Considering the effect of in-situ stress on the physical and geometrical attenuation of cylindrical stress wave propagation，and the interaction between cylindrical stress wave and a joint，the propagation equation of cylindrical wave in jointed rock mass under in-situ stress is derived. Meanwhile，a model test was carried out to study the propagation and attenuation law of cylindrical stress wave in the intact and jointed rock mass under different in-situ stresses，the measured and theoretical results are compared and analyzed. The results show the physical attenuation of cylindrical wave in the intact rock decreased firstly then increased with the increase of confining pressure，when the lateral pressure coefficient changes，the variation of the physical attenuation is related to the magnitude of the differential stress. The transmission coefficient of cylindrical wave in jointed rock mass is related to the angle of joints and the attenuation in joints and rock，the transmission coefficient decreased with the increase of the joint angle without confining pressure，and the variation law of transmission coefficient is contrary under confining pressure. The transmission coefficient increased firstly then decreased with the increase of confining pressure and the lateral pressure coefficient. The theoretical and measured transmission coefficients under different confining pressures are relatively close，the validity of derived propagation equation is verified.

In order to protect the breccia lava and the columnar jointed basalt of the Baihetan foundation，a bench blasting technique with shock-reflection structure arranged at the borehole was developed. The shock-reflection structure consists of spherical shock-reflection block with high sonic impedance and flexible cushion with low sonic impedance，the reflection of stress wave at the spherical shock-reflection block surface and the cushion effect of flexible cushion can reduce the impact of the vertical borehole blasting on the foundation rock mass. The field experiment results at Baihetan hydropower station indicate that the shock-reflection blasting technique can effectively reduce the disturbance of dam foundation rock mass，and the vibration reduction rate is over 40% under the bottom ignition condition，which is conducive to the vibration control in the excavation process. And the shock-reflection blasting technique can effectively control the blast-induced damage in foundation rock mass， protect the foundation rock mass，and get a smooth foundation surface as the pre-splitting blasting or the smooth blasting. According to the field experiment results，the vertical borehole shock-reflection blasting technique has been successfully applied to the excavation of the Baihetan dam foundation and the plunge pool foundation，It has achieved good foundation forming effect，speed up the construction progress，and achieved significant economic benefits.

Based on the problem of support load determination of mining under ultra-close goaf in shallow multiple seams，taking condition of ultra-close seams mining in Shenfu mining area as the background，the collapsed roof structure of the secondary mining in goaf is revealed by using physical simulation experiment and theoretical analysis. The roof structure model of ultra-close seams mining is set up，and the support load calculation formula is put forward. The study shows that the roof structure has free-caving zone and slanting pillar-beam zone in the upper seam goaf. In the mining process of lower seam，roof structure movement under slanting pillar-beam zone is divided into hinged separation section and sedimentation compaction section. Through the establishment of the two stages of roof structure model，the support load calculation formulas to determine the support resistance are set up，and it is determined that the formula of sedimentation compaction section should be the basis of support selection. It is verified reliable through case analysis of shallow buried ultra-close multiple seams mining in Shigetai coal mine.

A clamping effect，ends effect namely，on cylindrical specimens compressed axially，is induced from the rigidity loading heads to enhance rock strength. Specimens with various lengths of dolomite and granite were compressed under low confining pressures by Mogi K，ends effect on strength may be neglected with increase of confining pressure. However，test results of sandstone，trachyte，marble，dolomite，and various granites from public literatures show that the ends effect will enhance specimen strength at high confining pressure，even after the area correction to the barrel specimen. Mechanical properties are greatly different of crystals in granite，i.e. quartz，feldspar and mica. Extreme scatter of granite strengths from small specimens under high confining pressure results from the ends friction transferring by crystals in the specimen. Both ends effect and size effect are discussed on strengths of granites specimens under various confining pressures. The applicability of the exponential strength criterion is evaluated to predict the genuine fracture strength of granites under high confining pressure.

The fracture toughness(K_IC) of five typical granites taken from the Beishan candidate area for geological disposal of high-level radioactive waste was investigated through three-point bending test，with the purpose to study the influence of saturation process and grain size on K_IC of granite. By comparing the curves of dry and saturated granite under cyclic loading and unloading condition，it is indicated that the saturation process can result in a significant degradation of initial cracking strength and fracture toughness，and accelerate the crack propagation speed in post-peak phase. Experimental data show that K_IC of dry and saturated samples are 1 576– 2 139 N/cm^1.5 and 1 463–1 848 N/cm^1.5，respectively，and mean values of K_IC of saturated granite are about 90% of dry ones in the same group. Meanwhile，it is noticed that K_IC of Beishan granite decreases remarkably with the increase of average particle size，rock mineral composition and particle forms also have certain influence on the variation of K_IC. At last，the fracture propagation process were analyzed with the recorded AE events.

When implementing a highly nonlinear stress-strain model to solve boundary-valued problems，one of the major challenges is how to reduce the accumulative error and to maintain the effectiveness of the numerical integration. In general，the explicit algorithm tends to have higher accumulative error，and the requirement for accuracy may not be satisfied even when adopting very small increment sizes. When utilizing the Newton-CPPM implicit numerical integration algorithm，the complex Jacobian matrix for a highly nonlinear model may result in non-convergence or even become singular in the modelling process. In order to deal with these challenges，this paper proposes an improved-implicit algorithm，in which a semi-implicit method is used to determine the initial values for the implicit iterations. Using the highly nonlinear SANICLAY model for structured clay as an example，the convergence，the computational efficiency and the accuracy of four algorithms，namely the explicit algorithm，the semi-implicit algorithm，the implicit algorithm and the improved implicit algorithm，are compared via numerical simulations of single element tests. Comparing with the explicit algorithm，the semi-implicit algorithm effectively reduces error accumulation and improves the computation accuracy. The improved implicit algorithm can effectively improve convergence and avoid singularity of Jacobian matrix.

Analysis of failure modes of surrounding rock mass is the basic work of the stability analysis and control of surrounding rock mass and support design in underground engineering. The high geostress failure problems encountered in deep engineering cannot be included in the tradition failure mode classification. In the classification methods put forward recently，the rock mechanics problems were considered well. But the geological conditions have been overlooked in analysis. Aiming to this problem，the evaluations of geological condition and in situ stress levels were constructed firstly. Then several important factors including rock mass structure type，integrity degree，hardness grading，rock mass quality grade，and in situ stresses，were considered. The classification system of failure modes of surrounding rock mass was presented finally. This system can be applied in all of underground projects. And it is more suitable for the deep underground engineering with high stress. The application of geological condition evaluation makes it simpler to be understood and applied by the field engineers.

This paper studies on the triggering mechanism of sliding type rockbursts under weak disturbance. With variation method and by adopting the theoretical model in which a block slides along the interface，induced by weak disturbance under initial stress state. The basic conditions required for sliding type rockbursts were obtained as：(1) The surfaces(referred to the contact surfaces or the fracture surfaces) are in the quasi-steady state with the high initial stress in the tangential direction. (2) The fracture stiffness of the surfaces is larger than the rebound stiffness of the surrounding rock. (3) The impact energy factor which characterizes the movement of the rock mass reaches a critical value，or the relative displacement on the surfaces accumulated to a critical value under the dynamic disturbance. When rockburst occurs，the released energy is far more larger than the energy exerted by the disturbance，the weak disturbance just act as a“trigger”in the occurrence of rockburst，its effect is only to help the rock blocks to overcome the influence of friction on the surfaces. The magnitude of the critical accumulated displacement and the extruding speed of the rock blocks may not depend on the value of the disturbance. The movement(or the extruding speed) of the rock blocks is determined by the relations between the work of the rock pressure and the work of the friction along the surfaces. To prediction the level of sliding type rockburst accurately，the kinetic energy of all the rock blocks at the very time when rockburst occurs should be known.

For better understanding time-dependent evolutionary behavior of anchored bedding slope in corrosion environment，a prestressed anchored slope model test systems which can simulate complex corrosive environment was developed. Using the test systems，an anchor bedding slope geomechanical model test was carried out，in which the corrosion of the free section of anchoring is simulated. Based on test results，the electrochemical corrosion process of pre-stressed anchor bar，anchorage loss laws and long-term deformation characteristics of anchored slope were analyzed. It was found that：(1) The anchor bar enter activation corrosion state rapidly as contacting with the etching solution. The corrosion rate of anchor bar is high in initial stage，with the increase of immersion time，the corrosion rate decreases gradually，and the corrosion rate stabilized after about 30–60 days. (2) Cl^－，O₂ in the environment and pre-stress will significantly increase the corrosion rate of anchor bar. (3) Corrosive effects did not significantly accelerate loss of prestress when both ends are anchored well，and prestress losses of anchorage are mainly influenced by the initial anchoring force and rock deformation after corrosion of free section. (4) Deformation of different parts of anchored slope is mainly related to rock mass structure，gravity stress and anchor force，and reinforcement corrosion in free section does not directly affect the slope deformation. Anchoring force drastically reducing caused by corrosion of anchoring section or the failure of anchor bar caused by corrosion could significantly affect the deformation and stability of the slope. Test results can provide scientific basis for long-term safety assessment of anchored bedding slope.

