In order to study the deformation，failure and mechanical characteristics of bedding coal and rock under cyclic loading，parallel bedding and vertical bedding cylindrical coal samples were made，and uniaxial graded cyclic loading and unloading tests were carried out under different upper stress limits. Based on the test results，the residual deformation，elastic modulus and damage variables of the specimens during the cyclic loading process are analyzed. The results show that the elastic modulus of the two layered specimens varies with the number of cycles under low stress cycles. However，as the upper limit of stress increases，the fatigue damage in the specimen continues to accumulate，and the elastic modulus eventually shows a downward trend. At the same time，bedding coal and rock under cyclic loading have significant anisotropy characteristics. The specific manifestation is：for the sample with the loading direction perpendicular to the bedding，the damage variable increases sharply when the sample is locally damaged，showing brittle fracture，However，the damage variable of the specimen with the loading direction parallel to the layering showed a continuous growth trend before complete failure，showing obvious characteristics of plastic deformation.

There is still a challenge to reliably predict failure strengths of a rock subjected to complex loads by means of its experimental results under simple loading conditions. This work，based on the energy description of the mechanical model of Mohr-Coulomb criterion，suggests an approach to theoretically estimating the failure strength of the rock under complex compression from uniaxial compression test. It includes a critical energy condition for failure that is resulted from the energy conservation law between the elastic strain energy and the surface energy of crack at a point on the failure surface，and a failure criterion of the rock under polyaxial compression that is derived from the critical energy condition under the condition of constant shear modulus of elasticity and the volume change following a power law of the volumetric stress. Different from previously developed rock failure criteria，this criterion takes characteriscs of the rock deformation and cracking into account. Instead of being determined by fitting the test data of strengths，its three parameters are determined in calculation by using information of the uniaxial compression test. Applications show that the accuracy of its strength prediction may reach the same level as the best-fitting solution by using the Hoek-Brown empirical failure criterion.

In practical applications，unreasonable setting of the threshold value and the calculation time window will lead to a larger error in the algorithm of picking onset of P-wave. Based on this，a method based on tracking the power of damping energy to overcome the shortcomings of the traditional method. The method is that transform the signal into a response domain of a single-degree-of-freedom (SDOF) oscillator with viscous damping and then tracks the variation of the power of damping energy to pick P-wave phases by combining the histogram method and AIC method. This method has the advantages of recognizing noise signal，no detection threshold setting，and no detection window selection. The results show that the proposed method has better anti-noise performance than the traditional method under different SNR. Using this method，40 different Signal-to-noise ratio waveforms monitored in practice were picked up at the onset of P wave，and manual picking after local amplification was taken as the standard. By comparing and analyzing the results with the STA/LTA method，the mean error of the method in this paper was 1.17 ms. The errors within 2 ms account for 87.5% and the errors within 4ms account for 100%. While，the mean error of STA/LTA method is 3.46 ms，and the errors within 2 ms account for 55%，and the errors within 4ms account for 82.5%. It can be concluded that the method proposed in this paper is better. The results of microseismic monitoring in Shizhuyuan mine show that this method can significantly improve the accuracy of source location in microseismic and has important theoretical and practical significance.

In order to explore the bonding performance of mortar bolts under the coupling action of dynamic load and corrosion，the indoor dynamic pull-out test was carried out on corroded mortar bolts through the rapid corrosion test method of steel bars，and the corrosion effect，corrosion position and loading frequency and other parameters were explored The effect of the bond performance of the mortar-anchor interface is verified by modeling with ANSYS finite element software. The results show that the strain change trend of the rusted specimen and the rust-free specimen is relatively consistent. The strain and bond stress of the steel bar at the loading end increase with the increase of the load level，and expand along the anchoring area to the free end；the corrosion position is opposite to the interface The bonding performance has a greater impact. The surface shape of the steel bar at the front of the anchoring section(loading end) and the interface bonding are the most critical to the overall anchoring quality；the greater the loading frequency，the transmission distance of the strain of the steel bar and the interface bonding stress along the anchoring length also shorter；the compressive stress of the interface contact surface of the rust-free test piece and the uniformly rusted test piece is more evenly distributed along the steel bar，the interface contact pressure stress of the rust-free part of the test piece at different rust positions is larger，and the simulated value of the bonding stress is at the loading end It is slightly larger than the experimental value，and the curve distribution of the numerical simulation bond stress is smoother and uniform，but the overall distribution trend is basically consistent with the experimental results.

Holmquist-Johnson-Cook(HJC) constitutive model is widely used in numerical simulation of impact explosion engineering. In order to explore reasonable model parameters for coal-rock mass，furthermore to determine actual effect and related cracking range by liquid CO2 blasting，this article is relied on CO2 blasting project in a mining area in Shenmu of northern Shaanxi，based on static mechanical characteristics test and a split Hopkinson pressure bar(SHPB) impact test，the basic physical and mechanical parameters of coal-rock are obtained. By orthogonal experiment and numerical simulation methods，the entire process of the SHPB impact compression test is reproduced on LS-DYNA3D platform. According to Person correlation coefficient，this research judges the fitting degree between experiment and simulated strain signal，then backward deduces the main sensitive parameter B and N of HJC model. Introducing *MAT-ADD-EROSION failure condition and using compressive and tensile failure criteria，it truly reproduces the whole process of crack initiation，expansion and penetration，until a fissure zone is formed for CO2 blasting，which effectively simulates the fragmentation characteristics of blasting rock mass，and reflects the geometric nonlinear characteristics of rock mass in working face. Moreover，this study analyses crack propagation characteristics and blasting effect of CO2 blasting compared with traditional explosive blasting. Subsequently，the stress wave attenuation laws are analyzed，which give the crushing and fissure range. The results show that the process of stress wave attenuation and the energy release slopes relatively gently during liquid CO2 blasting，and the energy mainly produces elongated cracks in fissure area，which is much larger than the traditional explosive blasting. Under the same equivalence，comparing with traditional explosive blasting case，the effective range of liquid CO2 blasting is larger，meanwhile the crushing range is decreased，and the cracking range is increased. Correspondingly，coal rock is felled apart into massive fragmentations. The research results are applied to the industrial test of CO2 blasting in this mine，considering the simultaneous action of four crack devices，blasting holes are set in a square shape with a spacing of 0.7 meters which determined by calculating. The test results show that the actual blasting effect is good，lump coal rate is increases by 38.5% compared with tradition case.

