By the tests of shale under different water osmotic pressures and triaxial compression，the deformation，strength and failure characteristics of shale are analyzed，and a full stress-strain damage constitutive model of shale considering osmotic pressure is established. The results show that：(1) under the combined action of conventional triaxial compression and water seepage pressure，the strength of shale has obvious weakening effect，and its residual strength is more affected by seepage pressure. (2) Under the action of different confining pressures and water seepage pressures，five different shear failure forms are produced in shale from shear failure to tension shear composite failure and then to steep angle shear failure. (3) Under the combined action of conventional triaxial compression and water seepage pressure，the shale strength still meets the M-C strength criterion，but the internal friction angle and cohesion decrease with the increase of water seepage pressure. (4) A damage constitutive model that can reflect the whole stress-strain process of shale under different confining pressures and osmotic pressures is established，and the residual strength of shale can be predicted by the corresponding axial strain value at the inflection point of the total damage variable curve D=1. The theoretical curve is in good agreement with the test data.

In order to explore the deformation characteristics and stress mechanism of tunnel structure under the dislocation of strike-slip fault，and clarify the mechanical status of strike-slip fault，the distribution rules of surface cracks caused by earthquake in Daliang tunnel are analysed by means of field investigation，geomechanical analysis and numerical simulation. The results show that：(1) the strike of the fault is NW60°，which is consistent with the location of the Lenglongling fault in the region and belongs to the Holocene Active fault. The occurrence of the interrupted layer of the tunnel is 195°∠79°，the width of weak layer is about 100 m，and the size of surface crack dislocation is 3 m. About 700 m to the south of the exit of Daliang tunnel，the horizontal displacement is 2.8 m，and the thrust displacement is 0.91 m，which has the characteristics of thrust strike-slip movement. (2) The mechanical mode of seismic failure is the combined action of NE-SW60° principal stress，unidirectional compression and pure shear. Considering the characteristics of thrust surface deformation at the boundary of the main fracture zone，the surface fractures have a thrust fault orogenic flower shape. (3) Through the analysis of geomechanics，under unidirectional force and moment on the fault，the distribution law of cracks on the surface is consistent with that of field investigation. (4) Before the Menyuan earthquake，the deformation and failure mode of Daliang tunnel was mainly affected by the regional principal compression stress on the direction of on SW60°. After the Menyuan earthquake，it was mainly affected by shearing and compression，and the tunnel structure was subjected to the principal compression stress on the direction of NE-SW60° and the strike-slip shear on the direction of NW60° accorded with Lenglongling fault. The investigation and analysis results provide a reference for the engineering design of high-speed railway tunnels crossing active faults.

The complex fracture initiation mechanism and failure mode of discontinuous joints are significant to the mechanical behavior of rock mass. Considering the effect of the joint angles and length，the influence of non-persistent joint on the mechanical properties and fracture characteristics of rock mass are analyzed with granite rock specimens under uniaxial loading. Then a three-dimensional discrete element model was established，and the failure mechanism and crack propagation were investigated from the meso-scale. Finally，a fracture mechanical model with a non-persistent joint is established to analyze the fracture toughness，and the influence of joint inclination and penetration on the brittle fracture resistance of rock mass is quantified. The results show that：the degradation effect of initial damage on rock mass is obvious. Six kinds of cracks are distinguished according to the experimental results and the crack initiation failure mode of joint samples has a significant influence on the strength characteristics. The fracture toughness of the specimen increases with the increase of joint inclination at the range of 15°‐75°，and the brittle fracture resistance of the specimen with 15° joint is the weakest. With the increase of joint persistency，the fracture toughness of jointed rock mass decreases in an approximate hyperbolic trend.

