For the research of the permeability evolution of carbonate rocks under seepage corrosion effect of different solutions，Na2SO4 solution and distilled water were used to conduct rock permeation experiment for 15 d using the hydraulic-mechanical coupling permeability experimental system. The curves of carbonate permeability versus time and the variation of mineral ion concentration in leachate with time corresponding to the design conditions were obtained. The relationship between the law of permeability change，the law of mineral dissolution and various influencing factors was analyzed. The results indicate that the significant changes in the permeability of carbonate rocks in early stage are caused by stress conditions. With the development of experiment，the effect of stress decreases gradually. When the confining pressure and osmotic pressure increase equally，permeability is greatly influenced by confining pressure. The trend of permeability is less affected by minor changes of stress. In the stable stage，the change of rock permeability is the result of the joint action of the corrosion and mineral precipitation of the osmotic solution. The dissolution of Na2SO4 solution is relatively strong，CaCO3 dissolves strongly in the upstream of rock sample. After the concentration of Ca2+ reaches the maximum，the CaCO3 precipitates in the downstream，resulting in the heterogeneity of dissolution process，and finally the permeability decreased. The dissolution of distilled water to carbonate minerals is weak，a small amount of Ca2+ dissolves in the upstream and the dissolution rate of the downstream became lower. The Ca2+ concentration can't reach the supersaturated state along the path，that makes it difficult to precipitate，and the final permeability maintains stability.

The limit equilibrium method based on cantilever beam theory is a feasible method for analyzing flexural toppling in anti-dip layered rock slopes. However，most of the current calculation methods are iterated successively for all strata on the failure surface，which often requires a lot of mathematical calculation.It is difficult to evaluate the slope stability in the field quickly and preliminarily. Based on cantilever beam theory，the rock columns above the failure surface are divided into three sections：the stable section，the active toppling section and the passive toppling section by comparing the critical instability height with the present height of the block on the failure surface. Based on the limit equilibrium，the corresponding stability calculation method is proposed，and the risk of toppling failure can be preliminarily determined by using the geometric area of S area. 2 engineering examples and centrifuge experiments were illustrated for practical verification of the proposed approach. The research results of this paper have guiding significance and application value for the stability evaluation of flexural-toppling failure in rock slope.

Reliable test data constitutes the basis of studying rock strength and deformation features. In this paper，conventional triaxial compression(CTC) tests were performed systematically upon silty sandstone in order to study the size effect of rock samples by analyzing the influences of sample size on rock strength and deformation behaviors under different confining pressures. We consider first CTC tests on samples of the same diameter by varying the sample height. It is shown that given the confining pressure，as the height-diameter ratio increases，both the failure stress and the Poisson?s ratio decrease while the Young?s modulus increases. Particularly，when the height-diameter ratio is beyond the value of 2.2，the measured material strength，Young?s modulus and the Poisson?s ratio become stable. Further，an additional set of CTC tests with different confining pressures are carried out upon samples of 37 mm in diameter and with the height-diameter ratio of 2.0. We analyze the characteristics of rock strength and deformation and compare the results with those issued from the tests on the samples of 50 mm in diameter and with the height-diameter ratio of 2.0. It is concluded that in CTC tests the size effect on relatively uniform rocks like silty sandstone is mainly attributed to the influence of rock height-diameter ratio.

In order to investigate compressive behaviours of layered rocks with different dip angles under different impact loads，dynamic compression tests of phyllite rocks were carried out using the split Hopkinson pressure bar system. The failure modes of rock are analyzed in terms of fracture morphology，wave propagation and energy dissipation. The fracturing modes of layered phyllite specimens can be divided into four types. At lower impact velocity，most of the specimens are destroyed by one type of fracture surface，and at higher impact velocity，a variety of fracture types are mixed. With the increase of impact velocity，the fracture modes increase and the average fragment size of rock decreases. The dynamic compressive strength performs a U-shaped change with the increase of dip angle，which is more significant at high impact velocity. The strain rate presents the inverted shoulder shape，and the fracture strain shows a shoulder shape with the increase of the dip angle. At lower impact velocity，the fragmentation effect is more pronounced when the loading direction is 45°–67.5°. At higher impact velocity，when the loading direction is 90°，the fragmentation effect is the best.

Based on the laboratory basic mechanical tests of marble，the PFC3D was used to obtain a set of mesoscopic parameters reflecting the characteristics of marble. Monotone and cyclic loading of cracked chevron notched Brazilian disc(CCNBD) model were carried out respectively to study the stress distribution，fracture toughness and crack propagation law of marble under different loadings. The results show that the mode-I(tensile) fracture toughness( ) of marble under two types of cyclic loading have different amplitude reduction of the static ，and the specimens have clear tensile softening zone after the post-peak region，and subcritical crack propagation occurs. Under cyclic loading，the crack growth of the sample can be divided into three stages：initial stage，stable stage and accelerated stage. At the initial stage of loading，the number of microcracks increased significantly，and the crack growth rate was stable. At the stable stage of loading，the crack growth rate gradually decreased，and finally，the crack growth rate gradually increased，and the number of cracks increased rapidly until failure. The tensile chain distribution was more concentrated at both ends of the ligament and on both sides of the disc than the monotonic loading.

The concept of dynamic Mohr?s stress circle is proposed by extending the classical Mohr?s circular stress analysis to the static loading and dynamic unloading failure process during rock burst generation. Based on this，the dynamic Mohr-Coulomb criterion and theoretical model for predicting fracture angles of rock burst failure are established. These theoretical analyses well explain the cohesion loss phenomenon in dynamic failure such as rock burst，and show that the cohesion loss value and the rock fracture angles can be predicted according to the static loading stress. At the same time，rock burst experiment on granite was carried out and a good agreement between the analytical models and experimental results. Since the static loading stresses could be determined by means of instrumental measurement and prior knowledge in rock mechanics，the theoretical findings obtained in this research is of practical significance.

Based on a deep resource exploration project in the Plain of North China，six boreholes are arranged at various positions near the faults according to the requirements of mine facilities，mining and ground industrial sites design，and hydraulic fracturing technique is implemented for measurement of in-situ stress. By comparisons of stresses between near and far to the faults，the variability of in-situ stress near the faults and its change rule is revealed. The results have shown that the maximum horizontal principal stress ?[26.35 MPa，55.47 MPa]，stress concentration factor is 1.05–1.44； ?[1.22，1.65]，1.56 in average，which is approximately equivalent to that of far field stress； ?[5.90，22.80]，16.42 in average，exceeding the differential value far to the faults. In the adjacent zone，the orientation of in-situ stress near to the faults will diverse，the variation range of diversion is 0.60°–30.83°，24.2° in average. In-situ stress will evidently change at the lower wall of fault，between the faults，and at the junctions，it presents stress concentration，increase in differential value between horizontal principal stresses，significantly diversion in the orientation of stress and increase in stress increment per hundred meters at vertical depth. It shows significant difference with the change of measuring position.

The blasting excavation of water-division valve shaft may cause excessive vibrations to adjacent pile foundation and its superstructure，i.e. the shaft structure. Thus it is of great significance to analyze the vibration characteristics of the pile foundation and the superstructure. The velocity sensors have been mounted on the pile top，the bottom and the top of the superstructure，respectively. The vibration velocities were recorded at the three locations and then analyzed for each round of blasting. It is revealed that vibration response at the pile top is the largest during the cutting blasting，while vibration responses at the bottom and top of the superstructure become the maximum for the auxiliary-hole blasting and the surrounding-hole blasting. The vibration amplification effect exists at top of the superstructure，i.e.，its average peak vibration velocity is 4.2 times and 5.2 times those at the wall bottom and the pile top，respectively，when the ratio distance is greater than 15 m/kg1/3. The probabilities for the main blasting-vibration frequency exceeding 20 Hz are 99.26%，99.48% and 95.71%，respectively，for vibration velocities at the pile top，the bottom and the top of the superstructure. Therefore，the probability of structural resonance induced by blasting excavation of the valve shaft is extremely low.

The deformations of tunnels surrounding rock have the characteristics of dynamicity，sensitivity to time and space，nonlinearity，high complexity，etc. In order to improve the prediction accuracy of the surrounding rock deformation，the firefly algorithm(FA) was used to determine the delay order and number of hidden layer elements. And the prediction was carried out by nonlinear auto-regressive(NAR) dynamic neural network. A prediction model of tunnel surrounding rock deformation based on FA-NAR dynamic neural network was proposed. The deformation monitoring data of Beishan exploration tunnel was used to predict. And the prediction results of FA-NAR dynamic neural network algorithm were compared and analyzed with the BP neural network algorithm. It shows that the predicted values of FA-NAR dynamic neural network are basically consistent with the measured values. Its mean absolute error and mean relative error are around 1/5 and 1/4 of BP neural network respectively，which proves that the FA-NAR dynamic neural network algorithm model has higher prediction accuracy than the BP neural network algorithm model. The FA-NAR dynamic neural network algorithm model can solve the problem of surrounding rock deformation prediction well. It not only reduces the blindness of human input network parameters，but also improves the learning ability and prediction accuracy of the network.

The deformation of surrounding rock is prone to be large when TBM tunnelling into deep and weak ground，and the surrounding rock may squeeze TBM shield easily，then the jamming accident will happen. In order to reduce the risk of TBM jamming during tunnelling process，the monitored strain of internal shield surface was taken as the early warning index，and a real-time monitoring and early warning approach of TBM jamming was proposed. Based on the automatic task processing program and optical fibre communication technology，the proposed approach was equipped with functions of unattended operation，automatic data acquisition and transmission，remote control and automatic self-test. This monitoring and early warning approach was applied to the TBM tunnel of Lanzhou water resource project. Combined with the investigation report of the TBM jamming accident，the field monitoring data and operation parameters were analysed. The results show that the proposed approach can provide a potential effective way for early warning of TBM jamming. At the same time，according to the spatial and temporal variation law of the strain at each measuring point of internal shield surface，the direction and variation trend of the load acting on external shield surface can be speculated，which can provide references for tunnelling parameter adjustment and accident treatment during tunnelling process.