The PSO-Prophet model for slope deformation analysis and prediction is constructed to solve the problems of highly uncertainty of periodic term extraction and the increasing complexity of combination forecasting model. The Prophet model，with the function of time series decomposition and combination prediction，is introduced to deal with the slope deformation signal. What?s more，the PSO algorithm is used to optimized the parameters to improve the adaptability and prediction accuracy of the model. The prediction experiments of slope monitoring points are carried out，and the prediction accuracy of PSO-Prophet model is 46% higher than Prophet model in the original unequal interval time series. In the combination prediction of equal interval time series after interpolation，the root-mean-square errors of the PSO-Prophet model，the S-GSSVR model，the HP-ARIMA-LSTM model and SSA-Verhulst-FS model are 4.7，9.6，13.2 and 12.0 mm respectively. The experimental results show that the PSO-Prophet model has a simple process and higher prediction accuracy for slope deformation time series greatly affected by periodic term.

In order to improve the seismic safety of interface section of soft and hard surrounding rock of the tunnel in the high intensity earthquake area，the seismic performance of the fiber reinforced concrete secondary lining is studied based on the tunnel project of Urumqi Metro Line 1. Using the method of shaking table model test，the research of this paper is completed，and the research results are as follows. The structural safety of tunnels in hard rock is mainly controlled by the movement interaction between surrounding rock and lining，while that in soft rock is controlled by the seismic inertia force and the movement interaction between surrounding rock and lining. The strength and toughness of the lining structure are improved by the fiber reinforced concrete secondary lining. Because of the small increase of the seismic inertia force borne by the tunnel structure in hard rock，and the movement of surrounding rock and lining is not improved obviously，the minimum value of the structural safety coefficient increases greatly，and the maximum increase percentage reaches 71.40%. After using fiber reinforced concrete lining in soft rock，the effect of the lining structure to resist larger earthquake inertia force is significant. At the same time，the movement interaction between surrounding rock and lining is enhanced. The minimum increase percentage of structural safety factor is smaller than that in hard rock，and the maximum increase percentage is 29.11%. Considering the seismic peak acceleration，longitudinal strain，contact stress and structural internal force，the seismic performance and structural safety of steel fiber reinforced concrete are better than that of basalt fiber reinforced concrete under the condition of the same volume of fiber. The research results can provide reference for the improvement of seismic performance of traffic tunnels in mountainous areas with strong earthquakes.

Under the effect of continuous drying-wetting cycles，the rock mass in the water-level-fluctuating zone of reservoir would experience the weathering aggravation and the mechanical properties deterioration. Cyclic drying-wetting tests were carried out under the conditions of pH = 3，7 and 11 respectively using basalt samples. The degradation laws of uniaxial compressive strength of basalt under different pH and cycles were discussed. Chemical composition of solution were tested to analyze the mass transfer between solution and rock. Based on the basalt dissolution kinetic theory，the effect of reaction processes on strength degradation were studied. The results showed that the uniaxial compressive strength decreases with the increase of cycles in all of the three solutions. While there were significant differences in the decline level during the early stage. Acid condition exhibited the most severe corrosion impact on strength，neutral the moderate，alkaline the least. In the mid-late stage，the difference was minimized. The final deterioration level was almost the same in three solutions. The water-rock reaction in acid and alkaline condition underwent a transition from non-equilibrium to equilibrium. In neutral condition it was always in non-equilibrium state. The elements releasing order in non-equilibrium process under different pH condition obeyed the same rule，which were Ca the first，Al the second，and Si the last. In equilibrium reaction，precipitation and replacement of Al occurred on the solid phase surface. Precipitation would inhibit the release of Si，while replacement would promote the release of Si. The deterioration degree of rock strength in neutral solution was controlled by the stoichiometric dissolution in non-equilibrium state. In acidic and alkaline solutions，the strength degradation of rock was affected by the formation rate of Al precipitation in the early stage，and the replacement of Al in the later stage. The research results could provide scientific basis for evaluating the long-term stability of reservoir slope in basalt area.

In order to solve the problem of large deformation of crushed surrounding rock，grouting support is generally used as an effective means to prevent engineering disasters. For the artificial sawtooth structure surface，the laboratory direct shear test was carried out for the reinforcement of ungrouting and different water-cement ratio aluminate cement grouting，and the mechanism of grouting reinforcement was revealed. The results show that the grouting support can improve the peak strength，cohesion and interface stiffness of the structural surface. With the increase of water-cement ratio，the shear peak strength decreases under the same normal stress. With the increase of water-cement ratio，the cohesion of interface decreases. Interface failure forms：the sawtooth is composed of different relief angles. In the case of shear failure of the ungrouting interface，the modes are shear，wear，slope climbing and gnawing coupling effects. When shear failure occurs at the interface after grouting，the curve fluctuation amplitude is large after the peak strength，and the failure is transformed from failure of bonding force to failure of slip. The characteristics of grouting slip failure are similar to those of ungrouting interface failure. The normal displacement and shear displacement curves show that the ungrouting structural surface is mainly dilatancy，and the grouting structural surface shows the characteristics of first shrinking and then dilatancy.

Based on the viscosity and gel time，wettability and affinity of silica sol，and it?s gel deformation and strength were characterized，an experimental system of steady pressure grouting was developed. The law of grouting permeability of silica sol in mudstone and the evolution law of strength，pore fracture and permeability of grouting modified mudstone were studied. The results show that after adding catalyst，the viscosity of silica sol increases composite exponentially with time，and the gel time is related to the content of SiO2 and Na2O of silica sol and the amount of catalyst，the smaller the content of SiO2 and Na2O and the amount of catalyst is，the longer the gel time is. There is a certain phenomenon of dry shrinkage after silica sol gel，and the smaller the humidity of the curing environment is，the more serious the dry shrinkage is. The stress-strain curve of gel is similar to that of rock materials，and there are stress drop in pre-peak and post-peak. With the extension of curing time，the strength of gel increases，and the brittleness characteristic becomes more and more obvious during failure. After grouting，the uniaxial compressive strength of rock samples decreases in varying degrees，and is negatively related to grouting pressure and time. Under the same conditions，the strength increases with the increase of SiO2 and Na2O content in silica sol. The failure mode changes from the shear splitting failure before grouting to the coexistence of shear slip failure，fracture failure and drum failure after grouting. The pore shape distribution of rock samples has little change before and after grouting，but the pore volume of pore size larger than 20 nm pore is smaller than that before grouting，and permeability decreased significantly.