The mechanism of the deformation of Xiluodu Valley is still controversial，which is a key problem in the current engineering field. Based on the comparative analysis of Jinping I and Xiluodu valley deformation，the valley deformation of Xiluodu shows the feature of large value，large scale and integration. In this paper，we adopt the elasto-plastic method of deformation reinforcement theory as the approximation of visco-plastic method，and take the pore elastoplastic effective stress and the hydrogeological structure of Xiluodu Reservoir area into account. The key location which controls the Xiluodu valley deformation is studied by analysing the unbalanced force，which drives the plastic deformation of structure. The results indicate that the unbalanced force caused by the increase of pore pressure after impoundment is mainly concentrated in the basaltic layer and the interlayer dislocation plane at the bottom of the valley，that could drive the rock mass to produce large-scale deformation along the layers and may be the primary mechanism of the structural valley deformation of Xiluodu.

The geological structure of underground powerhouse caverns of hydropower stations is complex and the ground stress is high. Deformation and failure of surrounding rock mass occur frequently during construction. In order to solve the failure of roof arch during excavation of high stress underground powerhouse of one power station, the damage evolution process of surrounding rock was analyzed. The microseismic(MS) monitoring technology was used to record the process of surrounding rock mass microfracture initiation and propagation during excavation of underground powerhouse in real time. The response laws of deep surrounding rock damage and construction dynamics were revealed through routine monitoring and site survey. The progressive evolution characteristics of stress field and displacement field during excavation were reproduced by numerical simulation. The research results  show that the MS activity is closely related to the construction state and geological conditions. The MS events gathering in the K0–40–K0–60 area of the powerhouse are jointly controlled by strong unloading and joint fissures. The horizontal stress of the high side wall and the vertical stress of the top arch aggravate the damage evolution along the excavation axis. The focal parameters show that the moment magnitude increases，the apparent stress decreases，and the cumulative apparent volume remains unchanged before the deformation and failure of the surrounding rock mass. The research results can provide reference for the damage and stability evaluation of surrounding rock mass during excavation of similar underground engineering.

The explosive fracturing of shale with in-situ methane is a revolutionary technique，with a high temperature-shock wave synergy in the fracturing process. Therefore，it is important to study the dynamic characteristics and damage evolution of shale under high temperature to reveal the fracturing evolution of shale reservoir using explosive fracturing technology. In this paper，by comprehensive application of the rmogravimetric analyzer，muffle furnace，separated Hopkinson pressure bar(SHPB) experimental system，scanning electron microscope(SEM) and energy spectrum analysis(EDS)，the evolution law of shale dynamic characteristics with temperature was obtained，a dynamic damage constitutive model of shale considering thermal damage and compression-density stage was constructed and verified by experimental data，and finally the microscopic damage mechanism of the evolution of shale dynamic characteristics under high temperature was analyzed by SEM. The results show that the shale surface gradually develops connected fractures，and the high temperature thermal effect leads to water dissipation and thermal decomposition of the clay minerals and main carbonate minerals such as dolomite and calcite in this shale，and the pore-fracture structure is developed and connected，which integrally leads to the significant deterioration of the dynamic properties. With the increase of treatment temperature，the fracture form of the specimen changes from single fracture to complex fracture network，the dynamic compressive strength and elastic modulus first increase slightly and then decrease suddenly，and the strain rate and energy absorption ratio first decrease and then increase. These suggests that the high-temperature-shock wave synergy of the explosive fracturing of shale with in-situ methane facilitates the construction of complex fracture networks around the well perimeter of shale reservoirs. The dynamic damage constitutive model of shale is verified by experimental data，which proves that the model can better reflect the dynamic properties of shale under high temperature effect. The study is important to reveal the fracturing mechanism of explosive fracturing technology of shale with in-situ methane.