Many dipping translational rock slides occurred in purple mudstone of Badong formation of Triassic strata(T2b4) in western Hubei Province and eastern Chongqing City. In order to research the mechanism of these rock slides，a series of conventional triaxial tests and triaxial creep tests for mudstone from the strata were performed，and rock creep mechanical properties were obtained. By comparing the yield stresses from the conventional triaxial test and the long-term strength from triaxial creep test，an element with yield stress threshold switch and an element with long-term strength switch were proposed. The pattern of viscous coefficient could be fitted by the power function satisfactorily and a nonlinear Newtonian element was proposed. Finally，a new nonlinear constitutive creep model with eight elements was established. The experimental data at all stages of creep could be fitted by the new model very well and the model parameters were obtained successfully. At last，parameters sensitivity studies for the analytical solution of the proposed model was carried out and the results indicated that the parameters of nonlinear Newtonian element and creep threshold value could affect the creep time significantly.

The wedge-shape geometry of tunnel-type anchorage makes the bearing behavior of the system of rock and anchor change with the engineering load. The ultimate bearing capacity varies with the failure modes of the anchor-rock system. To figure out problems mentioned above，the possible failure modes，the bearing behavior and the estimation formula of bearing capacity of tunnel-type anchorage in different loading stages are discussed in this paper. Then the evolution law of the anchor-rock system progressive failure process is revealed with the methods of numerical simulation analysis，the author edited programming and the 2-D laboratory model test. Meanwhile，the influences of the anchor plug geometry parameter，such as wedged angle and burial depth，on the failure surface shape，rupture angle and ultimate bearing capacity are analyzed as well. Main conclusions are draw as follows. (1) The failure mode of anchor-rock system revealed by numerical model test is trumpet-shaped. And it is verified by the 2-D laboratory model test. (2) The bearing behavior is distinctly divided into three stages. In the initial stage，the additional interfacial pressure is not generated. Then the pressure increases linearly with the increase of engineering load in the mid-term. At the later stage，the pressure decreases rapidly because the damage of surrounding rock. The mechanical mechanics of tunnel-type anchorage’ stage characteristic can be described as follows. The initial bearing capacity of tunnel-type anchorage only depends on the geometry parameters of anchor plug and it is generated by the gravity of anchor plug. But the ultimate bearing capacity depends on the influenced range of surrounding rock. So the ultimate bearing capacity is determined by the position，mode and rupture angle of failure surface. And the reasonability of the mechanical generalization model and stage division method is verified by the numerical model test results，which mainly conclude the interfacial pressure change law with engineering load and the plastic zone evolution process. Moreover，according to the wedged angle and burial depth sensitivity analysis results，we find that the failure mode tends to a circular table shape when the burial depth and wedged angle is large. But the failure mode tends to trumpet-shaped while the burial depth is between 35–45 meters and the wedged angle is 2–6 degree. While the burial depth is greater，the failure mode tends to interface failure. Notably，if the failure mode is trumpet-shaped，the narrow section?s rupture angle of failure surface is two to three times the wedged angle while the wide section angle ranges from 20 to 25 degree. Besides，the distance between the turning point and the back anchorage face is about 1/2 times the burial depths. (3) The burial depths have no influence on the initial bearing capacity. But the ultimate bearing capacity increases with the increase of burial depth. It is also to be known that the initial bearing capacity decreases gradually with the increase of wedged angle. And the ultimate bearing capacity increases first and then decreases with the increase of wedged angles. The above phenomenon indicates that there is optimal wedged angle for the tunnel-type anchorage.

To compare the shear behavior of rough rock joints under the CNL and CNS conditions，a series of direct shear tests of rough artificial joints under both CNL and CNS conditions were conducted. The effects of boundary conditions，initial normal stress and joint roughness on shearing behavior of the artificial joints were analyzed. Test results showed that the effect of normal stiffness is significant under low initial normal stress level. The strain hardening behavior of shear stress-shear displacement curves were observed under the CNS conditions，which is different from the strain softening behavior under the CNL conditions，and the normal displacement was further suppressed in the CNS tests. The peak and residual shear strengths，peak shear and normal displacements were larger under the CNS conditions than that under the CNL conditions. With the increase of initial normal stress，the effect of normal stiffness is gradually weakened. Under the high initial normal stress level，the shear test results under both CNS and CNL conditions are similar. Test results could improve the understanding of the shear behavior of the rough joint under the CNL and CNS conditions.

Efficient and accurate extraction of crack geometry is fundamental for rock or concrete engineering. Traditional algorithms of crack identification，such as threshold segmentation，edge detection and region growing method，are based on limited human experience with tedious work and low accuracy. Artificial intelligence(AI) recognition is self-circulating dependent on big data，and can be positive feedback or even self-learning. The concrete as one of many artificial materials has the similar properties with rock，especially in geometric distribution. An intelligent recognition algorithm based on full convolutional neural network is proposed to identify cracks on rock and concrete surface. The dataset of crack geometry commonly seen in three scenarios of concrete used in building structure，pavement and tunnel surface is established. Through convolution operation，pooling operation and deconvolution operation，the error is quickly reduced with training times. A new convolution kernel parameter is introduced into a new full convolutional network，and a recognition model is evaluated based on the pixel-based two-classification problem. The results shows the better recognition of the new full convolutional network than traditional algorithms. Combined with the vectorization algorithm，the real-time statistical analysis of crack geometry including length，width and area is realized. Finally，the crack identification determined by artificial intelligence and traditional algorithm is compared by arbitrarily selecting five groups of images. The cracks extracted by the new algorithm are qualitatively similar to the ground truth，and the precision and recall are higher than the traditional algorithms. The full convolutional network can continuously improve the recognition accuracy，reduce the error，and will show great vitality in the application of rock or concrete engineering.

In order to explore the diffusion model of paste slurry in great numbers of plane crack containing moving water，the formula of paste slurry diffusion radius was derived by taking Bingham fluid as the research object firstly. The formula was based on the generalized Darcy?s law and the theory of mechanics，and could analyze the effect of self-gravity on diffusion radius of paste slurry. In addition，the laboratory model test was conducted to prove the formula，and the error between the test results and the theoretical calculated results was less than 10%. Then，the influences of different factors on diffusion radius were analyzed for the foundation pit leakage stoppage project of subway station. And the results showed that the effects of grouting pressure，slurry yield stress and fracture radius on slurry diffusion radius were significant and the changing rate of the diffusion radius was greater than 60%. At last，the field test was conducted，and the error between the field test results and the theoretical calculated results was less than 10%. Therefore，the diffusion model established in this paper was of great significance to grouting projects including great numbers of plane crack containing moving water.

In the 2018 version of Hoek-Brown criterion，it pointed out that H-B criterion is only applicable for brittle fracture of rocks rather than ductile failure，which constitutes a physical limitation not fully discussed yet on the value of geological strength index(GSI). A series of brittle inequalities of H-B criterion are then established based on the assumption of brittle fracture and the theory of brittle ductile transition. Constraints of stress-strength ratio on the GSI of different rock masses are given. The relationship between the GSI value and the buried depth is discussed. The H-B material will be invalid if the rock mass exceeds the ultimate depth to enter into the ductile failure range. The conclusions of the study are helpful for the rational use of H-B criterion to avoid unwanted deviations.

The shear strengths of thinly-infilled rock joints are different from both clean rock joints and thickly-infilled rock joints. In order to study their shear strength characteristics，fine digitization was performed on five standard profiles proposed by Barton，and on the bases of which rock joint surfaces with standard profile topography were duplicated by using 3D printing technology. Then cement paste was used to prepare rock joints specimens. Quartz sands were adopted as infill to prepare thinly-infilled rock joints with infill thickness to asperity height ratios of 0.0，0.25，0.5，0.75 and 1.00. The laboratory direct shear tests were carried out on and corresponding shear stress vs. shear displacement curves，shear dilation curves and failure properties were obtained，and then the effects of infill thickness to asperity height ratio and joint roughness on the peak shear strength and dilation of thinly-infilled rock joints were analysed. The results indicate that both the peak shear strength and dilation decrease with infill thickness to asperity height ratio and the influence of joint roughness on the peak shear strength also decrease with infill thickness to asperity height ratio. Furthermore，the failure characteristics of thinly-infilled rock joints after shearing were significantly affected by infill thickness to asperity height ratio and joint roughness.

A new procedure for elasto-plastic mechanical problems with VEM is proposed，by considering the specialties of incremental elasto-plastic calculation and bilinear projection operator. The shear strength reduction technique together with the inequality is implemented into the VEM to investigate the stability of slopes. Based on the proposed procedure，the deformation of homogeneous and heterogeneous slopes under different shear strength reduction coefficients is solved. In addition，the mesh dependency of the model is tested. A series of numerical examples are employed to test the correctness and effectiveness of the method. The results show that：(1) the arbitrary polygonal elements can be adopted and the calculation accuracy is independent of the shape of the element. The VEM is simple to implement and has a reliable mathematical foundation. (2) The proposed procedure is able to accurately predict the factor of safety of slopes，and capture the failure patterns of slopes. In addition，it can provide evaluation basis for slopes(landslides) design.

