In the flexible protection systems，the load applied on the cable anchor had a contain angle with the axial direction，but the axial pullout capacity was the only design principles currently which was not reflected the actual working conditions. The mechanical performance of the cable anchor with different bolt hole diameters and testing load directions were investigated. The results show that the anchor performance was improved and the displacement was decreased by increasing the bolt hole diameter or increasing the included angle between the anchor horizontal direction and the oblique load direction. In addition，the pullout capacity was enhanced with the heart-shaped ring consolidation when the pullout capacity of the cable anchor determined by the limited force. Finally，the way to design the cable anchor in the flexible protection systems was also presented.

It takes migmatitic granite of Xingshan iron mine as the object to study the failure criterion of brittle hard rock. According to the physical and mechanical parameters from laboratory experiments and grains section scanning，micro-geometric model of migmatitic granite grains were built based on particle flow theory and PFC programs，loading codes were developed and some functions were adjusted by Fish language to simulate uniaxial and triaxial( = 40 MPa) compression experiments. Based on comprehensive comparison and analysis of the complete stress-strain curves，acoustic emission and “crack” monitoring results from laboratory and simulation，the micro-mechanical characteristics and the cracks revolution laws from microcosm to macrocosm of migmatitic granite were obtained. On this condition，cohesion weakening and friction strengthening(CWFS) failure criterion model parameters of brittle hard rock were optimized and verified through laboratory curves of unixial rigid loading，relation curves between cracks and friction energy with plastic strain，and FLAC simulation. The optimized CWFS model parameters of initial cohesion，residual cohesion，initial friction angle，residual friction angle and critical plastic strain  ，  of migmatitic granite are 23 MPa，4.3 MPa，0°，46.3°，0.001 5 and 0.003 7 respectively，which is of great significance in theory and practice on the study of fracture mechanism，mechanical constitutive relations and engineering stability of rock mass during open pit mining transferring to underground mining in Xingshan iron mine.

The volume of Zhenggang large landslide accumulation body in Gushui hydropower station is up to 4.75×107 m3. Geological investigation shows that the landslide is mainly composed of bedrock，slip zone soil and unconsolidated accumulation，and that the slip zone soil layer is the transfixion slipping surface. Firstly，the history evolution process of the accumulation body and the formation mechanism of the landslide were analyzed in detail. Qualitative discrimination was made on the current situation and the future instability mode. The landslide is in the state of creep deformation along the transfixion slipping surface. Based on the analysis of basic characteristics of slip zone soil，the large-scale direct shear tests on slip zone soils in laboratory were carried out under different conditions. Not only the relations of deformation and strength and the values of shear parameters in natural state were studied respectively，but also the effects of stone and water content on shear strength were analyzed. The reasonable calculation parameters were found，and the stability analysis was conducted. The analysis results show that the values of cohesion and internal friction angle range from 30.31 to 43.94 kPa and 25.82°to 30.49°，respectively. The contents of stone and water have significant influences on shear strength. The threshold value for stone content is 75%，increasing the stone content which is less than 75% causes the increase of shear strength；However，the shear strength decreases when stone content is higher than 75%. The shear strength and values of parameters decrease with the increasing water content，with which the relations are approximate to exponential function. The stability results are consistent with the qualitative analysis，and the landslide is possibly slumped under any condition. Therefore，it is very important to choose the best economic and reasonable treatment and evaluation.

Based on the developed drainage segment lining-surrounding rock flow system，water pressure distribution law behind prefabricated drainage segment lining of a high water pressure tunnel is studied by employing indoor test as research methods. Discussion focus on water pressure distribution law behind the segment lining for different drainage schemes such as limiting discharge only，blocking groundwater-limiting discharge is conducted. Meanwhile，an attempted analysis for the effect of discharge capacity，grouting circle and discharge outlet density on water pressure behind the lining is carried out，so as to reveal the conic relationships of external water pressure discount coefficient or external water pressure and flow discharge for the whole lining and different parts of the lining. The study results can provide a reference for the design of high water pressure tunnel lining.

The discontinuity density is one of the most important parameters，which can express the distribution of rock masses discontinuities. However，the distributions of discontinuities in rock masses are random and irregular. It is impossible to obtain the true value of discontinuity density accurately in practical engineering. Based on the discontinuities data of rock mass outcrops in field investigation，two-dimensional(2D) and three-dimensional(3D) stochastic fracture network models are established by using computer simulation technology. The discontinuity density approximate value of rock masses is calculated based on mathematical statistics；and 2D and 3D distribution characteristics of discontinuity in rock mass are calculated by using fractal theory. The authors try to establish the mathematical relationship between discontinuity surface density，volume density and 2D，3D fractal dimensions. The calculation results show that discontinuity density and fractal dimension have the same change law that they increase with the increasing factual dimension. The discontinuity density increases linearly with the increasing fractal dimension of discontinuities. The volume density and 3D fractal dimension of discontinuities comprehensively reflect the spatial distribution characteristics of discontinuities in rock mass and the influence for rock mass mechanical strength parameters. The two indices are effective for engineering practice. The equivalent shear strength indices of rock masses can be calculated based on the volume density and 3D fractal dimension of discontinuities.

Equivalent construction method in statistics of coal?s pore structure was discussed；and the spatial- temporal evolution process of fluid flow was simulated at pore scale. First of all，the porous media model of coal medium was constructed using modified quartet structure generation set(QSGS) algorithm which integrates the nonlinear and anisotropic characteristics of coal?s pore structure. And then，single-phase gas flow through pores was simulated using lattice Boltzmann method. Based on the numerical simulation results，the main influential factors and the evolution pattern of coal?s permeability before fluid flow achieve equilibrium state were analyzed. The analysis results show that：(1) Permeability in porous media is dominated by the channels connected by pores with large size，but the migration in the paths connected by small pore and micropore was concentration diffusion behavior；(2) In the same spatial distribution variability pattern，there is a power law relation between porosity and permeability，but the power rate coefficient increases with the decrease of spatial variability；(3) Permeability is reduced gradually over time in porous media and the time needed before the flow reaches its stable state meets negative correlation power rate relation with porosity.

