In order to study the anchorage mechanisms of multi-stage control grouting inclined prestressed steel anchor pipes，it is necessary to make clear the structural form，reinforcement mechanism，scope of application and design calculation method of multi-stage control grouting inclined prestressed steel anchor pipes. Taking K42 slope of Guangzhou north third ring expressway as an objective，bearing capacity tests of prestressed steel anchor pipes with different free lengths were carried out. The effective anchorage length of prestressed steel anchor pipes was analyzed，and comparisons of the bearing capacity among prestrsssed steel anchor pipes，common anchor rods and common steel anchor pipes. The test results show that the ultimate bearing capacity of the prestressed steel anchor pipes increases by 50% than that of common anchor rods and the effective anchorage length of the prestressed steel anchor pipe is 6 m. Anchoring mechanisms of prestressed steel anchor pipes by Plaxis2D software were performed. It is shown that the improvement of the stability of landslides is not obvious by the crack grouting technology while that combination of the crack grouting technology and the prestressed steel anchor pipes plays a obvious role in enhancing the stability of landslides. The research work is of certain reference value for correct analysis of reinforcement mechanisms and engineering design application of multi-stage control grouting inclined prestressed steel anchor pipes.

Soft rocks have complex thermodynamic behaviors and their strength maybe increase or decrease with temperature. In this paper，the soft rocks were considered as heavily over-consolidated clays and their preconsolidation pressure was assumed to be the uniaxial compression strength. Based on the fractional thermal elastoplastic theory，a fractional sub-loading surface model for soft rocks considering the effects of temperature was proposed，which can decribe associated and non-associated flow rules without introducing the plastic potential. The analysis results show that the phenomena of heat-increase and heat-decrease are closely related to the angle of the plastic flow direction and the loading direction. Application of the non-associated flow rule in the undrained triaxial test results in that stress paths of soft rocks cross through the critical state line and finally reach the critical state，and the undrained shear strength of soft rocks will increase as temperature increases. On the other hand，the associated flow rule will do the opposite. In addition，the preconsolidation pressure of soft rocks will decrease as temperature increases，leading that the sub-loading surface is located outside the temperature loading surface in the p-q plane and that the overconsolidated ratio OCR is smaller than 1. Comparisons between the proposed model with test results indicate that soft rocks show the features of strain-softening and dilatancy，which can be captured by the proposed model，and that，increasing temperature will decrease the fragility of soft rocks as well as the dilatancy. Compared with the modified Cam-clay model，the proposed model introduces two extra parameters including the coefficient of linear expansion  and dilative related parameter m，which have clear physical meanings and can be determined through conventional tests directly.

In the effect of the seasonal fluctuation of the water level，a fluctuation belt of Three Goreges Reservoir Region with an elevation difference of 30 m，playing an important role in slope stability，was formed. Under the effects of external factors such as the reservoir water level fluctuation and wave erosion，the rock and soil mass of the fluctuation belt is constantly soured and carried out，and the reservoir bank keeps rebuilding. Based on a spot inspection of the fluctuation belt of Wu Gorge of Three Gorges Reservoir region，the stability influencing factors of the reservoir banks were analyzed from the aspects of geological and environmental factors，five kinds of disaster-causing rock formations and the deformation characteristics of three rock structures in rock bank slopes were summarized. On the basis of the analysis of 15 typical cases of bank slope reconstruction，five types of bank slope reconstruction in Wushan section were proposed. Typical cases of disaster prevention and control of bank slopes in Wushan were analyzed and as a result，some key points and suggestions of geological disaster prevention and control of bank slopes were put forward.