To seek the initiation mechanism of bedding rock landslide under seismic load，the geometry and stress conditions of landslide′s initial crack propagation are analyzed and the calculating formula of the most dangerous initial crack angle is deduced by theory of fracture mechanics. Furthermore，based on completely cut-through of landslide′s back fault zone，the starting speed of landslide under the composite effect of elastic impulse，peak-residual strength drop and wave oscillation is derived. The results prove that if initial crack angle starts to break along the secondary joint structural plane，the initial crack of landslides whose dip angle of secondary joint′s structural plane is 39.5°will crack more easily；the landslide′s initiation has experienced a process of cumulative fracture of initial crack，cut-through of landslide′s back fault zone，instantaneous fracture of the locking segment，release of elastic impulse strain energy and peak-residual strength drop strain energy into starting kinetic energy of the slip mass，further accelerated by wave oscillation，and finally being thrown from landslide shear outlet. Based on the analysis of the Qingchuan Donghekou landslide happened in the 5?12 Wenchuan Earthquake，it is concluded that the starting speed of landslide is significantly affected by the elastic impulse effect and decisively controlled by the height of elastic impulse area′s slices and length of locking segment under instantaneous fracture of locking segment，if the internal relationship between height of the slices and length of the locking segment is not considered，the upper limit of landslide′s starting speed will be 12.5 m/s when energy conversion rate reaches 100%.

In order to achieve the goal of safe，efficient and low-cost mining，it is necessary to determine the reasonable strength of the backfill. Firstly，the test materials are analyzed to determine the ratio of mortar strength test. Secondly，according to the test results of different proportion of mortar，the relationship between the strength of backfill and the curing age is analyzed，and the relationship expression between them is established. Then，the matching coefficient K is introduced to characterize the matching relationship between cemented backfill and ore rock energy，and the reasonable strength of backfill is determined accordingly. Finally，according to the example of Makeng Iron Mine，the matching characteristics are analyzed，and the reasonable strength of backfill with different rock properties is determined respectively. And then the matching analysis between the solidification time of cemented backfill in one-step goaf and reasonable mining time of two-step pillar mining is carried out. On this basis，the ratio of filling slurry and the mining time of two-step are determined，and is verified by industrial filling. The results show that under the same condition of cement-sand ratio and slurry concentration，the strength of backfill increases exponentially with the curing age；the matching coefficient K of cemented backfill and ore rock energy is closely related to the deformation modulus and bulk density of ore rock，mining depth and strength of backfill；According to the energy matching characteristics of cemented backfill and ore rock，combined with the actual situation of the mine，when the ore rock is moderately stable，the filling ratio of one-step goaf is cement sand ratio of 1∶4 and concentration is 75%. When the ore rock is partially broken，the filling ratio of one-step goaf is cement sand ratio of 1∶4 and concentration is 78%，after solidification for 12 d and 17 d respectively，two-step stoping is carried out. After verification of industrial filling，the strength distribution of the sample ranges from 2.35 MPa to 3.28 MPa，which meet the requirements of mine strength.

In order to simplify the rockburst intensity grade prediction index system，solve the problem of fuzzy classification of prediction，and help engineers to analyze the prediction results，a rockburst intensity grade prediction model based on SOFM neural network was established. The prediction model was expanded into three models according to the different topology of the competition layer. Taking the maximum tangential stress，the uniaxial compressive strength and the uniaxial tensile strength of the rock as the model input vectors，40 sets of rockburst engineering data at home and abroad were used as data sets to input three models for training and testing. The results of the testing indicated that the prediction accuracy of the three models was up to 90%. Through comparing the clustering，testing and training effects of the three models，the prediction model with 16 neurons in the competition layer was the best. Compared the prediction results of best prediction model with that of extension theory，Russenes criteria and cloud model based on rough set of FCM algorithm，the prediction method of rockburst intensity grade based on SOFM neural network was superior to other methods. It shows that the method proposed in this paper is feasible and practical，which provides a new method and means for rockburst prediction.

High temperature treatment has a significant effect on the permeability of granite. The permeability of granite after high temperature is closely related to the temperature experienced and the stress state. Using Pressure pulse attenuation method，we studied the permeability of granite after the high temperature(100 ℃–600 ℃) under different stress state. On this basis，we analyzed the macro-mesoscopic physical and mechanical properties of granite with temperature，and the evolution law of granite permeability after high temperature with volume stress，pore pressure and effective stress. The results show that：(1) After high temperature treatment，the permeability of granite increases gradually with the temperature experienced. The permeability of granite increases slightly under 500 ℃，and a step change occurs in the permeability of granite at 500 ℃–600 ℃. (2) After the same high temperature treatment，the permeability of granite shows a decreasing trend with the increase of volume stress，and the decreasing range gradually decreases. Under the same volume stress，the permeability of granite increases with the increase of pore pressure. (3) There is a negative exponential relationship between granite permeability and effective stress after high temperature，and the permeability decreases with the increase of effective stress. (4) The relationship between permeability and temperature and effective stress of granite after high temperature treatment under 600 ℃ was obtained by fitting. The research results can provide theoretical basis and technical support for the construction of hot dry rock geothermal artificial heat storage，and enrich and develop the connotation of high temperature rock mechanics.

Acceleration array-based shear stress-shear strain inversion analysis approach is widely used in model tests and in-situ monitoring，but its accuracy and credibility have not yet reached consensus in the geotechnical engineering community. One of the important reasons is the lack of research on the reliability of integration approach for evaluating displacement from acceleration records. A new type of adaptive robust integration approach(ARI) is developed to avoid the influence of traditional human interference，empirical parameters，filtering and other factors. It has the characteristics of sensor deflection correction，self-matching of the fitting function，and residual displacement recognition. The shaking table test of sandy slope is designed and carried out under different conditions such as dynamic and deflection，the accuracy and reliability of ARI integrated displacement are discussed. The test results show that：compared with the USGS approach，the ARI approach effectively reduces the peak errors and the irregular lead of the resolution time caused by filtering. Compared with the recorded displacement，the average peak error of the ARI approach to solve the dynamic integrated displacement is 7.69%，the correlation coefficient is 0.99，and the spectral area error is 1.97% under three different periodic loads. Compared with the recorded displacement，the average peak error of the ARI approach is 8.92%，the correlation coefficient is 0.97，and the spectral area error is 4.21% under the influence of deflection. The results of the two sets of blind test experiments show that the sensors of different types and performance parameters have negligible influence on the integrated displacement accuracy and reliability of the ARI approach. The average peak error of 7–15 mm small displacement with high frequency is 9.74%. The ARI approach can maintain good adaptability and robustness under different displacements and periodic loads. The new type of adaptive robust integration approach for evaluating displacements from acceleration records and verification test results has important theoretical significance and application value to improve the scientific understanding of geotechnical model tests and in-situ monitoring of acceleration integral displacement and to enhance the scientific understanding of the inversion of shear stress-shear strain response of the internal soil.