The attenuation characteristics of elastic wave propagation in granite，marble，red sandstone and limestone were studied by a PCI–2 system though the broken lead test. The results showed that：the amplitude and frequency of the elastic wave signals on the four kinds of rocks are decreasing with the increased source distance. On granite and red sandstone，the attenuation of amplitude and centroid frequency are obviously characterized by stages，the attenuation coefficient is larger in rapid attenuation stage and smaller in slower attenuation stage，correspondingly，the peak frequency is higher in rapid attenuation stage，and dramatically reduced in slower attenuation stage. However，the attenuation of amplitude and centroid frequency on marble and limestone is relatively moderate，and the peak frequency maintains at 120 kHz. By analyzing the microstructure of four kinds of rocks and their attenuation characteristics，it is found that the most important factor causing the attenuation of the elastic wave is the tightness of the mineral particles in rock，and secondly the development degree of internal structure is another factor influencing attenuation. Furthermore，the quality factor Q of different rock is highly related with its wave impedance，the lower wave impedance rock has smaller Q value，corresponds to higher wave attenuation. 

Due to pre-existing micro-cracks induced by the long-term tectonic loading，rock exhibits strong anisotropy. Using a split Hopkinson pressure bar(SHPB) system with International Society of Rock Mechanics (ISRM) suggested method for dynamic fracture test and the notched semi-circular bend(NSCB) specimen，the anisotropy of dynamic fracture energy of Barre granite and Standstead granite are investigated. The P-wave velocities of two rocks are measured to determine the three principal directions. The notches of the NSCB specimen are made along these three principal directions. Thus for each rock，three groups of NSCB specimens are fabricated. The pulse shaping technique was used to achieve dynamic force balance and a laser gap gauge was utilized to measure the crack surface opening distance(CSOD). Using these methods，the fracture energy for the specimen is determined using energy analysis. For samples in the same orientation group，the dynamic fracture energy of two rocks shows clear loading rate dependence，i.e. the fracture energy increases with the loading rate. The dynamic fracture energy is anisotropic for SG and BG. At the similar loading rate，the dynamic fracture energy for SG and BG along X direction is minimum and the fracture energy along Z direction is maximum. In addition，the fracture energy anisotropy of SG and BG increases with the loading rate. This is attributed to the increase of damage zone around the fracture path under higher loading rates.

The Hoek-Brown failure criterion has been widely used for the determination of the strength of intact rock and rock mass in isotropic conditions，but cannot describe the anisotropic characteristics of rock and rock mass. In this paper，an anisotropic failure criterion is proposed based on the Hoek-Brown failure criterion by introducing an anisotropic parameter，which is associated with microstructure tensor a_ij and loading directions l_ij，to the parameters m_b and s，and the sensitivity of parameters used in the anisotropic failure criterion are discussed，and the strength of rocks obtained by the proposed criterion are compared with test results. It is shown that the proposed anisotropic failure criterion can describe the variation of material strength in function of the orientation of the sample relative to the loading direction，and this criterion can be degenerated to the isotropic Hoek-Brown failure criterion. The principle value Ω_i of the deviatoric part of microstructure tensor has a significant effect on anisotropic characteristic of rock mass，and determines the degree of anisotropy. The mean value of microstructure affects the strength of rock mass，and the elasto-plastic parameterhas little effect on anisotropic characteristics of rock mass.

Loading rate dependency is basic content of rheological mechanics of rock material. Brazilian split tests on Jingkou Sandstone，Emochi andesite and Tage tuff were performed under the condition of alternating loading rate. The Brazilian splitting failure process and the loading rate dependency characters about stress-strain curve of pre-and post-peak were analyzed and the following conclusions were found：(1) In the case of alternating load rate，the Brazil splitting crack first starts from the center of the specimen and gradually extends to the two ends of the split face，and the failure process can be divided into four stages. (2) The stress-strain curve of Brazil splitting test，which is obtained by the high and low alternating load rate test，can clearly observe the characteristic of the load rate dependence of rock at pre-and post-peak stage. (3) The splitting strength of rock in Brazil increased with the increase of loading rate，and showed a significant dependence on the load rate. By calculating the loading rate dependence coefficient n value，quantitative analysis about loading rate dependence of the three rocks was performed.

Shale and limestone in situ are processed indoors into 6 different combinations of bedded composite rock，through which the author explores the damage and fracture process under uniaxial compression as well as its acoustic emission characteristics. Acoustic emission system is adopted to collect the acoustic emission signal released by the test specimen during the experiment. CT scanning is performed on the composite rock before and after the experiment. The development of the internal cracks before and after the fracture is analyzed，and the fractal theory is adopted to analyze the damage of fracturing specimen through its CT images of different parts. The results show that：(1) The damage of bedded composite rock is a coupling failure process of shale component material and limestone component material under load. In the process of damaging，limestone has a restriction on shale transverse deformation，while shale has a promoting effect on limestone. The strength of shale component material is greater than that of single shale，which also goes for limestone component material. (2) According to the different combinations，the failure mode of bedded composite rock can be divided into 3 kinds：tension splitting failure，shear slip-type failure and splitting shear compound damage. Combinations of rock play a decisive role in its stress and affect the failure mode. (3) The average number of CT-scanning composite rock and the box dimension of its fracture section is able to respectively reflect the damage of the rock，that is to say，the greater the CT number difference before and after the damage of the section is，the greater the box dimension of the section is，and the more serious the damage is.

Landslide induced by earthquake is a common geological disaster in mountain area of China. In order to understand deeply failure process and dynamic response of slope under earthquake load，in this paper the shaking table model test on failure mode of shatter-burst sliding slope is conducted. Physical process of slope¢s failure and seismic response of slope under earthquake load is analyzed in detail. Similarity model is designed and model tests for different parameters are done. Experimental results show that the loading wave has important influence on the variation of acceleration amplification factor along slope elevation under earthquake load. Under the same condition，acceleration amplification factor at slope is the largest under Wolong wave load，and that is the smallest under Sine wave load. The magnitude of acceleration amplification factor at slope under EL Centro wave is between Wolong wave and Sine wave. The relation between acceleration amplification factor and peak value of loading wave¢s acceleration is obviously influenced by loading wave and location of soil at slope. When the frequency of loading wave is smaller(e.g. less than 6 Hz)，acceleration amplification effect for all the location at slope is weak. When the frequency of loading wave is higher(e.g. more than 10 Hz)，acceleration amplification effect near the bottom of slope is weak and that is significant at middle-upper part of slope.

In order to study how the compression-shear fracture and fragmentation characteristics of rock mass of slope is influenced by counter-inclined flaw，model specimens containing counter-inclined flaw were prepared and compression-shear tests were conducted. The numerical model of fracture mechanics was established to calculate the stress intensity factor of flaw tip. Sieve tests were carried out for the fragments of these specimens after compression-shear tests. The fractal theory was introduced to quantify the compression-shear fragmentation characteristics and its correlation with fracture characteristics was investigated. With the increase of the absolute value of flaw inclination，the shear strength of specimens increases first and then decreases，which breaches the trends of the stress intensity factor of flaw tip and the fractal dimension of fragmentation. The failure generated in the specimen can be classified into three modes，namely mode I(sliding along the flaw)，mode II(interlocking) and mode III(cutting through the flaw). The specimen failing in mode I，has a largest stress intensity factor of the flaw tip，resulting in a lowest stress strength. The specimen failing in mode II，has a lowest stress intensity factor of the flaw tip，resulting in a largest stress strength. The specimen failing in mode III，has an intermediate stress intensity factor of the flaw tip，resulting in a stress strength between those in modes I and II. The fragment size distribution of fragments under the compression-shear tests exhibits significant fractal property. The fractal dimensions of these fragmentations are in the range of 2.06 to 2.59，which is similar to those in the fault cores There exists negative correlation between the shear strength of specimen and the fractal dimension of fragmentation. The compression-shear fragmentation characteristics of rock mass are closely related to the flaw geometry，stress condition and fracture characteristics.

Aiming at Nishihara model to describe the rheological characteristics of dual-pore-fracture media suggested by the author，a corresponding bolted body model was established，and the mathematical expressions were given for distributing uniformly the elastic modulus and shearing strength of bolt material into the bolted body. Simulating a hypothetical rectangular underground cavern，the 2D FEM analysis were carried out on the cases of cavern without bolting and with bolted body elements as well as with bar elements，respectively，and the displacements，stresses and plastic zones in the surrounding rock mass were analyzed and compared. The results show that the systematic bolting has certain restriction on the displacements of cavern boundary，but this effect is not proportional to the bolt length，and it is more obvious for the case with bolted body elements than for that with bar elements；there are obvious stress concentration phenomena in the bolted zones，and the distributions and values of stresses in the surrounding rock also have some changes with increase of the bolt length；the systematic bolting makes the plastic zones in the surrounding rock decrease obviously，but this effect also is not proportional to the bolt length；using bolted body elements and bar elements for the bolts with same length respectively，the areas of plastic zones obtained are close to each other，but the distribution shapes have some differences.