High rock slope and underground engineering excavations can easily induce rock mass tension-shear failure disasters. A kind of rock tension and shear device，which can be used in servo-controlled compression and shear test machine to ensure the accuracy of load and displacement control，is designed，and uniaxial tension，tension-shear and compression-shear tests of sandstone were carried out. The tension-shear strength envelope of sandstone is nonlinear and can be described by Hoek-Brown criterion in the full normal stress zone. In view of the failure of conventional PFC parallel bond Mohr-Coulomb strength criterion to effectively simulate the nonlinear strength envelope of rocks，a parallel bond Hoek-Brown strength criterion was established based on the sandstone test results and programmed into the PFC program through a simple conversion method to effectively simulate the tensile-shear strength，fracture characteristics and mesomechanical mechanisms of sandstone. The cracks on the fracture surface is relatively thin and more tensional in the case of tension and shear，while the number of microcracks is relatively large and the damage is more intense in the case of compression and shear. With increasing the normal stress sn，the failure surface becomes less tensile and more shear. Due to shear dilation，however，tensile-shear cracks are still dominant under a smaller normal stress. Based on the numerical simulation results，the damage evolution process of rock under tension-shear or compression-shear stresses can be roughly divided into four stages including elastic deformation，stable rupture development，unstable rupture development and overall failure. When sn is larger，the stages of elastic deformation and unstable rupture development are relatively longer，the pre-peak plastic deformation is more and rock under tension and shear condition is more elastic-brittle.

The difficulty of rock fragment discharging from small diameter boreholes drilled at a downward angle in coal mine roadway floors has long been the major factor that reduces borehole quality. Therefore，fuller understanding of rock fragment sizes is absolutely essential to fragments discharging. In this study，theoretical analysis and laboratory experiments were adopted to analyze the size characteristics of rock fragments formed by two-wring drill bits. The results indicate that the strength of rocks and bit blade spacing are the two keys factors that affect the mean fragment size. The proportion of larger-size fragments increases with the uniaxial compressive strength，which makes the mean fragment size increase with the uniaxial compressive strength as well. The rotation rate and drilling rate have no influence on the mean fragment size. In addition，the mean fragment size increases with the blade spacing. Therefore，the mean fragment size can be reduced by reducing the spacing between two wings. When drilling through high strength rock strata，the mean size of the fragments will increase and the discharge power should be enhanced to prevent fragment discharge blockages. This paper may provide a theoretical basis for discharge power settings and drilling tool optimization.

Heat transfer，meso-fracture and macro-mechanical properties are closely related to each other during the thermal damage of rocks. Thermal shock factor is an important physical quantity that can quantitatively characterize the strength of thermal damage to rocks，based on which the dynamic thermal stress in rock at a certain moment can be calculated to determine the time and degree of thermal damage. In order to study the evolution of the thermal shock factor during the heat transfer process，the temperature field，temperature gradient and thermal shock factor in granite under conductive heating were experimentally determined. The results show that granite undergoes three stages of rapid temperature increase，slow temperature increase and relatively stable temperature under constant heat source conduction heating，that the temperature gradient closely related to the temperature of the heat source and time changes greatly during the heating stage and the changing rate of the temperature gradient per unit time is different，and that the thermal shock factor in granite is heterogeneous and irregular in distribution and sensitive to rock mass structure and the peak of the thermal shock factor in the conduction heating process is dynamically mobile. The essence of the granite damage caused by cyclic heating is that mineral particles are separated under the dynamic thermal stress and cracks gradually present，expand and penetrate through the rock mass. The experimental determination of the thermal shock factor and the study of its evolution law，as well as the calculation of the dynamic thermal stress and the criterion of rock thermal damage based on the thermal shock factor，can promote the development of rock thermal damage theory.

Invert heaving diseases occur frequently in high-speed railway (HSR) tunnels，seriously affecting the normal operation of railway lines. A new method for simulating deformation-induced diseases in HSR tunnels was proposed. A refined HSR tunnel model with tunnel structure and accessory facilities was constructed by using 3D printing technology，and the working state of accessory facilities was considered in an all-round way. Those things related to the HSR tunnel model building were described in detail，including the classification of model components，3D printing materials and their selection method，printing process，etc. Based on typical disease cases，disease simulation experiment was carried out to reproduce the disease characteristics of the site，and the characteristics of drainage，external water pressure and structural displacement were also discussed. The results show that，with increasing the groundwater level，the tunnel drainage increases logarithmically.While the groundwater level is more than 20 m，the increment of the drainage decreases obviously，the external water pressure of the structure increases significantly(especially at the bottom and the vault)，and the uplift of bottom structure increases continuously with a feature of tunnel bottom＞inner rail＞outer rail. When the groundwater level is 50 m，the test results are in good agreement with the field disease characteristics，which verifies the feasibility and validity of the method. The research results are expected to provide reference for fine simulation of tunnel diseases and similar tunnel model tests.

