In order to prevent premature breakage of anchor cables under shear loads in support engineering，a structure named Anchor Cable with C-shaped tube(ACC) was proposed，which combines a C-shaped steel tube with anchor cables. Shear strengthening mechanism of this structure has not yet been fully revealed. A nonlinear finite element refined model of the ACC was established using ABAQUS software. The actual model of the seven-strand structure was adopted for the anchor cable，and shear resistance mechanism of ACC was studied considering the contact，failure，and other interactions of each component. The results show that in the initial stage of shearing，ACC forms an “S” shape of bending and symmetrical plastic hinge under the action of shear force at the shear plane and symmetrically distributed bending moment. Afterwards，the deformation is mainly caused by extension of the plastic hinge away from the shear plane and the stretching of the middle part of the anchor cable. Finally，the failure reason of ACC is the tensile-shear composite failure of the anchor cable，which is mainly tensile fracture. With the increase of the shear load，the C-shaped tube gradually closes within the bending range of the anchor cable，and works together with the anchor cable to enhance the overall bending stiffness of the structure. The slit opening and overall torsion of both ends of C-shaped tube are coordinated with the closure deformation of its middle part. C-shaped tube can make the distribution of the contact pressure more uniform between the structure and the concrete blocks，improving stress conditions. Partial concrete located at the interface of blocks is in a triaxial compression state. With the increase of the shear load，the bearing area gradually expands inside the concrete blocks，and the progressive failure of concrete occurs synchronously with the expansion of plastic hinge of ACC.

In underground engineering such as geological disposal of nuclear waste and geothermal development，the continued high temperature effect leads to a significant reduction in the strength and deformation properties of rocks，inducing engineering disasters. Therefore，it is great significance to investigate the characteristic stress and acoustic emission characteristics of granite under continued high temperature. Uniaxial compression acoustic emission(AE) tests were conducted on granite after different high temperature duration with 350 ℃ and 950 ℃ as the target temperatures. The influence of high temperature duration on characteristic stress points and acoustic emission characteristics was analyzed. The results show that：(1) The granite mass loss rate，volume expansion rate，and P-wave velocity decay rate increase exponentially with increasing high temperature duration. (2) The uniaxial compressive strength，elastic modulus，peak strain and characteristic stress increase exponentially with the increase high temperature duration at 350 ℃. The uniaxial compressive strength，elastic modulus and characteristic stress decrease exponentially with the increase of high temperature duration at 950 ℃ and peak strain opposite. (3) The sensitivity of the characteristic stress under high temperature duration is different，ie. closure stress＞cracking stress＞damage stress＞peak stress. (4) Under 350 ℃ continued high temperature，with the increase of high temperature duration，the AE main frequency of the characteristic stress decreases，the amplitude of AE increases，the multifractal parameters increase，and the small-scale fracture is gradually dominant. Under 950 ℃ continued high temperature，with the increase of high temperature duration，the AE main frequency of the characteristic stress decreases，the amplitude of AE decreases，the multifractal parameters decrease，and the large-scale fracture is gradually dominant. (5) The variations of thermal induced cracks and pores caused by high temperature mainly occur before the duration of 8 h，and after exceeding 8 hours，the impact of high temperature duration on them is significantly reduced.