Newmark rigid-block analysis is a permanent displacement calculation method which has been widely used in practice. However，the traditional method can only apply to the shallow linear slip surfaces which slip directions are close to the slope angle. In order to extend this method to circle slip surface and deep linear slip surface，the functions to calculate the seismic yield coefficient are improved based on the traditional methods. Then the permanent displacements of different slip surfaces are analyzed and compared with other Newmark methods including slices method and finite element decoupled method and the influences of slope height，angle and the form of slip surface on seismic yield coefficient are studied. Finally the proposed method is compared with large shaking table test. The results show that，when the slip surface is large，the traditional Newmark method is underestimated the permanent displacement of circle and deep linear slip surface. The improved Newmark method shows the great agreement with slicing methods and finite element decoupled method. The yield acceleration is related with stability coefficient，the range of slip surface and slope angle. The relationship between different levels of earthquake intensities and permanent displacement shows a good agreement with large shaking table test，which confirms that the modified Newmark method inherits the traditional method′s advantages and has better precision and wider application.

The failure patterns of tunnel-type anchorage could reveal the component and stage characteristics of its bearing capacity. Also it is the fundamental scientific problems to study the progressive failure process and the destructive patterns of tunnel-type anchorage. In order to figure out the failure process and the bearing characteristics of tunnel-type anchorage，the strain-softening constitutive and the searching methods of slope critical slipping surface are applied to simulate the generation and evolution of the failure surface of tunnel-type anchorage. Then the failure mode is also acquired. Besides，the degradation process of the mechanical parameters of rock is studied as well. Also，the distribution of additional stress and shearing resistance along the axis of anchor plug are analyzed in this paper. Finally，the bearing characteristic of tunnel-type anchorage is in-deep analyzed. Some conclusions are draw as follows：(1) The failure of tunnel-type anchorage happens progressively. And the failure surface always generates from the bottom of the anchor plug and evolves towards the upper surrounding rock until the anchorage is pulled out totally. Notably，the failure pattern of the anchorage is neither the shear failure along the interface of anchor plug and the surrounding rock nor the cone-shaped failure，but the funnel-shape which is narrow in the bottom and wide in the top. (2) The distribution pattern of additional stress along the axis of anchor plug is similar to trapezoid before the uplift resistances of anchorage achieving the ultimate bearing capacity. And the closer to the bottom face of anchor plug，the greater the value of additional stress. (3) The mechanical parameters on the failure surface and surrounding rock where the stress is disturbed degrade gradually in the failure process. (4) The bearing capacity of tunnel-type anchorage also changes progressively with the failure process. And the initial resistance of the study project is while the ultimate bearing capacity is kN.

The dynamic characteristics of tunnel lining-soil interface are very complex and affected by many factors. The propagation of subway vibration is spatial，and it will change greatly at the interface. A viscoelastic interface model was proposed to simulate the dynamic interaction between the tunnel lining and soil. The analytical expressions of the dimensionless spring coefficient and damping coefficient of the viscoelastic interface model were derived with the propagation law of cylindrical P-wave. And the low frequency limits and high frequency limits of the dimensionless spring coefficient and damping coefficient were given. The results showed that the viscoelastic interface model can effectively simulate the loss of wave energy at the interface of lining-soil compared with the continuous interface model. The dynamic response amplitude of the soil increases with the increase of the shear modulus ratio of lining-soil. The density ratio of lining-soil has little effect on the soil stress amplitude，and the radial displacement amplitude near the fundamental frequency increases as the density ratio increases. The Poisson's ratio of soil has little effect on the radial displacement amplitude when and ，and the corresponding radial displacement amplitude near the fundamental frequency decreases with the increase of the Poisson?s ratio of the soil.

Swelling of compacted bentonite buffer blocks plays a great role on the sealing of the high-level waste(HLW) depository，which is controlled by dry density and water content distribution in the blocks. Anisotropy in swell properties of bentonite blocks is inevitable because of the differential stress during compaction. This study provides a prototype of fan-shaped bentonite blocks compacted in specially designed mould for constructing HLW buffer barrier in China. The mixture of 70% bentonite and 30% quartz sand was prepared in a target moisture content of 12%，and compacted to a target dry density of 1.87 g/cm3. The compacted block was primarily cut in small cubes to measure dry density and moisture content，and then cut further into standard rings with specific directions to conduct a series of swelling tests. The results show that：(1) The compacted block has a better uniformity in dry density and moisture content distribution except the position far away from the pressure head. (2) Swell stress and strain distribution is highly corresponded to the dry density distribution，that is，the larger the dry density，the greater the swell. (3) Swell anisotropy is displayed in the vertical，or the compressed direction，rather than the horizontal directions of the block. By defining anisotropy coefficients of swell stress α and anisotropy coefficients of swell strain ?，statistic results indicate that ? = 0.856 to 0.926，while ? = 0.885 to 0.934，both of them are elevated with increase dry density.

Many researchers attribute the differential weathering of sandstone and conglomerate to differences in their physical and mechanical properties but pay less attention to external dynamic factors involved in differential weathering. We had a field study on twelve arched rock shelters and one natural arch developed in red-bed basins of Zhejiang province，conducted laboratorial wet-dry test and numerical modelling of moisture movement and moisture stress on sandstone and conglomerate. The failure characteristics of sandstone and conglomerate in wet-dry tests are consistent with the results of field investigation. Sandstone tends to collapse with spherical fractures，while conglomerate generally remains intact except that some gravels at surface drop off from the matrix. The disintegration rate of sandstone is much higher than that of conglomerate. Meanwhile，expansion and shrinkage deformation is 0.15–0.18 mm in sandstone，while 0.001–0.002 mm in conglomerate. The numerical modelling also reveals the mechanism of differential weathering of sandstone and conglomerate. Spherical moisture stress distributes in sandstone during water absorption and causes sandstone flaked like an onion. In contrast，moisture and moisture stress concentrate on the interface between gravel and matrix，and cause gravels dropped off from the matrix. The results reveal that moisture stress is the external dynamic factor controlling the differential weathering between red-bed sandstone and conglomerate

Deep rock mass engineering is facing complex engineering geological problems such as increasing unloading effect of excavation，growing joints and fissures，and strong groundwater environment. In order to grasp the influence law of excavation unloading on mechanical properties and permeability characteristics of rock mass，take the Dolomite as the experiment object，the triaxial unloading tests under different unloading confining pressure ratio ??(100%，90%，60%，30%，0) and pore water pressure P(0，5，10 MPa) were conducted through GCTS rock mechanics test system，and the rock porosity before and after the test was measured by nuclear magnetic resonance(NMR) technology. The test results show that the unloading deformation laws of rock under different pore water pressures are basically the same，which all have four stages：smooth transition，uniform growth，fast growth and rapid expansion，and the strain limit of rock is almost equal. Correspondingly，the rock permeability during unloading process also has four stages：slow permeability，stable permeability，accelerated permeability and sudden-increase permeability. The existence of pore water pressure accelerates the generation and expansion of cracks in rocks. The larger the pore water pressure is，the larger the porosity is，and the larger the permeability is，there are a significant positive correlation among porosity，deformation and permeability. However，unloading confining pressure ratio has more influence on rock deformation than pore water pressure，when ??＞60%，the number and penetration of cracks in rock will increase sharply，it shows that strong excavation unloading can lead to the formation of macro-failure surface of rock mass and then increase the permeability，which is not conducive to the construction safety of underground engineering in rich groundwater areas.

To investigate the anisotropic behaviour of layered slate under dynamic loadings，five groups of dip angles(θ = 0°，30°，45°，60° and 90°) of layered slate in Jiangxi Province were tested by the split Hopkinson pressure bar(SHPB). The critical failure mechanical characteristics and failure mechanism of the slate under high strain rates were demonstrated. In addition，a damage constitutive model was established by the component combination model theory，which considers the damage of macroscopic layers. Both experimental and theoretical results illustrates that the peak values of stress-strain curves are different under different dip angles，but the overall trends are similar，including both elastic compression stage，plastic stage，plastic strengthening stage and post-peak curve after reaching the peak value. The bedding plane plays significant role in the failure of the slate except for the case with θ = 0°. The main failure modes are mainly composed by splitting failure through the bedding，shear failure in the bedding direction，slip failure and splitting failure along the bedding. The dynamic damage constitutive models of layered rock mass take the superposition effect of micro-damage and macro-damage of layered rock mass into consideration. Comparing the predicted results with the experimental results，the proposed model can describe the variation of stress-strain curve of layered rock mass under dynamic loadings，and more importantly it agrees well with the peak strength，which is helpful to accurately demonstrate the deformations and failure behaviors of layered slate under high strain rates.

In order to research the scientific problems involved in fluidization mining of solid fluidization method，such as the crushing effect of multi-nozzle combination，the forming rule of the cavity，the particle size distribution，the flow field characteristics in the cavity and the solid phase transport characteristics，a new large-scale laboratory simulation experiment device of soled fluidization is developed independently，which mainly includes five parts：pressure water generation and control equipment，process simulation device，suction and lift simulation equipment，data acquisition and control system and auxiliary equipment. The jet mining characteristic is that it does not destroy the phase equilibrium of hydrate. The experiment device simplifies the experimental conditions by ignoring the phase factors and find a hydrate replacement sample based on the principle of similar materials，so as to directly simulate the large-scale crushing process of minerals under the multi-nozzle radial jet and the effective recovery process of mineral particles in the solid-state fluidization process. The original scale simulation of the jet mining process in the production test in South China Sea was carried out by using the experimental device. The critical velocity of the gas hydrate，diameter of gob areas and the solid fluidization effect were explored. The experimental device provides the first set of experimental platform for the development of the special solid fluidization equipment and the optimization of the jet mining process. These have practical meaning for engineering implementation of solid fluidization.