The evolution law of rock damage at macro and meso scales is the basis for evaluating the degradation process of mechanical properties of frozen rock. In this paper，the calculation method of macroscopic damage variable is proposed based on weighing method from the perspective of the volume of open fractures. Combined with the variation characteristics of rock composition and physical and mechanical properties under long-term freeze-thaw cycles，the difference of open porosity was reasonably corrected，and the meso-damage variables under freeze-thaw action were obtained. Considering the compaction characteristics of initial pores and cracks under load，a calculation model of mesoscopic damage variable under load is established by using statistical damage mechanics. The macro-meso coupling total damage is calculated by the macro-meso total damage calculation method based on Lemaitre strain equivalent hypothesis. According to the extended strain equivalence principle，the total damage constitutive model considering the influence of initial compaction section is constructed. In order to verify the rationality of the model，the prefabricated fractured sandstone samples with dip angles of 0°，30°，45°，60° and 90° and the intact sandstone samples were used to carry out the test of physical and mechanical properties after multiple freeze-thaw cycles. The research results show as follows. When the number of freeze-thaw cycles is small，the freeze-thaw damage variables increase rapidly，and the freeze-thaw damage variables gradually tend to be stable and increase slowly with the increase of the number of cycles. The influence of dip angles of fractures on the expansion of micro-pores and micro-fractures in sandstone rock samples is reflected in the different growth rates of damage variables. The increase rate of freeze-thaw damage variable of rock samples with 45° dip angle is the largest，and the expansion rate of micro-pores and micro-fractures of rock samples with 45° dip angle caused by frost heaving force is the fastest. The damage evolution curve of meso total damage model and macro-meso coupling total damage model tends to be consistent，and the coupling effect of freeze-thaw and load is the main source of damage and deterioration of sandstone samples in this test. The variation trends of macro-meso total damage test values of strains at the peak stresses are similar to those of theoretical calculation values，and the proposed theoretical model can reasonably describe the mechanisms of damage and degradation of fractured sandstone.

Freeze-thaw cycle is an important factor leading to accelerated weathering failure of rock in cold regions. Fine cognition of damage evolution and internal mechanism of sandstone under the synergistic effect of freeze-thaw and load will have important guiding value for accurately understanding the whole process of damage characteristics of rock in cold regions. In this paper，the in-situ CT real-time scanning test of the sandstone damage process under the synergistic effect of freeze-thaw and load was carried out. Based on the interactive threshold segmentation of CT images and the reconstruction method of the three-dimensional pore structure model，the fine identification and visual quantitative characterization of pore(crack) evolution in freeze-thaw sandstone during uniaxial compression were realized. The lattice Boltzmann method was used to carry out the three-dimensional simulation of the connectivity change of sandstone pore structure under the synergistic effect of freeze-thaw and load，and the damage evolution law of sandstone mesostructure under the condition of freeze-thaw and load was clarified. The results show that：(1) the damage to freeze-thaw sandstone pore(fissure) structure has the characteristics of continuous evolution，but the damage evolution speed has a mutation phenomenon. Among them，the sharp increase of pore(fissure) volume can be used as a precursory failure signal of rock samples. (2) Different from conventional loading，uniaxial compression failure of sandstone after freeze-thaw changes from single through the shear plane to tensile-shear mixed failure，and the number of failure surfaces increases with the increase of freeze-thaw cycles. (3) The number of pore channels of rock samples increases with the increase of freeze-thaw cycles，and the gap connectivity tends to large；the maximum pore radius，pore number，maximum pore radius and porosity of the sample increase with the increase of load. The compression failure of sandstone under the synergistic effect of freeze-thaw and load is the product of the cumulative effect of continuous dislocation and expansion of pores and pores. (4) The internal pore(crack) structure of sandstone after loading failure in the low freezing-thawing cycle is mainly small pores，and the proportion of cracks is low；after high freeze-thaw cycles，the sandstone is dominated by the penetration crack propagation，and the porosity ratio decreases sharply. The freeze-thaw action promotes the transformation of the failure mode of the loaded sandstone from the continuous pore(crack) fracture mode to the multiple main cracks. (5) The connectivity of sandstone pore structure evolves along two paths of freeze-thaw and compression load，and its pore connectivity is mainly determined by the number of pores inside the rock sample. The first 10 freeze-thaw cycles are violent changes in pore structure expansion and connectivity.