The characteristics of the fault stick-slip curve with different fault dip angles and confining pressure，and the time domain and frequency domain characteristics of microseism and charge induction signals in the process of fault stick-slip are inspected and analyzed by using the microseism and charge induction monitoring system and a large-scale double-axis test machine. The test material is a kind of coarse grained syenogranite. The results show that，in the biaxial loading process of oblique faults，the changes of the fault dip angle and the confining pressure changes the stress state of the fault plane，the characteristics of fault stick-slip curve and the stick-slip friction strength. The fault with a small dip angle is prone to stick slip with a small magnitude of energy release，while the fault with a large dip angle is not prone to stick slip and has a large stress drop when failure occurs. By analyzing the changes of the lateral pressure and the fault dip angle，the possibility of fault stick slip instability can be further judged. The possibility of fault stick-slip instability can be further judged by analyzing the changes of confining pressure and fault dip. High amplitude microseism and charge signals will be generated simultaneously at the moment of every oblique fault stick-slip and before the stress drop. The stress drop of fault stick-slip has a good corresponding relationship with the microseismic and charge signal intensity，and the charge signal amplitude at the fault is larger when the oblique fault is stick slip. With changing the fault dip or the lateral pressure，the amplitude and energy of charge signals have significant changes while microseismic signals almost keep unchanged. The frequency bands of both microseism and charge signals are in the range of 0-100 Hz with a main frequency less than 10 Hz. The frequency and power of microseism and charge signals increase before fault stick-slip and decrease rapidly after fault stick-slip. The test results show that the spectrum characteristics of microseism and charge signals have more obvious precursory characteristics than the signal amplitude. The time-frequency characteristics of microseisms and charge signals analyzed by Hilbert-Huang time-frequency analysis method can better identify the precursory information of fault stick-slip process.

Theoretical analysis，numerical simulation as well as microseismic monitoring were used to investigate the relationship between the stress transfer of stopes in the mine and the movement of thick and hard rock strata. Firstly，a space model and its balance condition of the semi-closed thick hard rock stratum considering the influence of the horizontal pressure were proposed. Secondly，the overburden state and load transfer law under continuous mining conditions were studied. Finally，the horizontal stress transfer mechanism in the vertical direction of the stope was discussed. The results show that，in the semi-closed stope space model affected by the horizontal stress，the mining process is accompanied by two processes of overburden rupture and stress transfer，and that the different motion states of thick and hard rock are the main reasons for the formation of complex overburden structure and stress evolution. According to different mining environments on both sides of the working face，the longwall panel is divided into five types such as initial mining panel，panel with one side mined up，panel with two sides not fully mined，panel with one side fully mined and the other side not，and panel with two sides fully mined. The types of the static support stress of the corresponding working face are obtained respectively，and the static abutment pressure corresponding to the panel type was achieved. An estimation method of horizontal stress concentration of overlying thick hard rock stratum was established，and the tensile fracture mode of thick and hard rock layer controlled by the horizontal stress and its mechanical expression were obtained. The model was successfully used in the mining practice of longwall panel 5301. The on-site microseismic monitoring results agrees well with the research which can guide the prediction of rockburst. The results have guiding significance for mine disaster prevention and control under similar conditions.

