The damage caused by TBM excavation is slighter than that by drilling and blasting method. The hollow inclusion stress gauge near the excavation profile cannot be easily damaged. So the hollow inclusion stress gauge can be embedded in designed position of surrounding rock in advance to monitor the stress evolution during TBM driving. Firstly，in order to analyze the tunnel face effect and crack initiation strength of surrounding rock，and confirm the ranges of relaxation zone and damage zone，the stress redistribution after tunnel excavation is calculated by numerical method. Due to the above research results，the embedded position and monitoring start time are both ensured. Secondly，the hollow inclusion stress gauges are installed by drilling from test tunnel to TBM driving tunnel and embedded in relaxation zone and damage zone of the tunnel separately；and the entire process of stress from start changing to be stable is also monitored. The monitoring results affirm the existence of tunnel face effect and show that the stress begins to vary from the one time of tunnel diameter of anterior tunnel face. The region of half of tunnel diameter of posterior tunnel face is the most violent stress redistribution area. The damage zone scope is analyzed through crack propagation sensitivity by hollow inclusion stress gauge. The crack initiation strength of surrounding rock is verified by the monitoring results which well meet the numerical calculation results. The research results can provide references for confirming damage zone scope and crack initiation strength of rock mass. The results can also provide scientific basis for supporting design and selection of supporting time.

Except the impact of soft soil，the main influencing factor of land subsidence is the long-term over- exploitation of groundwater along Beijing—Shanghai High-speed Railway(BSHR). Combining with the results of DInSAR and precise ground leveling，taking the land subsidence anomalous area(caused by deep-well pumping in a thermal plant) in Yangliuqing town，Xiqing district of Tianjin for example，through the analysis of geological structure and hydrogeological conditions of the pumping wells region，the hydrogeological conceptual model is established；and the numerical simulation research on groundwater level variation caused by groundwater exploitation is carried out with Visual Modflow software. Based on the research above，according to the correlation between land subsidence and groundwater level variation，the land subsidence under different groundwater exploitation amounts and different exploitation times are calculated；and the land subsidence amplitude and velocity under BSHR are predicted. The countermeasures can be put forward for the safety of high-speed railway according to the research.

The highly seismic region of Wenchuan earthquake locates in the Longmeng mountainous area，due to the landform condition of deep valleys，the earthquake induced a large numbers of landslide and collapse disasters. The disasters caused serious damage to the roads along the river valley. After the earthquake，site investigation on earthquake-induced landslide and collapse had been conducted along the highway with a total length about 6 056 km. According to geologic tectonics and seismic intensity，the studied area is divided into different sections. In this paper，the seismic landslide and collapse characteristics of each section is summarized and their relationship with the tectonic position，seismic intensity and lithology，the density and average scale of the geological hazards are calculated. According the density and the scale，the whole area is divided into five subareas，i. e. the strongest-developed area，the stronger-developed area，the strong-developed area，the medium-developed area and the less-developed area. The development rules of the earthquake-induced landslide and collapse are shown as follows：(1) Three deep fault zones controlled the distribution of hazards. The Dujiangyan—Zhuyuanba section of the front fault is the clear boundary of less-developed area of the footwall and medium- and strong-developed areas of the hanging wall；but there is not clear boundary at the NE direction of Zhuyuanba. There are significant differences on the two sides of the central fault from Yingxiu to Donghekou. The two strongest-developed areas are all on the hanging wall and strictly limited by the back fault and lithologic boundary；but the boundaries is not clear at the NE direction of Dongkehou. The Maoxian—Wenchuan fault，which is one of the back fault，is the clear boundary of the strongest-developed area and stronger-developed area. The Qingchuan—Pingwu fault，which is one of the back fault，shows a clear effect of hanging wall at the Qingchuan to Shazhou section. (2) There are significant differences among different lithologies. The hazards with the highest density and average largest scale occur in intrusive rocks and hard sedimentary rocks like limestone and dolomite，while those with the lowest density and smallest scale occur in phyllite. Sandy slate and petroclastic rock are in the middle level. (3) There are significant differences among different landforms. The steeper and greater the relative altitude of salley slope is，more developed the disasters are. The positions of steep slope and hard rock are the high incidence area of seismic landslide and collapse；and the failure position of slopes mainly distribute on the upside of slopes，near the point of gradient change. (4) The statistical results of 399 geological sections show the slope gradients of collapse are larger than 40°. (5) Under dynamic conditions，the slope structures have important controlling effect on the development of geological hazards. Generally，soil slopes，strong-weathered rock slopes and slopes with outward-inclined discontinuities are easier to failure.