At present，the complexity of geotechnical engineering problems is still difficult to be satisfactorily solved by theoretical research or numerical simulation methods. Physical model tests offer a more effective solution to these issues. Extensive research has been conducted on physical model tests and three-dimensional hydraulic loading devices. In response to that small-size devices are difficult to consider and involve the influence of geological structural factors，as well as the difficulty in sealing the box of large-sized three-dimensional hydraulic loading devices，a large-scale true three-dimensional hydraulic loading sealing test device was independently developed. The counter force frame of the device is 4 300 mm×3 580 mm×3 150 mm(length×width×height)，and the test loading box has overall dimensions of 2 050 mm×1 400 mm×1 300 mm(length×width×height). This box is a three-way true triaxial loading sealed box capable of conducting true triaxial loading tests on coal and rock samples under 10 MPa in-situ stress and 3 MPa high-pressure gas conditions. Simultaneously，a similar simulation test of coal and gas outbursts during tunneling in the area of coal seam thickness variation was conducted using a dedicated test platform，and the change rules of gas pressure，coal rock stress and temperature were studied. During gas charging，the coal adsorbs gas and releases heat，leading to a rise in temperature within the coal seam. Before the outburst，the stress value in the coal thickness variation area is large. At the moment of the outburst，the high-speed gas flow of the outburst carries the broken coal and rocks out，and the gas pressure near the outburst point drops rapidly. After the outburst，the gas desorption and external expansion work make the temperature in the coal seam drop. The temperature change near the structural belt in the coal thickness variation area is the most significant，the maximum drop can reach 7.3 ℃. The stress at the coal rock interface of the top and bottom plates decreases sharply at the same time. The coal thickness variation area produces a high stress concentration，and the stress value has a short rise process，with the maximum value reaching 1.4 MPa. The mass ratio of coal powder is 34.75%. Finally，based on the experimental results，the energy analysis of the outburst process in the coal thickness variation zone was carried out. The experimental results comply with the energy instability criterion for coal and gas outburst，and the disturbance caused by external forces on coal can directly or indirectly induce the occurrence of coal and gas outburst.

Bedded rock slopes are widely present in the nature. The research of the deformation and failure mechanism of bedded rock slopes is an important topic in slope engineering. Using bottom friction tests and numerical simulation methods，the failure mechanism of bedded rock slopes with different rock dip angles was contrastive analysis. The results show that：(1) the failure mechanism of slopes changes significantly with different rock dip angles. When the dip angle is10°，the failure mode of slopes is slip-tension，when the dip angle is 30°，the failure mode is plane sliding shear，when the dip angle is 45°，the failure mode is slip-compression，and when the dip angle is 75°，the failure mode is bending-toppling. (2) Based on monitoring point image tracking technology，the failure process of bedded rock slopes is obtained，and the displacement results of characteristic points indicate that the deformation and failure of bedded slopes have obvious stages. (3) The safety factor of slopes is non-linearly related to the inclination angle of rock layers. When the inclination angle of rock layers is 0°–25°，the safety factor gradually decreases with the increase of the inclination angle of rock layers. When the inclination angle of rock layers is 25°–70°，the safety factor gradually increases with the increase of the inclination angle of rock layers. After the inclination angle of rock layers is greater than 65°，the safety factor of slopes don’t change much. The results of bottom friction test matches numerical analysis on slope stability closely. The significant difference in stability of bedded rock slopes with different rock dip angles is attributed to the significant changes in slope failure mechanisms. The findings of this study can provide reference for the safety evaluation and disaster identification of bedded rock slopes.

In order to reveal the unloading creep failure mechanism of water-bearing mudstone，the rising axial pressure-reducing confining pressure creep tests，meso-structure tests and numerical simulation analysis were carried out for mudstone with different water contents. The test results show that the water content has a significant effect on the creep deformation of mudstone，and the axial strain is significantly more affected by the water content than laterally at the same creep stress level. SEM image analysis shows that the increase of moisture content leads to the increase of internal porosity of mudstone，and the mineral particles are dissolved and weakened，which is transformed from a dense and high strength to a loose porous and irregular accumulation structure with low strength. Based on the real meso-structure characteristics of mudstone，a statistically equivalent meso-structure network is generated，and the corresponding GBM-PSC numerical model is established and verified. The numerical simulation results show that the number of microcracks increases with the increase of moisture content，and the number of intragranular tensile cracks increases first and then stabilizes and then increases，while the number of intergranular shear cracks continues to increase with the increase of moisture content. The contact tangential force，angular deflection value and average porosity decrease first and then stabilize and then increase with the increase of unloading creep time，and the more the moisture content increases，the more significant the trend. Final，a three-stage unloading creep deterioration evolution model of dry and water-bearing mudstone is established. The research results can provide a theoretical reference for the study of the creep deformation failure mechanism of excavation and unloading of soft rock engineering under the action of water.

