By connecting the nonlinear viscoplastic body(NVPB) model put forward by the authors and five-component viscoplastic model in series，a new seven-component nonlinear viscoelasto-plastic rheological model of rock(Hohai model) is proposed，which can reflect fully the accelerative rheological property of rock material. The rheological equations of rock at the constant stress and strain are deduced. The nonlinear creep property and relaxation property of rock are carried out based on the theoretical analysis and investigation. At the same time，on the basis of complete creep curves gained by using rock servo-controlling rheology equipment，the identification of the proposed seven-component nonlinear viscoelasto-plastic rheological model of rock is validated. The comparison between nonlinear rheological model and experimental curve shows that the proposed nonlinear viscoelasto-plastic rheological model is available and reasonable. Based on the proposed seven-component nonlinear viscoelasto-plastic rheological model of rock，the central difference equation in three-dimensional condition of this nonlinear rheological model is deduced. By adopting the secondary development routine interface of software—fast Lagrangian analysis of continua (FLAC3D)，the numerical analysis code of nonlinear rheological model is investigated and developed. Through a uniaxial compression numerical example，the correctness and rationality of the proposed nonlinear rheological model is validated further. In the end，by adopting the developed nonlinear rheological numerical code，the three-dimensional simulation is conducted for the dam foundation of Jinping First Stage Hydropower Station，and the analysis results bring forward reasonable suggestion and evaluation for the long-term stability and safety of dam foundation of Jinping First Stage Hydropower Station.

With the development of national economy and defense，the depth of underground engineering becomes deeper and deeper，such as mines with depth of thousand to several thousands meters(for example，Jinchuan nickel mines and golden mines in South Africa)，diversion tunnels with depth of more than thousand meters for hydropower engineering，deep geological deposition of nuclear waste，deep underground protection engineering(for example，air defense headquarter in northern American in 700 m deep underground rock). The engineering response of deep rock mass shows several new characteristic scientific phenomena. In comparison with responses of shallow rock engineering，these new characteristic scientific phenomena have quite different features，and can not be explained by traditional continuum mechanics completely. They attract the attentions of scholars and engineers in the fields of geotechnical engineering and rock mechanics in the world，and become the focus of the study in these fields for last several years. A new branch of rock mechanics－nonlinear deep rock mechanics is being established. The tectonic，deformation and failure problems of deep rock are suggested according to the static and dynamic characteristic scientific phenomena and the characteristics of deep rock，such as the block structure feature，the state of high earth stress，the stored energy and the nonlinearity，discontinuity and incompatibility of deformation.

Many serious disasters are resulted from high-speed landslides，which take huge energy and high speed as their characteristics. So it¢s important to research the mechanism of high-speed landslides，sliding velocity and time to predict the damages. Based on the theory of eco-environmental catastrophe chain and mechanical model of sliding mass which takes water into account，a new calculating formula which is used to estimate the sliding velocity and sliding time is proposed；and the transformation and dissipation of energy during sliding are also involved in the formula. The coupling performance of pore water and atmospheric damping is considered in this formula；and it can fit actual situations very well. It can be used to predict the damage of high-speed landslides so as to offer theoretical proof to the design and construction of projects.

The mixed mode fractures in quasi-rock materials under compression-shear loading are usually simulated using Griffith cracks with zero thickness. It leads to the result that the initiation angles of wing cracks are independent of the fracture orientation angles and the confining pressure. However，many previous experiments showed this conclusion was not valid necessarily. Therefore，a theoretical and also an experimental analyes are carried out to investigate the influence of geometric characteristic on the initiation angles of wing cracks，e.g. the thickness of pre-existing fractures and the radius of curvature near the fracture tip. The proposed method will provide a theoretical frame for the experimental analysis of mixed mode fractures of samples under compression-shear loading，and also for further stress analysis of the morphologically complex cracks.