The simulation test for the integral lining specimens of railway tunnel by means of non-contact ground penetrating radar(GPR) detection is performed. The influences of different detection distances(the distance from the bottom of GPR antenna to the lining specimen surface) on the image quality and detection accuracy of GPR scans are studied. The test results show that：(1) The non-contact GPR detection on the integral lining can be performed by means of 400 MHz ground-coupled antenna with 10 or 20 cm detection distance. (2) With the increasing detection distance，the image quality of GPR scans decreases，and satisfactory images can be obtained if some measures such as using digital filtering and adjusting gain coefficient on GPR back wave are adopted. GPR image quality and equipment have particular concern，so the appropriate detection distance should be chosen through experiments before detecting in actual projects. (3) In the GPR scans，a variety of preset work conditions can be identified in the experimental design. The location and range of uncompacted backfill，cavity behind the lining，etc. are similar to those obtained when the antenna closes up to the lining specimen surface；and GPR scans can be interpreted qualitatively. (4) The deviation of test results of lining thickness increases with the increasing detection distance. However，apart from a few measuring points having larger deviation，the deviation range of other measuring points is similar to that obtained when the antenna closes up to the lining specimen surface，which can ensure the accuracy of lining thickness. The non-contact detection values after amendment can be consistent with the contact detection values. The deviation ranges of uncompacted backfill and cavity thicknesses behind the lining agree with those when the antenna closes up to the lining specimen surface. The study will be practical value for the development of the vehicle-system GPR detection and the application of non-contact GPR detection technology in actual project.

To study the progressive failure of schistose rock，three stress thresholds，i.e. crack initiation stress  ，crack damage stress   and uniaxial compression peak strength  ，and their relationship between each other are summarized and discussed systematically. Based on the uniaxial compression axial stress-axial/radial strain curves of Danba quartz mica schist，analysis of stress thresholds of schistose rock in progressive failure process are firstly applied to schistose rock. Stress thresholds under the three conditions of schistose foliation oriented perpendicular，parallel，and at 30° to loading direction respectively are obtained，which are compared with those of other sorts of rock in references. Results show that the crack propagation are related to rock type. Grain size of mineral，cement bond quality between mineral grains and schistose and joint plane development are all the factors to influence the progressive failure process of rock. Different stress threshold ranges of different types of rock are then got accordingly. Experimental research results of quartz mica schist indicate that due to the joint plane developments，strong anisotropy exists in the schistose rock crack propagation under uniaxial compression. This distinguishing characteristics should be considered quantitatively during underground excavation and support design.

According to the geological conditions，field test，numerical analysis and the entire process of supporting design and construction of tunnels in Jinping II hydropower station，a classification method for failure modes of surrounding rock of deep tunnel in hard rock is established. All of failure phenomena are divided into 3 categories and 9 typical failure modes by the proposed method respectively based on demands of supporting and controlling factors. Furthermore，failure mechanisms and manifestations are analyzed；and controlling measures are provided. Specially，the mechanisms and corresponding controlling measures of rockbursts are discussed. The classification method is applied to identify and analyze various kinds of failure modes，all of which are revealed during excavation of tunnels in Jinping II hydropower station. The recommended controlling measures are adopted referring to the failure modes. The engineering practice indicates that the classification method is comprehensive and practical，which provides an effective way for on-site designers，geologists and constructors to optimize excavation and supporting design of deep tunnel in hard rock.