As the coal mining goes deeper，strong mining induced earthquakes occur frequently，which seriously threaten the safety of underground miners and ground residents，as well as the productivity and effectiveness of mining activities. The key stratum theory and micro-seismic monitoring technology are used to analyze the distribution and evolution law of strong mine earthquakes during the mining of deep coal seams in Dongtan coal mine. The coordinated fracture characteristics of multiple key strata during the coal mining process is investigated. The results show that the mining induced earthquakes are mostly concentrated in the near-field overlying rock strata in the initial stage of coal mining. As the working face advances，the mine earthquakes gradually transfer into the far-field thick and hard rock strata. The far-field thick and hard overlying strata is the main breeding and occurrence place of strong mine earthquakes. The overlying rocks above a deep coal seam often contain multiple key strata. The cooperative fracture movement of overlying key strata may be induced by the coal seam mining activities. When the key strata is broken instantly，the accumulated elastic strain could be released suddenly，which is the main reason for the occurrence of mining induced earthquakes. The fracture in the key strata above the goaf is generally presented in the form of “O-X”. The range of “O-X” type fracture increases gradually from deep to shallow. The characteristics and classification of fracture structures are also investigated. The research results are of great significance to the safe and efficient mining of deep coal mines under similar conditions.

In order to clarify the influence mechanism of excavation disturbance and large-equivalent explosion ground impact disturbance on the damage of deeply buried caverns，a similar model test incorporating the whole process of ground stress loading，cavern excavation and ground impact disturbance loading was carried out using the self-developed ground impact effect simulation test system for deeply buried caverns. The tests successfully simulated ground impact disturbance-induced engineering disasters at a burial depth of 600 m，a confinement blast equivalent of 90 kt and a proportional blast distance of 133 m/kt1/3. During the test，the phenomena of particle ejection，plate cracking and block activation were simulated successfully. The changes of stress，strain and displacement around the cavern and the failure mechanism of the deep cavern under the impact disturbance were obtained. It is confirmed that the cavern is in the zone of slight damage when the proportional blast distance is 133 m/kt1/3. In addition，a research on the stability of the cavern under repeated ground impact disturbance was carried out. Engineering disasters such as rock burst，slab crack and face collapse were simulated successfully，and the failure mechanism of the cavern under repeated impact disturbance was obtained. The successful conduct of the tests has laid an important foundation for the determination of protection and safety limits for deeply buried caverns under the action of large yielding underground explosions.

As a new retaining structure for excavations，alternating combination of vertical and incline steel pipe piles has many advantages，such as convenient construction，recyclable and low cost. The previous engineering practices have proved the good supporting performance，but there is a lack of systematic and in-depth understanding of its deformation and stress mechanism. In this study，cantilever pile and two alternating steel pipe piles with angles ? of 10° and 20°，respectively，were investigated using model experiment. The pile top displacement change law，pile body bending moment and deformation，and soil pressure distribution characteristics were analyzed in the process of foundation pit excavation. The test results show that with the same excavation depth of foundation pit，the top displacement of straight inclined alternating combination steel pipe pile decreases with the increasing angle ?，and the displacement of cantilever pile top is the largest. The bending moment diagram of cantilever pile shows the distribution characteristics of “fish belly”，while the alternating steel pipe is “S” type. The alternating combination of steel pipe has significant bending phenomenon，and the maximum bending moment of the pile body decreases with the increase of the angle ?. Under the action of soil pressure，the force of straight inclined alternating combination steel pipe pile is more reasonable. The inclined pile is pulled and the straight pile is pressed. The damage mode changes from the curved shear failure of cantilever pile to the pull failure of inclined pile and straight pile. In addition，the alternating combination of steel pipe pile supporting structure has three beneficial effects：anchor pulling effect，gravity effect and space structure effect. The pulling anchor effect and the gravity effect increase the anti-overturning moment of the structure，while the space structure effect improves the stiffness of the support structure. Therefore，the support structure has a good promotion and application value.