The gap in plastic zone has been proved to be one of the most effective techniques for shielding against blasting stress wave. Based on the mini-chemical explosive technique，0.125 g TNT mini-spherical explosive charges was used as the explosive source for the laboratory researches of the gap shielding against blasting stress wave on the ?1 370 mm×1 200 mm loess samples. The shielding effects of gap on blasting stress wave were studied through the analysis of theory and experimental results. The results show that：(1) The gap in plastic zone is destroyed and the principle of the gap shielding against the blasting stress wave is different from that in elastic zone. (2) The shielding factors based on the amplitudes of the particle velocities and displacements exist maximum value in the shielding zone of gap. (3) The gap in plastic zone has delay effect for the blasting stress wave. (4) The experimental results qualitatively validate the theoretical analysis of the gap shielding against the blasting stress wave.

The elementary process of establishing numerical model based on digital image processing is introduced. According to the method，the particle flow numerical models of soil and rock mixture(SRM) can be obtained directly by field digital photos. Taking SRM in a landslide near the dam of Xiluodu hydropower station for example，the numerical model is established by field photo. The micro-mechanical parameters of gravel and soil are well studied by using the particle flow code in two dimensions(PFC2D)；and micro-mechanical parameters corresponding to their macro-mechanical features are selected. The numerical simulation of direct shear test for the SRM is conducted under serious normal pressures and the results of SRM are compared with those of heterogeneous soil. The main research results can be summarized as follows：Firstly，the microparameters of soil inversely calculated by biaxial compression test is used in direct shear test to get macroparameters of soil；and these macroparameters are consistent with practice. Compared with heterogeneous soil，the initial shear stiffness of the SRM with certain content gravel is higher，and the shear displacement required for the SRM reaching to its peak shear strength is reduced. Under the assumption that the bonded strength between gravel and soil is one tenth of the soil?s，the internal friction angle of the SRM is larger，while the cohesion is lower. Compared with the fracture plane in heterogeneous soil model after direct shear tests，the cracks developed in the SRM numerical model can be divided into two parts：some are around the shear plane formed broad fractures band，the others distribute between gravel and soil. Also according to the characters of shear failure，the reason for enhancing shear performance of the SRM which contains a certain amount of gravel can be introduced qualitatively.

Based on the theory of fracture mechanics，influence law of rock strength with single fracture，a set of fracture and multiple sets of fractures under the action of temperature stress caused by the temperature field higher than room temperature field is presented quantitatively. In the view of theoretical point，starting from elasticity mechanics，using the analytical method such as equivalent load method and principle of superposition，the thermal stress expression of a single fracture is added to the structural load expression of a single expression in representative volume element(REV). The micro-fracture strength expression of intermittent fractured media，of which crack tip of rock fracture is affected by certain temperature stress，is deduced. The microscale such as fracture length and fracture direction and so on is combined effectively and organically with the macroconditions such as temperature and strength. The strength expression of fractured rock at this stage has been improved. A exploration of new idea which could demonstrate the macro-，micro-levels and consider temperature factor fully and describe rock stability comprehensively is elicited. At last，the relevant experimental results show that the formula established has high reliability.

Based on fuzzy mathematics theory，a risk analysis model was established for the influence of deep excavation construction on surrounding environment. By using this model，reasonable risk loss evaluation index，risk grade division and risk loss formula were proposed through analytical and quantitative analysis of a concrete project example. After studying the evaluation index and relative weight of building damage，pavement damage and underground pipeline damage around the deep excavation，risk analysis and assessment of the influence on surrounding environment caused by excavation of foundation pit were achieved. The analysis and assessment is conducted through the membership degree which is given from the membership function structured for each evaluation factor. Then through the comprehensive risk evaluation，risk level can be finally determined. This result based on project example can be used as a reference for engineering decision-making.

Based on the field data of two extra large-scale riverside adjacent deep foundation pits in soft soil，the mutual impact of synchronized excavation of adjacent deep foundation pits，such as deformation characteristics of retaining walls，mutual impact on the axial forces of struts and the settlement of pillars were analyzed. The results show that the deformation of the retaining wall in the adjacent central position of foundation pits tends to increase，while those in the corner and in the positions away from the adjacent location are less affected by the adjacent pits excavation. The vertical displacement at the top of the retaining wall in the adjacent area is affected by the adjacent foundation pits excavation；and the horizontal displacement at the top of the retaining wall in the adjacent area increases when the distance between the foundation pits reduces. It is also concluded that the axial force of struts tends to decrease after reaching the peaks，while the vertical displacement of pillars keeps increasing. Comparing the deformation of retaining wall and settlement outside the pits with the classical theory，the retaining walls? deformation in the adjacent area is different from that of a single one.

Based on subway station deep foundation pit project in Nanchang city，in-situ monitoring data of the retaining structure deformation in the foundation pit are analyzed. The laws of the horizontal deformation of the retaining structure changing with excavation depth and time are studied；and the influential effects of groundwater on project are introduced concisely. At the same time，the three-dimensional finite element model of the second excavation zone is established by ABAQUS to simulate excavation of deep foundation pit of subway station. Comparative analysis of calculation and monitoring results of the retaining structure shows that，based on the characteristics of watery ground，the design of retaining structure of subway station deep foundation pit is safe and reasonable in Nanchang city. Composite structure of fender piles and support can control the soil deformation effectively in deep foundation pit of subway station.