The primary fractures of the rock would hinder heat flux flowing and redistribute temperature field，which in turn affect the thermal stress distribution inside the rock and lead to the cracking of the rock. Therefore，it is of great significance to investigate the mechanism of heat conduction and thermal cracking of multi-fractured rocks under high temperature. In this study，the particle flow code was adopted to simulate the dynamic process of heat transfer-crack inside the rock. Firstly，considering the difference in mineral composition inside the rock，the cluster model was adopted to characterize the meso-structure and composition distribution of the rock，and then the mesoscopic parameters were calibrated. Secondly，to more realistically simulate the influence of internal fractures on heat flux flowing and thermal cracking，the thermodynamic properties of cracks were assumed to be the aperture dependent，and the thermal and meso-mechanical parameters of the fracture were calibrated through the analytical solutions of macroscopic parameters under different fracture aperture conditions. Correspondingly，the aperture dependent models for thermal parameter and meso-mechanical parameter were proposed，respectively. Finally，combined with the random fracture network，the influence of the fracture aperture distribution on the thermal conduction and thermal cracking in multi-fractured rocks were investigated，in which the fracture aperture distribution was controlled by different shape parameters m .The results showed that with the increase of shape parameter m，the time cost for the thermal conduction reaching the steady-state was gradually reduced while the rate of thermal crack initiation increased. The feasibility of the proposed aperture-dependent model in simulating the thermal conduction and thermal cracking in multi-fractured rocks were also verified.

In order to explore the mechanical behavior and energy evolution law of rock damage and failure under the coupling effect of stress and water，the experiments of single and triaxial pore water pressure on yellow sandstone were carried out，and acoustic emission(AE) monitoring was carried out simultaneously. The strength and deformation characteristics of rock under the influence of effective stress are analyzed，and the energy transformation law in the whole process is obtained. Based on AE energy，the damage evolution equation is deduced，and the damage evolution stages and characteristics of yellow sandstone under different conditions are analyzed. The experimental results show that，there is a positive correlation between effective peak load and effective residual stress and effective confining pressure. The elastic modulus increases linearly with the increase of effective confining pressure. And Poisson's ratio is inversely proportional to water pressure. As the water pressure increases，the compaction phase becomes shorter and shorter，the elastic and plastic phases continue to increase，and the expansion point is also increasing. Besides with the increase of effective confining pressure，the main control cracks become more and more regular，the linear characteristics become more and more obvious，the micro-cracks become less and less，and the rupture angle is gradually increased. Under the hydraulic coupling condition，the main rock rupture is more obvious，and the micro rupture gradually decreases with the increase of water pressure and confining pressure. What is more，by analyzing the relationship between effective normal stress and effective shear stress，the τ-σ damage strength curve satisfies the Coulomb criterion. With the increase of effective confining pressure，the total energy，elastic energy，dissipated energy，energy released after the peak and surplus energy all show an increasing trend. And as the pore water pressure increases，the surplus energy becomes smaller and smaller，indicating that high water pressure can reduce the occurrence of dynamic damage. Based on the energy damage evolution equation，five typical stages of damage evolution are given，and the relationship between water pressure and rock brittleness damage is obtained. The research results have theoretical implications for surrounding rock control and prevention disasters with water injection in different stress states.

According to the law of time and space evolution of moisture wetting front in rock medium，Infrared radiation characteristics of conglomerate from dry to saturated water absorption were monitored by infrared thermography. The distribution of moisture wetting front in time and space is analyzed by the theory of moisture wetting front identification：(1) As time progresses，the irregular wetting front gradually moves from the bottom of the sample to the top of the sample. Under the main action of adsorption force and capillary force，the rising speed decreases continuously until it approaches zero. (2) Due to the unevenness of the conglomerate material，in space，the moisture wet front presents an array of asymmetric convex curves from the bottom to the top of the sample. By comparing the results of theoretical calculation and visible light monitoring，it is shown that the spatial distribution curve of water wetting front of conglomerate can be obtained by using the theory of water wetting front identification at any time，and the evolution law of water wetting front in time and space can be further traced. This method can realize the purpose of non-destructive and real time tracking of moisture wetting front，and can provide a new monitoring method to solve the problems of water damage in civil engineering construction，ancient architecture maintenance，cultural relic protection and other fields.

In the present study，acoustic emission(AE) technique is employed to capture the acoustic signals from granite uniaxial compression test，which include both S-wave and P-wave. From the aspect of event rate，energy rate，main frequency and the amplitude of main frequency，the similarities and differences of the characteristics of P-wave and S-wave in time domain and frequency domain in were studied. Apart from the traditional AE parameter analysis，the acoustic emission waveform information of different modes in rock fracture process were analysed. The results show that there is apparent “quiet period” of event rate in P-wave before the peak load，while the “quiet period” phenomenon in S-wave is not obvious. The energy rate of P-wave and S -wave both rise sharply When approaching peak load. However，the P-wave is generally higher than the S-wave. The main frequency of P-wave is mainly low frequency(35–110 kHz)，accounting for 96.4%. While that of S-wave is mainly high frequency(300–500 kHz)，accounting for 66.36%. Acoustic emission with high amplitude are concentrated in low frequency range for both P-wave and S-wave. It means that the acoustic emission with high energy all show low frequency and high amplitude characteristics. The research results extend the understanding of the acoustic emission characteristics of different modes，and provide scientific basis for rock fracture prediction methods based on acoustic emission technology.

In order to analyze the supernormal mechanics mechanism of NPR cable，first，an analytical model was applied to analyze the mechanical property of the NPR cable in elasto-plastic framework and was verified by the experimental result；Second，several parameter sensitivity analyses were performed and discussed. The relationship between the constant resistance and the geometrical parameters and mechanical parameters was then revealed；Finally，a 3D numerical model of NPR cable was established，and the corresponding parameters were calibrated in line with the experimental results. The numerical results were in agreement with experimental and analytical results. The variation trend of radial and axial displacement magnitude of pipe was discussed. The numerical and analytical models were proven reliable as assistant tools to design and improve the NPR cables in the future.

Uniaxial compression stress(UCS) is the important parameters of rock mass excavation and its stability analyzing in the underground engineering. UCS determination of rocks is really necessary to provide some scientific guidance for engineering excavation. This study focuses on how to get UCS of rocks with X-ray computed tomography. Five mudstone specimens for example are scanned with using of medical X-ray CT device. Then，volume data characteristics of different density materials have been identified and extracted from CT series images of rocks. UCS of rocks is quantitated with cumulative CT numbers of different density materials in X-ray series images. A new method which is called X-ray CT images prediction(X-CTIP) is proposed for determining UCS of rocks. The results show that cumulative CT numbers of mudstone composition range from 1 760 to 2 560 HU，which determining strength ratio is 0.94 to 0.96 and is also quadratic with UCS. Hence，the key task for predicting UCS of rocks extracted the CT cumulative value from X-ray sequence images and then re-calculated the corresponding UCS. The X-CTIP method can be used as determining relatively accurate UCS of rocks with a single composition，better homogeneity and integrity.

In order to study the precursor characteristics of rock burst induced by deep excavation of the underground powerhouse at Huanggou pumped storage power station in Heilongjiang province，microseismic(MS) and electromagnetic radiation(EMR) monitoring methods are comprehensively applied to identify the micro-fracturing of the surrounding rock. By analyzing the temporal and spatial distribution law of the microseismicity and electromagnetic radiation activity in the monitoring range，the precursory information of the induced fractures and the correlation between the both monitoring results，the results show that：(1) The microseismic events are characterized by the regional clustering in space and some clustering positions are highly consistent with the zones where rock burst happened during the initial excavation，revealing the local stress in a continual readjustment process. There is a positive correlation between the frequency of microseismic events and the intensity of external disturbance in corresponding time intervals. The sharp decline of the energy index(EI) and the explosive growth of the cumulative apparent volume(CAV) generally indicates the occurrence of rock burst or large-scale rock rupture events. (2) In the fault fissure zone of the underground powerhouse，the significant change of electromagnetic radiation intensity indicates that rock burst or large-scale rupture will soon happen. The distribution of the peak electromagnetic radiation pulse number is consistent with the migration direction of the local stress field，as well the adjustment time of the local stress field is about 8 days. (3) The spatial distribution of surrounding rock fracture revealed by the two monitoring methods is consistent，and the precursor time resulted from electromagnetic radiation method is slightly earlier. There is a good correlation between the both results of the local stress field in the event source region，and the distribution of the peak electromagnetic radiation pulse number is in full accord with the migration of the apparent stress. The engineering practice shows that the comprehensive monitoring method is effective for the identification of the precursor information about rock rupture in the underground caverns. It can provide the foundation for further research of rock burst monitoring and early warning based on the monitoring results. The research is very important for the safe construction of the hydropower engineering.

For some rock engineering problems，such as underground storage of nuclear waste，thermal stress is an important factor to be considered，because it may lead to rock fracture and bring harmful consequences. Traditional discontinuous deformation analysis method (DDA)，as one of the main numerical methods for stability analysis of rock mass，cannot simulate the distribution of temperature field and thermal stress in rock mass. In order to solve this problem，a high-order discontinuous deformation analysis method for simulating the distribution of temperature field and thermal stress is established by constructing higher-order displacement function and higher-order temperature field function on DDA block covered by an equilateral triangle outside it，supplemented by joint elements used to force the continuities of displacement and temperature between blocks. This method has established the relationship between DDA and partition of unity based finite element method (FEM). The mature theory of FEM in the simulation of temperature field and thermal stress can be directly used for reference. Finally，the established discontinuous deformation analysis method is applied to the numerical solution of temperature field and thermal stress in the analytical examples. The results show that the simulated results are very close to the analytical solutions and have very high accuracy. The correctness and effectiveness of the proposed method have been verified.