An integrated measuring system of real-time holographic interferometry layout linked charge coupled device(CCD) camera and computer graph process is experimentally used to continuously test and record the dynamic process of cracks growth and closure emerged in the whole stages of rock deformation and fracture on sand and granite specimens under unaxial compression and compressive-shear loading，respectively. The active interference fringe patterns captured from the holograms can reappear the development behaviour of rock cracks. Based on the fringes¢ quantitative analysis and its calculation，the initiation and propagation of rock cracks as well as its growth and closure in different loading states are directly shown. And the spreading velocity and reformative quantity of rock cracks resulted from cracks growth or closure are given. In addition，the velocity of cracks creep extension and the quantity of cracks creep deformation are obtained. The movement of active fringes in space and time expounds the distribution of rock deformation field. Consequently，the mechanical types of rock cracks can be distinguished effectively. Mode I crack perhaps keeps unchangeable or progressively transforms into mixed mode I–II or I–II–III crack under the different loading conditions，and crack modes are also varied with the evoluation and interaction of rock cracks，and the local deformation and inhomogeneous distributions of stress field become more intense in turn，which induces cracks growth and closure once again or secondary crack propagation. Actually the process of rock deformation and failure is the process of types alternation of rock crack in mechanics.

To explore the characteristics of fatigue deformation of red-sandstone under triaxial compression with cyclic loading，complete stress-strain tests under different confining pressures are performed with multi-function apparatus RMT–150B. Testing result shows that the terminal strain corresponding to fatigue failure is equal to the one corresponding to the point that the post-peak stress-strain curve and the line of the maximum cyclic load(s1－s3) are intersected. The development of irreversible deformation shows a law of three stages. The maximum of cyclic load and amplitude have remarkable effects on fatigue failure of red-sandstone.

Powerful and accurate computation is becoming one of the most important tools for rock failure process analysis and related rock engineering problems. It demands supercomputer or large-scale parallel computer and related software that can be run on them. Common personal computers(PC) and workstations are incapable when they are facing the accurate simulation of micro-scale crack formation and evolution in rocks and other different typs of materials，which requires terascale computing，even petascale super-computing in future. A parallel model of rock failure process analysis is proposed. This model is developed from serial version of rock failure process analysis (RFPA) directly，which has been presented before. Parallelism of finite element method(FEM) in stress module has been completed using discontinuous finite element method and domain decomposition parallel algorithms for parallelization of RFPA. Numerical test shows that the program is robust and possesses good scalability and pocketability. Stress analysis of tens of millions order linear equations has been finished within twenty five minutes on 32-node PC-cluster.

A dynamic model of test system is established to study the seepage properties of non-Darcy flow in rock specimen，and seepage properties parameters(permeability，non-Darcy flow b factor，and acceleration coefficient) of limestone specimens are picked up based on the analysis of individual time series of porous pressure gradient. A new phenomenon comes to light in the test process that the non-Darcy flow b factor of the specimen in post-failure stage is less than zero. The discovery of this new phenomenon makes it possible for engineers to verify，forecast，and analyze the instability of seepage flow in rock in laboratory. Test results show that seepage flow in limestone does not obey Darcy¢s law whether it is in post-failure stage or in ante-failure stage. The permeability of non-Darcy flow is less than that of Darcy¢s flow when the non-Darcy flow b factor is positive；the seepage flow would be instable when the non-Darcy flow b factor is negative because of the interpenetration of fracture in the specimen. With the help of test results，the mechanism of water inrush in coal mines can be explained more convincingly by the nonlinear dynamics theory，and a new idea is provided to engineers in the control of water seepage in surrounding rock strata in coal mines. The tests adopt previously familiar methods，and more efforts are involved only in the data process. It does not increase the test cost，nor does it make the test more difficult. So it is doubtless to be used widely in the near future.

Acoustic emission(AE) tests are performed on rock samples under uniaxial compression with and without seepage flow，respectively；and four kinds of rock¢s AE characteristics are identified and analyzed. Results of the AE tests show that，at lower stress levels，almost no AE occurs in the rock and the seepage flow has little effect on AE activities. However，when the compressive stress reaches to the value of 60%–80% of rock strength，the AE activities increase remarkably. Drastic AE events occur at the moment when the seepage flow is loaded or unloaded and almost no AE signals are able to be received when the seepage flow is unloaded in steady state. Rock breakage process can be divided into four phases according to its AE characteristics，that is，beginning phase，tempestuous phase，drop phase and dreary phase. During rock breakage，dominant frequency of rock AE is broader than that of intact rock，where the percentage of low frequencies exceeds 50% without seepage flow through the rock. Comparing the dominant frequency of hard rock¢s AE to those before and after its breakage，the maximal dominant frequency during breakage increases remarkably. However，the percentage of low frequencies exceeds 60%–80% for rocks with seepage flow through them or marinated for a long time(about 130 h)，and the maximal dominant frequency of intenerated rock does not change significantly. Furthermore，the dominant frequency of rock AE varies with the rock strength；the larger the strength is，the broader the dominant frequency is. With the increase of the compressive stress，the maximal dominant frequency exhibits an increasing trend for some kinds of rocks.