The influence of intermittent joints on the strength of rock masses and its evaluation method have always been one of the hotspots and difficulties in the field of rock mass mechanics. In this paper，45 samples of intermittent jointed rock mass are made from gypsum with different combinations of joint inclination，density connectivity，and ultrasonic wave speed and uniaxial compression strength(UCS) tests are performed. The correlation characteristics between the mechanical and acoustic parameters are investigated，the influence of the distribution characteristics of joints on the rock mass failure mode and UCS is explored and consequently a determination method of the UCS of intermittent jointed rock mass is proposed. The results show that the P-wave velocity is positively correlated with the joint connectivity and has an approximately V-shaped change with increasing the joint dip angle，and that both the UCS and the elastic modulus(E) of the jointed rock mass increase with increasing the joint connectivity and the UCS presents an approximately U-shaped change with increasing the joint dip angle. Four fracturing modes of intermittent jointed rock masses are proposed and it is pointed out that samples are most prone to fail when the joint forms a 45°angle with the loading direction. Finally，a fitting relationship between the UCS of jointed rock masses and intact rock block is proposed by considering not only the P-wave velocity but also the internal friction angle of the rock block and the joint dip angle.

Landslide tsunamis，as a complex type of fluid-solid coupling problems，are widespread in nature and often cause huge catastrophes. Aiming at the deficiencies in existing numerical methods of landslide tsunamis，starting from the dynamic process and physical mechanisms of landslide tsunamis and fully taking advantages of different numerical methods，the large deformation and discontinuity process of landslides and the hydrodynamic process of water were respectively simulated by using the discrete element method(DEM) and smoothed particle hydrodynamics(SPH)，and a GPU-accelerated parallel SPH-DEM coupling code，named as CoDEM，was developed to realize large-scale high-performance computing of landslide tsunami simulation. The tsunami model test of a granular landslide performed by Fahad was simulated using the developed code and the reliability of the code was verified. In the SPH-DEM coupling simulation，the ratio of the SPH particle spacing to the DEM particle size will affect the coupling accuracy and the simulation scale. Generally，the ratio less than 1/6 has a certain impact on the accuracy of the tsunami near the landslide entry point while less influence on the far field(more than 1 wavelength from the water entry point). Taking the landslide in Vajont reservoir，Italy in 1963 as an example，the 3D numerical model of the landslide and reservoir area was reconstructed，and the whole process from landslide movement，formation and transmission of tsunamis to impact on dam and floods was simulated by using the developed SPH-DEM coupling code. According to the numerical results，the final morphology of the accumulation body(similarity larger than 90%)，the maximum flood peak flow(about 350×103 m3/s) and the maximum force on the dam(about 3.9×1010 N) were compared with the previous documents，showing a good agreement. The study shows that the SPH-DEM coupling method can well simulate the dynamic process of landslide tsunamis and the developed CoDEM can provide efficient technical support for landslide disaster prevention and mitigation in reservoir areas.

Faults in underground engineering areas have complex influences on the direction of local stress field.  In order to accurately obtain the distribution of in-situ stress field due to fault disturbance，a two-stage inversion analysis method based on equivalent tectonic load is presented. Firstly，based on qualitative cognition and a simple numerical experiment，the deflection laws of the principle stress direction near a fault are analyzed for providing a judgment basis of identifying the abnormal measured stress data affected by the fault. Secondly，mainly considering the influence of valley topography，the improved lateral pressure coefficient method is applied to invert the in-situ stress field of big model，and then，a refined small model with faults is built. The equivalent tectonic load is obtained by the stress field calculated by interpolation from the big model，and the second-stage inversion calculation for in-situ stress is conducted based on elastic-plastic theory. Finally，the in-situ stress field of Jinchuan underground powerhouse area is inverted based on the measured in-situ stress data，verifying that the abnormal data at point #3 are affected by the fault，and the distribution laws of the stress field near the faults are studied. The results indicate that the local stress field direction deflects differently inside and outside the fault and has a significant relationship with the occurrence of the fault. The inversion method can comprehensively consider the influences of valley topography，fault and complex tectonism，has a high inversion accuracy to measured data and can better reflect the non-uniform characteristics of stress magnitude and direction near faults.