The installation of the buffer layers is of advantages to the seismic resistance of the tunnel. A set of flexible airbag loading system suitable for dynamic model test on shaking tables was developed to simulate the gravity stress of tunnel overburden. Dynamic response mechanism of loosen zone and buffer layers were analysed and compared based on tests data of acceleration，additional strain，additional bending moment and structure failure. It could be concluded that：(1) Both the loosen zone and buffer layers did not change the dynamic response rule and the damage mode of tunnel structures；(2) Due to the existence of loosen zone，the restraint effect of the surrounding rock on the tunnel structure is weakened，resulting in the increase of the deformation in tunnel structure. The additional bending moment of the structure increases，indicating that it is more vulnerable to damage in earthquakes considering loosen zones；(3) The installation of the buffer layers can effectively reduce the structure additional strain caused by seismic load，which improved the mechanical performance of the structure. This layer coordinated the overall deformation of the tunnel and improved the seismic performance of the structure；(4) In such problems，that tunnel structure surrounded by a softer medium layer，stiffness is the key factors which could be concluded in material thickness and strength.

Joints and weak layers are the key factors for possible rock mass failure or sliding，within which the heterogeneous infilled materials in joints strongly influence the shear mechanical behavior of rock mass and then its shear failure. Considering the effect of crack in infilled materials on the fracture characteristic of pre-existing jointed rock mass under compression-shear stress state，mortar infilled jointed rock mass specimens including various artificial lengths were prepared，and uniaxial compressive tests were carried out to investigate their compression-shear fracture mechanisms and the effect of pre-cracks sizes on fracture modes and fracture energy of jointed rock mass. The experimental results show that：(1) under uniaxial compression，the failure process of infilled jointed rock mass can be divided into two stages：fracture stage and friction stage. The former was the process of initiation，propagation and coalescence of cracks. The load bearing capacity was rapidly reduced after the peak load，and then gradually increased due to the increasing friction force. Finally，it failed when the shear stress reached its shear strength. (2) With the increasing pre-existing crack length in infilled jointed rock mass，the peak load of specimens was decreased linearly，while the fracture process was more brittle. (3) For the infilled jointed specimens without pre-crack，multiple micro-cracks were generated throughout the infilled joint during the fracture. However，for the pre-cracked specimens，they cracked from the tips and propagated to the adhesive surface of infilled mortar and joint. The stress-induced cracks concentrated with relatively low density in the infilled joint. (4) The volume of ligament in joint V_jc was used to modify the formula of fracture energy G_f-V. Based on the fracture mechanism of the infilled joint，the front boundary effect model，whose local fracture energy g_f-V was bilinear distribution along the ligament，was proposed. It explained the reason why the average fracture energy G_f-V decreased with the increasing of pre-crack length，and then it was well verified by the experimental data.

In order to study the adverse effect of subway tunnel drilling and blasting method on adjacent buried pipeline，the laboratory similar model test taking into account the influence factors such as the charge and the explosion center distance，was carried out based on the project of Dalian metro tunnel. The results show that the vibration characteristics of rock mass and pipeline under the same blasting load are different. The maximum vibration velocity of pipeline is smaller than rock mass，and the attenuation time is slightly different. The ratio of the maximum vibration velocity of pipeline to that of rock mass increases nonlinearly with the charge increasing and the distance decreasing. In order to describe this law，the maximum velocity transfer coefficient and the relative stiffness coefficient of pipe-soil were defined，and the formula of the maximum velocity transfer coefficient for various pipelines and rock mass was established. The relationship between maximum dynamic stress and maximum vibration velocity is linearly increased. Based on this conclusion，the pipeline safety control standard considering the design value of fatigue strength and the current velocity control value of pipeline was proposed. The safety control standard of C30 concrete pipeline is determined to be 2.5 cm/s by the method.

The construction process of underground engineering like tunneling would face with the risks of complex geological disasters such as water inrush and mud outburst constantly，and transient electromagnetic method which is based on the difference of resistivity between surrounding rocks and water-bearing bodies could detect and position the water-bearing structure ahead of tunnel face. However，the data quality at middle-later period is relatively poor during the practical detection process. In this paper，the uniform half-space model and the three-layer classical model are studied to investigate the applicability of transient electromagnetism to detect apparent resistivity. The results show that the late-stage data conversion is good without interference and the late-stage data conversion is worse under strong interference difference. Compared with 3 filtering de-noising algorithms aiming to optimize the data quality at middle-later period，we are certain that they can improve the signal-to-noise ratio and apparent resistivity imaging of TEM induced electromotive force under strong interference circumstances. Using the filtering algorithm compared with the traditional direct truncation method after field testing，it is found the amendments to the unstable data which occurred in the late response period partial time-channels can improve the overall apparent resistivity imaging and the resolution of the detection results by the truncation method and filtering algorithms.

Abandoned mine pits around city are gradually used for the construction of large public service projects with the basis locating on slopes，which is causing new problem. A large-scale shaking table test was carried out to study the dynamic characteristics and response of pit slope，single and multi-span frame structures，and interaction between slope and structures. The results show that，with the increase of vibration time and amplitude，the self-vibration frequency of slope model tends to decreases，while the damping ratio tends to increase. The structure models are in elastic stage during the vibration process，and its self-vibration frequency decreases slightly，while the damping ratio increases slightly. Slope dynamic response increases with slope position rising. Due to slope material nonlinear characteristics，slope dynamic amplification effect decreases with the increase of vibration amplitude. Moreover，model dynamic response is associated with the type and direction of wave excitation. Low-frequency waves have greater influence on slope than high-frequency waves，and dynamic response in excitation direction is stronger than that in other directions. Dynamic response of structures increases with base location rising. Due to the influence of coupling beam，dynamic response of middle part of multi-span structure is stronger than that of other parts. Dynamic response of the structure top，which is coupled by foundation and upper structure，is always larger than the bottom plate. Dynamic response of bottom plate is always greater than around ground due to dynamic reaction of superstructure. In addition，there is notable interaction between slope and structure. Multi-span structures with good stability and high stiffness can improve seismic performance of surrounding ground，and ground dynamic response decreases 10.4%–24.3%. In contrast，single-span structures with poor stability and low stiffness probably reduce seismic performance of surrounding ground，and ground dynamic response increases 12.3%–51.1%. The research results can provide guidance for geotechnical engineering design of development and utilization of existing pit underground space.

A series of fresh and dried rock samples from Daqiang coal mine were conducted by intelligent testing system for water absorption in deep soft rocks(a self-developed experimental system)，including tests of water absorption with pressure and without pressure. Then，uniaxial compressive strength tests were applied to obtain the characteristics of the strength weakening processes of the rocks after interacting with water in two different original states. The results demonstrated that the strength of deep soft rock after absorbing water decreased linearly with the increasing of water ratio. Comparing to the speed of the strength decline of rock specimens with and without water pressure，it could be found that the former was slower. The speed of the strength declining of dried rock samples was faster than that of fresh rock samples in the process of water absorbing. To better understand the mechanism for weakening of soft rocks in deep mines when absorbing a certain volumes of water，variances of chemical compositions of aqueous and microstructures of the rock samples were analyzed before and after water absorption tests，and the analysis demonstrated that：when interacting on water，clay minerals of the soft rock generally showed a series of interfacial phenomenon，and it caused the solution of soluble minerals and ionic exchange in the rock，and then it led to the dissolution and secondary of minerals. It can be concluded that the dissolution and secondary of minerals contribute to the variances of the concentration of ions and the strength softening of the rock specimens after absorbing water.

The traditional rock mass classification method focuses on the stability of surrounding rock. For TBM tunnel，the machine performance should also be considered in construction. It is necessary to establish a new method of surrounding rock classification for TBM tunnel. Based on the field data of Hanjiang to Weihe River Valley Diversion Project，the correlation among field penetration index(FPI)，geological parameters and tunneling parameters is analyzed. Then the boreability classification of rock mass is established. The main geological factors affecting the machine utilization were analyzed and the adaptability classification of TBM is also established. In order to reflect the TBM performance，the rock mass is finally classified by evaluating the advance rate，which is affected by the boreability of surrounding rock and the adaptability of TBM at the same time. Five factors，including the rock strength，rock mass integrity，groundwater state，in-situ stress state，tunnel axis and weak structure characteristics，were selected in the study and finally to establish the comprehensive classification of rock mass. The results show that the comprehensive classification of rock mass for TBM tunnel can be used to predict the TBM performance，analyze the duration and cost of project，and effectively solve the practical surrounding rock classification problem of open TBM.