In the process of close-distance seam group mining，multiple mining will cause significant cyclic loading and unloading effects. In order to study the stability of coal pillar and surrounding rock under cyclic stress，uniaxial cyclic loading and unloading tests of coal or rock single body and coal-rock combination combined with acoustic emission signal monitoring and PFC3D numerical simulation calculation were carried out. The results show that，under cyclic loading and unloading，the stress-strain curve of the specimen presents the characteristics of “thinning- dense-thinning”. Combined with the acoustic emission count and the number of cracks derived，the deformation process can be divided into the pore and fracture compaction stage，the elastic deformation and crack stable development stage，and the crack unstable development stage. Cyclic load can strengthen the strength of coal，but weaken the strength of rock. In the test，the average elastic modulus of different compositions increases by 7.03% to 18.95% compared with that of single coal，and decreases by 0.48% to 6.76% compared with that of single rock. The strengthening effect for coal or weakening effect for rock is positively correlated with the strength difference between the single specimens that forming the combination. In the process of cyclic loading and unloading，the crack initiation rate and crack number of specimens are related to their strength and deformation characteristics. The crack development of brittle rock specimens is mainly concentrated in the stage of crack unstable development，and the higher the strength of specimens，the more concentrated the stage of crack unstable development，while the crack development of plastic rock specimens is in a relatively active state during the whole process of cyclic loading and unloading. The fracture pattern of coal and rock single body specimens under cyclic loading and unloading test is mainly compression-shear failure，showing a single inclined plane shear failure crack. When the coal-rock combination fails，the end of the coal body first forms columnar splitting or inclined plane shear failure，the fracture surface is deflected when extends to the coal-rock interface，and extending to the combination boundary. The deflection angle increases with the increase of rock strength in the combination. In the cyclic loading and unloading test，both the elastic energy and dissipative energy of the specimen showed an increasing trend，and the elastic energy and dissipative energy generated in a single cycle were negatively correlated with their own strength characteristics，but the elastic energy and dissipative energy generated in the cyclic accumulation were positively correlated with the specimen's own strength. According to the research results，it is beneficial to improve the supporting capacity of coal pillar under the disturbance of cyclic mining stress to change the strength of surrounding rock and the cementation between coal pillar and surrounding rock.

The rock-breaking technology of ultrasonic vibration has significant advantage and development potential. In order to study the evolution law of micro damage and utilization efficiency of fracture energy in rock under the action of ultrasonic vibration，combined with physical experiment and microscopic parameter calibration，the relationship of macro and micro mechanical responses in green sandstone was established. The evolution laws of contact force field，failure characteristics and crack characteristics under the action of ultrasonic vibration were analyzed，and the utilization efficiency of fracture energy was studied. The results show that：(1) in the initial stage of excitation，the maximum contact force is concentrated in the upper end of the green sandstone，while the internal contact force is relatively small，showing an obvious “V” shape. With the increase of the excitation，the contact force continues to increase，and the original disorderly distribution of the contact force is gradually distributed in the regular distribution，transmitting to the lower end in the form of wave. (2) The failure process of green sandstone can be divided into the three stages of emergence，expansion，and penetration，and the final failure is characterized by unilateral shear failure. Under the same vibration frequency，with the increase of amplitude，the number of damaged blocks and cracks in green sandstone generally shows the upward sloping trend. Under the same amplitude，with the increase of vibration frequency，the number of damaged blocks and cracks in the green sandstone shows the up and down fluctuating trend. (3) The order of crack generation time is as follows：maximum value of shear crack(acoustic emission)，maximum value of tensile crack(acoustic emission)，equal cumulative crack (tensile and shear cracks). In the initial stage of ultrasonic vibration excitation，the green sandstone is dominated by shear cracks，and eventually by tensile cracks，and the tensile effect plays the major role in the failure process. During this process，the cracks mainly expand in the direction parallel to the ultrasonic vibration load，while cracks expand less in the horizontal direction. (4) Under the same vibration frequency，with the increase of amplitude，the utilization efficiency of fracture energy in green sandstone shows the decreasing and fluctuating trend. Under the same amplitude，with the increase of vibration frequency，the utilization efficiency of fracture energy in green sandstone shows the up and down fluctuating trend. The range of the utilization efficiency of fracture energy is 9.448%‐12.456%. The research results not only preliminarily explore the damage evolution law and utilization efficiency of fracture energy in green sandstone under the action of ultrasonic vibration from the microscopic perspective，but also provide reference for the reasonable selection of parameters in the crushing process of rock.