Pre-reinforcement technology of tunnel face bolt is studied through large-scale similarity model test. A series of forepoling pre-reinforcement model tests around the tunnel as auxiliary contrast analysis are conducted to confirm the characteristics and mechanism of tunnel face bolt. By analyzing the model test results and stress field characteristics，the conclusions can be drawn as follows：(1) It is verified that tunnel face bolt improves the stability of the surrounding rock，relying on longitudinal arching effect by means of load transferring and distributing. In addition，the extent of longitudinal pressure arch for the case of face bolt reinforced is less than that of the case of non-reinforced tunnel and small pipe reinforced；(2) The excellent control effects of surrounding rock stress in front of tunnel face in horizontal and vertical directions by tunnel face bolt are the basic premise of forming effective longitudinal bearing arch. So the longitudinal pressure arch possesses great ultimate bearing capacity. (3) The tunnel face bolt can effectively control the extrusion deformation of tunnel face. The study results have important engineering significance for the construction of tunnel with weak surrounding rock.

Simulated rock joint samples with different first-order and second-order asperity heights are casted by high strength gypsum material. A series of CNL(constant normal load) shear tests are carried out to study the shear strength characteristics of joints with different first-order and second-order asperity heights under different normal stresses. The influences of first-order and second-order asperity heights and normal stress on shear strength are analyzed. Based on the experimental results，it can be found that the joint samples with second-order asperity have multi-peak shear stresses，while the joint samples only with first-order asperity have not apparent peak shear stress. The shear strength increases with the increasing first-order and second-order asperity heights and normal stress. With the increasing ratio of second-order asperity height to first-order asperity height，shear strength first increases and then decreases. Finally，an empirical formula is proposed by regression analysis of experimental data to predict the shear strength. The formula can reflect the influences of first-order and second-order asperity heights and normal stress on shear strength.

Aiming at the deformation and failure of slope rock mass and supporting structure under extreme ice-snow conditions in south China，an indoor model test of rock-shotcrete layer structure is put forward to conclude the deformation laws under freezing-thawing cycles. Sandstone-concrete integration sample is placed in the self-developed high-low temperature environmental test chamber. Static strain testing system and fiber bragg grating(FBG) testing method are used to synchronously monitor the strain of sample. Deformations and deformation reasons of sandstone，concrete，sandstone-concrete cementation face under freezing-thawing cycles are analyzed. The strain data on rock surface show that principal strain increases when the temperature dropped below 0 ℃ and decreases with the increasing temperature. The strain data on concrete surface show that principal strain increases with the increasing temperature and decreases with the decreasing temperature. The two monitoring methods both show that the strain data on cementation plane are the combined action of rock and concrete. Based on the coincident data，the fitting relationship formula of maximum strain and freezing-thawing cycles are formulated. The mechanisms of freezing-thawing damage of sandstone，concrete and cementation plane between rock and concrete are concluded.

Applied with self-developed three-dimensional interface test apparatus，three-dimensional monotonic and cyclic shear mechanical behaviors of ideal spherical granular media-steel plate interface are investigated，which is direct proof and of great significance to its numerical simulation using discrete element method. The test results indicate that the mechanical behavior of ideal interface is very different from that of actual coarse grained soil-structure interface. Ideal interface also presents obvious shear volumetric change，which can be divided into irreversible and reversible components during cyclic shearing. The irreversible component is mainly yielded by particle rearrangement and void reduction. The reversible component is induced by particle climbing or even rolling；and shear path has an obvious influence on reversible component. The hardening behavior of ideal interface due to cyclic shear application is not so apparent as actual gravel-structure interface for little particle crushing. The shear stress-shear displacement relation curves present obvious nonlinearity and the curve patterns are also influenced by shear path. The relationship between shear strength and normal stress of interface can be described with Mohr-Coulomb criterion，in which the friction angle of the interface ?i is approximately 20.2°，which is smaller than internal friction angle of granular media. Shear path has a notable influence on cyclic history curve patterns of principal shear stress ratio of ideal interface，while it has a little influence on peak value of principal shear stress ratio.