The Daguangbao landslide(12×108 m3) is the largest landslide triggered by the Wenchuan Ms8.0 magnitude earthquake in 2008. The seismic records show that the landslide area not only suffered strong horizontal ground motions，but also received almost equal vertical ground motions. In this paper，an improved Newmark model considering vertical seismic force is used to study the influence of the shear strength parameters of the sliding surface on the earthquake permanent displacement response of the landslide. The results show that vertical ground motions increase the cumulative permanent displacement of the landslide(the maximum increase is 903%)，and the contribution of vertical ground motion to the permanent displacement(cumulative total amount and cumulative rate) is significantly affected by the friction angle of the sliding surface(the influence level ranges from 87.8% to 90.7%)，but is less affected by cohesion(the influence range is only 5%–27.4%). The maximum cumulative rate and duration of the permanent displacement of the landslide during the seismic process are determined by the concentrated release period of the seismic energy，and 50% of the energy is released within 30–50 s during the 120 s earthquake holding time in the Daguangbao landslide area. It is inferred that the instability of Daguangbao landslide may be in the early stage of earthquake. The improved Newmark method used in this paper can be used to evaluate the contribution of vertical ground motion to the initiation of the seismic landslide.

Microbially Induced Calcite Precipitation(MICP) method has emerged as a new geotechnical technology that is widely applied for soil reinforcement. However，few researches on MICP applications in rock mass reinforcement had been reported. Herein，a single rock joint was chosen as an object，and artificial rock joint specimens were prepared by using rock-like materials and reinforced by MICP method and cement slurry，respectively. Laboratory direct shear tests were carried out on these specimens and the shear strength results were obtained. From the experimental results，it indicated that the peak shear strength of MICP reinforced artificial rock joint specimens increased with curing time，of which the increasing rate was rapid in early time，but became relatively slow in later stage. It was also found that the peak shear strength of MICP reinforced artificial rock joint specimens increased by as much as 15.3% by comparisons with that of unreinforced specimens. Furthermore，as a result of the cementation of CaCO3 layer between the upper and lower joint surfaces，the shear failure of MICP reinforced rock joints initiated from the shear failure of the interface between rock joint wall and CaCO3 layer and developed with increased normal and shear stress，then the final shear failure properties including the compression of CaCO3 layer and the shear off and crush of joint surface asperities were formed.

Damage induced by blasting excavation influences the surrounding rock state，which directly affects the construction safety and support design. The effect of stress filed has on blasting damage mechanism has not been fully revealed，and the existing damage simulation method has deficiencies in simulating large-scale explosion. Based on the excavation in the auxiliary tunnel of Jinping II hydropower station，a method of blasting damage simulation based on the normal direction impact load is proposed. And the simulation and field detecting test results is compared to verify the feasibility of the simulation method. Meanwhile，the method is adopted to discuss the influence ground stress has on damage zone. The results indicated that the damage zone can be effectively simulated by the normal direction impact load，and the ratio of the maximum mesh size to the minimum mesh size can be reduced by 82% and the calculation time can be reduced by 50% to 87%. The results also show that the blasting damage depth of tunnel excavation has a significant correlation with the in-situ stress level，and the damage depth increase after decreasing with stress level increases. And the reason why the ground stress "inhibited" the blasting damage zone was due to the fact that when the damage zone was simulated with ground stress，the application of the blast load increased the yield limit of the surrounding rock to some extent；under the conditions of the study of this paper，when the ground stress level is low(less than 12.5 MPa)，the shearing damage is the main part of blasting damage，while the local stress level continues to increase，shear damage is inhibited，and the blasting mainly causes pure shearing damage.

Taking the sandstone block as the research object，the anomalously low friction effect of sandstone block under the condition of stress wave disturbance in vertical direction was studied by using the self-developed anomalously low friction test device. The stress environment of the deep block was simulated by using the coaction of vertical stress wave disturbance，vertical axial pressure and horizontal impact. The influence law of stress wave disturbance frequency and amplitude on anomalously low friction effect of sandstone block was analyzed. The results show that under the coaction of vertical stress wave disturbance，vertical axial pressure and horizontal impact the sandstone block?s instability process of anomalously low friction sliding can be divided into four stages: stress wave disturbance stage，anomalously low friction accelerated sliding stage，unsteady sliding stage and stable sliding stage. Vertical direction stress wave disturbance is not only the key factor to bring out the anomalously low friction effect，but also the catalyst to induce the anomalously low friction effect. The low-frequency significant influence zone was found that is，when the stress wave disturbance frequency is in 1 ‐3 Hz scope，the anomalously low friction effect in sandstone block occurred most obviously. Under the same horizontal impact，the relationship between the horizontal displacement，the peak value of the horizontal acceleration of the sandstone working block and the intensity of vertical stress wave disturbance is linear.

In order to study the mechanical properties and synergistic deformation characteristics of the tailings cemented filling material assembled with various cement-tailings ratios，the uniaxial compression test was used to study two different cement-tailings ratios assemblies. Experimental results show that：(1) the overall peak strength of assembled material body depends on the peak strength of the small cement-tailings ratio specimen. When the peak strength of the small cement-tailings ratio specimen is close to the proportional ultimate strength of the large cement-tailings ratio specimen，the overall peak strength of the assembled material body is reduced by 29.22%. The smaller the peak strength ratio of the two specimens is，the larger the overall elastic modulus of the assembled body. The Poisson?s ratio of the specimen with a large cement-tailings ratio becomes smaller，while becomes larger with a mall cement-tailings ratio，with the peak strength ratio of the two specimens in assembled body. (2) The stress-strain curve of the assembled backfill body is similar to the curve of the specimen with a smaller peak strength in terms of value and change trend. The failure mode is mainly manifested as the shear failure and tension failure penetrated in the specimen with a small cement-tailings ratio. Although the failure deformation of two specimens in the assembled body shows a certain hysteresis in time，its synergistic deformation characteristics are obvious. (3) The acoustic emission of the assembled body with different cement-tailings ratios has different activity characteristics in the four stages and the stress peak lags behind the peak of acoustic emission ringing count. The count peaks of the large cement-tailings ration specimens in the assembled body account for 13.77%，14.16% and 6.56% of the corresponding small cement-tailings ratio ones. As the strength ratio of the assembled body increasing，the acoustic emission ringing count of the combination decreases gradually.

To study the deformation mechanism and acceleration response of the multi-sliding surface landslide body under the action of vertical earthquakes，take the seventh block of the Yushu Airport Road landslide group #0 landslide as an example，we carried out shaking tables test under 4 earthquake intensities and 4 loading conditions. The model test focuses on the horizontal and vertical accelerations peak and time-history curves of the multi-slip surface landslide body subjected to vertical excitation，and then analyzes the deformation and failure mechanism of the multi-slip surface landslide body . The results show that：with the continuous increase of the input seismic wave energy，the acceleration peak of each measurement point increases obviously. Along the sliding belt，with the continuous increase of the elevation，the acceleration peak increases gradually. In the vertical section A6–1‐A6–4 points，the acceleration peak inside the sliding zone is greater than the bedrock and sliding body，and the sliding zone has a certain absorption effect on seismic wave energy. The vertical acceleration peak inside the sliding zone is approximately horizontal 2 to 6 times.