This study explores the macroscopic dynamic mechanical properties，crack propagation rules and failure mechanisms of plate specimens with prefabricated interface cracks. A separate Hopkinson pressure bar was used to apply impact dynamic loads of different strengths to three specimens with different interface inclination angles，and a high-speed camera system was used to record the crack expansion process. The research results show that the dynamic stress-strain curve shapes of different types of samples are quite different，showing single or double peaks at the stress peak. The smaller the incident wave peak，the greater the influence of the joint plane angle on the dynamic compressive strength of the sample. A total of 6 crack types were identified based on the crack shape，crack initiation position and fracture mechanism. As the incident energy increases，the number of cracks in the sample increases，and the sample changes from a single splitting tensile failure mode to a complex tensile-shear composite failure mode. A “transition zone” of material strength is formed at the specimen interface. Factors such as the interface inclination，the elastic modulus of the rock masses on both sides，and Poisson?s ratio determine the stress state and strength characteristics of the transition zone. The sample cracks first at the end of the prefabricated crack and the new cracks will generally expand across the weak-side strengthening zone and the weak-side part. As the peak stress of the incident wave increases，they will transform from type I tensile cracks to type II or type III shear cracks. Far-field cracks appear relatively more on the weak side，while tensile cracks only appear on the strong side. The interface and prefabricated cracks create a complex stress environment and strength conditions in different areas of the specimen，making the crack interface and crack tip jointly dominate the typical crack path. Experimental research on the failure characteristics of rock masses containing interface cracks is the basis for the calculation of crack propagation in layered rock masses at an engineering scale and is of great significance for solving engineering stability problems of layered rock masses.

The high temperature-water cooling effect causes different degrees of damage to rock in underground engineering. The mechanical properties of the damage rock are related to the safety and stability of the engineering，and its acoustic characteristics are related to the failure analysis，prediction and early warning of surrounding rock. Relevant research has important scientific value and engineering significance. In this study，the biaxial compression test of granite with different damage degrees after high temperature-water cooling treatment was carried out by using true triaxial test system. Acoustic emission(AE) and microseismic(MS) systems were used to monitor the failure process of rock. The biaxial strength and deformation，acoustic signal evolution characteristics and precursor information of granites with different degrees of damage were analyzed. The influence of initial damage of rock on its fracture type was discussed，and the time-frequency domain characteristics of microseismic and acoustic emission signals were compared. The main conclusions are as follows. (1) The higher the initial damage degree(D) of granite，the lower the biaxial strength and elastic modulus of rock are. When D＞0.4，the decrease of biaxial strength and elastic modulus is significantly larger than that when D＜0.4. At the same time，the failure of rock samples changes from brittle mode to ductile mode，and the rock internal fracture changes from tensile type to shear type. (2) With the increase of rock damage degree，the AE cumulative absolute energy of rock samples decreases greatly. The evolution characteristics of acoustic signal parameters show obvious differences when D＞0.4 and D＜0.4. Compared with the rock samples with low damage degree，the moment of first sudden increase of AE hits and MS amplitude evolution curves of the rock samples with high damage degree generally appears earlier，more high amplitude signals emerge，and the duration of signal active period sustains longer. (3) Based on AE and MS signals，some precursor information of rock failure and the criterion of rock initial damage degree can be concluded. For example，the phenomenon that the MS fractal dimension increases and decreases sharply after the peak load can be used as a failure precursory information of the rock with different damage degrees，and the sudden decrease of MS or AE b value below 1 can be used as a failure precursory information of the rock with a low damage degree. The phenomenon that the AE b value decreases to less than 1 in the plastic stage occurs many times，and the MS fractal dimension fluctuates sharply before the peak load，which can be used as the basis for judging the initial damage degree of rock. The research results can provide reference for the analysis of surrounding rock stability and the evaluation of rock damage degree in underground engineering.