The macro and micro analyses of soft soil before foundation treatment are important to predict the effectiveness of vacuum preloading treatment. Through the laboratory macro and micro tests，the properties of soft soil from Zhuhai Jinwan area are investigated，including mineral composition，specific surface area，microstructure，pore properties before and after consolidation，etc.. The key factors are concluded which indicate vacuum preloading treatment effect，such as amount of bound water，strength index. Research result shows that clay content of soft soil from Zhuhai Jinwan area is not high，with the clay content about 50%；and specific surface area is small. The soft soil grains are curved flocculation polymer. After consolidation，microscopic structure has noticeably aggregated with compactness and no particle breaking. The micro-pore distribution is mainly between 400 and 2 500 nm. The cumulative intrusions sharply decrease after consolidation，and pores turn smaller. Therefore，the amount of bound water is not high with more free water. The change of internal friction angle is not big，and cohesion has larger growth. It shows good availability of the vacuum preloading method in soft soil from Zhuhai Jinwan area.

Excavation always induces a certain degree of ground settlement. Using separation of variable methods (SVM) to solve partial differential equations of plain strain problem，in which the movements of retaining wall are assumed as the given displacement boundary. The present theoretical solution is attempted to show the relation between the wall movement and the induced ground settlement. Firstly，the solutions to the induced ground settlement are given for two basic cases，i.e. wall translation and rotation about toe. The two other solutions to rotation about top and triangle-bugling movement can be available based on two basic solutions. The translation of wall tends to cause a spandrel-type settlement profile in which maximum surface settlement occurs at the position close to the wall back. The rotation of wall about toe causes a concave-type settlement profile，in which maximum surface settlement occurs at some position away from the wall back. The present curve of surface settlement agrees with that by the classical empirical methods. Finally，comparisons between the present method and elasto-plastic FEM and in-situ measured data in soft soils，have illustrated the validity of this analytical solution.

Some key issues including inner and outer influencing factors of trench face stability，overall and local instability mechanism of trench face，and stress path of soil element near trench face are discussed in detail to investigate the trench face stability and instability performance during slurry trenching for diaphragm wall panels. The research results show that shallow ground collapse is the major trench face overall instability pattern during slurry trenching，and trench face local collapse is commonly caused by heavily sandy of soil and excessive fluctuation of slurry flux level. Some precautionary construction measures，including increasing unit weight of slurry appropriately，raising slurry fluid level，pre-reclamation of trench face soil，control of trenching machine overloading and manipulation of soil disturbance during slurry trenching，are the most effective countermeasures to ensure the trench face stability. The trench face stability decreases with the dissipation of negative pore pressure after slurry trenching. Therefore，reinforcement cages should be placed into trench in time and concrete should be casted as soon as possible to guarantee the trench face stability.

The multipoint settlement measurement equipment in the soil based on rope measuring has been developed. It is used to measure the vertical displacement of the soil，the precision of which is higher than the commonly used measuring methods. Also it can meet the measuring requirements of single-port and multipoint and successfully be used in Kunming Yinxing Jinchuan foundation pit field measurement. The equipment of measuring multipoint settlement in the soil combines with the horizontal displacement measurement of the soil，which can achieve the displacement measurement of any point in the deep soil. The linear strain and volumetric strain are analyzed according to the actual displacement measurement of the foundation pit soil. The soil unit made vertical compression and horizontal swelling and the vertical deformation is larger than the horizontal deformation，which manifests that the area of the ground surface settlement curve is larger than that of supporting structure horizontal displacement curve in the macroscopic. 

A set of laboratory model test equipment for electrochemical reinforcement of soft soil is designed to carry out a chain of model tests，the whole physical and chemical processes of ferruginous cemented piles are reconstructed，and structural features of cement piles are clarified. The electrochemical characteristics and the main control parameters of the electrolytic reinforcement in the pile are discussed through tracking and monitoring of current，resistance and salinity of the reinforced soil. On this base，the research on the strengthen distribution law，load capacity property and water stability is made though the micro-penetration test，indoor plate loading test and disintegration test. The results show that，the ranges of ferruginous cemented piles are respectively 8 times and 12 times thickness of electrode diameter. The strength of cemented soil is inversely proportional to the diameter distance of electrode. There is strong discontinuous surface between the coral layer and the affected layer. The cemented ground load force and the deformation modulus are 10 times better than the former，and it has good water stability.

According to geological characteristics of recently sedimentary layer in Huaibei plain，such as existence of different soil and calcareous concretions，a large number of dynamic plate loading tests are carried out relying on highways under construction. The range and variation of dynamic deformation modulus   are analyzed for different soils，and distribution characteristics of   are discussed for different geological area in Huaibei plain. On this basis，relationships between the   and penetration resistance，bearing capacity of foundation are established through static cone penetration tests，screw plate tests and plate loading tests. Studies show that，dynamic plate loading test is a fast and convenient in situ test，and mechanics characteristics and regularity of foundation soil can be reflected well by ，which has good relativity with penetration resistance of   value and bearing capacity of the foundation.  can be used in highway engineering as a foundation bearing capacity determination index.