On the basis of the numerical simulation of dynamic finite element method(DFEM)，the dynamic response of rock-anchored beam of large underground powerhouse under blasting vibration is studied. It is found that the key to ensure the safety of the rock-anchored beam under blasting vibration is to prevent the cracking of the bonding interface between the beam and the vertical rock wall，and to control the horizontal peak particle velocity，which is vertical to the side wall. Combined with the blasting vibration control practice of the rock-anchored beam at Longtan Hydropower Station，considering the comprehensive factors such as the structure characteristic of rock-anchored beam，the strength properties of concrete，the strength development with the increase of the cured age of young concrete，the microstructure and the strength of the bonding interface，the feasibility of rock excavation by blasting in underground powerhouse below the beam is studied under the condition that the cured age of concrete is no older than 28 d；the control standard of peak particle velocity(PPV) for rock-anchored beam in different cured ages is proposed. It is concluded that the PPV control standard for young concrete proposed by code could be used to rock-anchored beam with an age no older than 28 d；and the PPV of 7 cm/s for rock-anchored beam with an age older than 28 d has certain safety margin.

Most landslides are induced by groundwater activity；and the stability of landslide is directly related to the dynamical variation of groundwater. Due to the slope medium heterogeneity and the slope deformation discontinuity，it is a complex process for the groundwater table variation and the change of seepage system when landslides happen. The groundwater pipe seepage system is often developed in pebbly clay slopes in the long-term geological processes. It is important to prevent groundwater table rising and to keep the slope stability. According to the study on the landslide No.6 along Shangyu—Sanmen Highway，it is found that the groundwater seepage is inhomogeneous；and it flows tubularly generally. When the slope deforms and failure happens，the pipe seepage system will be damaged due to the discontinuity deformation of the slope，which causes the groundwater table to rise fast，even to overflow the ground surface. Therefore，the slope stability decreases and the failure of the slope speeds up. The underground drainage tunnel can stop the groundwater table rising effectively；especially，it can prevent the accumulation of the prior period precipitation in slope. So it is an effective engineering measure for landslide control and is worth to be applied.

Characteristics of tunneling engineering tend to be long，big，deep-buried and difficult. Seepage in tunnels threatens large-scale underground excavation，and gives rise to engineering troubles such as landslide，roof caving，water bursting，etc. The characteristic of groundwater occurrence is discrete and seepage is anisotropic. Relying on the longest highway tunnel in Gansu Province，Qidaoliang Tunnel，based on the achievements from non-continuum seepage in rock mass，seepage fields in the area with the maximum flow rate inflow into the tunnel is simulated numerically. Properties of the groundwater seepage in the tunnel and changes of the surface waters level are simulated under all kinds of conditions. Comparison between the simulated results and the measured ones shows that the theoretical analysis is correct and the calculating results are reliable.

After effective fluid model and Darcy¢s law in partially saturated porous media are introduced to Biot-Geertsma-Gassmann(BGG) equation，the elastic wave propagating from a saturated porous medium to a Biot-type porous medium saturated by a liquid-gas mixture is investigated. Theoretical formulation is developed for the computation of amplitude reflection and transmission coefficients，and energy density flux reflection and transmission coefficients at the interface，which are considered as the functions of saturation degree and incidence angle. All the coefficients are studied in a wide range of frequencies and angles of incidence. Numerical results are given to illustrate the influence of saturation degree on amplitude reflection and transmission coefficients and energy splitting at plane interfaces. It¢s found that even a slight decrease of complete saturation may lead to a substantial change of the reflection and transmission coefficients. The reflected and transmission type II waves of Biot at the contact interface of two media carry little energies at low frequencies，but they carry much more energies when frequency arises. The energy carried by reflected or transmission shear wave is affected slightly by frequency. The results imply that more attention should be paid to saturation degree effects in the interpretation of field observations.