Due to affect of many factors，cracks might appear on the top surface of slope along river. The slope would become more and more unstable under hydraulic situation so as to lead to slope instability. Therefore，it is of great significance to study the stability of slope with crack near river under hydraulic situation. Based on methods of linear sliding surface，circular sliding surface and a new method of searching for sliding surface，the stabilities of slopes with crack near river are analyzed. In consideration of seepage，flow nets are reasonably simplified；and soil mass and soil skeleton are taken as research object respectively or method of equivalent bulk density are used to analyze the force of sliding mass. When sliding surface is linear，formulae for calculating safety factor are derived in slopes with shapes of broken lines and steps. The influences of water levels outside slope or in crack on stability of slope are studied respectively by case study. Some conclusions are drawn as follows：(1) According to the calculation results，the minimum safety factors got by method of linear sliding surface are the largest；and values got by a new method of searching for sliding surface are close to，but smaller than those got by method of circular sliding surface. (2) When the type of method of searching for sliding surface is same，the research results obtained by taking soil mass and soil skeleton as research object are consistent. The research results obtained by taking soil skeleton as research object and using method of equivalent bulk density are equivalent. (3) When the water level outside slope is at or below a certain height，all different types of methods of searching for sliding surface show that slope would be unstable. (4) The minimum safety factors got by different types of methods of searching for sliding surface gradually decrease with increasing water level in crack，which indicate that the higher the water level in crack is，more unstable the slope is.

Using the self-developed triaxial servo-controlled seepage equipment for thermo-fluid-solid coupling of coal containing methane，permeability of coal sample under different effective stresses，different gas pressures and different temperature conditions is determined；and the relationship between permeability and temperature under different effective stresses and different gas pressures is concluded. Based on the experiments，in order to eliminate the deviation due to individual difference，a temperature sensitivity coefficient which can objectively reflect the influence of temperature on the permeability of coal samples is proposed. And then the relationship between temperature and effect of temperature on permeability is also studied. The experimental results are shown as follows：(1) When effective stress and gas pressure keep constant，permeability and temperature sensitivity coefficient both decrease with the increasing temperature，which indicates that the higher the temperature is，the less the effect of temperature on permeability is. (2) If the temperature is same，the larger the effective stress and gas pressure are，the lower the temperature sensitivity coefficient is and the less the effect of temperature on permeability is.

Soil-rock mixtures are seen as the macro-density and equivalent homogeneous medium constituted by soil and rock under random distribution；and the explosion effect of deep explosion source is replaced by equivalent impact load. The platform of continuum media mechanics of discrete element method(CDEM) is used；and the uniform random technique is adopted. By studying the impact of internal structural properties of soil-rock mixtures on stress wave propagation process，the relationships between internal structural properties(including percentage of rock，feature size of rock block and distribution of soil-rock) and wave responses are established. The study results show that in certain of the same loading and material properties，the maximum amplitude and dominant frequency of acceleration wave have regular changes under the effect of percentage of rock and feature size of rock block. Under the uniform distribution，the impact of different distributions of soil-rock on wave response is very small and can be neglected. The fitting surfaces of wave response(maximum amplitude and dominant frequency) with the variations of percentage of rock and feature size of rock block are given；and the maximum amplitude and dominant frequency both meet the testability of actual project. Taking an assigned wave response for example，percentage of rock and feature size of rock block are given easily on the fitting impact surface by means of the assigned maximum amplitude and dominant frequency. The feasibility of wave method for detecting structural properties of soil-rock mixtures is illustrated from three aspects of regularity，testability and handleability.