According to the nonlinear characteristic of displacement-time curve of landslide and deficiency of traditional prediction models，the combination model based on surface monitoring data and nonlinear time series analysis was proposed to predict landslide displacement. Taking Xintan landslide and Sanzhouxi landslide for example，deformation characteristics and influence factors were researched by analyzing information of displacement，rainfall and reservoir water level and so on. On the basis of testing trend and periodic characteristics of landslide displacement by using athwart order method and wavelet analysis，nonlinear combination model was used to predict it. Trend item displacement was fitted and predicted by polynomial function. Using a trigonometric function based on wavelet analysis(WA-TF model) to predict periodic item displacement. BP neural network whose parameters were optimized by genetic algorithm was used to predict random item displacement. The accumulative displacement was obtained by adding up all items displacement and it was compared and analyzed with the monitoring values. The results indicate that nonlinear combination model has high accuracy and good versatility. This provides a possible thinking for quantitative prediction of landslide displacement.

Considering the influence factors of slope stability and selecting multi-indexes to build a set-pair system of evaluation indexes and classification standards，the unified，different and opposite connection degrees of each index and standard level were built in evaluation system to determine the slope safety level. According to benefit type index and cost type index，the multiple set pair connection degrees consisted of multi-index and evaluation standards in different forms were further calculated based on the set pair analysis theory. The entropy and weight of each index were determined based on entropy theory，the comprehensive connection degree evaluation model of slope entropy weight-set pair were established by coupling entropy weight to the set pair connection degree. Analyzed the multi-index and multivariate connection degree deeply and adopted the confidence criterion to assess the stability comprehensively. The evaluation results meet engineering requirements and show that，the second phase of slope stability status is in accordance with the actual，the third phase of slope stability after excavated will be stable basically which is a little better than before excavated，so that it is beneficial to make a forecast about slope stability and avoiding danger in the third phase of excavation engineering. The proposed evaluation system of entropy weight-set pair can give a comprehensive evaluation of the slope and excavation stability objectively and deeply.

Based on the fault crossing situation of Xianglu mountain tunnel of water diversion project in central Yunnan province，the axial mechanical response of the lining was calculated by FEM. It was found that the influence of the fault movement on the lining is concentrated on 30 m in each side of the fault plane. The segment length and the width of the flexible joints of the articulated design were determined tentatively based on the distribution of the bending moment along the axial direction. The orthogonal test was conducted to investigate the influencing degree of the main factors and their different levels on the internal force of lining. Finally，the optimal combination for articulated design was obtained by range analysis. The results showed that the articulated design is an effective measure to accommodate the displacement of fault dislocation by the deformation. Moreover，the internal force of lining can be significantly reduced. The maximum reduction of bending moment，shear force and axial force are over 80%. Aiming at flexible material，the advantages and disadvantages of fiber-plastic concrete and high-performance foam concrete in strength and permeability were compared. It was concluded that the fiber-plastic concrete with a certain elastic modulus，good impermeability and higher tensile strength can be used as a flexible material for articulated design. The general regularity of this paper can provide some reference for the design of tunneling across fault zone.

In the gas drainage of coal mines，it is difficult to seal boreholes and determine the sealing length of upward long crossing boreholes under biaxial unequal stress fields. To solve the problem，No.6 mine of Pingdingshan coal group was taken as the engineering example. On the basis of elastic-plastic theories and Mohr-Coulomb criterion，the boundary equations of plastic zones in the surrounding rocks of the circular roadway under unequal stress fields were deduced. The theoretical analysis results were then verified by numerical simulation(FLAC^3D). It was concluded that the boundary shape of plastic zones in surrounding rocks was not circular but symmetrical butterfly-shaped form under equal stress fields，when the lateral pressure coefficient was not equal to 1. The stress of surrounding rocks was distributed unevenly and its gradient changed significantly. Moreover，the obvious difference was observed on the scope of stress-relaxed areas of surrounding rocks with different angles. The deviation of plastic-zone depth calculated by theory and numerical simulation was lower than 5%. The reasonable sealing length of boreholes was determined finally considering the change laws of plastic zones. In addition，a new sealing technology was proposed aiming at sealing upward boreholes. The field test results show that the negative pressure of gas drainage in boreholes is more than 13 kPa，and the maximum concentration of gas drainage is 1.4 times that of testing boreholes under equal stress fields. Furthermore，the concentration of gas drainage decays slowly. The test effect can meet the need of long-term and high-efficient gas drainage.

Based on the reality of frequent collapse accidents in subway construction in China，a method of collapse risk prediction based on numerical simulation，artificial neural networks and Monte Carlo method is put forward. The risk of collapse accident is predicted under the condition of pipeline leakage and damage. On the basis of investigation of accident statistics，the main reason that resulted in collapse accidents is leakage of pipelines. Through the method of finite difference fluid-solid coupling numerical simulation，the maximum ground settlement values of the three different pipeline locations，namely，just above the tunnel，above the tunnel 5m on the right and above the tunnel 10m on the right，are calculated. When pipelines are not damaged and leaking，the maximum ground settlement is located at the surface just above the tunnel and the values are 0.012 85，0.016 05 and 0.018 53 m，respectively. When pipelines are damaged and leaking，the maximum ground settlement located at the surface just above the tunnel and above the tunnel about 2 m on the right. The maximum ground settlement values are 0.028 75，0.027 17 and 0.021 8 m，respectively. The numerical simulation results are used as the training and test samples of neural network，and the non-linear mapping relationship between the basic parameters and the ground settlement is established by RBF neural network，which is used to replace the performance function of Monte-Carlo method. According to Monte-Carlo method，the probability of collapse risk of the three locations under the condition of damaged and leaking pipelines is calculated when the tunnel is excavated. The probabilities are 36.75%，25.08% and close to 0. This research can provide reference for similar risk control of subway tunnel construction.

In order to research the relations between rock energy dissipation and the dilation evolution during process of failure，an incremental loading for one cyclic loading mode is designed and put into practice. Granite gneiss rock are taken as research objects sampled from Southern Sinkiang region，and variable cyclic loading triaxial tests are carried out under confining pressure from 0 to 50 MPa all over the whole process stress-strain curve. From viewpoint of energy dissipation，the damage variable is defined，and its relationships with the energy dissipation parameters and principal strain(residual strain and residual shear strain) are deeply analyzed during cyclic loads. Moreover，the confining pressure effect on the energy parameters and variables are studied as well. For each cyclic loading and unloading，the relationship between residual volumetric strains versus residual principal strains are acquired from the curves，which provide the fundamental data for further dilation property research. According to the evolution law of damage variable versus plastic shear strain curves，the relationships between energy dissipation ratio and shear dilation angle are constructed. Summarily，the research reveals that the damage evolution process of rock based on energy dissipation mechanism and these relationships with its dilation to failure has important significant for which sets up a bridge between energy mechanism and dilation during failure process.

As a special weak structural plane，interlayer shear zone often forms the control factor which threatens the stability of engineering rock mass. The preliminary cognition and existing problems of main quality classification methods of rock mass about interlayer shear zones are analyzed. Based on the viewpoints of control by rock mass structure and consideration of layered rock mass structure types，according to the size characteristics of interlayer shear zones and their impact mechanism on the stability of stratified composite rock mass，the quality classification and evaluation methods of stratified composite rock mass with interlayer shear zones are established. (1) The interlayer shear zones with good continuity and bigger dimension，whose thickness is more than 10 cm，are set as independent weak interlayer structure of shear dislocation. For this circumstance，the quality classification and evaluation of stratified composite rock mass with interlayer shear zones are carried out separately，according to the shear strength parameters of interlayer shear zones. (2) The interlayer shear zones with smaller dimension，especially the siltized interlayers whose thickness is less than 10 cm，are regarded as the reduction factors. The modified BQ method of quality classification of stratified composite rock mass with interlayer shear zones is founded by weakening treatments. The quality classification results of surrounding rock mass at two exploration adits with obvious interlayer shear zones in the dam site are obtained by the modified BQ method，taking some large-scale water control project in the Middle Yellow River. By comparison and relevant analysis with RMR，Q，and HC methods，the validity of the modified method of stratified composite rock mass quality classification with interlayer shear zones is verified.

In response to the condition that coal face spalling and roof-fall occurring frequently in the large-cutting-height mining face，taking panel 8101 of Wangzhuang coal mine as background，the“roof-coal face-support”system mechanical model has been established to conduct the influence factors sensitivity analysis of coal face stability. Experimental test for coal face stability study has been designed to conduct similarity simulation test in order to study the relations between coal face stability and influence factors such as mining height，support working resistance，coal face pressure and coal strength. UDEC numerical simulation was used to simulate the coal face deformation in changing mining height，cohesion，support capacity and advancing length. The study shows that coal face pressure and coal strength are the main reason that causing coal face failure. The larger is the mining height，the smaller is the limited coal face failure pressure. The larger is the support capacity，the smaller is the coal face pressure. However，improving of support capacity only has limit impact on coal wall failure controlling. Guard board of support can prevent the fractured coal face from sliding down effectively but has little impact on coal face failure controlling. There is a large deformation in coal body before the coal face failure. The coal face failure position locates as the upper part of coal face，usually 60%–70% of mining height. These results provide a foundation for coal face spalling prevention.