The undulation and roughness of joint plane are important factors affecting mechanical parameters of rock mass. The existing statistical methods of joint profile roughness parameters usually adopt the equal interval sampling method，and there are deviations between the obtained sampling points and the turning points of joint profile fluctuation. In view of the fact that photographing and digital image processing technology are widely used in joint measurement，and pixel is the smallest unit of an image. A unequal interval sampling method based on describing the set of joint plane points is proposed，and then all adjacent sampling points are represented by vector. A new formula for calculating root mean square Z2 of the first derivative of joint profile is also proposed. The conclusions are as follows. (1) The sampling points of the unequal interval sampling method are located at the turning points of the structural surface fluctuation，which are in good agreement with the original contour. (2) Based on the vector representation of the joint profile，the deviations of the joint profile roughness parameters can be calculated quantitatively. (3) The unequal interval sampling and vector representation will make the process of roughness solution more accurate and faster.

In order to improve the accuracy of predicting rockburst intensity grade，the four coefficients(rock mass stress coefficient( )，rock brittleness coefficient( ) and elastic deformation energy coefficient( ) were selected to construct the rock explosive intensity level prediction index system. Based on 145 sets of rockburst case engineering data at home and abroad，adopting six machine learning algorithms to establish the prediction model of rock explosive intensity level respectively，combined with random cross-validation methods. the correlation coefficients were calculated using the principle of correlation coefficients. According to the correlation coefficients between variables，there is no strong correlation between them. Meanwhile process the engineering data of the original rock explosion case first and then standardize standardization，eliminating the influence of extreme values in the data on the model. The T-distributed neighborhood embedding(T-SNE) dimensionality reduction method is introduced to reduce the dimensionality of the data and visualize the data. Finally，the accuracy of the six established rockburst intensity grade prediction models were analyzed，discussed and evaluated. The research results show that：Based on the T-distributed neighborhood embedding(T-SNE) dimensionality reduction method，the results show that each rockburst intensity level has obvious aggregation phenomenon. Support SVM has high prediction accuracy for rock burst grade 1. For samples with rockburst intensity levels of 2 to 4，the linear discriminant model has a high prediction accuracy and also has a relatively stable model performance；the linear discriminant model(LDA) is applied to Jinping rockburst case projects，such as the secondary hydropower station，the riverside hydropower station，and the Cangling tunnel，have found that the LDA model prediction results are the same as the actual rockburst levels. The research results provide a good guide for rockburst prediction problems in geotechnical engineering.

The ground synthetic aperture radar remote sensing technique has been widely used in slope deformation monitoring due to the advantages of high precision，wide range and all time. Unmanned aerial vehicle (UAV) remote sensing is a newly-developing technology that integrates UAV，remote sensing sensor，GPS differential positioning and other technologies to achieve rapid collection，processing，and application of geographic environmental information. In this paper，the digital elevation model and image model of 3D geomorphic are obtained by UAV aerial survey，and the high-precision point cloud data are extracted by software. The algorithm monitoring was established to screen the point cloud data within the monitoring field according to the geometric relationship of radar linear orbit. The unit monitored by each microwave beam of the S-SAR was regarded as a "basket"，and r and thresholds were solved and set. The r and at each point were calculated，the "shot pattern" method was used to quickly match the deformation values measured by each radar wave to generate a deformation diagram that matched the slope. This method has been successfully applied to the emergency rescue monitoring of slope and landslide in open pit mines，and can accurately identify the dangerous and large deformation area within the scope of radar visual field monitoring，so as to provide the basis for landslide early warning and forecast.

The quantitative prediction of fractures is of great significance to the exploration and exploitation of fractured reservoirs. While the accuracy of fracture prediction model is very important in prediction. Based on the theory of strain energy and the law of thermodynamics，a prediction model for calculating the volume density of new fracture is built. Firstly，the plastic strain and the condition of triaxial stress in origin of new fractures，which had been neglected by predecessors in fracture prediction，are fully considered. Secondly, the total energy，elastic strain energy and plastic strain energy absorbed by the rock to generate the new fracture are calculated through the formula and derivation of elastic-plastic theory. Finally，the prediction model of the volume density of new fracture is caculated. This new volume fracture prediction model theoretically revealed the relationship between the origin and development of fractures and triaxial principal stress and lithology. Using ANSYS finite element software，the stress field of Chun 41 block in Dongying depression during the period of Eocene Es3–2 deposition is simulated. Using the APDL programming language of ANSYS software，the stress value of each node is obtained. Then，the prediction model of fracture density is added into ANSYS software to predict fracture density. The prediction results show that the northern arc of Chun Bei fault in the study area is a fracture zone for oil and gas exploition. Compared with the fracture prediction of traditional structural stress field simulation，this new model based on the theory of strain energy and the law of thermodynamics is more accurate with a higher accuracy than previous model in fracture prediction. Therefore，it is of great significance to the exploition of fractured oil and gas pool.

The change of temperature and humidity in micro-environment is the main factor affecting weathering of sandstone grottoes. In order to find out the influence of different cave shapes and opening regulation on the micro-environment of the grottoes，13 typical caves in the North Grottoes were selected for monitoring the micro-environment for 9 years. The results show that the opening regulation is the main factor affecting the micro-environment of caves. The open caves without cave eaves are the most affected by the external environment，followed by those with cave eaves. The changes of semi-open caves，super-large caves and closed caves decrease in sequence. Humidity in caves mainly come from external environment，and the influence of water seepage from the cliff is less. The absolute humidity and variation of all caves is basically the same as that of the outside. The change of relative humidity is mainly caused by the change of temperature in cave. Once the eaves are shaded and the door is closed，the relative stability of temperature in the cave can be controlled，thereby reducing the change in relative humidity. These changes of micro-environment characteristics can provide scientific basis for preventive management and risk assessment of the North Grottoes.

With the development of electronic technology，various in-situ stress testing equipment is gradually developing towards wireless measurement. This paper develops a digital integrated system that can automatically measure and collect data，a wireless in-situ stress measuring deformeter based on the principle of aperture deformation method is designed，and the composition，testing principle，measurement method and calibration verification is introduced in detail. In order to demonstrate the reliability of this probe，all four steel ring strain sensors are calibrated by using Carlson deformation gauge calibration station，and the relation between the voltage signal and the deformation of the steel ring is obtained. The results show that there is a good linear repetition relationship between the voltage change of the steel ring and the deformation of the steel ring. The resolution of a single steel ring can reach 0.025 ，and the measurement accuracy is improved by about 3 times. The overall calibration test of the probe with aluminum cube and granite cube show that the measurement error of the deformeter is less than 5% and the absolute error is less than 0.6 MPa，indicating that the measurement result of the probe is accurate and can meet the requirements of field use. The wireless design of in-situ stress measuring deformeter facilitates the measurement of in-situ stress in deep holes，and can realize the continuous reading of the measured data in the whole process of over-coring，thus avoiding the precision shortage of limited discrete data obtained by manual measurement and reading.