It is very important to reasonably describe the creep law of soft rock for buildings＇long-term stability in Tianshui area，Gansu Province. In order to study the creep behavior of Tianshui mudstone，triaxial creep tester was used with different loadings and water contents. The strain-time relationship was obtained. The creep process and creep characteristics were analyzed. And suitable creep model was established. The results showed that with the increase of stress level and time，the creep value increased slowly，but eventually kept a certain stable value. The creep of mudstone also increased with stress dispersion，confining pressure and moisture content. Under different confining pressure and water content, the creep increased with time，and the isochronous curve gradually shifted to the strain axis. It is inferred from the inflection point of isochronous curve of the specimens that under certain stress level the creep reached long-term strength. Based on creep parameters identification，the Xiyuan model，logical regression model and exponential empirical model were in good agreement with the experimental data. The three creep models could well reflect the whole creep process from elastic deformation to attenuation creep and even to stable creep at low stress level. The logical regression model and exponential model can better reflect the creep characteristic curves and parameters of mudstone. The established nonlinear creep model could be used to describe the creep mechanical properties of mudstone in Tianshui，therefore it has certain significance for engineering application.

The size and direction of ground stress determine the deformation and stability of underground coal-rock mass. Therefore，it is of great significance to study the real-time ground stress measurement technology for monitoring coal-rock dynamic disasters. In this study，a three-dimensional stress sensing device based on the principle of hydrostatic pressure was developed，and its stress sensing performance was tested and analyzed. Meanwhile，the solution formula of three-dimensional ground stress was analyzed. In addition，the size and direction of three-dimensional stress of Shoushan No.1 Coal Mine were measured and calculated by installing two sets of stress sensors. The results show that the stress sensed by the device is linearly related to the actual load stress，with a correlation coefficient of 0.989 57，the sensing spring plates of three-dimensional stress are mutually independent. The maximum principal stress of the mine is 22.86 MPa，the azimuth is 140°，and the dip angle is 2°，the ground stress is dominated by horizontal stress，the side pressure coefficient is 1.22. It was a typical tectonic stress field. The test results agree with the results of previous studies. The results show that the three-dimensional stress sensing device and method proposed in this study are not only simple and easy to operate，but also able to accurately measure the size and direction of ground stress. They have bright prospect in engineering applications.

In order to explore the characteristics of crack propagation around the gas drilling borehole，the uniaxial compression test of the pore samples under different water conditions was carried out，and the evolution characteristics of the strain field in the surface crack propagation process of the samples during compression was measured by the digital speckle correlation measurement. The transmission waveform，the wave velocity and time during compression was measured by RSM-SY7 ultrasonic system. According to the calculation formula of time difference during the acoustic wave transmission process，the equivalent crack width of the sample during the failure process is calculated，and the influence of water content on the crack propagation rule of the sample with holes is revealed. The results show that：(1) In the progressive failure process of the sample, the crack propagation decreases obviously with the increase of water content，and the dispersion of peak stress σp decreases obviously. (2) The ultrasonic testing results show that the arrival time of the first wave in the saturated state is delayed by 8–10 ?s compared with that in the dry state，and the acoustic wave energy decays rapidly in the time domain. (3) Fitting the test curve of equivalent crack width and stress level in the failure process of the sample，it is concluded that the equivalent crack width increases exponentially with the increase of stress level，which can quantitatively describe the crack propagation parameters. The crack propagation rate decreases significantly with the increase of water content，with the equivalent crack width of the control water content group being between 0.003 mm and 0.004 mm，and the equivalent crack width of the dry sample being between 0.012 mm and 0.013 mm.

Because of the little research on the influence of rock-lining interface on the dynamic response of underground engineering，the author established two different forms of models in consideration of rock-concrete interaction which is simulated by the interface zone. The comparison with existing test results is conducted to verify the reliability of the calculation method. The influence law of rock-concrete interaction on the seismic response for an underground engineering is studied. The influence law of the mechanical properties of the interface on the seismic response for the lining structure of an underground engineering is further analyzed. The summarized results are noted as following points. Under the action of earthquake，the interface has a significant impact on the displacement response of the surrounding rock，especially the surrounding rocks at the arched shoulder are more vulnerable to damage. In the horizontal direction，the surrounding rocks in the top arch area are mainly tensioned，and other surrounding rocks are mainly pressed. At the same time，in the vertical direction，the surrounding rocks at both sides of the chamber are tensioned，and the surrounding rocks at the invert arch and the top arch are mainly subjected to compression. The interface destroys the integrity and continuity of the rock-concrete system，so that the superposition of reflection and refraction generated by the incident wave after passing through the interface increases the displacement response of the lining，especially the lining at the inverted arch and the side walls. The internal forces response of the lining has a decreasing trend，but there is a certain regional effect，in which the shear force at the vault，the arch bottom and the arched sides are larger than the shear force without the interface. The influence of the mechanical parameters of the interface on the seismic response of the tunnel lining is different. Among them，the stiffness of the interface plays a leading role to the influence on the internal forces. The friction coefficient，cohesion and tensile strength of the interface have little effect on the thrust and bending moment of the lining. Moreover，the influence of cohesion and tensile strength on the axial force and bending moment of the lining is“anti-symmetric”along the centerline of the cavern. The response of the thrust and bending moment of the lining is nonlinearly related to the tensile strength. These research results reflect the necessity of considering rock-concrete interaction.

Aiming at the problem of jointed rock mass with different angles in the stope roof of Hongtoushan Copper Mine，the acoustic emission test of diabase specimens with natural weak faces was carried out under uniaxial compression. Research results have shown that：(1) The diabase specimens with longitudinal weak plane have higher strength than those with transverse weak plane，and the oblique weak plane with triangle is the lowest compressive strength. Under the same stress，the axial strain of the specimen with longitudinal weak penetration will change less than that of the complete specimen，while the axial strain of the specimen with transverse weak penetration will change more than that of the complete specimen，while the transverse strain will change opposite；(2) The complete specimens and the specimens with natural transverse weak surfaces are brittle fractured failure under compression，the specimens with longitudinal weak surfaces are tensile failured along weak surfaces under compression，and the specimens with oblique triangular weak surfaces are shear failured along weak surfaces；(3) Acoustic emission signals of diabase specimens with longitudinal weak face are similar to those of complete specimens when compressed. Acoustic emission signals of diabase specimens with oblique triangle weak face are very active，and the impact rate of specimens has several peak stages. Acoustic emission signals are more active in the case of weak cross-section with double cross-section under compression than in the case of weak cross-section with single cross-section；(4) This test can provide guidance for excavation and support of rock mass with structural planes in stope. The research results can reflect the loading deformation and strength characteristics and failure modes of rock mass with different weak faces.

Four kinds of 1/5 scale model linings have been designed based on the normal two-lane highway tunnel linings under vertical soil pressure，which are normal concrete(NC)，reinforced concrete(RC)，ECC and reinforced ECC(R/ECC) linings. Vertical loading tests have been done on the four linings. ECC Arch，R/ECC Arch and RC Arch strengthening were designed for 1/5 NC model lining. Subsequently，FE models of the NC and ECC linings were established based on the damaged plasticity model. After the FE models were validated with comparing the numerical and test results of NC and ECC linings，the numerical simulations on ECC，RC and R/ECC arch strengthened damaged NC linings with different damaged levels were carried out. The results show that the toughness and ductility of ECC and R/ECC linings are obviously better than the traditional NC lining，whereas the R/ECC lining gave better load-bearing and deformation capacities. R/ECC arch strengthened NC lining gave the best load-bearing capacities and the largest displacement，and it was mostly suitable for the NC linings from severely to seriously damaged level. Nevertheless，ECC arch strengthening method is suitable for both slightly and severely damaged linings. RC arch strengthening method is mainly suitable for the extremely damaged NC linings. Above conclusions can provide the basis for the application of ECC in tunnel maintenance and strengthening.

The soft joints are widely applied in high concrete-faced rockfill dams. This type of joint is usually used to prevent the extrusion damage of the concrete face. To reproduce the actual loading and deformation conditions of soft joint，a test apparatus is developed. A series of laboratory tests are performed by using the rubber as the soft filler. The loading and deformation features of soft joint are analyzed for different loading status. The test results indicate that the deformation of soft joint can be divided into three stages：the initial stage，the steady stage，and the hardening stage. Due to the strong constrained condition，strong squeeze-out is observed during the hardening stage，giving rise to rapid increase of extrusion modulus. Based on the test results，a polynomial extrusion model is proposed. This model is applicable for the finite element simulation and the evaluation of soft joint.

Decay heat generates from the cave of high-level radioactive waste disposal repository，which results in temperature climbing among the surrounding rock. Therefore，the influence of temperature in permeability of surrounding rock plays an important role in evaluating nuclide migration. In this context，the paper represents an evolution of Beishan granite permeability with an experiment of triaxial compression test in vary temperature，in an effort to obtain the evolution of permeability in the process of complete stress-strain curve. The permeability dependent curve of liquid ?p-t is fitting precisely by virtue of pressure drop attenuation model，which introduce the Mittag-Leffler function into the model of the traditional exponential permeability via the fractional derivative approach. By adhibitting fracture connectivity parameter C，the relation between fracture connectivity C and fractional order ? is established to reflect the density of original rock sample and the connectivity degree of the fracture network under triaxial compression. In the perspective of permeability model in fractional derivative，the influence of temperature on rock characteristic parameters is discussed，drawing a conclusion on the influence mechanism of temperature on the permeability evolution. Ultimately，the quantitative expression of the permeability of Beishan granite with respect to temperature is given.