By using the hydraulic and servo-controlled pressure testing machine and the split Hopkinson pressure bar(SHPB) testing apparatus of 100 mm in diameter，which is improved by pulse shaping technique，the experimental tests of sericite-quartz schist and sandstone with strain rate varying from 50–160 s－1 under shock compression loading are carried out to study the quasi-static mechanical properties and relationship among wavy curves，dynamic compressive strength，specific energy absorption and strain rate effect of fracture forms of the two rocks. The experimental results show that the dynamic compressive strength，specific energy absorption and fracture forms of sericite-quartz schist and sandstone have significant correlation with strain rate. However，there is no significant correlation with strain rate can be seen for elastic moduli of the two rocks. The dynamic mechanical comparison results of sericite-quartz schist and sandstone show that sandstone is more sensitive to strain rate than sericite-quartz schist. In the sight of microstructure characteristics and energy absorption of sericite-quartz schist and sandstone，dynamic fracture process is analyzed；and crucial factors influencing the characteristics of fracture are discussed. The research method and conclusions can provide references for analyzing dynamic mechanical behavior of other kinds of brittle materials.

According to the disaster prevention problem of support crushing and water inrush when mining underlying unconsolidated confined aquifer in Qidong coal mine，the actual measurement and experimental study of connected effect between water level variation and roof weighting of working face are conducted. The study results show as follows：water level drawdown appears before support crushing and water inrush；and the velocity of water level drawdown basically keeps constant. The scope and speed of water level drawdown are closely related to the intensity of the roof weighting of working face. The greater the scope and speed of water level drawdown are，more intense the weighting pressure is；thus the danger of support crushing and water inrush increases. Different modalities of overburden stratum breaking movements are the main reason for the above connected effect. When the key stratum breaks one by one，the overburden strata rotates and descends slowly；and the scope and speed of water level drawdown are smaller. There is no danger of support crushing and water inrush accident. When compound breakage of key stratum happens，the overburden strata slide unstably and collapse holistically；and large numbers of volumes of caving spaces transfer to the top surface of bedrock in a short time. Meanwhile，the water level descends greatly and quickly，in which case the danger of support crushing and water inrush accident exists. Using the connected effect between water level variation of unconsolidated confined aquifer and roof weighting of working face，the warning method using drawdown speed of groundwater level for support crashing and water inrush accidents when mining underlying unconsolidated confined aquifer is put forward. Based on the theory of groundwater dynamics，the calculation formula for critical warming values of drawdown speed of water level are given when support crushing and water inrush accident happen at the working face. The calculation formula are served as guidance for the support crushing and water inrush prevention practice at working face 6130.

In order to investigate the creep damage property of surrounding rock of the nuclear waste disposal repository at different temperatures，temperature effects on the whole creep damage process are analyzed on the basis of the experimental results of granite specimens under uniaxial creep compression. It is shown that the temperature results in thermal damage on instantaneous elastic modulus and accelerates the subsequent creep damage process. Based on the Nishihara model，instantaneous thermal damage variable and creep damage variable considering temperature effect are presented to establish the creep damage constitutive model of granite at different temperatures. Creep test data of granite at different temperatures are used to carry out the identification of the creep damage model；and the creep parameters are obtained. It is found that the model could well describe the creep properties in whole process by comparing the results obtained from the creep damage model and the creep test data. The rationality and correctness of the creep damage model are identified. The variations in creep parameters with temperature are analyzed. The analytical results indicate that the creep damage failure time decreases rapidly with the increasing temperature；and the relationship between creep damage time and temperature satisfies negative exponent reduction law. The creep fracture property transforms from brittleness to ductility with the increasing temperature；and the creep fracture property satisfies negative exponent increase law. The relaxation time for granite decreases rapidly with the increasing temperature.