The focus of prevention and control of water inrush from floor is to study the evolution of the intact floor from aquifuge to water-conducting. According to the elastic stiffness variation characteristics of floor rock mass in mining process，which beard loading of compression-tension-compression，using double scalar D-P elastoplastic damage constitutive model，finite element model was built based on the engineering geological conditions of Chengzhuang mine，the evolution law of water-conducting was analyzed in working face advancing process. The main conclusions are as follows：(1) Compression and tensile damage zones exist in mining floor. Compressive and tensile damage zones lead and lag coal wall respectively，both of them are connected，forming a water-conducting，which is inclined to pass through the plane of the coal wall. (2) Floor damage depth increases with the increase of the roof hanging area，and leads to the fracture depth increases again in last calculation step. Under the influence of filling body，the growth rate of the floor compression damage depth at the position of the coal wall is rapidly decreasing(the first roof caving)，and finally reaching stability(the periodic caving). (3) Floor failure depth will rapid increase if elastic modulus of filling body is too low. Under the action of the filling body，the tension crack closure and the elastic stiffness of floor rock mass are restored，permeability of rock mass is decreased at the same time. The monitoring results obtained from the water injection experiment are in agreement with the numerical simulation results.

Monitoring on the deformation of the engineering rock mass is one time and cost consuming task，especially for the cases with large monitoring section and long monitoring distance and when the power supply is not properly available. To overcome these difficulties and improve the efficiency of monitoring，we present anon-contact measurement system. The principle of this method is converting the internal displacement of surrounding rock to the rotation angle of the disk. A diaphragm is arranged below the rotating disk with an observation window. The intensity of the light reflected from the different regions of the diaphragm is changed，and the rotary angle of the disk is calculated by the intensity of reflected light. Through the laboratory test，it shows that there is a good linear relationship between the intensity of the reflected light and the rotary angle of the disk. By modeling，the monitoring precision of the internal displacement of surrounding rock can be effectively improved. The new measurement scheme was verified in Long men tunnel. Comparison test and surrounding rock grade survey show that the results of measurement are in line with the actual situation. The new measurement system can achieve non-contact measurement and reach the accuracy of engineering measurement.

As of now，to some extent most of existing thermal insulation measures are dependent of experiences in absence of relevant technical support，typically involving serious issue associated with frost damage of tunnel structure. To predict frost damage of tunnel，by surveying 156 tunnels subject to frost damage，we found the tunnels in cold region can be preliminarily classified into two groups：the tunnel at high latitude as well as the tunnel at high altitude. According to both of the average temperature in the coldest month and the frozen depth，tunnels were further subdivided into 5 sub-regions where thermal insulation and drainage technologies of tunnel were discussed. Probing into the results reveals that the method of thermal insulation layer is well applicable to the region where the average temperature in the coldest month ranges from －5 ℃ to －15 ℃. For region with average temperature in the coldest month below －15 ℃，other active insulation measures should employed at the section where surface temperature of the secondary lining exposes below －15 ℃. When the surface temperature of secondary lining rises to 0 ℃，thermal insulation ditch and central deep drain together with cold protection drain tunnel can be ignored. Moreover，combining drainage technology outside the tunnel and insulation measures is capable of helping facilitate ideal drainage effect in these observed scenarios. Finally，this paper concludes that the prevention principle of frost damage for tunnel in cold region is：“construction quality is the foundation；drainage is the core，and insulation is the key，the interaction of which should be considered simultaneously for a specific tunnel”.

In order to understand the broken energy dissipation of magnetite，impact compression tests were conducted with split Hopkinson pressure bar(SHPB). Results show that：(1) The energy distribution following： transmitted energy＞absorbed energy＞reflected energy. (2) The energy absorption efficiency of magnetite increased up to 39.5% firstly，then keep stable with the growth of incident energy. (3) In addition to absorbed energy，the ratio of transmission energy to total incident energy reduces gradually with the grow of incident energy and the form of energy dissipation was transmission(when less than 180 J)，the ratio of reflected energy to total incident energy increase with a small growth rate，when the incident energy was more than 180 J，the ratio of transmission energy and reflected energy to total incident energy keeps unchanging with the growth of incident energy，and the form of energy dissipation were transmission and reflection. (4) The broken forms of magnetite specimens presents columnar，columnar mixed with needles，fine needles，powdery respectively with the growth of incident energy，and the average particle size is 15–18 mm(when incident energy is 180 J). (5) The broken energy density increases linearly with the growth of incident energy，the average particle size of broken fragments decrease with the broken energy dissipation growing.

It is the essential prerequisite for mechanical analysis of the underground cavern with the complex variable theory that the conformal mapping function must be solved. According to the boundary correspondence principle，a conformal mapping function is established that can transform the exterior of the arbitrary excavation cross-section in half-plane to the area between two concentric circles. A method for calculating the conformal mapping coefficients is also proposed. By using the method of odd even point interpolation and genetic optimization and sequential quadratic programming algorithm，the high resolution is realized. Based on the analytic property of mapping function，a simplified method of mapping function in the process of solving complex stress function is given. The results show that：(1) The proposed mapping function method can solve the difficulty caused by horizon，and the existing research results can be applied to the solution of the function coefficients directly. (2) The tunnel boundary mapping accuracy is very high，the relative error can be controlled within 0.5%，the surface boundary mapping accuracy is slightly worse，but all can be controlled within 5%，and the mapping accuracy increases with the increase of the number of coefficients，which can meet the needs of engineering and research. (3) Taking a shallow buried rectangular project as an example，the proposed solution method and simplification method of mapping function are adopted. The results are in good agreement with the finite element results，with a difference of less than 1%.

Taking ten standard joint profiles proposed by Barton as an object，professional image processing softwares PHOTOSHOP and MATLAB were firstly used to digitize the image of ten standard JRC profiles by removing stray dots located close to the profiles and interpolating pixels between discontinuities in the profiles，then accurate coordinates data of ten standard joint profiles were obtained. On this basis，the root mean square of slope Z₂ and amplitude parameter h_A of the standard profiles were calculated at different sampling intervals，and a new empirical equation between JRC and Z₂ and h_A was established. Then the new equation，as well as other commonly-used empirical equations，were employed to calculate the JRC values of ten standard profiles and some natural rock joint profiles. The predictions of JRC were compared with the back-analysis values from shear tests，from which it can be concluded that the prediction accuracy of the new empirical equation is greater than that of the former empirical equations，and it has a good prospect in engineering applications.

Few researches were conducted on the law of the ground vibration induced by heavy haul trains and the influence on the houses nearby，based on field test of vibration velocity and acceleration around Shuo-Huang railway bridge above Shenshan Village，the propagation and attenuation law of the amplitude of vibration velocity is analyzed，a regression analysis method for vibration propagation attenuation of railway viaduct is proposed，it is found that the attenuation of each measuring point on the beam-end line is faster than that of the middle line of bridge，and the attenuation law is nonlinear. Based on the analysis of the measured data, the relationship between the peak vibration velocity of the particle and the distance from the excitation source，the train speed and the axle load is obtained. There is a big difference between the same type of empty and full load trains，but there is little difference between the different models. Based on the analysis of the peak vibration velocity and acceleration level of the roof，indoor and basic measurement points，the comfort effects of the nearby houses and indoor people are studied. It is found that the vertical vibration of the roof is larger than that of the transverse direction between 10 and 20 Hz，and the vibration level of some bands have exceeded the standard.

In order to study the seismic performance of rock underground engineering during whole life in western China，a calculation method with Matlab-Abaqus-BP based on the time-dependent reliability theory is proposed for researching the seismic performance of underground structures in strong earthquake areas. The method has the advantages of high precision and small computational amount based on Latin hypercube sampling and neural network. Taking the Xianglushan Tunnel of Water diversion project in central Yunnan as an example，the calculated results show that both the mean values of structural resistance and load response show a slowly decreasing trend during the service period. However，the standard deviation of structural resistance increases more rapidly，indicating the samples of structural resistance are more discrete，which lead to the rapid decline of the reliability index in the late stage of service. The method can quickly and effectively study the seismic performance of the lining structure during the whole service period，and provide a theoretical basis for the reasonable selection of the structural reinforcement time. The method can be used to provide reference for the seismic performance of underground engineering to analyze the seismic performance of the tunnel during whole life.

As a common ill geologic phenomenon in mountainous areas，debris flow has brought about great number of disasters. Due to the complexity of formation and evolvement of debris flows，however，it is difficult to exactly evaluate the risk of debris flows. In this paper，on basis of the investigation of 55 debris flow cases in southwest China，it was proposed to assess the risk of debris flows according to three parameters including rain intensity，slope gradient and unstable material source. Effects of rain intensity，slope gradient and unstable material source on the risk of debris flows were discussed and corresponding influence coefficients of the three parameters were given out. A three-parameter method for evaluating debris flow hazards was developed through back analysis and improved by a correction factor considering the block conditions of debris flow gullies. The method was applied to an amount of debris flow cases and proved to be reasonable.