Based on the general principle of three-dimensional numerical manifold method，a model for rock anchor bolts is proposed and the corresponding algorithm and formulas are given. Stability analysis of rock slope shows that the model can better describe the deformation behaviors of anchor bolt-supported rockmass and the reinforcement effect of the anchor bolts.

It¢s usually difficult to determine the actual safety factors of rock masses in ordinary 2D stability analysis if the safety factors of different cross sections in the rock mass vary significantly. Besides actual slope，arch dam abutment，and actual foundation of a high building，another example is that the different cross sections of the foundation in a monolith of a gravity dam vary significantly，just like the condition at the overflow dam in Baise Project. 3D stability analysis method based on the upper-bound theorem is employed to solve this problem. The parameters used in the analysis are obtained from the geomechanical tests as well as continuity simulations of the random distributed joints. Two failure patterns against sliding are analyzed. One pattern is that the foundation slides along deep seated planes which are determined by calculations. Another pattern is that the foundation slides along the planes across the bottom of the high steps in the foundation pit. The results indicate that a special overflow dam monolith can be considered to be safe in case considering three-dimensional effect. However，a key wall with a depth of 5 m must be constructed at the upper side of this monolith in order to ensure the safety of the foundation.

Utilizing the evolution images of crack or damage in rock mass and soil offered by computerized tomography(CT) technology，the changing value of CT number at each pixel is defined to be the maximum of absolute value between the margin of the pixel CT number and that of the proximate pixels in the same row and column respectively. According to the distribution of CT number on scanning section，the changing criteria of CT number at pixels where x equals 20 are defined；and then the doubtful crack is obtained. Simultaneously，the geometrical and CT information in the region of crack is computed. Then the length and width of crack are defined and calculated. The work is important to advance the quantitative analysis of CT image in geotechnical engineering forward.

Based on in-situ observation about stress in inclined coal pillar for fully-mechanized top-coal caving face of thinner coal seam and the elastoplastic limit equilibrium theory，taking the thickness and angle of coal seam into account，the results and relations are analyzed systematically and completely；and the formula and the distribution laws of stress peak value are obtained. The study will provide some references to the reasonable design for gateway and the determination of parameters for coal pillar preservation in the condition of gob-side driving in fully-mechanized top-coal caving face，and to improve the maintenance of gateway and increase the recovery ratio. And it will provide some available references for other similar mining areas.

Considering some sinkholes found in loess area along the high speed railway(TGV) in France，which affect the foundations of TGV during the very rainy periods，the geological and geotechnical properties，especially the collapsibility of loess have been analyzed. Based on the geological presentation of loess deposits in northern France，tests on the collapsibility of loess located at the place 140 km north to Paris along the TGV have been carried out. The effects of initial water contents on the magnitude of collapse are also examined to find out the effects of seasonal change of water content on the loess collapsibility. Test results show that the effects of water content change on the magnitude of collapsibility are significant. The collapsibility linearly decreases with the increase of initial water content. So，the criteria for collapsibility should include the initial water content. The evaluation of various criteria for collapsibility are discussed according to the testing results obtained.

It is a universal matter that the earthen architectures were eroded and deflated seriously under the specific climate in arid areas. It is fairly necessary to study the reinforcement of earth-structure sites. So，more attentions are paid to consolidate the earthen architecture using chemical techniques instead of traditional ones all over the world. Potassium silicate(PS) is an inorganic cementing-consolidating material of aqueous solution. It plays an effective role in protecting the earthen architecture sites from weathering in arid region. 20 years¢ experimental researches and applications have proved that the effects of modulus and concentration of PS material on consolidation are noticeable. Experimental analysis indicates that the strength of consolidated soil by PS material has been improved generally. Both its strength and capability to prevent the erosion of wind and rain have been enhanced with the increase of concentration，while they reduce with the increase of modulus. In addition，the resistance of the consolidated soil to freeze-thaw has been improved，so it¢s helpful to preserve the earthen architecture in the arid-cold region. Meanwhile，the modulus and concentration have remarkable influence on its freeze-thaw resistance. It is the best for the concentration with 5% and the consolidated soil modulus with 3.84 to prevent freeze-thaw. The slight changes in density and porosity demonstrate that the consolidated soil still retains good gas permeability and water one. Based on the comprehensive consideration，the consolidation with concentration 5% and modulus 3.84 is optimal. On the basis of research and practice，it could be considered that the PS is an effective material for reinforcement of earthen architecture sites in Northwest China and has an ideal effectiveness.