The existing deterministic models that can consider rainfall effects have disadvantages such as high computational cost and inability to solve the uncertainty of geotechnical parameters when assessing regional-scale landslide hazard. To address this problem，the fast shallow landslide assessment model(FSLAM) was proposed，which can be used for rapid assessment of rainfall-induced shallow landslide hazard. The FSLAM model can consider both antecedent effective and event rainfall conditions to calculate slope groundwater and stochastic parameters were used in the model to calculate probability of failure to reflect landslide hazard. A homogeneous slope was used to do sensitivity analysis of parameters of the model. The results showed that soil cohesion，friction  angle，and vegetation root cohesion were the most important input parameters of the model. The engineering application of the FSLAM model for regional landslide hazard assessment was carried out by taking the landslides induced by typhoon Megi in Wenzhou City of Zhejiang Province in 2016 as an example. The analysis results indicated that the FSLAM model can accurately capture the effect of rainfall on the probability of failure of shallow landslides，and the accuracy of receiver operating characteristic curve reached 76.4%. The model can effectively reduce the uncertainty of geotechnical parameters and improve the accuracy by using stochastic parameters. Since the simplified SCS-CN method was used to calculate the vertical flow of groundwater instead of the complex Richards equation，the computational efficiency at the regional scale of the FSLAM model is 25 times better than the TRIGRS model，and the accuracy of the TRIGRS was only 69.8%.

Under the background of global warming，rock and glacier-related geohazards on the Qinghai-Tibet Plateau are increasing gradually. Wedge landslide is a typical instability form of rock slope in alpine regions. To study the initiation mechanism and failure processes of wedge landslide，the centrifugal model tests under various freeze-thaw cycles and hydraulic conditions were carried out with a self-designed temperature control device adapted to geotechnical centrifuge. The results show that：(1) the failure processes of wedge landslide in alpine regions can be summarized into four stages，including the crack generation stage，creep deformation stage，crack accelerated expansion stage and wedge instability stage. (2) Melt water is a critical catalyst for the initiation of wedge landslide in alpine regions and its impact on landslide instability is both long-term and sudden：on one hand，the deterioration of rock mass structure affects the long-term stability of the landslide；on the other hand，the sudden instability of the landslide is caused by the surge of pore water pressure on the structural plane. (3) The freeze-thaw cycle is a significant external driving force for the initiation of wedge landslide in alpine regions，which causes frost heaving damage to the rock mass structure in the freezing process and the deterioration of the rock mass structure and the surge of pore water pressure in the melting process. The freeze-thaw centrifuge test method can relatively truly reproduce the evolution process of wedge landslide under the action of melt water and freeze-thaw cycle. The initiation mechanism of wedge landslide in alpine regions are preliminarily revealed，which lays a foundation for further exploring the influence laws of relevant factors.

To investigate the relationship between anelastic attenuation and damage of saturated sandstone in the elastic range，the forced resonance and uniaxial cyclic loading experiments were carried out in the frequency range of 0.01–1 000 Hz and the temperature range of −60 ℃–190 ℃. The experimental results show that the response curve of the rock exhibits a relaxation attenuation peak，and the dispersion effect in the rock becomes more apparent with the increase of temperature and frequency. The research results indicate that stress induces micro damage movement and interaction within rocks. The increase in vibration frequency promotes the growth of rock microcracks. The rise of temperature and small activation energy contribute to the initiation and propagation of microcracks. Cyclic stress also generates new fatigue micro damage in the uneven microstructure inside the rock. Although the anelastic micro damage that decreases the rock quality occurs within the elastic range，its cumulative effect will accelerate development under dynamic and high-frequency loads，which is worthy of concern.