To ensure the computational efficiency of large-scale models using finite element method(FEM) and the accuracy of their seismic response results，a seismic wave input formula adapted to the viscous-spring boundary is deduced according to the wave field separation theory，a method for extracting the control area of boundary nodes is given，and the program for automatic setting of viscous-spring boundary and seismic wave input is realized and verified after the secondary development of ABAQUS. On this basis，a two-dimensional soil model under the action of vertical incident shear wave(SV) is established to compare 12 different combinations of boundary conditions and seismic wave input methods. Based on the principle of transmission and reflection of seismic waves on discontinuous interfaces，the mechanism of interaction between viscous-spring boundary condition and several seismic wave input methods is revealed. The results illustrate that for the viscous-spring boundary，the calculation results using the equivalent nodal load input method are in good agreement with the theoretical solutions with a high calculation accuracy，while the energy absorption capacity of viscous-spring boundary is lost using the acceleration input or the displacement input methods. The research work can provide a reference for the accurate application of viscous-spring boundary and the reasonable selection of seismic wave input methods in seismic analysis of underground structures.

In this paper，a geotechnical seismic isolation system(GSI-GBSC) based on glass bead-sand cushions is proposed to protect structures against the destroying effects of earthquakes，which is to backfill the glass bead-sand cushion material between the structural foundation and the foundation soil for isolation. A large-scale shaking table model test which considers the field was carried out through the single-layer masonry structure model with and without isolation system. The scale ratio of the single-layer masonry structure model was 1/4. The north-south component of the El-Centro wave recorded in 1940 was selected as the input wave，and the peak input acceleration(PIA) was adjusted to 0.1 g，0.2 g and 0.4 g respectively. The test results show that the isolation effect of GSI-GBSC system is not significant enough when the minor earthquake occurs but the isolation effect strengthens with enhancing the earthquake intensity. When PIA is 0.4 g，the GSI-GBSC system decreases the roof acceleration and the inter-story drift of the structure by 50% and 47.5%，respectively，which means the GSI-GBSC system can significantly reduce the earthquake response of the superstructure and achieve seismic isolation.

Based on the periodic characteristics of wave field around the periodically distributed scatters under incident plane wave，an analytical method is creatively proposed to solve the vibration isolation effect of infinite periodically distributed group piles barrier against elastic wave. Graf addition theorem which is suitable for wave function transformation between arbitrary coordinate systems is derived firstly. Then，the wave function expansion method and one different phase in the frequency domain around different period units is used，so that only one periodic unit needs to be selected for analysis to solve the scattering wave field of the whole pile group barrier. This analytical method makes up for the shortcomings of the previous theoretical analysis when there are a number of piles，and at the same time， has the advantages of high accuracy，low calculation amount and significantly reducing the solution time，which is convenient to analyse the vibration isolation law of pile group barrier with a large number of piles. In this paper，the influence of pile row number，pile spacing and arrangement on the vibration isolation effect is discussed. The results show that the isolation effects of group piles barrier on SH，SV and P waves are mainly reflected in the lower frequency band (0.2–1.2)，in the middle frequency band of (0.6–1.8)，and in the middle and higher frequency bands (1.2–1.5 and 2.2–2.8)，respectively. With increasing one row piles，the isolation effects against SH，SV and P waves can be respectively increased by 50%，33% and not more than 10%. Reducing the distance between piles is helpful to improve the vibration isolation effect of pile group barrier，and compared with reducing the distance between rows，the effect of reducing the distance between columns is more obvious. On the whole，the vibration isolation effect of the quincunx arrangement is better than that of the rectangular arrangement except for the case of the incident wave frequency h = 0.7–1.8.