Qinghai—Tibet railway crosses 550 km continuous permafrost regions and 82 km discontinuous permafrost regions，where high temperature regions(annual average ground temperature is above －1.0 ℃) occupy 275 km，ice-rich regions cover 221 km，overlapped sections of high temperature and ice-rich occupy about 134 km. As a result of the influences of both global climate warming and railway engineering on the permafrost degradation，design and construction of roadbed in permafrost regions are faced with quite great difficulties. As the natural thermal state and underground ice are the important factors influencing the roadbed stability，the choice of roadbed structure to protect permafrost is the leading principle of engineering design. Therefore，many measures are put forward and adopted including crushed rock slope protection，crushed rock embankment，embankment of heat pipe，embankment of awning，thermal-insulation treatment embankment，widened and heightened embankment and duct-ventilated embankment，etc. The crushed rock slope protection，crushed rock embankment，embankment of heat pipe，embankment of awning，and duct-ventilated embankment are all actively protective technologies. The embankment of crushed rock slope protection，crushed rock embankment and duct-ventilated embankment are chosen to study the protective effects of the three kinds of embankments on the permafrost based on the in-situ monitoring results of the roadbeds in Qinghai—Tibet railway. The basic data of actively adjusting and cooling roadbed measures in permafrost regions have been obtained and analyzed. Results show that all of the three measures have certain effects on adjusting and cooling roadbed，and are advantageous to protect permafrost under the roadbed. However，the rising of artificial permafrost table needs to consume the cold energy of soil below ground，which indicates that the temperature fields of permafrost foundation are in instable phase.

Mechanical effects of surrounding rock and composite lining are studied after small-distance tunnels located in soft strata achieves stability under different excavation manners with 3D fast finite difference software；and analysis is focused on the mechanical characteristics of bolt，shotcrete，the deformation and stress of surrounding rock characteristic points nearby the tunnel. The variations of bolt axial force and shotcrete moment with construction sequences in the recommended excavation manner are analyzed. The result shows that the excavation manner of the subsequent tunnel should be chosen carefully；and it has great influences on stress state of bolt and shotcrete of the former tunnel directly. The weak parts of composite lining and corresponding engineering measures are pointed out especially.

Three-dimensional finite element method is used to simulate the dislocation of a fault beneath the core wall of a rockfill dam；and the influence of the dislocation upon the core rockfill dam，especially upon the seepage prevention system(including clay core wall and concrete cut-off wall) is investigated. It is supposed that the maximum dislocation is 50 cm，and the dislocation direction is vertical or horizontal. Furthermore，the stress-deformation behavior of dam with fault dislocation is compared with that of the dam without fault dislocation. The simulated results indicate that the overburden consisted of granular soils which is about 70 m in thickness plays an important role is reducing the dislocation to transfer to the dam including the core. In the case that fault dislocation is 50 cm，the stress level of the clay core increases with a magnitude of 0.4–0.6 MPa，and there is no abrupt deformation in the core. If the dislocation is limited with 50 cm，it will not induce the failure of the dam itself，but will result in the local damage of the concrete cut-off wall nearby the fault. Further study on seepage is necessary due to the damage of the concrete cut-off wall.

In the construction processes of tunnels，the disturbance to soil or rock mass and underground water conditions should be decreased to the minimum according to new Austrian tunneling method(NATM). In urban underground tunnels，cross-sea and cross-river tunnels，more attentions are paid to drainage or waterproof methods with the consideration of circumstance protection，architecture and landscape protection，safety of tunneling and the decrease of ground subsidence. NATM with compressed air may be a good choice. Compressed air can be used to prevent water inflow into the tunnel，and it can be also used to prevent too large ground subsidence. One of the important problems for NATM with compressed air is to understand the rules of the distribution and variation of seepage field，the disturbance to groundwater condition，and to predict the supplementary amount of air. Numerical method is employed to solve the problem. Finally，the distribution of seepage field，the influence area of the compressed air，air loss amount and proper working air pressure are determined when using NATM with compressed air.

