By carrying out unloading experiments of high stress on granites in the style of unloading confining pressure with loading axial pressure, the stress-strain curves which describe the gradual damage of rock and the degradation laws of mechanical deformation parameters are both acquired, the Mogi-Coulomb strength criterion is applied to explain deformation characteristics, the varying laws of strength parameters and the evolutionary features from compression-shearing cracks to tension-shearing cracks of rocks are also built up. Then the relation between compression-shearing Mogi-Coulomb criterion and tension-shearing Mogi- Coulomb criterion is expressed by the lateral deformation which has a primary affect on unloading damage of rock; and the new strength criterion is established. Finally, based on the above experimental results and stress-strain curves from the unloading experiments, the mechanical constitutive equations, which involves the degradation laws of mechanical deformation parameters, the effect of lateral deformation and the evolutionary features of unloading damage are deduced in the strain space.

Based on the research of the propagation paths of the wing cracks under uniaxial compression by the methods of experiments and numerical simulation. It is found that the wing crack extend along a curved path and gradually approximate to the line which passes the middle point of the main crack and is parallel to the direction of maximum principal stress. According to the geometric characteristics of the wing crack paths, a hyperbolic equation is set up to describe the curved paths of wing cracks approximately. In the equation, the unknown parameters are determined by the crack initiation angle, the crack length and the angle between the direction of the maximum principal stress and the crack surface. Then the comparative analysis of the paths by the hyperbolic equation and the experiments is made; and the results show that the paths by the hyperbolic equation are in concordance with those by experiments, so as to prove that the hyperbolic equation can be used to describe the propagation paths of wing cracks under compression. Furthermore, the stress intensity factors along the hyperbolic path are calculated by ABAQUS; then the extending loads of the wing cracks are analyzed. Through comparing with the experiment results, it is found that the extending loads by the hyperbolic wing cracks fit better with ones by the experiments so as to show validity of the results in the paper.

Modified Cam-clay model assumes that volumetric plastic work being dissipated is equal to which is stored. But it is more common that the division between dissipated and stored work is not equal. A reference state parameter is suggested to describe the ratio of volumetric plastic work to plastic free energy. A new volumetic harding model is proposed based on generalized thermo mechanics, Since the dissipation potential functions of geomaterials depend on the current stress, non-associated flow rule must be used. Modified Cam-clay model is a special case which obeys associated flow rule; and a special case of the model presented in this paper.

A groundwater control system has been designed to simulate various groundwater conditions in centrifuge tests. The system consists of a water supply part and a control part. A desirable groundwater table can be obtained via a solenoid valve and a feed-back pore pressure transducer. Due to the rotation of a centrifuge model, accuracy in the determination of groundwater table and the location of transducer are discussed. The design of the groundwater control system was verified in a centrifuge slope test and satisfactory results were obtained.

Through the resonant column test on such 6 sorts of typical soils such as mud, muddy soil, silty caly, silty clay and silty sand interbedded strata, silt and residual soil, the influences of confining pressure and soil property on dynamic shear modulus G and damping ratio ? of the 6 typical soils have been explored in detail. By means of tests and theoretical analyses, the average curves of G/Gmax and ? /?max with the change of ? under different confining pressures as well as their recommended values of parameters for the 6 sorts of typical soils in Fuzhou area are presented. Besides, the influence patterns of the average curve parameters for G/Gmax and ? /?max of such 6 soils with the change of ? are also quantified. The above findings would be used as reference for practical projects.

Based on the centrifuge of Tsinghua University, a new device was developed to conduct the excavation of a slope in flight. The centrifuge model test was conducted to simulate the excavation of a cohesive slope. The displacement field was measured during the excavation. The results show that the failure process of the slope begins at the bottom of the slope and extends to the top eventually, including two stages: small deformation stage and rapidly increasing deformation stage. Cracks occurred in the top due to tension, however, their extension can be attributed to the cooperation of tension and shear along with the shear zone.