Many submarine landslides are associated with rapid sedimentation. However，relevant research on the contribution of rapid sedimentation to submarine landslides and its influencing factors wer he character of submarine landslides associated with rapid sedimentation was firstly summarized by analyzing relevant cases. Subsequently，the mechanism of submarine landslides triggered by rapid sedimentation was clarified and the corresponding implementation method based on ABAQUS was provided. Finally，the influencing factors of submarine slope instability caused by rapid sedimentation were discussed systematically. The results show that the generation of excessive pore pressure caused by rapid sedimentation will make the effective stress and strength of sediment grow slowly and even decrease. A low gravitational field formed by rapid sedimentation makes submarine slope easier to failure when it suffers from some geological processes like earthquake，hydrate dissociation and diaper. In addition，a short-period shallow slide is more likely to occur when the submarine slope is with a steep gradient，sediment with high compressibility and a depositional environment with high sedimentation rate. It is noted that sediment with high compressibility will also lead to a under-consolidated stratum even if the sedimentation rate is low，which is unfavorable for stability of submarine slopes.

In order to investigate the impact of stress transmission from the filling body on the underlying rock layer during the filling mining process，a composite structure model of the filling body-bottom plate was constructed using the similarity principle in a coal mine in Qinshui coalfield. The laboratory experiments and numerical simulations were carried out to study the movements of the top and bottom plates，the failure modes of the bottom plate，and the plastic zone ranges of the column-and-pillar filling mining under different filling body strengths and filling distances. The results indicate that：(1) the most significant stress concentration occurs under the filling body in the shallow bottom plate. This stress is diagonally transmitted downward at a 45° angle，causing horizontal stress and ultimately spreading to the entire bottom plate. As the stress transmits downward，the vertical stress becomes smaller and more uniform and the horizontal stress becomes larger. The change of filling distance has a significant impact on the stress level in the bottom plate. (2) Within the load-bearing range of the column-and-pillar structure filling，the amount of top plate sinking is mainly determined by the filling body strength，while the bottom bulge is mainly determined by the filling distance. The overall relationship between filling body strength，filling distance，and top and bottom plate movements is represented by a quadratic parabolic surface. (3) Under the current working conditions，the maximum depth of the filling column under the bottom plate shear slip is 2.38 m，above which an elliptical shear failure plastic zone is produced，and below which a wavy tensile failure plastic zone is produced，ultimately penetrating the bottom plate of the two weak rock layers. The research results can provide a basis for the rational design of column-and-pillar structure filling.

In order to provide a more comprehensive and effective new method for real-time monitoring of slope deformation，a set of technical methods for real-time monitoring of reservoir bank slope deformation using Micro Electro-Mechanical System(MEMS) inertial sensors is proposed. On the basis of the traditional displacement measurement，the rotation angle measurement is added in the proposed methods，which can more comprehensively observe the three-dimensional motion state of the slope deformation. To observe the slow static deformation of slope body at the initial stage of bank slope deformation，a three-dimensional electronic compass composed of a micro-accelerometer and a micro-magnetometer is used to measure the gravitational acceleration and magnetic field strength of the observation point in the three-dimensional direction of the installation position of the sensor. Using the principle of inertial measurement，the measured axial gravitational acceleration components and magnetic field strength components are converted into the horizontal and vertical rotation angles of the observation point. Furthermore，referring to the global navigation satellite system(GNSS) measurement data，the rotation angle and translational displacement of the observation point can be obtained at the same time. To observe the dynamic deformation of the slope body from the accelerated deformation of the bank slope to the failure stage，the linear acceleration and angular velocity of the observation point are measured by the inertial measurement unit composed of micro-accelerometer and micro-gyroscope. According to the principle of inertial navigation，the measured linear acceleration and angular velocity are converted into the motion velocity and displacement of the observation point. So that，the rapid early warning of the bank slope landslides is achieved. In this paper，an application example of the static deformation monitoring of the reservoir bank slope in the initial stage of deformation is given. Furthermore，the inertial sensor measurement of the dynamic deformation of the bank slope from the acceleration deformation to the failure stage is simulated and analyzed. The example monitoring and simulation results show that it is feasible to use the inertial sensor measurement technology to monitor the static and dynamic deformation of the reservoir landslide in real time，which is helpful to fully understand the real-time state of the slope deformation.