In Shenzhen area，geotechnical types are wide，geological conditions are changeful，and engineering environment is complex. These factors cause the excavation engineering support changeful and complex. The development history of excavation engineering in Shenzhen could be divided into five stages，i. e. such as primary experience，rapid development of many technologies，soil-nailing wall era，all kinds of technology rational application and deformation controlling. In the process of excavation engineering development，many new technologies are made or first used in Shenzhen，such as rotating drilling-mixing secant pile，rotating drilling secant pile，punching soil-cement secant pile，self-feed mixing anchor，high pressure jet expand head bolt，capsule type expansion body anchor，large diameter single pipe jet grouting pile，powder water pile，double-row pile，composited soil-nailing wall，inserts-anchor mixed supporting，etc.. These technologies represent the domestic advanced level. Seven typical excavation engineering examples such as Baoji Industrial Park Reconstruction etc.. have different and various style characteristics in the excavation engineering scale，depth，surrounding environment，construction process，supporting method，etc.，could stand for excavation engineering characteristics and the newest technology level in Shenzhen area.

Foundation pit excavation in the building compact district of urban will absolutely induce soil lateral movement，which may generate the additional deflections and bending moments in the adjacent pile shaft，and may lead to their superstructures distress，even failure. To avoid the drawbacks of three-dimensional numerical analysis，such as complexity modeling and time consuming，the two-stage method(TSM) is presented for determining the behavior of adjacent pile caused by foundation pit excavation. Firstly，the additional lateral displacement of soil mass due to adjacent foundation pit excavation is calculated by the virtual image technique. Secondly，the governing differential equations are built up based on Winkler model and their analytical solution of matrix is derived. Finally，analysis of case histories show that the calculated results of analytical solution are reasonable and could be used to analyze the influence of excavation on adjacent pile foundations.

Taking the deep foundation pit of open-cut tunnel in Xiamen City for example，safety monitoring is carried out on the surrounding environment as well as on supporting structure itself during the construction period. The monitoring measures for the safe construction of deep foundation pit mainly include tour check，settlement，horizontal displacement，deep displacements，underground water level，axial stress of anchor and blasting vibration，etc.. Combined with the geology condition and in-situ construction environment，the monitoring results are comprehensively analyzed on the surrounding environment as well as on supporting structure. Research results show that geology condition is the main factor that causes the difference of deformation distribution. Large displacement will appear after the creation of new free face，so the stability of the retaining pile are affected.  When the blasting excavation is applied on the deep foundation pit，the selection of design parameters are demanded to further verify their rationality. Monitoring and analysis are carried on dangerous situation such as high displacement velocity of the supporting pile，landslide and collapse of slope etc.；and the monitoring results show that emergency measures relevant to the dangerous situation are reasonable and effective.

Inner force of soil-nailing wall mainly includes axial force of nail，shear force between soil and nail，and distribution force of composite facing. The process of soil-nailing wall deformation is the process of distortion coordination and interaction of several factors among nails，composite facing and soil mass. Traditional calculation model based on moment equilibrium can not give a reasonable explanation of relationship between inner force and deformation of soil-nailing wall. Through analysis of the mechanism of force and deformation of soil-nailing wall，lateral displacement of soil mass under combination of virtual excavation stress and shear force between soil and nail by Mindlin solution is calculated，by combing with linear relationship between shear force and relative displacement with zero shear force at potential sliding plane，axial force of soil nail，shear force between soil and nail and deformation at excavation surface can be calculated. Parts beyond limited value for shear force of nail in passive area is transferred to composite facing，and its incremental force is assumed as triangle distribution. And then distribution force of composite facing is obtained according to static equilibrium. Finally，the measured data from three projects of soil-nailing wall are used to illustrate the validity of the calculation model.

Inner force of soil-nailing wall mainly includes axial force of nail，shear force between soil and nail，and distribution force of composite facing. The process of soil-nailing wall deformation is the process of distortion coordination and interaction of several factors among nails，composite facing and soil mass. Traditional calculation model based on moment equilibrium can not give a reasonable explanation of relationship between inner force and deformation of soil-nailing wall. Through analysis of the mechanism of force and deformation of soil-nailing wall，lateral displacement of soil mass under combination of virtual excavation stress and shear force between soil and nail by Mindlin solution is calculated，by combing with linear relationship between shear force and relative displacement with zero shear force at potential sliding plane，axial force of soil nail，shear force between soil and nail and deformation at excavation surface can be calculated. Parts beyond limited value for shear force of nail in passive area is transferred to composite facing，and its incremental force is assumed as triangle distribution. And then distribution force of composite facing is obtained according to static equilibrium. Finally，the measured data from three projects of soil-nailing wall are used to illustrate the validity of the calculation model.

Considering the nonlinear failure characteristics of jointed rock mass，the critical slip field method is modified based on the generalized Hoek-Brown failure criterion to calculate the bearing capacity of joined rock mass foundation. By transforming the shear strength of each point on the Hoek-Brown strength envelope into the Mohr-Coulomb linear relation，transient internal friction angle and cohesion of each point are calculated；and the critical slip field method based on the Mohr-Coulomb criterion is improved and a new iterative procedure is thus established. Using the newly developed critical slip field method based on the Hoek-Brown failure criterion，the passive earth pressure and ultimate bearing capacity of jointed rock mass foundation are computed. The effects of values of GSI and mi on ultimate bearing capacity of foundation are comprehensively analyzed. The results of comparative studies show that the proposed method can accurately determine the critical slip surfaces and associated values of ultimate bearing capacity of jointed rock mass foundation with reasonable accuracy.

Mechanical properties of soft rock materials in deep shaft are tested with experimental system of split Hopkinson pressure bar(SHPB). The experimental results indicate that the dynamic stress-strain curves of soft rock materials are of distinct plastic yield characteristics. Based on modified excess stress constitutive model，according to the function relationships of strain，strain rate and  ，to simplify constitutive equation of modified excess stress model with dimensionless analysis，the simplified constitutive equation of modified excess stress model is obtained. And then，continuum damage theory and statistical damage theory are incorporated into the simplified constitutive equation of modified excess stress model account for the influence of damage on dynamic strength of rock，so the simplified constitutive equation of damage excess stress model is established. The simplified constitutive functions are fitted out respectively on the basis of experimental data. There is a good coherence between the stress-strain curves fitted by the simplified damage excess stress constitutive model and the experimental stress-strain curves.