Damage evolution of rock under loading can be expressed to some extent by the deformation and crack propagation of the specimen surface，which could be observed or analyzed with the digital images recorded from the specimen surface during loading. However，current methods to evaluate deformation from digital images are either qualitative(semi-qualitative) or quantitative，and very complicated computation and special software are demanded(for example，digital speckle correlation method). In this paper，a very simple quantitative analysis method for digital images recorded from loaded rock specimen to evaluate its damage evolution is proposed. To realize the method，a reference image is firstly selected from the series of digital images；and then the gray correlation of all other images is calculated using a pre-defined calculation scheme. When the image coordinate is fixed，the deformation will change the pixel aray，therefore，the correlation will decrease when there is a large deformation. Likewise，intensity of crack position will change sharply because of the existence of new exposure part by crack，then there is a sharp decrease of the gray correlation. Therefore，the distribution of gray correlation will reveal the damage distribution. The validity of this evaluation method is verified through two simulated image pairs，one deformation and one crack. Then，a series of surface images recorded from an en-echelon rock structure are analyzed using this method. The result shows that the spatial and temporal parallelism exists between the evolution of the gray correlation and the deformation localization. Therefore，gray correlation is expected to be a useful tool to evaluate the damage evolution of rock.

As a rule，it is prior for large-scale projects to avoid strong earthquake areas. Thus there are little researches on the failure condition of rock mass in strong earthquake areas. The Daliushu dam is locates in the VIII potential seismic region，where the rock mass has been damaged by earthquake many times in history. Different from the general rock mass，it is characterized by dynamo-relaxed rock mass. Rock mass elastic wave velocity is the synthesized reflection of rock quality，rock mass structure，and rock mass existing environment. Quantities of in-situ wave velocity tests have been carried out at the site of Daliushu dam，among which cave wall wave velocity tests on 261 segments，in-between caves rock mass penetrating wave velocity tests on 65 fans，and in-between caves rock mass CT penetrating wave velocity tests on 6 sections. Compared with other dam sites，it is found that the wave velocity of rock mass at the site of Daliushu dam is obviously low，and it is generally equivalent to the wave velocity of weathered strip and faultage of other dam sites. What¢s more，its cave wall wave velocity，the in-between caves rock mass penetrating wave velocity，and the in-between caves rock mass CT penetrating wave velocity have no distinctive difference，which is the specific characteristic of dynamo-relaxed rock mass. Comparison between rock mass elastic wave velocity and rock mass basic quality evaluation BQ shows that there¢s a good linear relation between them. The wave velocity reflects the rock mass quality in the tested area.

To study the influence of refuse pore gas pressure on the landfill settlement，a mathematical model was developed，which simplified the landfill as a one-dimensional unsteady gas seepage field. The model incorporated Gibson and Lo model，U.S. EPA Landgem model，Darcy¢s law，ideal gas law，principle of effective stress and theory of dynamics of fluids in porous media. According to the model，the landfill settlement was calculated by the active stage and closed stage，respectively. During the active stage，the landfill continually received refuse，which led to the increase of loads. During the closed stage，the loads kept constant. The result of the finite difference solution represented that the pore gas pressure in the landfill was influenced by the depth，time and permeability. The pore gas pressure increased with the depth and time in the active stage，and dispersed gradually in the closed stage. The landfill with a high permeability has a high rate of pore gas pressure dispersing. The decrease of settlement rate，caused by the increase of gas pore pressure，will decrease the capacity of the landfill. The gas pore pressure should be considered to calculate the settlement and to evaluate the stability of landfills.

Single-line method and double-line method are adopted respectively to carry out uniaxial compression tests on undisturbed loess(Q3) in the case of moistening or demoistening. By employing secant-modulus method，the experimental results from two methods are analyzed. It indicated that，whether double-line method or single-line method，the relation curves between secant modulus and pressure for unsoaked samples and soaked samples under the same initial moisture content can be considered as parallel，although there is a little difference between the slopes of the two curves. It is reasonable to fit the relation curve between secant-modulus difference and pressure by using exponential form.