Based on the macro-meso structures of layered rocks，the anisotropic multiscale damage model and deformation-dependent permeability evolution equation for saturated layered rocks were derived in the framework of thermodynamics. On this basis，the hydro-mechanical coupled numerical model of layered rocks was established in combination with TOUGHREACT，which is a well-designed open-source code for fluid flow simulation. The proposed model well considered the mechanisms of damage growth，sliding dilatancy and normal compression of small-scale arbitrary microcracks，and shear sliding of large-scale bedding planes. The influences of multi-scale structural changes(microcracks and bedding planes) on the characteristics of hydro-mechanical coupling in layered rocks were commendably reflected. Numerical validation and application of the proposed model were done on the simulations of water injection responses at laboratory and field scales. The simulation results demonstrated that the water injection-induced hydro-mechanical coupling responses，such as rock damage，water pressure enhancement，bedding plane opening and permeability evolution，were affected by the structural variations of microcracks and bedding planes as well as the spatial development characteristics of bedding planes. Better modeling the macroscopic hydro-mechanical responses of layered rocks depended on the accurate characterization of the internal macro-meso structures. The research may provide a good practical value for the evaluation of engineering disturbances in deeply layered surrounding rocks under coupled hydro-mechanical loading conditions.

It becomes extremely easy to revitalize ancient landslides and increases the risks of engineering when excavation engineering crosses the ancient landslides. To meet the technical requirements for stability control of railway cuttings crossing huge ancient landslides，taking the framed anti-slide retaining structures(FARSs) as study object，the internal force calculation method of FARS was derived based on several calculation assumptions. Combined with the construction of an excavation engineering crossing the huge ancient landslide of Lindai—Zhijin railway，theoretical calculations，numerical simulation，construction method and filed test were carried out to reveal the internal force and displacement response characteristics of FARSs，the design method and construction technology of FARS were also proposed. The results：(1) The theoretical calculation results of the internal force of FARS were close to the results obtained from numerical simulation and filed test. The extreme values of bending moment and shear force were mainly located at the junction between piles and beams. These junctions were the key nodes for local strengthening of FARS. (2) It suggests that the front pile, the back pile and beam should be strengthened with the shear design when FARSs were applied to double–track railway，but secondary beam should be strengthened with the bending design. The internal forces of the front pile，back pile and beam were less affected by the operation speed，and the internal forces of the secondary beam increased slightly with the increase of operation speed. (3) The beams and secondary beams played a coordinated role in the deformation of front pile and back pile. The maximum lateral displacement of the front pile and back pile was less than 6.0mm under the landslide thrust，and FARS had good seismic performance in earthquake areas of nine degrees magnitudes and below(where the peak acceleration varying from 0.05 g to 0.4 g). (4) To build FARSs in an ancient landslide，the construction process should be from front to back，from top to bottom，alternate between piles，the construction technology should be sequential construction of front pile and back pile，partial cuts are reserved for connecting steel bars for beams，secondary beams and piles，back piles and beams are integrally poured. The results can be used a technical support to guide the subgrade construction and geological disaster prevention of Sichuan–Tibet railway，which is the representative railway in the complex and dangerous mountain areas.

：Because of the deterioration of lining materials or corrosion of steel bars, it is easy to cause shallow concrete spalling，which will seriously affect the safety of tunnel operation. It is necessary to find the concrete spalling phenomenon in time through non-destructive testing technology and judge the possibility of spalling. The purpose of this paper is to explore the feasibility of using infrared thermal imaging technology to detect the peeling defects of lining concrete. The methods of numerical analysis，indoor tests and field tests are used to analyze the influence factors on the temperature field of lining inner surface under natural environment and heating conditions. These factors include stripping depth，size and temperature difference between the two sides of the lining. The results show that，the square shallow peeling defects with side length of 80 mm can be detected when the spalling depth is 10 mm and the temperature difference between the two sides of the lining is 8.06 ℃. And when the spalling depth is 50 mm and the temperature difference reaches 11.9 ℃，it is possible to detect the peeling range with side length no less than 150 mm. It is feasible to detect the shallow spalling defects of tunnel lining within 50 mm depth by infrared thermal imager under natural conditions，and the detection feasibility increases with the decrease of defect depth. Moreover，the temperature difference between the stripping position and the intact position on the detection surface is proportional to the temperature difference between the two sides of the lining，and increases linearly with the increase of the side length of the peeling range. Under the heating condition, the effect of infrared detection is obviously improved，but it is still not available for defects with side length less than 20 mm.

The influence of pore-salt solution concentration on deformation behavior of soil is an important scientific issue in environmental and energy geotechnical engineering. In order to achieve the quantitative description of the deformation behavior of saturated clay under the coupled action of external load and the pore-solution concentration，a unified virgin compression model of clay considering the influence of salt solution concentration is established based on the intergranular stress equation that considering the physicochemical interactions between solid-liquid phases of soil. Then，consolidation test data of GMZ01 bentonite under different pore salt solution concentrations is used to validate the existence of unified compression theory. What?s more，the unified virgin compression model is used to calculate the void ratio changes of clay under the increasing of salt solution concentrations under constant vertical stresses. At last，pore salt solution concentration-external stress coupled loading test paths are calculated by the proposed model. Calculation results show that the deformation characteristics of clay under different pore salt solution concentrations is well described by the model，which further verifies the correctness of the unified virgin compression model.

Helical anchors have been widely used to support the structures suffering from cyclic uplift loading，such as wind turbines and transmission towers，due to their good uplift resistance. And the studies on cyclic performance of helical anchors are limited. Therefore，centrifugal tests of helical anchors(wished-in-place) in dense sand under cyclic loading were conducted to investigate the effects of embedment ratio and number of helices on cyclic uplift stability and cyclic capacity. Test results show that the uplift displacements at the beginning of ultimate cyclic loading level are very close to the failure displacements under monotonic loading for single-helix anchors. Relative ultimate cyclic uplift capacity for single-helix anchor increases gradually with the increase of embedment ratio H/D and reaches the maximum value 0.9 at the embedment ratio of 6，and then the value of almost keeps constant when embedment ratio is more than 6. Moreover，the relative accumulated displacements during each cyclic loading for single-helix anchors with embedment ratio less than 6 are all higher than the anchors with embedment ratio more than 6. Therefore，minimum embedment ratio for single-helix anchor is proposed as 6 when it is used to resist cyclic uplift loading. The relative ultimate cyclic uplift capacity of double-helix anchor is the same as that of single-helix anchor with the same embedment ratio，but the accumulated displacements during each cyclic loading for double-helix anchor are all less than those values for single-helix anchor. Double-helix anchor should have higher cyclic uplift capacity than single-helix anchor if displacement is taken as control condition.