Due to the limitations of investigating instruments and liquefaction evaluation methods after the 1976 Tangshan earthquake，it is very useful to perform the re-investigations at liquefaction and non-liquefaction sites nowadays. The multifunctional seismic piezocone penetration test(SCPTu) method was used for this work. The nearly continuous profiles of tip resistance，sleeve friction，pore water pressure，and shear wave velocity were obtained. The liquefaction potential of testing sites was evaluated by comparing the SCPTu measurements，the indoor experiments and historical investigation data. Several popular CPTu-based liquefaction evaluation methods at home and abroad were analyzed particularly. Results from Chinese Standard method，Robertson deterministic method and Moss probabilistic method indicate that most of the testing sites that liquefied during the 1976 Tangshan earthquake will liquefy again. The CPTu-based Robertson deterministic method and the Moss probabilistic method based on Bayesian theory show respective advantages and disadvantages. Both of them have reasonably comprehensive calculation procedures. The Robertson deterministic method has special advantage in predicting vertical settlement and lateral large deformation，while the Moss probabilistic method can present the liquefaction probability for every site and serve for the seismic evaluation and engineering design. However，due to the slow development of SCPTu technique in China，kinds of current international CPTu-based liquefaction evaluation methods are seldom used，which require further study after technology have been breakthrough in future.

Referring to the concept of coordination number in crystallography and mineralogical science and powder material science and engineering，based on the formulas of Smith，Fisher and Young-Laplace，the corresponding relationship between macro variables such as water content，dry density，void ratio and micro variables such as saturation angle，volume between two soil particles，the quantitative calculation formula of matric suction is deduced. Calculation results show that：(1) Matric suction of unsaturated soil decreases with the increasing water content nonlinearly. (2) There is a linear correlation between matric suction and dry density，as well as void ratio. Matric suction increases with the increasing dry density at low water content while keeps no changes at high water content. The calculation result matches existing experimental results.

Based on analysis of high-steep slope at Jiangping River hydropower project，the block overturning analysis method is used to determine the potential damage zone under seismic loading，and then wave propagation equation and boundary condition equation are derived. The collapse disaster of high-steep slope is studied according to two-dimensional granular flow method. The results show that the stability of slope can be determined by particle trajectories with the collapse hazard analysis of granular discrete element method. Then the path of destruction can be studied. By modifying the properties of boundary particles，the incident seismic wave and transmitting boundary condition can be simulated，so it will maximally simulate the coupling process of loading，rock properties and the development of disaster. It also shows that the development of longitudinal unloading fissures whose dip angle is approximately equal to slope free surface is the controlling factor to the stability of high-steep slope under seismic loads，and local collapse and block instability may occur on the superficial slope. The process of collapse starts from the partial avalanche of surface rock mass when an earthquake occurs，then it extends rapidly along the fissures until it gets up to the upper rock under high-intensity earthquake. The scale of collapse is mainly decided by the depth of development of fissures. Therefore，the proposed method can provide a theoretical basis for the stability study of high-steep slope as well as the disaster prediction.

Reasonably describing creep law of coastal soft soil is very important for the long-term stability and running safety of buildings in soft soil area. By the unidirectional oedometer and improved direct shear creep apparatus，the creep tests in different loading methods are conducted. The relationships of stress，strain and time are got，the structural effect and influencing factor of creep character are also analyzed，and the relevant creep model is established. The test result indicates that the soft soil in littoral area of Tianjin has obvious nonlinear creep character and the creep evolutional characteristics are influenced by the structure. At low stress level，the creep deformation is very small，and there is an obvious transition in  curve of consolidation test. At high stress level，creep rate and creep deformation are high enough. When the pre-consolidation is carried out，the creep deformation turns low and the boundary of primary consolidation and secondary consolidation is influenced. The modified logarithm function can describe the transient elastic strain，attenuation creep and steady creep of soft soil in littoral area of Tianjin. The shear creep deformation assumes double line at low stress level and linear at high stress level. Shear modulus decreases over time and increases-before-decreases with the increasing stress，coefficient of viscosity increases over time and with the increasing stress.

The difference and connection between blastability classification and zoning of the blasting compliance are discussed. According to the need of blasting operation in production，the factors affecting the result of blasting operation were analyzed；liner correlation was made on the data obtained from tests of physico-mechanical properties and joint geometric parameters of 15 types of rocks. The study results show that tensile strength，compression strength，density and average distance of joint could be used to appraise zoning of the blasting compliance of rocks. An appraisement system for zoning of blasting compliance of rocks based on weighted clustering analysis was established. At the same time，the method of decide weight comprehensively is adopted to solve the flaws in determining the weights of decide weight objectivity and subjectivity. This application of zoning of the blasting compliance of rocks to Baiyunebo west iron mine shows that this method is scientific，reasonable and practical.

On the basis of quasi-static theory of Mononobe-Okabe，the angle of sliding surface is obtained according to the static equilibrium after analyzing the stress of the filling behind retaining wall. Considering soil arching effect，the static equilibrium and moment equilibrium equations are then derived from analysis of the stress of microelement of filling layer which is in a normal stress state，using the method of horizontal layer analysis. After that，the formulas of active earth pressure，coefficient of earth pressure and action point of resultant force of filling behind the retaining wall under seismic activity，which are more usable，are respectively obtained. The influences of internal friction angle，wall friction angle，horizontal and vertical seismic coefficients on the angle of sliding surface，active earth pressure，coefficient of earth pressure and action point of resultant force are numerically analyzed. Furthermore，the results obtained by the proposed method are compared with those computed by other methods and experimental observation.