Mechanism study between earth-rock mixture in pit backfill and super-high arch dam is of great significance to save dam stability during the initial impoundment and operating period. Based on the backfill design，construction and site monitoring experience of super-high arch dams such as Xiaowan，Baihetan and Wudongde，a mechanism model of the backfill earth-rock mixture and dam was proposed. Combined with theoretical and the finite element simulation method，three aspects of the mechanism are discussed including dam foundation seepage field distribution，the heat exchange state of the dam upstream surface and the overall working behavior of the dam-foundation. The analysis results shows that：(1) Backfill shows a reduction effect on seepage behavior by reinforcing bedrock fissures and extending seepage paths，and its height，equivalent permeability coefficient are the main factors. (2) Backfill enhances insulation effect of the dam surface，favorable for dam cracking control. (3) Backfill improves seismic behavior，and ameliorates the dam stress state during the construction stage. The general design principle and work flow for backfill construction of a super high arch dam is proposed，which can be used for reference in similar engineering construction.

With the rapid development of asphalt concrete core rockfill dams，the construction of 200 m ultra-high asphalt concrete core rockfill dams(UACCRDs) are inevitable in the future. However，there are neither experience for the construction of UACCRDs，nor corresponding design codes for reference. Based on the Rankine?s earth pressure theory，the mechanical feasibility of UACCRDs is analyzed at different periods. The stress states of asphalt concrete core(ACC) are divided detailedly and the algorithm that calculates the stress level of ACC is improved via the passive earth pressure theory. The safety control standard of UACCRDs is determined. And the reasonable material parameters of ACC and transition material for the suitable construction of UACCRDs are back calculated. Besides，the engineering measures that improve the safety of ACC are given. The results show that it is feasible to build 200-m UACCRDs. However，the internal friction angle and cohesion of ACC，and the internal friction angle of transition material are necessarily controlled within the reasonable range： ≥30.5°， ≥0.25 MPa and ≤43.5°，with the growth gradient adjusted by 0.5%，1.5% and －0.5%/(25 m). That is，the purpose that builds UACCRDs can be achieved by the engineering measures that increase the internal friction angle，cohesion of ACC and reduce the internal friction angle of transition material. The purpose of this paper is to provide a reference for the construction of 200 m UACCRDs.

The permeability coefficient is the key parameter to demonstrate the permeability of soil，and its calculation model with a high preciseness is hard to be determined. Based on Poiseuille￠s Law，the soil in laminar flow is assumed as fine tubular clusters and a permeation physical model is then established. According to the meso-mechanism of water head loss，an overlapping coefficient is introduced，and a theoretical formula for calculating permeability coefficient is derived with specific physical meaning based on Darcy?s Law，where porosity and equivalent particle size both function as basic parameters. Permeability tests of six groups of coarse-grained soils with single particle size are carried out. The overlapping coefficient is fitted according to the experimental data，and the formula for calculating the overlapping coefficient is then obtained. It is found that the calculated results obtained from the permeability coefficient formula are almost in accordance with the experimental ones. In order to verify the applicability of the permeability coefficient formula，the experimental data of sandy soil and mixed coarse-grained soil in relevant literatures are calculated by the formula proposed in the study，and the results are in accordance with the measured values. It is also found that the accuracy of the formula in this paper is much higher than those in existing literatures with a high accuracy and reasonability when considering a comparatively large size range of particles(Mixed coarse-grained soil with particle size less than 20 mm and sandy soil with particle size ranging from 0.1 to 5 mm are considered). Finally，the applicability of the formula is analyzed and summarized.

The hysteresis curve is the core of building the dynamic constitutive model of soil. The evolution law of hysteresis curve was studied under different confining pressure，loading frequency and dynamic stress amplitude by GDS dynamic triaxial test. The defined parameters，i.e.，the gradient k of the long axis，the area S of hysteretic curves，the ratio ? of the long axis to the short axis of the hysteresis curve and the plastic deformation ，were applied to analysis the hysteresis curve quantitatively. The results show that：the hysteresis curve of expansive soil is narrow and oblique，and k decreases with increasing dynamic strain，and increases with increasing confining pressure and loading frequency. The low frequency loading has less effect on the value of k，S and increase little in the early stage of the development of dynamic strain and increase exponentially later. The influence of confining pressure on S， is in the range of ，while the influence of frequency on S， is in the range of and respectively. There is a clear turning point in the relationship curve between ? and dynamic strain，which firstly decreased and then increased，and the value of ? decreases with the increasing confining pressure and frequency. Compared with the unmodified soil，k of the modified soil decrease while S，?， increase. The stiffness and the expansion of soil were reduced by improving the soil with sand，which has the advantage of reducing vibration when the modified soil was used as subgrade.

The macro-efficiency and intrinsic mechanisms of low-carbon and environmental-friendly reactive MgO-fly ash blend，which is innovatively introduced into solidification of dredged sludge from Wuhan Eastlake，China，are deeply discussed. Based on unconfined compressive strength，X-ray diffraction，scanning electron microscopy，thermogravimetric and mercury intrusion porosimetry tests，a systematical study has been performed to analyze the strength，hydration products，structural morphology，thermal stability and microscopic pores of reactive MgO-fly ash solidified sludge. The test results indicate that the unconfined compressive strength of reactive MgO-fly ash solidified sludge increases with curing time，MgO-fly ash content and MgO/fly ash mass ratio. The formation of Mg(OH)2 and M-S-H(magnesium silicate hydrate) gel is the main reason why the strength property of solidified sludge is obviously improved. The increase in reactive MgO-fly ash content and MgO/fly ash mass ratio leads to an intensified diffraction peaks of Mg(OH)2 and M-S-H，an increase in thermogravimetric weight loss，a transformation of inter-aggregate pores to inter-particle pores. This induces a denser microstructure and better integrity，which promotes greatly the strength gain of solidified sludge. The obtained result further deepens the understanding of macro- and micro-characteristics of reactive MgO-fly ash solidified sludge，and establishes a full microscopic reaction model of reactive MgO-fly ash to clarify the intrinsic micro-mechanisms for the property improvement of solidified soils. The research results provide a theoretical basis for the application of green and low-carbon reactive MgO-fly ash blends in the practical engineering such as sludge solidification.

In order to study the effect of temperature on the particles transport in saturated sand，a self-developed sand layer transportation，deposition testing system was adopted，and two kinds of tests(i.e.，transport tests of particles in porous medium under different temperatures，and transport tests of particles in porous medium under variational temperatures) were conducted. Four size compositions and four typical temperatures(i.e.，5 ℃，15 ℃，25 ℃ and 35 ℃) were adopted in our study. The results shown that，when the flow rate is constant，the peak of relative concentration will decrease with the temperature increases，while the pore volume at the peak of relative concentration will increase. Meanwhile，the peak of relative concentration will decrease with the flow rate increases，while the pore volume at the peak of relative concentration will increase. The change of temperature can affect the process of particles transport in porous medium observably. Compared to the contrast group，the relative concentration and the concentration of particles will decrease when the temperature increases，and the falling range will increase as the change of temperature get earlier. We also find a hysteresis phenomenon in the breakthrough curves when temperature changes，and the smaller particles are more sensitive to the change of temperature. Water viscosity，absorption，kinetic energy of particles and surface potential can all affect the transport process of particles under the effect of temperature，while the main controlling factor will change as the test condition changes.

Based on the numerical simulation method and the field measured data，the law and computational method of the ground surface settlement initiated by the excavation of the double-line tunnel located in the upper-soft and lower-hard stratum are studied. The results show that after the completion of the tunnel excavation，the lateral settlement curve of the ground surface is asymmetrically distributed. The ground surface settlement above the preceding tunnel is larger than the ground surface settlement above the rear tunnel. During the excavation of the double-line tunnel，the location of the maximum settlement of ground surface gradually moves from the centerline of preceding tunnel to the direction of the rear tunnel，and the settlement mainly occurs before the trailing tunnel crosses the monitoring section. The numerical simulation results indicate that the depth and spacing of the tunnel significantly influence the ground surface settlement. Therefore，the influence of tunnel depth and tunnel spacing on ground surface settlement is recommended to be fully considered during tunnel design stage. In addition，the non-linear fitting analysis of orthogonal experimental results presents that the parameter i in the calculation formula of ground surface settlement is independent of the tunnel excavation order，and the maximum settlement ratio γ decreases slightly with the increase of tunnel spacing. When the staggered distance of the excavation is within the longitudinal influence range of tunnel excavation，γ has a little change. Accordingly，the parameter γ is introduced to improve the calculation formula of ground surface settlement for double-line tunneling scenarios，and the calculation formula is validated by comparing the calculated results with the measured data.

A series of laboratory model tests were conducted to study the passive earth pressures with different limited widths of cohesionless soils against flexible retaining walls，such as cantilever piles. To simulate the forward flexure deformation mode of flexible retaining walls，such as cantilever piles，the homemade equipment model was applied in the tests. The failure characteristic and the passive earth pressure distribution were analyzed. The particle image velocimetry technique was employed to observe the development of a failure zone in the soils. The results show that the failure surface in the limited width soils behind the flexible retaining wall is a continuous and curved surface，which extend continuously to central wall body closing to or reaching passive state. Vertical soil arch appears between the sliding surface and the back of the wall，which compacts the soil at the bottom of the slip surface. With the increase of the lateral displacement，the passive earth pressures on the upper part of the moving retaining wall increase significantly and keep growing for finite soil. The pressures on the lower part of the wall increase and more easily achieve stability. With the increase of the soil width，the passive earth pressures increase and tend to be stable，reaching critical state or semi-infinite state. Moreover，the horizontal pressures distributed nonlinearly along the wall height，the passive earth pressures increase gradually and then rapidly decrease with the increase of the depth. The ratios of the backfill width is smaller，the peak value of passive earth pressure on the retaining wall is greater. And the peak value increase with the increase of the embedded depth of the wall，under the condition of the same aspect ratio.