The problem of membrane penetration can be studied quantitatively based on digital image measurement system. By non-contact measurement technique of the digital image system，the precise volume changes of specimen and water pipe can be gained. The volume change of water pipe includes the specimen¢s volume change and that caused by membrane penetration. Through the drained-loading tests of some sand materials，using the planar deformation assumption，the membrane penetration is obtained by subtraction the specimen skeleton¢s volume change from the discharge pipe¢s in the process of drained-loading test. Based on the test results，the relation between the membrane penetration and its mainly influential factors，such as s3，d50，are analyzed and the formula of membrane penetration is improved. It is not reasonable for graded sand including high percentage of fine particle using d50 to analyze the membrane penetration. The influence of gradation¢s uneven or other characteristic particle size should be taken into account.

The tunnel in soft surrounding rock with maximum buried depth was modeled based on Bijiashan Tunnel of the 2nd Project of Yuqian Expressway；and three-dimensional elastoplastic numerical simulation is conducted for construction process. Variation laws and magnitudes of settlement and horizontal displacement in designated cross section are attained. Computing results show that the maximum range of influence on the settlement and horizontal displacement is within 3 meters before and after the designated section and magnitudes account for two-third of gross amount；and the influence of upper bench excavation is obviously greater than that of lower bench；and the settlement and horizontal displacement have accomplished 40% before heading face is excavated；and the area with concentrated displacement is 3–5 m away from the tunnel wall. In addition，comparison of arch crown settlement and horizontal convergence of haunch between in-situ testing data and computing ones shows that the variation laws fit preferably.

Based on real-time computerized temography(CT) experiment on concrete samples with three sets of cracks under uniaxial loading，some new phenomena and laws on meso-crack and meso-damage by numerical computation for non-interpenetrated jointed media are presented；and the effect of six material parameters on the meso-damage of sample is predicted by Monte Carlo probabilistic design method. Over double decades，the experimental technology of computerized tomography has provided an efficient approach to obtain visible picture for micro or meso damage and fracture of rock and soil media，which leads to the micro or meso problems not to be guessed. However，some complicated phenomena and evolutional laws have to be explored and discussed through the numerical analysis due to the limit of equipment，method and sample of experimental situation，etc. Hence，the latest development of CT experiment results is reviewed firstly. Considering the elementary concept of the problem，the data from test and special criteria about meso-crack and meso-damage，the parameters of grey-scale are regarded as the main variable for computing simulation. In fact，the meso-crack and meso-damage could occur in the case of tension and shear based on the damage criteria for 3D elements. According to computing demand of higher precision，the main program is compiled by Fortran language using 3D isoparametric elements with 16 nodes to simulate the crack and the surrounding elements，and that with 8 nodes to simulate the elements far from the crack. Meanwhile，except for shear transfer coefficient for crack open and that for crack closure obtained by probabilistic design approach，all the other parameters are determined by the experiment. As a consequence of computation，the grey-scale distribution，meso-crack distribution，meso-damage distribution，average grey-scale curve and meso-damage isoline distribution on the middle section of the sample are presented in detail. Furthermore，meso-crack and meso-damage inherent evolution laws are come out as well. Finally，the influential parameters of meso-damage model on the middle section such as initial elastic modulus，Poisson ratio，shear transfer coefficient of crack open，shear transfer coefficient of crack closure，limit uniaxial stress of tension and initial density are predicted. The study shows that the characterization of meso-crack and meso-damage for rock or soil is of a stage-like behavior，which varies with material properties，initial situation of sample and loading style，etc. The results may be useful for the research on the evolution law of non-interpenetrated jointed media.

According to the failure mode of soil mass observed from tests，the corresponding failure mechanism is proposed to solve the lateral bearing capacity of rigid piles embedded in c-j soil with upper bound analysis method. The three-dimensional failure mechanism that consists of three deformation failure regions and the reasonable velocity field that meets kinematical boundary condition of each deformation failure region are assumed. The mathematical model of the upper bound solution of the lateral bearing capacity for smooth rigid piles is established and solved. It is found that the difference between the upper bound solution and the finite difference solution of the lateral bearing capacity of smooth rigid piles is little. In addition，the upper bound solution of the lateral bearing capacity of rough rigid piles is obtained by modifying that of smooth rigid piles according to the results acquired from finite difference method. The three-dimensional limit analysis provides a simple and effective computing method for the lateral bearing capacity of rigid piles.

谢骏博士论文摘要