Joint surface morphology is one of the most important factors for peak shear strength of jointed rock. Artificial joints are used for direct shear tests under five levels of normal stresses，i. e. 0.5，1.0，1.5，2.0，3.0 MPa，to study the relationship between 3D morphology parameters and peak shear strength. Effective joint surface 3D mean angle  ，surface roughness coefficient   and the maximum possible contact area ratio are selected to describe the joint roughness. Scanning joint surface after each direct shear tests by TJXW–3D topography scanner and the above selective morphology parameters are calculated. A new peak shear dilation angle model is proposed with relationship to 3D morphology parameters of  ， ， . Then，a new strength criterion with three morphology parameters is suggested for modeling the peak shear strength of rock joints. A comparison between the proposed models and the experimental results show a relatively good agreement. At last，the calculated results by the new criterion is compared to the well-known Barton?s criterion. It is shown that Barton?s criterion underestimates the observed peak strength.

Particle size and flow rate play an important role in particle transportation and deposition in porous media. Different suspended particles were studied under different flow rates in soil columns tests，and the corresponding breakthrough curves were analyzed. The effects of particle shape and chemical factors on test results were excluded from the tests. Test results show that the peak concentration of effluent increases and the quantity of deposition particle decreases with the increasing flow rate for the same particle size. However，the deposition particle decreases with the increasing flow rate. There exists a critical flow rate of 0.173 cm/s，and the effect of flow rate on particle transportation can be negligible when the flow rate is larger than the critical value. On the other hand，the peak concentration of effluent decreases and deposition increases with the increasing particle size for the same flow rate. Furthermore，the effect of particle size on particle straining is obvious at low flow rate.

The number of geotechnical samples is usually limited in engineering practice. Evaluating the influence of sample number on slope reliability analysis so as to ensure the reliability of analysis results is of great importance. Considering unconsolidated-undrained shear strength of slope，the influence of the number of geotechnical samples on slope reliability is analyzed by two ways：(1) Assuming that the variability of parameters is known and statistical uncertainty is considered in slope reliability analysis. (2) A simple method for simulating geotechnical sampling and testing of actual slope is presented. Slope reliability is computed based on different numbers sampling results，and the frequency distribution of failure probability of slope is obtained，so as to determine the required number of geotechnical samples. The analysis results by the two methods show that when the parameter variability is large，a small number of samples is required；and when the parameter variability is small，large number of samples is required，which differs from the results by classical probabilistic methods. Results from the second method also show that：from the view of practical slope design，the required number of samples for the undrained strength with common coefficient of variation ranging from 0.2 to 0.5，is generally between 10 and 15.

Laboratory experiments and field fracturing practices have shown that complex radial fracture-network extended system is easily formed in the area around borehole due to the effect of natural fractures during fracturing of fractured reservoirs，which greatly differs from the single，bi-wing，symmetric planar fracture generated in the homogeneous reservoirs. As the forming of radial fracture-network is mainly controlled by the initiation and propagation of hydraulic fracture at the beginning stage of hydraulic fracturing，studying the initiation mechanism of hydraulic fracture for fractured formations is the prerequisite for understanding the forming of radial fracture-network. Based on the theories of elastic mechanics and rock mechanics，taking account of the spatial relation of natural fractures and perforations under intersection，and integrating with the criterion of tensile initiation，the calculating model of initiation pressure in which the hydraulic fracture is tensile initiation along natural fractures is established. The calculation results show that the deeper position of natural fractures intersecting with perforation is，the lower the tensile initiation pressure is. Tensile initiation pressure in the position where natural fractures intersect the top of perforation is the minimum value. The difference of tensile initiation pressure may sharply decreases from perforations in different azimuths around borehole due to the effect of natural fractures and geostress azimuth，which leads to the extending of hydraulic fracture simultaneously from perforations in different azimuths and forms radial fracture-network. The example calculation results indicate that this calculating model can obtain high calculating accuracy and reliable calculating results，and can be used to calculate initiation pressure of fractured formations and analyze the probability of radial fracture-network propagation during fracture-network fracturing.

The plastic-flow and tensile crack-type collapse or soft foundation-type collapse are very common in Southwest mountain region and Three Gorges reservoir area in China. These types of collapse occur frequently when weak layer distributes under the perilous rock mass. Suffering from the influence of gravity，water softening，long-term weathering and spalling，the weak layer will generate horizontal plastic flow towards free face. Meanwhile，the hard rock will generate tensile cracks. At last，perilous rock mass will generate uneven deformation in a weak layer. The deformation and failure processes of numerical simulation by discrete element method(DEM) are mudstone weathering and sheet-like peeling，hard rock falling，weak pedestal squeezing out，tension crack opening，deformation increasing and collapse occurring. According to two different failure modes of perilous rock mass caused by inhomogeneous deformation of weak layer，the computing formula of stability coefficient of plastic flow and tensile crack-type collapse is deduced by means of the method of geomechanics. Taking a typical rock slope in Wanzhou area of the Three Gorges area for example，the serious contrast and analysis of ratio of compressive strength to compressive stress and stability analysis of inhomogeneous deformation of weak layer are conducted. The results show that under static condition，the perilous rock mass is stable in a short term，on the contrary，it is unstable under high seismic intensity conditions.