The existence of cracks in rock mass can affect the stability of rock engineering，and the distribution form of cracks and the groundwater have a significant impact on the mechanical properties and fracture evolution law of rock mass. By conducting uniaxial compression tests on sandstone samples with tip intersecting cracks，the effects of the intersecting angle between tip intersecting cracks and the groundwater on the strength，deformation，and fracture evolution characteristics of sandstone were studied. The research results indicate that the intersecting angle between the tip intersecting cracks and the groundwater have a significant impact on the mechanical properties and fracture evolution law of sandstone. The tip intersecting cracks will cause the stress-strain curve of the rock sample to enter the crack initiation and propagation stage earlier，and there will be a significant stress drop phenomenon before the peak stress，while a stepped drop phenomenon will appear in the post peak failure stage. As the angle between the tip intersecting cracks increases，the peak stress and initiation stress of the sample gradually increase，and the stress concentration area transitions from the inner tip of the inclined crack to the outer tip. The presence of groundwater will increase the ductility of rock samples with tip intersecting cracks，weaken the stress drop and step drop phenomenon generated by tip intersecting cracks in the stress-strain curve，and make the peak stress and initiation stress of rock samples show a trend of first decreasing，then increasing，and then decreasing with the increase of the angle between tip intersecting cracks at. In addition，the presence of groundwater will weaken the degree of stress concentration at the cracks of rock samples，reduce the number of crack initiation，and make horizontal crack the dominant crack for the failure of saturated rock samples with tip intersecting fractures.

In this work，direct shear tests，DEM simulation and theoretical analysis were conducted to reveal and characterize the multi-scale failure mechanism of soil-rock mixtures with lower rock block proportions. The experimental results show that the shear dilatancy of soil-rock mixture is determined jointly by soil density，volumetric block proportion(VBP) and normal stress condition. Significant nonlinear characteristics appears in the internal friction angle evolution of cohesionless soil-rock mixture(VBP＜30%)，and the apparent cohesion induced by the rock block structure was generated from the strength analysis of Mohr-Coulomb criterion. Indicated by the DEM simulation results，the special mechanical pattern of soil-rock mixtures is formed by the block-in-matrix fabric on the micro and meso scale，such as the uneven distribution of contact force and the tortuosity of shear zone，which is distinguished from that of the homogenous sand matrix. Furthermore，based on the in-depth discussions on engineering geological characteristics and failure mechanism of soil-rock mixtures，a new formula was proposed to interpret the mechanism of the rock block structure. Through the stress transfer analysis，it was figured out that Lindquist's modified strength model is a simplified expression. Meanwhile，a novel strength criterion(equivalent roughness model) has been established，which presents the rationality in predicting the nonlinear strength evolution of soil-rock mixtures under medium to low VBP，in confrontations with the experimental results of cohesive and non-cohesive specimens.