In order to study the effect of stress level on the deformation characteristics of frozen clay during loading process，a series unidirectional rotation of the principal stress axis tests was conducted on frozen clay under different mean principal stress at －10 ℃ using a frozen soil hollow cylindrical apparatus in this study. The experimental results indicate that，the mean principal stress p has a great influence on the axial strain and shear strain in unidirectional rotation loading process. The ratio of difference between maximum and minimum axial strain to minimum axial strain can reach 121.7%，and axial tensile strain decreases with the increase of p-value. The peak value of shear strain lags behind the peak value of shear stress，showing strong viscoplastic deformation characteristics. And the larger the shear strain is during loading process，the greater the degree of lag behind of shear strain is. At lower p-value，the strength of frozen clay increases with the increase of p-value. However，when the p-value exceeds the threshold value，it will decrease with the increase of p-value. The threshold p-value is reduced with the increase of intermedia principal stress. After the unidirectional rotation tests，there is obvious plastic shear strain in specimen. By analyzing the curve of p-value versus plastic shear strain，four stages can be got，which is strengthening，weakening，weak strengthening and weakening again.

In order to study the evolution of stress status of expansive clay，a series of compaction tests for ML clay had been carried out. The samples with different initial water contents were compacted via a home-made one-dimensional compaction apparatus. The evolutions of suction and deformation of samples were analyzed during the compaction process. It shows that compression index( ) is significantly affected by initial water content. The value of increases with initial water content if the initial water content is smaller than 21.4%，otherwise it keeps almost constant. The initial water content has little effect on the unloading-reloading index( ). Due to the “mechanical wetting”effect，the matric suction gradually decreases during compaction. During the unloading stage，the matric suction increases significantly. For the sample with same initial water content，the increment of matric suction due to unloading effect increases with the degree of saturation. Based on the post-compaction suction，the compaction plane could be divided into parts：the post-compaction suction is not affected by the degree of saturation of samples，and the post-compaction suction increases with degree of saturation. It also clearly shows that soil water retention curve of sample with constant volume is strongly affected by the void ratio. Based on suction，the degree of saturation，average effective stress，modified suction and void ratio，models for soil water retention curve and compaction curve have been established. The predict of suction and volume evolution during the compaction has been carried out.

Understanding the mechanical properties of mixed frozen geotechnical materials，such as frozen soil-rock mixture，is fundamental to guarantee construction safety in cold regions. A series of uniaxial compression and Brazilian tensile tests were conducted to acquire the strength and deformation characteristics of artificial ice，ice-rock mixture，frozen soil，and frozen soil-rock mixture(FSRM). The mesostructured and crack patterns of ice-rock，soil-rock and soil-ice interfaces were also analyzed using a microscopic imaging technique. The result shows that：(1) Ice and frozen soil present comparative flat fracture surfaces while frozen soil-rock mixture and ice-rock mixture mainly present tortuous cracks. (2) Influenced by the shape of rock blocks(convex or concave/serrated boundary)，there are two types of cracks in the ice-rock mixture：cracks along the accurate ice-rock interface or cracks inside the ice near the interface；cracks in FRSM mainly develop between the frozen soil and the soil-rock interface. (3) The compressive and tensile strengths have an increasing linear trend with decreasing freezing temperature. The strength increasing rate of FSRM and frozen soil is more sensitive than that of pure ice and ice-rock mixture. The ratio of compressive and tensile strength is about 5. (4) Under a temperature of－10 ℃，the compressive and tensile strength of samples are present in decreasing order as follows：ice_rock mixture＞frozen soil＞FSRM＞ice. However，under a temperature of－30 ℃，frozen soil has the maximum compressive strength，followed by FSRM，ice-rock mixture，and ice，and the tensile strength is decreasing in the following order：FSRM＞frozen soil＞ice-rock mixture＞ice. (5) In frozen soil-rock interface，ice could fill small pores or fractures of blocks，namely，having the interface interlocked. With a higher soil water content，soil particles from frozen soil could dissolve in water and form an ice_soil mixed layer on one side of the soil layer at the ice-soil interface after freezing. Hence the strength of this layer is higher than that of pure ice，which effectively improves the strength of frozen soil.

In the construction of subway，tunnels crossing the adjacent pile group of the existing high-rise buildings may cause excessive settlement and tilting of the piles. In this study，a series of three-dimensional centrifuge model tests and numerical simulations using an advanced hypoplastic soil model were carried out to investigate the response of an existing pile group to side-by-side twin tunneling at two typical depth，namely near the pile toe(Test TT) and below the pile toe(Test BB). Firstly，the sand layer with pile group foundation was prepared by rain flow deposition method. Secondly，under the condition of 40 g，the effect of staged excavation was simulated by drainage of water bags. Meanwhile，the settlement and rotation of the pile group was measured by linear variable differential transformers. Finally，through the finite element analysis，the settlement and lateral inclination of pile foundation are computed and compared with the centrifuge test results. The results show that：In the two tests，the maximum settlement of pile foundation is 2.1% and 2.4% of pile diameter respectively，and the maximum inclination occurs after the first tunnel excavation，which is 0.2% and 0.08%，respectively. When the depth of tunnels is large，the settlement of pile foundation is large but the rotation angle is small，the pile group changes to the friction pile，and the strength utilization of the soil unit at the base of pile decreases. When the depth is small，the settlement is small but the rotation angle is large，the pile group changes to the end bearing pile，and the strength utilization of the soil unit increases.

The cyclic shear behavior of the interface between soilbags has an important influence on the dynamic stability of soilbags-built structures. In order to study the cyclic shear behavior of the staggered stacking soilbags and the effect of cyclic shear on the interlayer shear strength of the soilbags，a series of large-scale direct shear tests and cyclic shear tests were conducted on the staggered stacking soilbags. The focus is on the effects of the number of cyclic shears，vertical stress，and amplitude of shear displacement during the cyclic shearing process on the dynamic deformation characteristics and shear strength of the staggered stacking soilbags. The results show that the shear failure of the staggered stacking soilbags? interface before and after the cyclic shear follows the Mohr-Coulomb failure criterion. The shear strength of the staggered stacking soilbags′ interface increases after cyclic shear. In the low stress range，the damping ratio of the staggered stacking soilbags′ interface increase with the shear displacement amplitude，and is basically independent of the number of cycles and the vertical stress. Due to the internal embedding effect of the staggered stacking soilbags，the soilbags exhibit recoverability similar to that of laminated rubber bearings during cyclic shearing.