Based on the study of time functions during dynamic analysis of mining subsidence both at home and abroad，the probability integral method is used to study the regularity that surface subsidence caused by underground mining varies with the changes of time and space；and the coordinate-time functions of dynamic surface movement and deformation are proposed. Compared to Knothe time function W(t)，the coordinate-time functions not only add a coordinate variable x，but also add several strata movement parameters(q，r，v，ω，?，t0) which are unified with the parameters used in static analysis of probability integral method. Relation formula of starting time t0 changing with coordinate variable x is studied. Compared to some typical time functions such as Knothe time function，subsidence coordinate-time function W(x，t) can overcome the imperfections of first derivative and second derivative that exist in Knothe time function. What?s more，the changing regularities of subsidence，subsidence rate，subsidence acceleration are correctly revealed. Besides，coordinate-time functions of dynamic tilt，dynamic curvature，horizontal movement，horizontal deformation，etc.. can be obtained from partial derivative calculation of x . Then，basic formulae of dynamic analysis of surface movement and deformation are established under conditions of semi-infinite mining and finite mining. Based on the above topic and analysis，practical verification combined with examples is accomplished. The results show that the conventional static analysis function is just a special case of the coordinate-time functions of surface movement and deformation；and the coordinate-time functions correctly describe the dynamic process of surface subsidence. The coordinate-time functions including several well-known strata movement parameters could fully reflect geological mining conditions and it deserves to be spread widely.

In order to study the mechanism of pile-soil interaction and the effect of variable rigidity design after the settlement adjustor is installed，two sets of comparative model tests are carried out to analyze the behaviors of frictional single pile and pile groups under conventional condition and settlement adjusting. The analytical results show as follows：(1) The application of settlement adjustor in single pile can obviously change the load transfer rule，give top priority to soil beneath the raft and its bearing capacity can be well developed；and the load bearing ratio of pile to soil is optimized. However，it is found that negative friction resistance distributes in a certain range below pile top. (2) By use of the settlement adjustor in friction pile group foundations，the supporting stiffness of pile foundation can be optimized. The variable rigidity design of pile raft foundation is realized successfully when the bearing capacity of foundation soil is well developed，which effectively reduces the differential settlement of pile raft. The conclusions can provide the experimental basis for further theoretical research.

Because spatial variability often exists in natural soil slope，which is mainly dominated by its geologic origin under the same soil parameters statistical variability，the slope stability is not really same. Traditional deterministic slope stability analysis method and reliability slope stability analysis method based on random variable model can not deal with the geologic origin of slope mass. The scale of fluctuation of soil parameters can be estimated by its geologic origin. Thus geologic origin can be included in the slope stability analysis framework by means of scale of fluctuation of soil parameters. Reliability analysis of soil slope stability considering geologic origin employing 1D random field and first order reliability method(FORM) is proposed and its specific analysis flow is also introduced. The proposed analysis method is illustrated by an example of embankment. Example calculation results indicate that spatial variability of parameters of rock and soil has great influence on slope stability. Estimation of scale of fluctuation of soil properties through geologic origin provides a realistic solution for the reasonable consideration of spatial variability of soil parameters in reliability analysis of slope stability. The proposed method is practically applicable and quite valuable for practice.

Microscopic analysis of soil mesostructure and direct shear test for Q2 loess with different water contents under different freezing speeds are conducted. The results show as follows：(1) When the water content of loess sample is low，with the increase of freezing speed，the statistical frequency of low-density area increase a little，while the statistical frequency of middle-density area scarcely changes and that of high-density area decreases a little. So the freezing speed has little effect on each density area of Q2 loess. When the water content of loess sample is higher，the freezing speed has great impact on high-density and has little impact on low-density area. The greater the water content is，the greater the impact is. (2) When the freezing speed is slow，the effect of water frost function on the behavior of loess is not obvious. When the freezing speed is faster，the water in loess freezes before it migrates to the loess sample? freezing front；and the water frost heaves in loess. When the volume of ice is larger than its expansion in the loess free space，the volume of loess increases a little；and the density and cohesion decrease because the water in loess frost heaves. The greater the water content is，the greater the volume increase，and the greater the decreasing degree of loess sample?s density and cohesion are. The frost heave force makes the proportion of large pore in loess decrease and the contact points between particles of soil increase，which make the internal friction angle of loess increase. The faster the freezing speed is and the larger the water content is，the greater the increment of internal friction angle is.