On the basis of the theory of BBM model and elastoplastic two-surface model，an elastoplastic two-surface model for unsaturated soils considering the anisotropy under static and cyclic loading is established. A hardening parameter reflecting the anisotropy is introduced in the model. The initial anisotropy is reflected by the initial value of the anisotropy parameter and the evolution of the anisotropy produced by cyclic loading is described by rotation hardening rule. The model contains a bounding surface and a loading surface，which evolve according to the isotropic hardening，kinematic hardening and rotational hardening rules in the stress space. Besides，radial mapping rule and mobile memory center are adopted to reflect the cyclic plastic characteristics of unsaturated soil. The comparison between experimental results and model simulations shows that the proposed model is capable of describing the anisotropy and dynamic mechanical behaviors of unsaturated soils under cyclic loading.

The ability of electro-osmotic drainage in unsaturated soils is always overestimated using the consolidation theories for fully saturated soils. In this study，a one-dimensional model for vertical electro-osmotic drainage under unsaturated conditions was proposed，based on the law of fluid mass conservation，Darcy?s law and electro-osmotic flow equation. Exponential functions were incorporated in the model to represent the relationships of hydraulic and electro-osmotic conductivities with matric suction and the soil-water characteristic curve. The analytical solutions for pore water pressure，volumetric water content，and drainage were derived，and a laboratory test was performed to verify their effectiveness. After that，the parametric study was conducted to illustrate impacts of the ratio of saturated electro-osmotic conductivity to saturated hydraulic conductivity(ke/ks)，desaturation coefficient(?) and residual moisture(?r) on the behaviour of electro-osmotic drainage. The result shows that the drainage increases non-linearly with an increase in the values of ke/ks and α. The influence of the water retention capability of soil is significant on the drainage behaviour of electro-osmosis in unsaturated soils. Thus，the proposed analytical solution can provide guidance for the design and effect evaluation of electro-osmotic drainage system in unsaturated soils.

The volume change of the buffer/backfill materials in geological repositories is affected by several factors during the long-term operations. For example，the variation of ion concentration in groundwater caused by the fluctuation of groundwater level and temperature，the variation of additional stress caused by the changing geological tectonic activity and geological environmental，and the backpressure from the restriction of surrounding rock and waste container. To simulate the volume change of the buffer/backfill materials affected by above-mentioned factors，a serial of swell-compression-rebound tests have been conducted on as-prepared compacted bentonite specimens with initial dry density of 1.6 g/cm3 using high-pressure consolidometer. Deionized water and NaCl solutions with different degrees of concentration were used as infiltration solutions. And these tests were performed under different chemo-mechanical stress paths. The volume change behaviours of the compacted bentonites under coupled chemo-mechanical conditions in these tests were systematically analyzed from the macro and micro perspectives. The results show that the final swelling strain and compression index of bentonite samples decrease with increasing NaCl solution concentration. By comparing the volume change behaviours of samples underwent desalination-salinization cycle with those did not undergo this cycle，it is found that the plastic behaviour of macrostructure is irreversible，while microstructural behaviour is reversible. For the samples under the desalinization cycle，with the increase of solution concentration and decrease of vertical stress，the final cycle swelling strain increases.

The subsurface fluids could show shear-thinning property at certain pressure and temperature. The shear-thinning property affects the viscosity field of the fluid，thus altering the displacement behaviors during immiscible displacement. In this work，a lattice Boltzmann two-phase model implemented with a power law rheological model is adopted to simulate the displacement process of a Newtonian fluid displacing a shear-thinning fluid in heterogeneous porous media. After validating the model with non-Newtonian Poiseuille flow，the effect of the shear-thinning property of the displaced fluid on the displacement process is investigated from various aspects such as interface evolution，displacement efficiency，velocity field and viscosity field. The simulation results show that with stronger shear-thinning property in the displaced fluid，the interface evolves more rapidly and the displacement efficiency is increased，the invading fluid could better displace the residual displaced fluid. The mechanism for this phenomenon is that with stronger shear-thinning property，there are lower viscosities in the fingering paths and higher viscosities in the regions without fingering. The displacement process is dominated by the viscosity in the high mobility regions at the fingering paths. Increasing the shear-thinning property has similar effects to decreasing the viscosity of the displaced fluid，thus increasing the displacement efficiency. This research reveals the influence of the shear-thinning property on immiscible displacement in heterogeneous porous media，and is of guidance for industries concerning displacements of non-Newtonian fluids.

An analytical model，in which the dynamic pile-fluid interaction is considered，is proposed to investigate the lateral dynamic response of offshore elevated pile in layered soils. Firstly，on the basis of boundary conditions and radiation condition，the governing equation of water is solved by using separation variable method，and the solution for hydrodynamic pressure is derived. Considering the boundary condition，the governing equations of soil are solved by introducing potential functions，and the solution for dynamic soil reaction is derived. On the basis of the continuous condition at pile-fluid interface and pile-soil interface，the analytical solution of lateral dynamic response of offshore elevated pile in layered soils is obtained，and analytical expression of dynamic impedance of pile is also obtained. In order to verify the proposed solution，comparison with earlier solution is performed. Finally，a parametric study is conducted to investigate the effect of hydrodynamic pressure，water depth，soil modulus and soil layer thickness on lateral dynamic impedance of pile. The results show that water depth and property of surface soil have significant influence on the lateral dynamic impedance of offshore elevated pile. The analytical method ignoring the dynamic pile-fluid interaction overestimates the lateral dynamic stiffness of the pile.

The paper presents a fundamental understanding of the liquefaction characteristics in the engineering sites of coralline soils and points out the key issues in the further research on liquefaction of coralline soils. The post-earthquake investigation of liquefaction damages in the engineering sites of coralline soils and comparison of knowledge obtained from the research on the liquefaction events of the terrestrial soils are conducted. The analysis indicates that the liquefaction destruction phenomenon of the coralline soils will be same as those of the terrestrial sites of sandy and gravelly soils when subjected to strong earthquakes，and it will even become the main cause of the seismic damage of the artificial islands and reefs. The PGA of 0.1 g is the minimum seismic intensity that triggers the liquefaction of coralline soils and the liquefaction may occurs in coralline fill layers or lagoon sediments. The coralline soils in the actual engineering sites are composed of a wide graded cohesiveless soils from gravel to silt instead of pure calcareous sand. It is discovered that the grain size distribution of liquefied coralline soils are similar to those of the liquefied continental gravelly soils. The layers of coralline soils with high shear velocity can liquefy and triggering the liquefaction of coralline soils with good permeability requires special burial conditions. As a result，the method for evaluation of the terrestrial sand liquefaction is not applicable to coralline soils. There is objective risk of strong earthquake in the area of South China Sea and the grain size distribution of the reclaimed coralline soils in the artificial islands. Moreover，reefs in the area is comparable to the liquefied coralline soils and gravelly soils in the historical earthquakes. The key issues to evaluate liquefaction risk of coralline soils are the reappearance of the liquefaction process of coralline soils in the laboratory，the technique of defining the density of the coralline soils in the field and the liquefaction discriminant technology for engineering sites of coralline soils.

In order to study the effect of micro-pile reinforcement in soil slope under the effect of earthquake action，the acceleration response data of inter-pile soil in soil slope with weak structural surface strengthened by micro-pile is obtained through large-scale shaking table test，and the experimental phenomena are analyzed in series. In the different seismic wave loading directions，analyze the different acceleration response of the pile group at different positions，the acceleration time-history curve is decomposed by the wavelet packet，the spectrum characteristics are analyzed，and compared with the general law of the slope acceleration response of soil slope without the weak structural plane，in this way，the micro-pile support effect is qualitatively evaluated. The results show that：(1) In the micro-pile reinforced slope，a variety of ways to release kinetic energy will be generated to ensure the stability of the entire slope. (2) The acceleration response of measurement point in the micro-pile reinforced slope tends to the general law of acceleration amplification obtained by the homogeneous material without the weak surface，while the unreinforced mountain side measurement point will produce the phenomenon of “acceleration staggered platform” under the sliding surface. Destructive characteristics of unsupported natural landslide bodies. (3) When horizontal loading，the low frequency is the dominant frequency that affects the acceleration response，while in the vertical direction，except for the mid-range response，the other frequency bands have obvious effects. (4) Around the slip zone of the river side of the rear row piles，the high-frequency filtering effect is obvious，while this effect of the mountain side of the rear piled is not obvious. The micro-pile reinforced slope has a significant effect on the overall structural improvement and the stability of the slope.