Consolidation behaviour results in non-homogeneous engineering properties of the cutoff wall along the depth，thus affecting the transport characteristics of heavy metal pollutants(HMPs) in the cutoff wall. However，the associated studies are limited. In this paper，a two-dimensional transport model for HMPs in a non-homogeneous cutoff wall system(consisting of a buffer layer，a non-homogeneous cutoff wall and an aquifer) is developed，where the consolidation effect and the Langmuir adsorption features are considered. Then，the proposed model is solved through a numerical approach and its validity is verified by comparing with the experimental measurements and the calculation results of the two other calculation methods. On such basis，a study on the transport characteristics of HMPs is performed and the results show that the concentration in the upper zone of the cutoff wall increases and the concentration in the bottom zone reduces when the consolidation effect is considered compared to it is neglected. The transport rate of HMPs in the Langmuir adsorption scenario is higher than that in the linear adsorption scenario，and the difference in relative concentrations between the two scenarios becomes more significant with growing concentration of the pollution source. Furthermore，the evaluation of barrier performance reveals that the increase of the buffer layer?s thickness is beneficial in prolonging the cutoff wall?s service life. Nevertheless，the buffer layer?s thickness should not be too large given that the “enclosure” cutoff wall is widely applied in practical engineering. Besides，ignoring the consolidation scenario may overestimate the barrier performance of the cutoff wall compared to considering the consolidation scenario. Both the increase in the cutoff wall?s thickness and its adsorption capacity can improve its barrier performance，and the two aspects can be combined to conduct the design of anti-fouling barriers in engineering practice. The proposed model as well as the obtained laws in this paper can provide guidance for the effective design and the service performance evaluation of cutoff walls.

A significant amount of roof overhang can be formed behind the deep hard roof working faces. This can result in a high degree of strain energy accumulation and fast release speed，which can induce roof dynamic load and rock burst disasters. To achieve effectively control of rock burst disasters in the hard roof working face，taking the 1123 longwall panel of Gucheng coal mine as the background，theoretical analysis，physical simulation and on-site measurement are used to study the influence of the backfilling ratio on the movement model of the hard roof，and to propose the multiple synergetic control technology. At the primary mining stage，the backfilling ratio is less than 80%，the concentration of the mining stress in the fault-influenced area is high，and the thick top coal and hard roof exhibit local dynamic damage，which becomes a significant risk of inducing rock burst. The subsidence movement model of the hard roof under the backfilling body supporting is established，and the length of the insufficiently compacted zone and the maximum tensile stress inside the hard roof show a logarithmic decreasing tendency with the increase of the backfilling ratio. The subsidence model shows that the backfilling ratio reaches up to 90%，so that the movement mode of the hard roof is changed from periodic breaking to continuous subsidence. The proposed secondary high-pressure grouting technology reduces the volume of thick top coal expansion and sinking by 5% after grouting. Additionally，the backfilling ratio of the gob area is increased to over 90%. The microseismic monitoring and physical simulation results indicate that a high backfilling ratio prevented the hard roof from breaking. This prevented strong dynamic loading of the stope and rock burst of roof fracture type caused by the release of strain energy. To prevent coal body compression-type rock burst caused by hard roof subsidence，pre-splitting blasting of the hard roof and large-diameter drilling pressure relief measures are proposed based on filling the gob area and thick top coal grouting measures，forming the “four-in-one” multiple synergistic control technology for rock burst disaster. The large-scale blasting fracture in front of the working face released energy，resulting in an increased proportion of low energy microseismic events on the roof to 64.7%. The backfilling body was loaded quickly，reducing the degree of mining stress concentration. The hard roof subsided slowly，and the phenomenon of rapid increase in resistance of the hydraulic support disappeared. The use of synergistic prevention and control technology has successfully reduced the load and impact on the deep and hard roof working face，and reduced the risk of strong dynamic load and rock burst disaster of the 1123 longwall panel.