On the basis of the main factors affecting the test of ground shock induced by explosion，the empirical formulae of ground shock parameters are deduced by means of dimensional analysis. With the data of field tests in sandy clay，the attenuation curves of peak stress which is an important parameter of ground shock at different scaling depths of burst(SDOB) are drawn out. It can be concluded from the curves that the SDOB，ranging from －0.20 m/kg1/3 to 1.00 m/kg1/3，has great influence on peak stress of ground shock；and the tendencies of attenuation curves of peak stress at different SDOB are in concert. That is to say，the empirical formulae of peak stress at different SDOB have the same attenuation exponent；and the attenuation coefficient of empirical formulae will enlarge with the increasing SDOB. When the SDOB are close to 0.80 m/kg1/3，the space between the attenuation curves of peak stress of ground shock is already very small，which indicates that SDOB have no obvious effect on the parameters of ground shock after it reaches 0.80 m/kg1/3. When two explosions at different SDOB in one medium produce the same ground shock magnitudes in the same scaling distance，the relationship between the explosive charge with different depths in the yield of above two explosions is defined by“DOB coefficient of equivalent yield”. According to the attenuation law of peak stress，the prediction method of ground shock parameters in free field at different SDOB in sandy clay has been given with DOB coefficient of equivalent yield，which provides the computing method of explosion load for the antiknock study and structure design during underground construction.

Certain earthquake wave with 10% exceeding probability in the following 50 years of the field is input as vibration wave to conduct the dynamic test firstly. The residual dynamic strain calculation expression is amended based on the test results. According to repeating verifications of a great many groups of test data，it is shown that there is good correlation between the amended expression and test results. Secondly，Through controlling the correlative parameters of power spectrum and envelope function of artificially synthesized seismic histories，earthquake waves with different predominant frequencies and effective times are obtained to control the axial stress of dynamic triaxial test. The effects of predominant frequency and effective time on the residual strain of loess are studied. The study results show that the sample suffering the earthquake acceleration wave with higher predominant frequency and longer effective time indicate larger residual strain under the same dynamic stress. In addition，moisture content and consolidation ratio have greater effect on the residual strain of loess. Under the same dynamic stress，the sample with higher moisture content and suffering higher consolidation ratio would produce more seismic residual strain.

For offshore engineering，dynamic characteristics of supporting system of foundation are extremely important for the stability and security of upper structures. Based on the Euler-Bernoulli beam model，transfer matrix method is used to establish lateral vibration model for the partially embedded single pile considering the coupling effect of lateral load and vertical load. The main influence factors for impedance and effective pile length are analyzed；and the shortages of existing theory are indicated and also amended. The pile-pile interaction is studied from three aspects，i.e. length ratio，wave incidence angle and axial force；and a simplified approach for calculating partially embedded pile groups is put forward on the basis of superposition theory. Furthermore，solutions of the proposed model are compared with theoretical results for fully embedded pile groups. Through the discussion of parameters，it is concluded that the axial force(N)，pile spacing(s/d) and length ratio(L1/L2) are very important for the lateral vibration properties of partially embedded pile groups，which cannot be ignored by designers. Finally，the introduced model is used to study the effects of lateral vibration properties of the pile groups for an offshore wind power plant and variation of impedance of the pile groups foundation on natural vibration characteristics of overall structure.