In order to effectively solve the problems of the delayed settlement，personnel and environmental unsafe conditions during the tunneling of water-rich sand and pebbly strata in Chengdu，a shield construction safety risk management information system based on the intelligent interconnection technology was developed. The data utilized in the system include the technical characteristics and the key parameters of shield tunneling，as well as the result of the design，the construction，the supervision，the monitoring and the third party monitoring. The system has five function modules including the public affairs，the security risk，the remote video monitoring，the on-site access control and the remote video meeting management. These modules can realize shield real-time data monitoring，measurement data monitoring，video monitoring，integrated safety risk management(“three monitoring，one management”) and the site inspection management functions. The intelligent interconnection technology，which taking "Internet +" thinking as the concept，is based on the mobile internet and network transmission. It can achieve the integration，analysis and management of different types of data by combining with the internet of Things，Web GIS and the big data technology. The research and application of the system have provided a technical support for the safety risk control of shield tunneling construction in Chengdu metro，and a strong guarantee for reducing the economic losses and casualties caused by safety accidents in construction.

The method for multiple surface deep anti-sliding stability in current design code for concrete gravity dams，has a serious mistake to sum up the scalar ΔQi in different directions which is the resistance resultant force on both sides of each slider. In view of the shortcomings of the standard method，this paper proposes a modified method with ∑ΔQ = 0 to really satisfy the balance of internal forces. At the same time，the modified method adds an unknown variable φm，which solves the problem of redundancy assumption that each φi for ΔQi is known in the standard method. For the revised formulas mentioned above，two solving methods，i. e. internal force balance method and η equality method，are proposed in this paper. The accuracy and practicability of the modified method are proved by test questions and engineering example. Sensitivity calculation of different variable φm is carried out. It is found that better calculation accuracy can be obtained by choosing slider m which has less influence. This method corrects the errors in the code and can obtain accurate calculation results，which is beneficial to the popularization and application of the multi-slip surface calculation method for dam foundation.

The application of DTS on the integrity testing of cast-in-place piles has an economic significance which improves pile foundation quality and saves construction time. The optimization of the optical fiber detection system for DTS detection of the integrity of the cast-in-situ pile was studied by physical and numerical model test methods. According to the theoretical analysis，the basic principle that determines proper fiber spacing is proposed. The physical model test is used to set the heating power of the built-in fiber heat source by 4 W/m，8 W/m，12 W/m and 16 W/m. The meta-analysis is carried out by applying the corresponding central thermal loads in 22 ℃，24 ℃，28 ℃，32 ℃ to the physical model respectively. The results show that the higher the heating power is，the higher the centerline temperature is，and the larger the critical radius of the fiber heat source is. The closer the heat source is to the centerline，the higher the temperature rise value. The boundary conditions are different，and the temperature rise at the same distance from the heat source is different. The critical radius of the fiber is also different；the fiber structure has a significant influence on the heat conduction characteristics；when the fiber with a length of 28 m is heated by 4–16 W/m，the spacing of the U-shaped fiber is about 48 cm. The numerical model is in good agreement with the physical model test results and can effectively make up the insufficiency in the physical model test. The research results and methods provide a theoretical basis and technical guidance for the design of the detection system for DTS detection of the integrity of the cast-in-situ pile.

Chemical environment has a significant effect on the mechanical and microscopic characteristics of the dredger fill. In this paper，a set of laboratory tests were carried out to look into the strength，deformation as well as the microscopic structure of dredger fill with various NaOH content，including direct shear test，triaxial shear test，one-dimensional compression test and microscopic test. The experimental results show that the shear strength and structural yield stress increase by 15.1–79.3 and 5–169 kPa respectively，and the reason is that the intergranular cement strength was greatly enhanced due to the insoluble substances generated in the alkaline environment. Moreover，the stress-strain relationship of dredger fill changes from strain hardening to strain softening in the alkaline environment，meanwhile，the compressibility being greatly reduced with the maximum reduction of the compression index being 60.3%. Finally，the intergranular cement of the dredger fill in the alkaline environment develops well. The particle morphology is transformed from granular structure and flaky structure to agglomerate structure，and the surface-to-surface contact is the main form of the intergranular connection.

The distribution of initial excess pore water pressure in clays caused by external load is usually non-uniform with depth，and the rheological characteristics of soft clays and the threshold hydraulic gradient in clays have also been recognized. However，an analytical solution for rheological consolidation of soft clays with consideration of threshold hydraulic gradient in clays and non-uniform distribution of initial excess pore water pressure has been rarely reported in the literature. In this study，the rheological characteristic of soft clays are described by Merchant three-element rheological model，and the governing equation for one-dimensional consolidation with consideration of threshold gradients and non-uniform distribution of initial excess pore water pressure with depth is developed，and analytical solutions for this consolidation model are derived by Laplace transform method. Based on the verification of analytical solutions，a large number of calculations are investigated by analytical method. The results show that：the larger the threshold hydraulic gradient is，the slower the speed of moving boundary is，and the smaller the average consolidation degree and the final settlement are. With an increase in the ratio(?) of the initial excess pore water pressure at the top surface( ) to that at the bottom surface( )，the speed of moving boundary and the final average degree of consolidation decrease，and the consolidation rate and the final settlement of clay layer increase. The ratio(a) of the elastic modulus of spring( ) in Kelvin body to the elastic modulus( ) of independent spring has little influences on the consolidation behavior in the early stage of consolidation. However，in the late consolidation stage，the greater the ratio a is，the larger the average degree of consolidation and the final settlement of the layer are. In the early stage of consolidation，the viscosity coefficient( ) has little influence on the consolidation characteristics of the soil. In the late stage of consolidation，the larger the value of ，the faster the consolidation rate and the settlement rate of the soil. But the viscosity coefficient has no influence on the final settlement of clay layer.

Based on the existing and improved test equipments，a unidirectional frost heaving test was carried out in the laboratory in order to explore the regularity of force and deformation in the process of frost heaving under different paths. Considering that the constraint force will cause a compression deformation of the unfrozen soil，therefore，a series of conversion formulas were fitted through a group of compression tests of thawed soil under different loads，and then these formulas were applied to the results analysis of the frost heaving test. During the frost heaving test，the variables including temperature，force and displacement were monitored，the appearance of soil samples were observed in real time，and the water contents by layers were measured after the test. Through the analysis of the relationships among those variables during freezing，it was proved indirectly that the mechanism of constraint force to restrain the frost heaving was to restrain the water migration actually. The relationship between constraint forces and constraint rates affected by the path was not significantly，the coordinate points were enveloped by the upper and lower edge lines and presented a zonal distribution，while the upper edge line was the safest curve. In addition，the variation of forces and deformations under different paths can also be inverted according to the regularity of frost heaving. The results of this experiment can provide a theoretical guidance and proposal for the design of foundation in permafrost regions and for the study of interaction between pipes and frozen soil.

In this paper，the double yield surface model with modified plastic work as hardening parameter is introduced into the analysis of Shanghai soft soil foundation pit. Based on experimental data from triaxial consolidation undrained tests and isotropic tests of the Shanghai soft soil，the expression and parameters of elastic part and plastic shear part of the model are modified. The modified model are applied to analysis of soft soil foundation pit engineering in Shanghai soft soil，and three typical foundation pit engineering are selected. Comparing the calculated results with the measured ones，the calculated values are in good agreement with the measured values. The model has good applicability in excavation calculation of soft soil foundation pit in Shanghai.

According to the problems such as sinking lag，transient sudden sinking and so on of caisson foundations caused by the increasing frictional resistance in the middle and late period of sinking construction due to the increasing plane area，the theoretical formula of static and dynamical friction coefficients were proposed based on the theoretical study of the force composition of the bottom resistance，the friction resistance on the cutting edges and the lateral wall friction resistance during the sinking of the caisson. Taking the caisson foundation of Wufengshan Changjiang River Bridge as example，the friction resistance characteristics and the mechanism of the transient sudden sinking were investigated based on the measured data and the theoretical calculation results in the middle and late stages of sinking. The further control countermeasures of caisson sinking were analyzed. The results show that the lateral wall friction increases with the increasing sinking depth and accounts for more than 70% of the total resistance in the middle and late stage of sinking，which is regarded as the dominant factor of sinking stagnation. The force difference of instantaneous static and dynamical friction is the key factor causing the sudden sinking when the basement excavation is uneven and with local over excavation. The static and dynamical friction coefficients calculated from measured data of several cases of sudden sinking were between 0.444–0.525，0.245–0.401 respectively. And the dynamical friction coefficients were 0.56–0.77 times of corresponding static friction coefficients，which produced significant unbalanced force causing accelerative sinking of the caisson. The friction coefficient was effectively reduced to 0.225–0.325 with the sinking assistant methods such as air curtain，water level lowering，and the sinking coefficient was increased over 1.10，which are critical measures for avoiding sinking lag and sudden sinking of the caisson.

Compared with the traditional circular shield，the research on the influence of shield tunnel construction on pipeline deformation and soil settlement is relatively rare and of certain novelty. For the influence of quasi-rectangular-type shield tunnel construction on adjacent underground pipelines and soil settlement，the indoor shrinkage model test is adopted，normal pipelines，non-continuous pipelines，discontinuous damaged pipelines and soil settlement factors under four different depths are considered. The deformation law of the deformation of the underground pipeline and the settlement of the soil in the sand-soil layer under the vertical conditions of the tunnel and the tunnel are analyzed. The test results show that the settlement and deformation laws of several types of underground pipelines are consistent，and the tunnel axis is symmetrical，and the distribution is V type. The maximum settlement of the discontinuous pipeline is smaller than that of the continuous pipeline，and the settlement of both ends of the pipeline outside the tunnel width is larger than that of the continuous pipeline. The change trend of bending moment of discontinuous pipelines is more relaxed than that of continuous pipelines，and the maximum positive and negative moment of discontinuous pipeline is less than that of continuous pipeline；The negative bending moment of the discontinuous damaged pipeline changes greatly on both sides of the pipeline；The settlement of deep soil conforms to Gaussian distribution，and the maximum settlement of soil increases with the increase of soil depth.