In order to study the temperature distribution and variation of piles and the pile-soil heat transfer process after concrete pouring in permafrost regions，a systematic study was carried out based on the observation results of in-situ test and theoretical analysis of cast-in-place piles in Beiluhe of Qinghai—Tibet Plateau. The results show that，with the completion of concrete pouring，the pile body presents an obvious stratification phenomenon in terms of heat transfer between the pile and the surrounding soil. The exothermic heat flow of the pile above the upper limit of permafrost is relatively weak，while the lower part is relatively strong. The direction of the heat flow vector is mainly horizontal and heat flow mainly concentrates near the upper limit of permafrost. In terms of temperature change，the upper and lower parts of the pile body show different temperature change processes. The upper part experiences a rapid heating and slow cooling process while the lower part shows a relatively stable cooling process，which results in a large temperature difference in the depth direction of the pile with a maximum temperature gradient of about 11℃/m. The heat mainly concentrates in the upper part of the pile，forming a high temperature core. Therefore，there may be a problem of insufficient strength due to low temperature at the pile bottom，and large temperature difference along the depth of the pile may lead to temperature cracks in the concrete. In order to raise the curing temperature of concrete and to reduce the generation of temperature cracks in concrete，it is suggested to control the molding temperature reasonably or to use low-temperature early-strength concrete.

Under the situation of increasingly serious global climate issue and increasingly urgent treatment of industrial solid wastes in China，how to effectively store CO2 and to use industrial wastes to prepare novel cementitious materials attracts significant attention from all around the worldwide. The combination of CO2 carbonation and industrial waste residues is an environmentally friendly and sustainable solidification technology，which cannot only sequester permanently CO2 emissions but make effective use of industrial residues and solidify soils. In order to explore the effect of many factors such as industrial residue content，carbonation mode and carbonation time on the carbonation effect，two kinds of bulk industrial wastes，i.e. slag and fly ash，were selected as binding materials to mix with soils and prepare samples for CO2 carbonation tests. The unconfined compressive strength(UCS) and pH detection tests were carried out to evaluate the mechanical properties of carbonated samples，and the X-ray diffraction(XRD)，mercury intrusion porosimetry(MIP) and scanning electron microscopy (SEM) tests were performed to reveal the microstructure evolution and carbonation mechanism. The test results show that the compressive strength of samples subjected to CO2 carbonation of 3 h raises by 5%～15%，and increases initially with waste residue content followed by a slight reduction or an almost constant. The carbonation effect varies greatly under different carbonation modes，and the optimal carbonation mode is proved to be confining pressure of 300 kPa and carbonation pressure of 150 kPa. The compressive strength of carbonated samples increases to the maximum at 3-6 h and then decreases as the carbonation time extends. The microscopic results reveal that CaCO3 crystals are formed and identified in the forms of aragonite and calcite within carbonated residue-solidified samples. These crystals can fill in the pore spaces and bond fine particles together，which without doubt contributes to the promotion of the compressive strength of carbonated samples. A reasonable prolongation in carbonation time produces more CaCO3 crystals and reduces the cumulative pore volume and quantity of large pores. However，the carbonate crystals are loosely arranged and fail to be firmly interconnected to form a reticulated skeleton skeletal structure，which leads to a limited improvement in the compressive strength of carbonated residue-solidified samples. This study can provide a preliminary basis for further research on the performance improvement of novel solidification technique combined industrial residue and CO2 carbonation.

A series of loading and unloading tests under isotropic compression and shear were carried out by using the large true triaxial apparatus，the resilience characteristics of coarse-grained soils were described，and the value of the resilience modulus in different unloading stages was analyzed. The test results show that the resilience modulus changes greatly due to the influence of stress path in the shear process and cannot be replaced by the average resilience modulus. A prediction model which involves the spherical stress and the minor principal stress was obtained from a stress-dependent analysis and the Janbu model. When one of the variables is constant，the resilient modulus changes nonlinearly with the other variable and the function relationship is linear in the double logarithmic coordinate. Using the prediction model，the resilient shear modulus under different shear paths is obtained，and the regression parameters fit well in the model. The model reflects the influence of stress path and material response on the nonlinear resilience deformation characteristics and is conducive to a better understanding of the unloading characteristics of coarse-grained soils.