Results of geostress measured respectively in 2003，2008 and 2010 in four boreholes located in Baoxing County and Kangding district in Sichuan Province，together with seismic geological data，were used to study the geostress state and seismic risk in Southern segment of Longmenshan fracture belt after Wenchuan Ms 8.0 earthquake. The study results show that the present stress conditions do not appear to be totally relieved after the region tectonic stress field adjustment caused by Wenchuan earthquake，and the adjustment tendency of geostress is accumulated after Wenchuan earthquake in this region. Primary analysis reflects that the maximum horizontal principal stress values have reached the lower limit of fault activity in the Southwest segment of Longmenshan fracture belt. The fault has been in critical state and will probably slip in the way of reverse fault in the future. Based on the measured geostress state and earthquake migration data，there is a potential seismic risk in the Southwest segment of Longmenshan fracture belt. It is suggested that more attention should be paid to this region. The research results have great significance for mobility analysis of fracture，long-term monitoring of geostresses and disaster prevention and mitigation in the Southwest segment of Longmenshan fracture belt.

In shield-driven tunnel，too large support pressure may lead to the upheaval of ground surface，even blow-out failure of tunnel face. In order to reveal the mechanism of blow-out failure and to obtain the limit supporting force，based on Mohr-Coulomb model，the blow-out failure of shield tunnels in sand is simulated using ABAQUS. Accordingly，the prism part of three-dimensional wedge model，which is based on limit equilibrium method，is modified to an inverted truncated pyramid，which is consistent with the actual upheaval zone better. The formulas of limit supporting force with regard to the angle of wedge   are deduced. The minimum value，which is obtained by trial calculation，is the limit supporting force. The results obtained from the modified limit equilibrium model are well consistent with the numerical simulations results，and just fall in upper and lower bound solutions calculated by E. Leca et al. The model will provide reference for determining the upper value of supporting force of shield tunnels in sand.

Dongshankou station of Guangzhou metro line #6 is constructed by expanding shield driven tunnel. The ground building?s piles are in the strata of high moisture content and void ratio，so the new station construction is easy to cause large surface settlement. Taking into account the influence of construction on the groundwater level，the application effect of in-situ deformation control measure is predicted by numerical simulation method，which is compared with the measurement data. The results show that：(1) The ratio of water loss settlement to expanding excavation settlement is 2∶3. (2) Settlement during upper-bench excavation is large，and there is little difference between two-step and four-step excavation scheme. The maximum surface settlement of shield tunnel expanding method accounts for 65% of CRD construction method. (3) the advance pre-support in the arch increases the width of the settlement trough and decreases the surface settlement and inclination. The axis deviation scheme of shield machine reduces the area of plastic zone，making the effect of the advance pre-support more obvious.

Excess pore pressure and post-construction consolidation settlement of soil above tunnel axis caused by shield tunneling were studied. A calculation method for stress release rate caused by shield tunneling was put forward. Based on the Henkel pore water pressure theory，the excess pore water pressure of soil adjacent to the tunnel lining was deduced. Supposing that the points around the lining have the same stress release rate，the calculating method for excess pore water pressure of soil at tunnel arch crown was obtained. Using the theory of stress transfer，the distribution mode of excess pore water pressure above the tunnel axis was proposed. Assuming that the thickness of compressed soil equals that of the soil above tunnel，the theoretical calculation formula for consolidation settlement of ground above the tunnel axis was suggested based on Terzaghi?s one-dimensional consolidation theory. The results of case study show that the calculated results are in good agreement with the measured data.

During slurry shield tunnelling in silty sands during construction of Hangzhou Canal Tunnel，the cutter head of shield was trapped by sand adhesion. Due to the additional torque imposed by adherent sands，the cutter head stopped to rotate. The reasons for trap of shield?s cutter head were analyzed，and the measures taken to relieve the cutter head were described. Based on experiences and lessons learned from this case study，measures to avoid trap of slurry shield?s cutter head by adhesion of sands in silty sands were presented. In order to relieve the trapped cutter head，a pit was excavated at the front ground，and then high-pressure water jetting was used to clear sands adhered to the cutter head. Practice shows that the measures taken in this case were safe and effective for relieving the trapped shield?s cutter head. Attention should be paid to ensure the safety of surrounding environments，especially the completed tunnel nearby when the pit is excavated. To avoid the cutter head of slurry shield being trapped by sands while tunnelling in silty sands，unobstructed and continuous slurry circulation should be maintained，high-quality slurry should be guaranteed to balance the excavating face，the ability to sweep away sands should be enhanced，and the cutter head should be rotated at set intervals when the shield stops to assemble the segmental linings.

Ground settlement induced by subway tunneling is becoming one of the main causes of ground subsidence. It strongly affects the serviceability of superstructures and pipelines around the subway tunnel. Therefore，it is very important to predict the settlement accurately. Numerical simulation was conducted to investigate the influence of grouting pressure and working face thrust force on the ground settlement caused by tunneling. The grouting pressure and working face thrust force were normalized using the gravity of the overburden soil and the lateral static earth pressure，respectively. Based on the equivalent ground loss method proposed by K. M. Lee et al.，procedures considering the construction effect during shield tunneling were put forward to estimate the ground settlement. Comparison numerical and calculated results demonstrates the effectiveness of the proposed method.