The composite foundation of top-shaped concrete blocks(TSCB)-sand bag well(SBW) were found to perform very well in soft clayey deposit treatment. However，relevant study about the optimum design of TSCB-SBW foundation were seldom reported. This research compared the engineering performance normal TSCB-SBW foundation and the non-connecting bar(NCB) TSCB-SBW foundation to investigate the features and functions of connecting bars in the TSCB-SBW system. The results showed that (1) the NCB TSCB-SBW foundation has only 10% higher settlement and 20% larger lateral displacement than the normal TSCB-SBW foundation. In addition，the NCB TSCB-SBW foundation showed a better mechanical performance and an equivalent plastic strain with normal TSCB-SBW foundation. (2) Compared with the gravel cushion，as the excellent self-balance of TSCB，TSCB-SBW foundation behaves good integrity and deformation controlling. In general，NCB TSCB-SBW foundation and normal TSCB-SBW foundation presented similarity in settling controlling，pore pressure dissipation，stress in blocks and distribution of plastic strain.

Damping ratio is one of the important dynamic parameters of soil. Based on the freeze-thaw cycles tests，the dynamic triaxial tests are carried out to study the damping ratio of remolded Qinghai—Tibet silty clay under dynamic loading. In the test，the influences of the freeze-thaw cycles，water content and dynamic loading frequency are considered. The relationship curve and model parameters of damping ratio vs. dynamic shear strain( - ) are obtained. The results indicate that the damping ratio of remolded Qinghai—Tibet silty clay under dynamic loading is most significantly affected by moisture content，significantly affected by freeze-thaw cycles，and less affected by dynamic loading frequency. With the increase of the number of freeze-thaw cycles，the - curve shifts upward and the damping ratio corresponding to the same dynamic shear strain increases，the - curve changes most significantly after one freeze-thaw cycle，then tends to be stable after three freeze-thaw cycles. With the increase of the water content，the - curve keeps moving upward，the shape of the curve also changes gradually from gentle to steep，and the damping ratio corresponding to the same dynamic shear strain generally increases. With the increase of the dynamic loading frequency，the - curve moves down slowly，and the damping ratio corresponding to the same dynamic shear strain decreases slightly. The research results can provide a reference for the selection of the damping ratio parameters in the seismic response analysis and foundation dynamic response analysis in cold region.

Red mud-phosphogypsum-cement(RPPC)，red mud-phosphogypsum-quick lime(RPCA) and ordinary cement(PC) were used to solidify/stabilize the artificially prepared lead，zinc，and cadmium contaminated soil. Then the ratio of red mud-based curing agent was optimized. After the samples were cured for 7 days and 28 days respectively，unconfined compressive strength，toxic leaching test and pH gradient test were carried out. The research results show that with the increase of curing agent content and curing age，the unconfined compressive strength of the samples cured with red mud-based curing agents gradually increases. The difference between the strengths gradually increases. The pH of the leaching solution of the samples cured by the three curing agents are in the range of 7–9. After 28 d curing age，the red mud-based curing agents with 15% content have good strength and curing effect. In comparison，RPPC has better solidifying/stabilizing effect than RPCA. And RPPC has higher unconfined compressive strength and lower heavy metal leaching concentration. The pH gradient test results show that the leaching concentration of heavy metals in RPPC solidified samples was the lowest when pH = 8. Under different pH values of the extractant，the leaching concentration still meets the trend of increasing with the increase of the content.

For reasonably determining the bottom resistance during sinking stage of super-sized caisson foundation，a method based on the data of the soil pressure on tread of foot blade is proposed. Based on the monitoring data during the sinking stage of the super-sized caisson foundation engineering of the main tower of Changtai Yangtze River Bridge，the bottom resistance of different zones within the bottom of the caisson foundation is calculated by the proposed method，and the distribution characteristics and variation of the bottom resistance are analyzed. At the same time，the scale factor of soil pressure on foot blade incline and soil pressure on tread of foot blade is studied. The analysis results of engineering practice show that in the process of caisson soil sampling from the internal area to the external area，the bottom resistance of inner bulkhead and inner partition walls decreases，while the bottom resistance of outer bulkhead and outer partition walls increases. The distribution characteristics and variation of the bottom resistance can actually reflect the global mechanical behavior of caisson foundation，which helps guide the safe sinking of the caisson foundation.

The purpose of this paper is to study the multi-point non-uniform excitation effect of subway viaducts and the laws of ground vibration attenuation. Based on the elastic semi-infinite space theory，a semi-analytical solution of the vertical acceleration of the soil surface under the action of multi-point non-uniform excitation is established. By testing the environmental vibration of a subway viaduct on a soft foundation，the accuracy of the theoretical model was verified by comparison. Study the influence of multi-point excitation and time delay effect，and analyze the law of vibration attenuation. Research indicates that the ground vibration around the viaduct attenuates rapidly with distance in the early stage and slowly at the later stage，and the main frequency distribution range is 60–100 Hz；It is necessary to consider multiple non-uniform excitations in the calculation，and 4–5 bridge piers can meet the calculation accuracy；The load amplitude has little effect on the vibration attenuation law，but the frequency has an impact；the vibration attenuation in the middle of the bridge span is slower than that at the pier，and the outside of the curve section is slower than the inside. The research results have guiding significance for the calculation，analysis，testing and evaluation of subway environmental vibration.

Moisture retention capacity(MRC) is a key parameter to evaluate the pre-dewatering of municipal solid waste(MSW). In this paper，eight sets of MRC tests were conducted on fresh MSW with high food content，and the influence and mechanism of stress and degradation on MRC were analyzed. MRC of MSW decreased with an increase in stress，which was mainly caused by the decrease of inter-particle water retention capacity and the increase of intra-particle water release. MRC of MSW decreased faster with elapsed time under more favorable degradation conditions，which was related to the increase in release rate of intra-particle water. A mathematical model was then proposed for the prediction of MRC in which the influences of stress and degradation were considered. The pre-dewatering effects of MSW piles were evaluated by using the proposed model，in which six levels of applied stress and six different degradation conditions were studied. The results can provide theoretical basis for the design of pre-dewatering project of MSW piles. An optimal technical program was then recommended：mixing the cellulose enzyme into MSW with a dosage of about 1.5‰ of the dry mass of MSW，and then applying a stress of about 100 kPa on top of the MSW pile，and then introducing air into the MSW pile at a rate of 300–400 L/kg-dry-MSW/day from the side wall and applying negative pressure at the bottom，and meanwhile controlling the temperature at (40±3) ℃. Under the above conditions，the dewatering rate of MSW pile is promising to reach above 50% after treating for at least 3 days.