Based on the methods of physical modeling of large-scale excavation explosions in the vacuum chamber，the similarity conditions for the experimental material parameters are given. By use of shear cell module of the FT4 multifunctional powder flow tester，the main physical parameters of the quartz sands with particle sizes from 0.3 to 0.6 mm have successfully gained for the first time，and the relationships between the shear resistance and particle size，moisture(glycerin) content for the quartz sand are presented. The applicability in the laboratory model of large-scale throw blasting was also discussed. The results show that，the characteristic grain sizes range from 0.3 to 0.6 mm for the experimental materials could be used as the simulation material of the large-scale underground explosions with the equivalent of 0.1–100 kt TNT. The material parameters for the shear strength of quartz sands are well satisfied the similarity conditions of large scale excavation explosions considering the effect of gravity，and suggested wide applicability to the model test. The material parameters can provide important reference and basis for the experimental simulation and numerical calculation of large scale throw blasting.

In order to analyze the micro-stress situation and crack initiation and propagation of rock under extrusion and crushing，the numerical simulation of extrusion and crushing of particle model which is established by defining different scale characteristics of the unit body and different strength characteristics of bond between the unit bodies is conducted based on the EDEM software. The initiation and growth of multiple cracks is simulated and analyzed according to bond fracture and stress situation inside the particle model，which could reveal the microscopic mechanism of crushing of rock. At last，the influence of bite rate on the crushing of the model is analyzed，The results show that the influence of the biting velocity on the crushing of the particle model is only on the action time，but not on the fracture state and the fracture form of the model and the multi-scale cohesive particle model constructed could well reflect the characteristics of grading broken.

In order to improve in-situ stress calculation method applied in hollow inclusion measurement，the normal equations are built by least square method to obtain the mathematical expressions of in-situ stress components. Based on the Shengjin′s formulas to have characteristic equation of the stress state，the discriminant for estimating the stress state and calculation method of principal stress are obtained. According to geometric relations among the direction cosine of the principal stress，a method of determining octants of principal stress is given and the calculation formulas of azimuth and dip are deduced. With LabVIEW，a program of in-situ stress calculation is programmed to study the stress state of Xincheng gold mine. The results reveal that the in-situ stress is dominated by horizontal tectonic stress field and the maximum horizontal principal stress is oriented in SE-NW direction to nearly E-W direction.

In order to avoid the discreteness in laboratory test of rock mechanics，with the current prevailing technology of non-destructive testing，in view of the Hertz contact theory and energy conservation law，and based on the principle of rebound detection，the mechanism of rock-strength prediction by “ultrasonic- rebound-density” comprehensive screening method is studied，and multiple regression models are established concerning the relationships of rock uniaxial compressive strength with density，rebound and compressional wave velocity. Thus combined with stratigraphic CT scanning technique，a new method to predict the compressive strength of rock mass is put forward. Then after the non-destructive testing of granite and sandstone，this paper obtained their predicted compressive strength with the models mentioned above. The predicted results deviate from the results obtained by lab test by no more than －2.53% to 2.06% and 3.09% to 4.84%，and the correlation coefficients of the two fitting formulas are both more than 0.9. Conclusions are that this method is much more accurate than previous empirical formulas and can provide reference for rock grouping under different working conditions，and the prediction error of the grouped rock samples ranges from －5% to +5%.

The construction of inclined tunnel by shield method is the first applied in New Street of Shenhua Company in China. The tunnels are excavated by a tunnel boring machine and supported by a 350 mm segmented concrete liner，which is quite different from the traditional way using in a coal mine. In order to study the structural stability of inclined tunnel under deep mining activities，a physical model test is adopted by using a self-developed multi-functional model test bench，and the whole process of shield excavation and coal mining are simulated. During the test，tangential force and displacement of the measuring targets around the liner are measured，safety factor method is used to evaluate the structural safety of the inclined tunnel and finally the suitable coal pillar width under deep high stress is determined. In the same time，during the mining process，the vibration effect by the overlying rock mass collapse on the segment is recorded and the influence of deep mining on structural stability of inclined tunnel under high in-situ stress is analysed. The test results show that the most suitable coal pillar width of the researched cross-section is 108.5 m. Moreover，the most unsafe position appears in the spring line next to the side of excavation. It is found that in deep mining，as the coal excavation，the maximum amplitude of the measuring targets increases，which promotes the cracking of segment.

The excavation of tunnels in the soft rock stratum with high geo-stress is easy to cause large squeezing deformation，which is one of the main problems in tunnel construction. This article relies on Maoxian tunnel of Chengdu-Lanzhou Railway to analyse the deformation characteristics and failure modes of Maoxian tunnel，and the deformation and supporting mechanism of large deformation tunnel in squeezing-shattered soft rock was researched. The results show that，during the construction of high geo-stress soft rock tunnel，the magnitude and velocity of deformation might maintain a high level for several days，and the extrusion flow of the surrounding rock was obvious. The loosening circle of surrounding rock had a large radius and appeared to be multi-layered. The bolts in vault area were under pressure. Thus，the bolts and the rock mass turned into a compressing zone together，bore the load jointly. The support structure was under considerable deformation pressure. The steel girders were mostly working at yield state or became failure in various forms，but the failure point was concentrated at some specific locations. As for the rock mass，the shear failure took the main part，and the expansion of joints was obvious. Grouting took a remarkable effect in strengthening the surrounding rock and maintaining the anchor effect. Multi-layer support could release the deformation potential of the surrounding rock gradually，improve the bearing performance of the structure，and reduce the impact of rheological behavior.

To evaluate the stability of filling grouting slurry，the slurry stability test device was designed. The slurry stability coefficient index was defined to quantitatively evaluate the stability of clay cement slurry and pure cement slurry under different grouting parameters. The influence of slurry stability on practical engineering was deduced，and the results were verified by practical engineering. The results show that the grouting parameters and strata conditions have significant impacts on the stability of pure cement slurry and clay cement slurry. Under the same condition，the stability of clay cement slurry is better than that of pure cement slurry. They are both negatively correlated with water solid ratio，and positively correlated with strata grouting pressure and drainage conditions. The slurry with better stability can provide a higher filling rate and its effective diffusion distance is relatively large，but its diffusion distance is relatively small. When the stability coefficient of the clay cement slurry is less than 83% or the stability coefficient of cement slurry is less than 71%，the shear failure along inclined plane occurs easily. In the practical filling grouting project，to ensure a better filling rate，it′s advised to choose slurry that with better stability and greatly match the relationship between hole spacing and slurry stability. Under critical strata condition，the slurry stability coefficients can be obtained by adjusting the slurry water-solid ratio and grouting pressure. The experimental results can provide some reference for filling grouting theory and practical engineering case.

Until now，the formation process of debris flow from natural dam failure is still unclear and there has not been a formation condition for outburst debris flow. In this paper，we present the results of a series of laboratory tests that assessed three different materials，five different flume bed slope angles (2°，7°，9°，10°and 13°)，two in-flow rates and four types of dam geometric shapes. It shows that debris flow is easier to form from natural dam failure than gully erosion. The unit weight of water-sand mixture in the downstream increases firstly，and then decreases with time developing. The results also show that the unit weight of water-sand mixture is seriously affected by channel bed slopes. In addition，the decrease of median diameter and the increase of downstream slope can both increase the unit weight of water-sand mixture，and the unit weight of water-sand mixture is less sensitive to downstream slope of the dam than channel bed slopes and dam geometric shapes. Based on the theory of stream power and experimental data，we established a critical condition for debris flow formation from natural dam failure，which is simple to calculate and the parameters can be obtained easily. Combining four cases，it indicates that the established critical condition agrees well with the field.

Based on the three-dimensional axisymmetric model which only considers the vertical wave effect of soil，the vertical vibration of a large diameter pipe pile is investigated considering the compacting effect. First，the outer soil and inner soil are respectively divided into finite vertical annular zones，and the soil within the same zone is considered as homogeneous. Then，the vertical vibration governing equations of each soil zone are built. By solving the equations and together with the continuity of the displacements and stresses at both the interfaces of pile-soil and the interfaces of the adjacent soil zones，the dynamic interactions of pile-outer soil and pile-inner soil are obtained and are substituted into the governing equation of pile to obtain the analytical solution for dynamic response at the pile head in the frequency domain. Finally，a parametric analysis is conducted within the low frequency range to analyze the influence of pile parameters and the compacting effect on the complex impedance at the pile head. Meanwhile，comparison with the published solution is carried out to verify the reliability of the present solution.