During the actual construction process of subway tunnel，the surrounding rock is in a complex process of loading and unloading. Meanwhile，the excavation and support are completed in multiple steps. During this process，the previous excavation step will influence the subsequent excavation. Based on the characteristics of underground engineering，that is，loads are applied first，then excavation is conducted，and supports are provided at last，the actual construction process of subway tunnel under excavation unloading effect was described and simulated. The excavation unloading effect during the process of subway tunnel construction was analyzed in detail；and the 4-stage simulation method was put forward，which can simulate the excavation unloading effect during the construction process of subway tunnel. Taking the tunnel in Xisanqi—Qinghe section of Beijing metro line No.8 as engineering background，the actual process of shield construction of subway tunnel and the excavation unloading effect were simulated. The effects of excavation face supporting pressure，supporting time and filled grouting on excavation and support of metro tunnel were studied，with and without consideration of the excavation unloading effect. The surrounding rock-support working mechanism of metro shield tunnel was obtained based on the excavation unloading effect.

Based on the shear mechanical properties of structural plane under condition of constant normal stiffness，the load transfer mechanism of rock-socketed pile was studied. Considering the bond strength of pile-rock interface，a complete shear mechanism of pile-rock interface of rock-socketed pile was proposed，including bond damage，sliding dilatancy and shear slipping. According to the mechanical properties of pile-rock interface in different shear stages，complete shear constitutive equations for pile-rock interface were put forward. On the basis of shear mechanical properties of pile-rock interface，the enhanced effect of skin friction was analyzed theoretically. The results show that the enhanced effect occurs at the whole pile side and is the most distinct in the vicinity of pile tip. Considering the enhanced effect of skin friction，the theoretical formula for vertical bearing capacity of rock-socketed pile was proposed，which is obviously different from the traditional method suggested by specifications. Comparative analysis of case study shows that the vertical bearing capacity calculated by the proposed method is much closer to the field static load test result than the value calculated by the specifications. It provides a new procedure for design and application of rock-socketed piles.

Wave barrier has been widely employed in engineering as an effective way to harness vibration pollution. Studies on vibration isolation using barrier are mainly based on elastic half-space soil at present，and little attention is paid to the vibration isolation in layered foundation in accordance with reality. The semi- analytical boundary element method(BEM) with the basic solution of thin layered method(TLM) using orthogonal coordinates and the second shape function was employed to investigate the isolation effect of passive wave barriers in layered foundation. The numerical results indicate that：(1) Based on the numerical study of a upper-soft lower-hard foundation，the normalized depth of piles in row as passive vibration isolation is about 2.5 for providing satisfying vibration isolation effect，which is greater than that in homogeneous ground(1.0)；(2) The normalized depth of piles in row is about 2.0 for a upper-hard lower-soft foundation；(3) If the ratio of shear modulus of pile to that of topsoil，G* meets the requirement of 5≤G*≤30，the vibration isolation effect obviously increases with G*.

According to weak regions of rigid pile composite foundation and piled embankments with bearing stratum penetration，the reinforcement of weak regions by using stretching net，rigid grid and additional pile of rigid gird-pile composite foundation was analyzed. The changing characteristics of force and deformation of rigid grid-pile composite foundation with and without bearing stratum penetration were investigated under different pile lengths；and the feasibility whether the rigid grid-pile composite foundation is applicable to the case without bearing stratum penetration was evaluated. The results show that，without bearing stratum penetration，the bending moment and shear force of most side piles are large，and their distribution regions would increase along the direction of embankment center when the pile length decreases. When the pile length increases，the load ratio of most piles increases，and the bending moment and shear force of side pile，embankment settlement and vertical deformation outside the embankment decrease. By increasing the pile length，applying PTC pile to enlarging the  cross-section of central pile，and decreasing the additional pile?s diameter，the rigid grid-pile composite foundation can be optimized and be applicable to the case of bearing stratum penetration.

At present，few in-situ experiments have been conducted on thin-wall tubular piles about load transfer properties，and few studies have been reported about thin-wall tubular piles in tidal soil foundation treatment. Hence，based on the region #1 of the first-period peninsula in Wenzhou tidal land，in-situ static load tests were performed on thin-wall tubular piles. According to test data，load transfer properties were analyzed. The results indicate that about 75% of the load at pile head is shared by the outer frictional resistance，and the long piles work as end-bearing frictional piles under the maximum load while the short piles work as pure frictional piles. In order to increase bearing capacity，thin-wall tubular pile can be lengthened and widened appropriately. Industrial workshops within 5 floors can be built in this area. The axial force decreases with the increasing depth，and the outer frictional resistances of upper and lower soils work asynchronously. With the increase of load，side resistance softening happens when the frictional resistance of upper soil is up to the ultimate value. The inner frictional resistance is generated from the end of pile and it is about 20%–25% of the outer frictional resistance. When the thin-wall tubular piles are applied to reinforcement of tidal soil foundation，the contribution of inner frictional resistance of soil to bearing capacity should be taken into account.

The cause of laterite overlying carbonate rocks has not been resolved and became the key problem for the restriction to further study of laterite，karst etc subject area. It is an important problem to be solved for the not objective scientific research results. Related academic circles in carbonate rocks on the overlaying laterite causes appeared in the process of cognition is discussed，the main problems is reviewed，a new perspective and established carbonate on the overlaying the formation of the laterite model is proposed. The model can not only system science to explain China science for a long time not solved many of the red clay and carbonate complex relations between and objective reasonably explain nature carbonate on the overlaying laterite forming the real reason. The research result has important guiding significance to laterite and karst.

The vibro-replacement stone pile can form composite foundation by replacing and squeezing the soft foundation. It can increase the soil deformation modulus and bearing capacity，improve the soil inhomogenity，reduce uneven settlement of foundation，and effectively prevent earthquake liquefaction of foundation. Although this method has been widely used，it is generally applied in small range and shallow depth. By using high-power equipment and taking corresponding engineering measures，foundation treatment can be carried out in large range and great depth with vibro-replacement stone effectively under complex condition of engineering geology. The problems of sand liquefaction，bearing capacity and shear strength of foundation can be solved effectively.