To explore the load-bearing characteristics of the rock joints under seismic loads，the shear experiments about the mechanical behaviors of a rough joint surface under the dynamic normal load stress were carried out. The influence of the amplitude and frequency of the dynamic normal load on the intensity parameters，morph parameters and failure characteristics of the joint surface were obtained. The results show that：(1) Increasing the dynamic load amplitude results in a linear decrease of 48.27% to 55.59% in the peak shear strength. The dynamic load frequency has less impact on the peak shear strength. In the stable residual stage，the shear stress amplitude width increases linearly by 1.24 to 2.83 times with increasing the amplitude，and the dynamic loading frequency increases from 0.2 Hz to 0.5 Hz，resulting in a rapid decrease of 36.28% to 40.61% in the shear stress amplitude. This decline continues gradually after the frequency exceeds 0.5 Hz. (2) The shear stiffness in the pre-peak stage is a normal stress-dependent. And，both the amplitude and frequency of the dynamic normal load decrease the shear stiffness in the pre-peak stage and dilatancy in the post-failure stage. (3) A significant phase shift between the shear stress and normal stress occurs. The phase offset decreases with the increase of the amplitude and frequency of the dynamic normal stress. When the frequency reaches 2.0 Hz，the phase shift becomes negligible. (4) When the frequency is below 0.5 Hz，the proportion of the joint surface wear area increases sharply by 36.10% to 69.37%. Conversely，when the frequency exceeds 0.5 Hz，the wear area proportion shows an approximately linear increase of 5.17% to 10.18%.

The bedding rock slope with sand-mudstone interbeds is mostly developed in the coal-bearing strata of Shanxi Province. Affected by rainfall and groundwater，landslide disasters are frequent. Based on the limit equilibrium method and considering the slope parameters such as the height h of the free surface at the foot of the slope，the slope angle ?，the strata inclination ，the weight ? of the sliding mass，the length L of the slip surface，and the mechanical parameters( )of the soft rock strength of the slip zone，a mechanical analysis model is established to study the multi-stage deformation law of bedding rock slopes with weak interlayers under the support of NPR anchor cables. Through formula derivation，two types of NPR anchor cable-supported slopes under different strength parameters in the softening and creep process of the rock and soil in the slip zone are determined：the overall stable type and the local stable type，and the multi-stage deformation laws of the two types of slopes during strong rainfall are analyzed from the mechanism. The formula is derived to qualitatively analyze the change of the length of the sliding surface when the slope is unstable under the same condition of whether the NPR anchor cable is set，and the influence on the change of the landslide scale is obtained，for the same condition slope with NPR anchor cable whether considering the hydraulic action or not，the change of slip surface length is qualitatively analyzed when the slope is unstable，and the influence on the change of landslide scale is obtained. Finally，the application of the remote monitoring and early warning system of Newtonian force of landslide geological disaster developed by He Manchao?s team in the Lujumao landslide in Liulin County，Shanxi Province is used. The actual early warning results reflected by the monitoring data are consistent with the theoretical derivation of the slope instability model.

In order to study the influence of factors such as the number of freeze-thaw cycles，confining pressure，and salt content on the mechanical properties of salinized loess in Ili，triaxial tests of salinized loess under the action of indoor freeze-thaw cycles were carried out. The deterioration mechanism of salinized loess after freeze-thaw and salt erosion was analyzed，and the strength deterioration formula and constitutive model of salinized loess were proposed. The results show that the increase of salt makes the stress-strain curve shift from softening type to hardening type under the action of freeze-thaw cycles. When the salt content is higher，the shear strength of loess decreases rapidly with the increase of the number of freeze-thaw cycles. The cohesion is exponentially related to the number of freeze-thaw cycles. The internal friction angle shows an increase and then a decrease with the increase in the number of freeze-thaw cycles and decreases with the increase in salt content. A degradation model of cohesion under freeze-thaw is established，which can predict the degradation characteristics of cohesion in specimens with different salt contents. The weight of the freeze-thaw effect on cohesion degradation is greater than that of salt corrosion. A modified Duncan-Chang model with multi-factors is proposed，which can more accurately reflect the strength and deformation characteristics of salinized loess after freeze-thaw and salt erosion.