Based on the isotropic compression law of soil，the total deformation of soil is divided into instantaneous and time delayed. Referring to the calculation methods for instantaneous and delayed compression of united hardening(UH) model，an one-dimensional elastic-viscous-plastic(EVP) constitutive model is developed. On the basis of an elastic plastic(EP) constitutive model for soil considering the stress paths dependency， influences of over consolidated ratio(OCR) and shear stress ratio on instant compression are considered；the delayed compression law under isotropic condition is extended to three-dimensional stress state by combining with overstress theory and plastic potential function of the modified Cam-clay model. Then a calculation method for instant and delayed compression under three dimensional stress state is proposed，meanwhile a 3D EVP model is built. The new model contains 7 material parameters，physical significances and determination of parameters have been analyzed and given. Comparisons between model predictions and experimental results show the 3D model can describe viscosity properties of clay and sand reasonably under not only conventional stress path，but also typical stress paths of stress ratio loading under excavation.

To investigate the permeability of fresh municipal solid waste(MSW) during the process of gradually filling，a self-made permeability and compression combined test apparatus was used to perform 180 permeability and compression combined tests with 31 fresh MSW samples in geo-environmental laboratory，and the effects of pressure，compression time，compression strain and density were considered. Six different vertical pressures of 0，25，50，100，200 and 300 kPa were applied，and six compression times were 0，1，2，6，12 and 24 hours，were selected for every vertical pressure during the compression process. Besides，six hydraulic gradients were applied. Testing results showed that：(1) There exists a critical hydraulic gradient for the permeation of fresh MSW，the permeation will start only after the hydraulic gradient has reached the critical hydraulic gradient. (2) The relationship between permeation rate and hydraulic gradient can be formulated as a linear function that corresponds to Darcy's law. (3) The relationship between permeation rate and pressure can be formulated as an exponential function with the correlation coefficient greater than 0.93. (4) The relationship between logarithmic permeability coefficient and density can be formulated as a linear function with the correlation coefficients greater than 0.98. The equations that express this linear relationship are provided. (5) The relationship between logarithmic permeability coefficient and compression strain can also be formulated as a linear function，and the correlation coefficients are greater than 0.97. The equation express this relationship is also provided. The test results from this study can be used as reference for the permeability analysis of a municipal solid waste landfill.

The magnitude and modes of horizontal displacement of reinforced soil retaining walls are important to structural design. Based on four large scale model tests and relevant literature, the magnitude，forms and evolution modes of horizontal displacement of tiered geosynthetic reinforced soil retaining walls are investigated. The following conclusions are obtained from the tests：the maximum horizontal displacement of retaining walls appears at the top of each retaining wall，and the displacement decreases with increasing step width；The horizontal displacement distributions along the upper walls change gradually from linear curve to exponential，while the distributions along the lower walls are logarithmic curves；Considering the effect of step width on the lower wall horizontal displacement，the critical step width is suggested to be 2/3 of the lower wall height；The panel bottom layers of upper walls translate along the top layers of lower walls，the translation decreases with increasing step width and frictional resistance of panel bottom layers，and the translational direction is influenced by many factors；The horizontal displacement could be reduced by increasing numbers of geosynthetics layers or geosynthetics length in the bottom part of the upper wall and the top part of the lower wall. The results of this study can provide reference for similar structural applications.

This paper studies the characteristic of remolded expansive clay in Hefei. A series of three-dimensional swelling tests were conducted for cubic expansive soil of different initial moisture contents and dry density as well as the swelling pressure tests under the control of the vertical strain and the lateral strain. The vertical swelling pressure is always bigger than lateral swelling pressure. Moreover，the range of R₀ change is between 0.525 and 0.904. Secondly，under the same initial moisture contents，R₀ will increase with the rise of dry density. At last，the study shows that the trends of evolution of swelling pressure under the control of the vertical strain and the evolution of the lateral swelling pressure under the control of the lateral strain are similar. The tiny strain would lead to the dramatic decrease of swelling pressure. Moreover，with the decline of the strain，the rate of decay of swelling pressure will increase.

In order to improve the seismic stability calculation method of retaining structure，a formula of the reinforcement tension coefficient under seismic actions is established，which is based on pseudo-static method and horizontal slice analysis. The derivation aims at the waterfront reinforced-soil wall under partial submerged conditions. And two types of failure surfaces in the forms of linear and polyline in the backfill are considered. Besides，according to the difference of permeability，soil and water pressure together or separately are calculated by this method respectively. The effects of horizontal seismic inertia force，vertical seismic inertia force，seismic excess pore pressure and hydrodynamic pressure are taken into accounted. Compared with the dry backfill condition，reinforcement tension required in the submerged condition will be greater significantly，which should be paid reasonable considerations in engineering design. The parametric studies demonstrate that the reinforcement tension coefficient of linear failure surface is higher than that of polyline failure surface. The coefficient calculated by soil and water separately is larger than that obtained by soil and water together. Seismic excess pore pressure and water level have a significantly increasing effect on tension coefficient. And the increasing amplitude is related to the forms of failure surfaces and the calculation mode of soil and water pressure. Both soil friction angle and wall friction angle have a decreasing influence on tension coefficient，but the influence of soil friction angle is more obvious.

In pit excavation，cement is introduced into ground by deep mixing method to form an improved soil raft below final formation level to diminish deflection of retaining wall and effect on surrounding structure. Owning to complicated site conditions and improper workmanship，there are always some regions left untreated in the embedded improved soil raft. In this work，Several schemes of cement-soil mixed piles arrangement are modeled in order to discuss the effect of different cement-soil reinforced regions on protection for adjacent running tunnels. Finite element results show that：when lateral regions above tunnels are not enhanced by cement-soil mixed piles，effect of enlarging vertical enhanced regions around tunnels on diminishing lateral displacement of tunnel is really small；enhancing the lateral regions next to retaining wall is more effective in reducing the deflection of tunnel and retaining wall；uplifting of tunnel under the middle pit mainly depends on lateral reinforced regions and lateral displacements of retaining wall；as cement-soil mixed piles near retaining wall in east pit are removed during east pit excavation，effect of cement-soil mixed piles in east pit on reducing the final wall deflection can be neglected；upward shaft resistances are exerted along left side of diaphragm wall during excavation，which helps to reduce the wall deflection；positive effect of single-head cement-soil mixed piles in east pit is to decreasing the uplifting of soil inside east pit. Double-head cement-soil mixed piles arranged in "T" shape decrease the effect of east pit excavation on tunnels under middle pit apparently.

The macro- and meso-mechanical behaviors of shear band were simulated using discrete element method. Loop structures were taken as the basic meso-mechanical unit of granular material after tessellation. The evolution of numbers，geometrical morphology，mechanical characteristic and sliding stabilities for different loops during shearing were analyzed in details，and the essential relationships were discussed between the variation of loops and the strength，dilatancy of granular material. Numerical results show that the variation of numbers and geometrical morphology of loop structures are approximately consistent inside and outside the shear band during shearing，but the degrees are different，the mechanical states and sliding stabilities of different loops inside and outside the shear band are obviously different. Proportions of higher-order loops are increasing and shapes of them are more flat，while proportions of lower-order loops are decreasing and shapes are keeping unchanged. The macro-scale dilatancy is reflected by the conversion from lower-order loops to higher-order loops in meso-scale mechanical structure，which forms a kind of self-organized structure under specific force and boundary condition. Two kinds of definition of sliding rate were proposed to analyze the sliding stabilities of loop structures. Evolution of sliding rate inside the shear band after peak stress state is obviously different from that outside the shear band，and the location of maximum sliding rate are not coincide with the location of peak stress point on stress-strain curve. The strong force chains，which are formed by higher-order loops，undertake larger load and have higher sliding stability than lower-order loops. The contact sliding and recombination during the conversion from lower-order loops to high-order loops are the main causes of plastic deformation for granular material.

To systemically research into pull-out resistance properties of roots and the effect of root-soil interface microstructure feature on the interface friction strength between root and soil particles，the shrubs Caragana korshinskii Kom. and Zygophyllum xanthoxylon Maxim. with a growth period of two years being planted in a self-established testing area were selected as the research objects and indoor pull-out test was carried out to them. Then scanning electron microscope(SEM) was applied to further investigate surface microstructure features of root and their effect on the friction strength between root and soil. The test results are the following：The mean values for maximum pull-out resistance of C. korshinskii roots and Z. xanthoxylon roots are 78.89±24.47 and 67.78±32.82 N，so the mean value of maximum pull-out resistance of C. korshinskii roots is greater than that for Z. xanthoxylon roots；the mean values for displacement of C. korshinskii roots and Z. xanthoxylon roots at maximum pull-out resistance are 4.02±1.84 and 10.67±4.04 mm，so the mean value for displacement of Z. xanthoxylon roots is greater than that of C. korshinskii roots；both integrated pull-out pattern and fractured pull-out pattern appeared in the process of roots pull-out for C. korshinskii，meanwhile fractured pull-out pattern and periderm slip pattern appeared for Z. xanthoxylon roots；the maximum pull-out resistance of C. korshinskii roots and Z. xanthoxylon roots tends to increase with roots surface area，roots volume，total roots length，roots dry weight and lateral root number increasing，among these five root morphology indexes，roots surface area has relatively more significant influence on roots maximum pull-out resistance；along axial direction of C. korshinskii root，grooves and ridges densely distributed in the surface of root with more net-like structures，so root surface microstructure for C. korshinskii is more complex than that for Z. xanthoxylon, and interface friction strength between soil and root for C. korshinskii is greater than that for Z. xanthoxylon. The slope protection ability of C. korshinskii is greater than that for Z. xanthoxylon. The research conclusion is useful to further investigate mechanics mechanism of interaction between roots and soil for shrubs in cold and arid environment，and meanwhile this conclusion has a theoretical significance and practical value in preventing soil erosion，shallow landslide and other geological hazards in the testing area.