Air-boosted vacuum preloading(AVP) is a newly emerging soft soil improving technology. The studies on the analytical theories of the consolidation with AVP are at the starting stage for few related reports in the literature. To fill this gap，an analytical model for the consolidation of soft ground improved by AVP is proposed based on the assumptions of equal volumetric strain and Darcy?s law. Firstly，the varied well resistance effect of the prefabricated vertical drains(PVDs) is considered based on an assumption that its permeability coefficient decays exponentially with elapsed time and linearly with depth simultaneously. In addition，the smear effect of PVDs and the coupled radial-vertical seepage within soil are also considered to obtain analytical solutions. Then，the reasonability of the present analytical model is verified by degeneration and comparing it to the existing solution and applying it to analyze two field tests. Finally，the present solution with instantaneously loading is adopted to investigate the influence of several parameters on the consolidation behavior. The results show that the AVP can accelerate the consolidation rate more effectively，comparing to the conventional vacuum consolidation technique. The consolidation process of the ground will be retarded with consideration of the clogging effect of PVDs. Moreover，the time well resistance factor ?b has a great influence on the consolidation rate in the later stage. The following factors will lead to a faster consolidation of soft ground，such as a denser layout of PVDs，or a larger Poisson?s ratio of soil，or a smaller influence area of air-boosted pipes or a larger pressurized pressure.

According to the transfer requirements，a transfer underpass of the Nijiaqiao Station of Chengdu Metro Line 8 is constructed under the existing station of Line 1 with zero clearance. Based on the project，the dynamic responses of the underlying transfer underpass under the influence of trains? dynamic loads from the existing metro station are compared and analyzed by in-situ tests and numerical simulation methods. The effects of the following three factors on the dynamic responses have been investigated，including ceiling thickness，sidewall thickness，and middle wall thickness. The results show that in the time domain，the overall dynamic responses of the closely underlying underpass tend to attenuate with the thickness ratio of the underpass ceiling to the existing metro station floor slab(RRF) or the thickness ratio of the middle wall to the side wall of the underpass(RMS)，but the attenuation rate decreases with the RRF or RMS. From this view，the RRF and RMS are recommended to adopt 1.5 and 1.0 as the optimized values，respectively. The dynamic response magnitudes (i.e.，acceleration peak values，ignoring their directions) of the underpass decreases spatially from top to bottom and from the middle to the sides，i.e.，ceiling＞middle wall＞sidewall＞floor slab. The frequency domain shows that the underpass has a dynamic frequency response ranging from 40‐160 Hz. The increase of RRF and RMS have no influences on the frequency response distribution but have appreciable suppression effects on the dynamic magnitude，especially high-frequency dynamic magnitude.

In order to study the bearing capacity of dynamic driving pile in mudstone foundation，the influence of driving process and water on the mechanical properties of mudstone is considered. The model tests of pile driving and static load，needle penetration test and electronic magnifying glass test were carried out. Combined with the field test data，the penetration characteristics and bearing capacity of the driven pile are analyzed，and the damage characteristics of mudstone around the pile are clarified. The results shows that：(1) the mudstone has strong heterogeneity，and the soft and hard interbedded phenomenon is significant. The maximum strength is 13.5 times of the minimum value，and the variation trend of mudstone strength and hammering number is synchronous. (2) The strength of the mudstone at the soft interlayer decreases by 64.2% on average after immersion，and the static load test is damaged by large settlement at the soft interlayer，and the steep drop characteristics are the same as the field test. (3) The damage range of pile driving is 2d(d is pile diameter). The strength of mudstone decreases by 66%，40.5%，17% and 7% on average in 0‐0.5d，0.5d‐1.0d，1.0d‐1.5d and 1.5d‐2.0d around the pile. (4) There is compaction relaxation phenomenon at the pile end. The strength of mudstone at the pile end is 11.1% higher than that at 2d around the pile，and 194.5 % higher than that at the same position of the pile. (5) Mudstone heterogeneity is the cause of mudstone pile bearing capacity problem，which is easy to be ignored in geologic investigation. It is considered that mudstone is always uniform，stable，and its strength increases with depth. This phenomenon should be recognized and paid attention to.