The traditional vacuum preloading method is time-consuming and has poor dewatering effects in the treatment of sludge，making it crucial to efficiently dewater the sludge and enhance resource utilization. Therefore， a composite treatment method combining pH adjustment，compound flocculation and vacuum preloading was proposed. The treatment scheme of pH adjustment combined with compound flocculation is obtained through sludge specific resistance tests and settling column tests. Subsequently，vacuum dewatering model experiments are conducted for application to validate the effectiveness of the proposed method. The mechanism and treatment effects of this composite technology are evaluated and analyzed in terms of specific resistance，drainage volume，pore water pressure and shear strength. The results indicate a significant improvement in sludge dewatering performance with appropriate acidic adjustment. When the pH value of the sludge is adjusted to 4.2，the stimulating effect of the coagulant is more significant，and the treatment effect of compound flocculation is much higher than that of single flocculation. In addition，the addition of coagulants can improve the sedimentation performance of sludge in a short period. Compared with the traditional vacuum preloading method，this composite treatment method exhibits remarkable improvements in drainage volume，water content，and soil strength. The water content of the treated soil is reduced to below 60%，resulting in denser soil and a 2.7-fold increase in shear strength，highlighting the excellent volume reduction and reinforcement effects of this composite treatment technology.

During the process of freezing and thawing，temperature-induced changes in the content of unfrozen water and ice affect the dynamic properties of the soil. Based on this，taking into account the actual operation conditions of trains，this study employed unsaturated silt，a fine-grained filler commonly used in the subgrade of the Shuozhou-Huanghua Port Heavy-Haul Railway，and conducted nuclear magnetic resonance (NMR) and temperature-controlled dynamic triaxial tests on samples with different initial water contents (10%，14%，and 18%) during both freezing and thawing processes. The aim was to analyze the relationships of the unfrozen water content and ice content with dynamic elastic modulus of unsaturated silt during freezing and thawing，thus to explore the impact of phase changes between ice and water on macro-dynamic properties. The main conclusions are as follows. (1) During the freezing process，from the freezing temperature to the supercooling temperature，the unfrozen water content decreases significantly，while the ice content and dynamic elastic modulus increase rapidly. Subsequently，as the temperature continue to drop，the unfrozen water content decrease slowly，and the ice content and dynamic elastic modulus increase gradually. Limited water phase changes occur during the subsequent freezing to －15 ℃，and approximately 1% of liquid water remains in all samples. (2) When the soil is in a thawed state，due to the lubricating effect of free water，the dynamic elastic modulus decrease as the initial water content increases. In the frozen state，the dynamic elastic modulus of the sample with an initial water content of 14% is the highest due to the ice cementation effect and the different modes of ice distribution within the sample. The dynamic elastic modulus of the sample with an initial moisture content of 10% is slightly lower，while the sample with an initial water content of 18% exhibit the lowest dynamic elastic modulus. (3) All three groups of samples exhibit an inverse relationship between the dynamic elastic modulus and the unfrozen water content，and a direct relationship with the ice content during the freezing and thawing processes.

In order to deepen the understanding of soil stress direction dependence，biaxial rotation of principal stresses was realized by integrating specimen rotation and stress rotation，and a series of undrained fixed-axis shear tests were carried out on saturated dense sand. The results show that the strength of sand is closely related to the principal stress direction and the specimen bedding angle，and is subject to the coupling effect of these two factors. With the increase of the principal stress direction and the specimen bedding angle，the phase transition strength decreases gradually，and the failure strength is first enhanced and then reduced. However，there are differences in the coupling effects of various principal stress directions and specimen bedding angles on the phase transition strength and the failure strength. Furthermore，it is found that the development pattern of the shear band is mainly affected by the principal stress direction.