sand soil model tests，theoretical derivation and numerical simulation methods were adopted to study the influence of principal stress axis rotation on the active limit support pressure for deep shield tunnels. Firstly，the influence of the soil arching effect on the limit support pressure was analytically discussed when the tunnel face was local instability and global instability. Then，combined with the traditional Terzaghi loose earth pressure formula，a general solution of the local instability limit support pressure was derived. Further，considering the principal stress rotation of the front soil during the deformation of the tunnel face，a formula of the active limit support pressure for the global instability of the deep-buried shield tunnel face was derived. The limit support pressure gradually increases with increasing the burial depth and tends to be constant while the burial depth ratio is greater than 3. The limit support pressure of the tunnel face decreases with increasing the internal friction angle，while increases with increasing the cohesion. Both the inclination angle of the wedge and the height of the prism have a significant impact on the limit support pressure.