A large-scale constant stiffness shear test apparatus of pile-soil interface was designed and developed to investigate the mechanical characteristics of pile-soil interface in clayey soil. Ideal cluster spring loading system was adopted on normal loading direction to generate the desired load. In the normal direction，the boundary condition including the constant normal stiffness could be imposed，while in the tangential directions，the displacement path，static upper shear box，linear and reciprocating motion of lower upper shear box，could be imposed. It was shown that this apparatus could be employed to represent the response of clayey soil and structure interface under various loading paths and simulate shear process of pile-soil interface. The results of shear stress-shear strain curves obtained under different interface roughness，shear rates and water content of clayey soil，are consistent with the existing conclusion of shear mechanical characteristics factors affecting.

Under various vertical stresses and number of geogrids layers，three types of geogrids were used，respectively，and 30 groups of simple shear tests were conducted on geogrids reinforced sand to study the change of shear behavior of soil. The three geogrids used were rectangular and elliptical bidirectional geogrids along with a tridirectional geogrids. The experimental results show that the thickness of the ribs and nodes as well as the relative opening area positively correlated with the shear resistance while the length and width of ribs negatively correlated with the shear resistance. Besides，the number of layers of geogrids influenced the mechanical properties of sandy soil. The strength decreased when geogrids were added with their laying directions corresponding to the shear direction. The shear failure surfaces were in the upper part of the specimens while in the lower part showed small relative displacement. Meanwhile，the cohesion appeared but friction angle reduced. Therefore when adding geogrids to the same direction with the shear direction of sandy soil will result in a weak soil-geogrid interface，and thus the shear strength decreases. However，the reinforced sandy soil shows an apparent cohesion due to the restriction from the geogrids to the sand.

To solve the problems related to the displacement measuring devices in the static load tests of foundation piles，such as small measuring ranges，necessitating datum beams and the critical demands for perpendicularity，the differential pressure connected pipe displacement meter based on liquid-gas coupling formed of connected pipes and differential pressure sensors is proposed，based on the combined use of theoretical analysis，comparative tests and field tests. In the design of the composition of the displacement meter，a kind of liquid level elevation control method and structural formation were chosen，by considering that the liquid surface can automatically look for equal elevation and keep remaining in a horizontal plan under the action of gravity，which allows the initial liquid level elevations at the two ends of the displacement meter to keep the same and reduce errors. The comparative testing within the displacement range of 100 mm demonstrated that the data gained from this displacement meter were in compliance with those gained by dial indicators and stepping motor control type mobile platform，with a maximum absolute error of 0.04 mm. In the field tests for the trial pile project of a Yangtze River Bridge，the maximum downward displacement measured was 36.46 mm，and the maximum upward displacement 127.34 mm，which were basically in agreement with those measured by relative devices，with a maximum difference of +0.28 mm. The matched application procedure to the displacement meter developed were compiled by Labview，supporting the manual intervention short-term measurement and automated continuous long-term measurement. No datum beams were needed during the testing period of the displacement meter. The displacement meter has no requirements for perpendicularity in the installation，which has low costs and great environment adjusting ability and easy to operate. Therefore，it has good publication value in the static load tests for foundation piles.

In order to investigate the effect of salt on water and salt redistribution in freezing process, unidirectional freezing tests of soils with different salt contents were conducted. Moreover, model tests with four different boundary conditions(freeze-thaw cycle，evaporation, radiation, and precipitation) were used to investigate the transfer mechanism of salt and water in saline frozen soil. The results indicated as follows：due to the existence of salt，moisture migration will be weaken in the soil during freezing，so that the frost heave was mitigated. As no salt crystallizes in the freezing process，only frost heave exists in NaCl soil. However，Na₂SO₄ is sensitive to temperature，both salt and ice may crystallize during cooling，resulting in frost heave and salt expansion in sodium sulfate soil. Besides，the permeability of soil was decreased by Na₂SO₄ crystals，thus the water movement was reduced. In Na₂SO₄ soil with high salt contents(e.g. 3.6%)，in-situ salt expansion and frost heave occur at the initial freezing process，and segregation heave is negligible. For the Na₂SO₄ soil with salt content 2%，the water and salt migration are also negligible in freezing-thawing process. Salt effloresces in the evaporation process，and surface soil salinity moves downward with water infiltration. Dry-wet cycle is the main cause of salt expansion，which has a stronger effect on salt movement than freezing process. Salt expansion exists at the soil surface，while frost heave is observed at freezing fringe. Finally，the water and salt transfer mechanism have been investigated，including the cause of salt expansion and frost heave.  

Geosynthetic-reinforced and pile-supported embankment，has been considered as an effective and economic solution to reduce the total and differential settlements of the embankment constructed on soft soil. In this paper，a simplified method for analysis of an embankment on soft soil and supported by a rectangular grid of piles and geosynthetic is proposed. In this method，the soil arching effect is analyzed by arching effect in granular material initially proposed by Low B.K. et al.，and subsoil resistance，geosynthetic effect and especially load transmission of pile and soil are taken into consideration. Quadratic parabolic equation is employed to described the deformation of the geosynthetic. Ultimately the expression for subsoil resistance has been deduced，and then the tension and the deformation expression of geosynthetic can be worked out. Through comparative analysis with field test and other current design methods，it is found that the proposed method is conceptually and mathematically simple，and the results agree well with field test data and that of several current design methods.

The change law about soil shear strength under freezing-thawing cycles was controversial，and calculation basis for projects were absented. In this paper，based on new sample preparation standard，by triaxial test，the representative soils in seasonal frozen region are selected as the sample，the change law about soil shear strength index under freezing-thawing cycles were studied. We define the correction coefficients of freezing- thawing cycles，on basis of soil shear strength index before freezing-thawing cycles，to present the typical soils¢ shear strength calculation formula under freezing-thawing cycles. The results show The conventional sample preparation standard shouldn¢t be applied in the freezing-thawing cycles experiments，or the discreteness of sample density will be amplified to further result in that the experimental results likely become discrete and ruleless. Under freezing-thawing cycles，the cohesion of clay，silty clay and silty sand decreased exponentially；meanwhile，the internal friction angle increased exponentially with the times increase of freezing-thawing cycles. After freezing-thawing cycles，for silty sand，the cohesion decreased about 20% and the internal friction angle increased about 10%，the freezing-thawing stability of silty sand was the best；for silty clay，the cohesion decreased about 55% and the internal friction angle increased about 20%，the freezing-thawing stability of silty clay was better；for clay，the cohesion decreased about 70% and the internal friction angle increased about 40%，the freezing-thawing stability of clay was the worst.

When the classical Seed¢s liquefaction resistance shear stress analysis method is used to evaluate the liquefaction potential of an engineering site，seismic magnitude and other several key parameters are essential. However，it is often difficult to determine the seismic magnitude parameter for some ocean engineering sites，because of the lack of nearby referential engineering sites. In order to solve this problem，we proposed that the equivalent seismic magnitude determined from the comprehensive seismic risk probability analysis method could be used as the reference magnitude for the evaluation of site liquefaction potential. The proposed method was applied to two ocean oil platform sites in Bohai Sea to evaluate the liquefaction potential of the saturated sand layers with a thickness of 15 m below seabed mud. The results showed that the method has satisfying effect and practical value in liquefaction potential evaluation for ocean engineering sites. 

Starting from the conservation of resources and protection of the urban environment，the development of underground space should avoid large-scale demolition and reconstruction. Therefore，the research of additional basement constructed of the urban center has great significance under the premise of retaining existing buildings. The excavation beneath the existing building will result in changes of the stresses at the pile-soil surface and reduce the bearing capacity of piles. With a case of constructing additional underground parking garage below the existing high-rise buildings on soft soil foundation，expounding the technical difficulties and the key technologies of operation processes，typical operating conditions，designing of vertical supporting structure，underpinning design of additional vertical member(wall，column) in constructing additional building basement with top-down excavation below the existing building. Furthermore，a new control technology for differential deformation of vertical members was proposed. The research results can provide references for the additional basement beneath existing high-rise building in soft soil.