In consideration of the importance of multi-scale characterization of coal fractures for understanding the mechanisms of multi-scale fluid transportation, we propose a new approach for a detailed-accurate representation of pore structure of coal rock on CT image with multiple scales based on image processing techniques. The multi-scheme segmentations are employed to extract the object of interest. Representation of the relations among the interested objects, establishment of such image descriptors as the regions, the borders, the statistical moments, and fractal characteristics of the objects are systematically investigated. The proposed approach is applied to characterize the macro- and meso- fractures on the CT image of the coal rock samples. The obtained results show that the object segmentation for macro-fractures can be achieved by thresholding segmentation method. For extraction of the meso-fractures, complex segmentation strategies should be adopted, for example, the Sobel gradient operator with watershed transformation in our study. The multi-scale and detailed-accurate descriptions are achieved on pore structure of the coal rock by using chain code representation, image descriptor and fractal descriptor in Euclidean and fractal spaces.

Rubber mixed with soil are applicable in lightweight fills for slopes, retaining walls, and embankments, utilizing it as a kind of seismic isolation material in base isolation, and see if it can produce fine seismic isolation effect. This paper researches on the dynamic properties of granulated rubber-sand mixtures from the angle of base seismic isolation. The dynamic shear modulus of the different proportions of the mixtures under different consolidation pressures were measured using cyclic simple shear test. And the curves of G-? (where G is shear modulus, ? is shear strain) were obtained and compared. Results show that the granulated rubber can efficiently reduce the dynamic shear modulus of the rubber-sand mixture, which increases with the increase of the consolidation pressure.

Through compaction test of 2 kinds of fine-grained soil and 18 kinds of soil containing coarse granulae in the lab, the optimum compaction energy of the soil containing coarse granulae is studied when it is used as the embankment fill material. The test results show that the suitable test method of the maximum dry density for the soil containing coarse granulae is heavy compaction test; and the compaction times should be increased to 130 for each layer. The relationship between the maximum dry density and the granulae size group is analyzed through multiple linear regression; and the results show there is a good linear relationship between them.

The stress-strain relation of undisturbed loess during triaxial shear test is studied by using real-time computerized tomography(CT) scanning. The curves of loesses Q2 and Q3 are analyzed; and the method how to determine the initial damage stress and strain threshold value is proposed. Based on analyzing the test results, it is pointed out that the loess Q2 will be damaged easily under low confining pressure; and its damage strain threshold value is lower than that of loess Q3. At last, damage variable formula defined by CT values and the relationship of the damage variable, axial strain and deviatoric stress is given.

Based on Suining-Chongqing high speed railway, the dynamic characteristics of ballastless track soil subgrade are analyzed through an indoor large-scale model test under dynamic loading. The result indicates that along the subgrade surface cross section, dynamic responses have the W-shaped distribution. But gradually become the basin-shaped distribution with the increase of depth. The largest dynamic response measured are under the concrete track position base, while the responses under the centre-line and the two ends of the concrete slab are smaller. The most intense dynamic responses are measured on the surface and graded gravel area; it reduces sharply with the increase of depth. Dynamic stress is slightly affected by loading frequency, while acceleration and dynamic deformation are fairly affected by it. In addition, a comprehensive field test has been conducted on the test course in Suining-Chongqing line by using CRH2-EMUs and freight train. The dynamic response of ballastless track subgrade under diffident speeds have been collected and the dynamic characteristics are analyzed. The results verify the suitability and adaptability of subgrade construction on Suining-Chongqing line.

The author presents the general invariant formulation of constitutive equations based on the representation theorem for the isotropic materials. The equations are a linear combination of three irreducible tensor function bases, which depend on the zero, first and second order power of stress tensor and are orthogonal to one another. Three coefficients depend on three invariants of stresses and plastic strain increments respectively. The internal variables are defined in terms of three invariants of the plastic strain increments. Therefore, the evolution equations of the internal variables are needed to be determined to form a closed constitutive theory. Using the representation theorem, the evolution equations are obtained in a general form. It depends on the increment of invariants of the stress, and therefore is independent of the rotation of the principal axes of stress. It is discussed how the evolution equations are specified from the experiment data in combination with some assumptions. Finally, the constitutive equations presented in this paper are compared with the classical plastic potential theory and the multi-yield surface theory. It is showed that the former is a general representation of the latter two theories, and is more simple and convenient for use.

In order to know about the rheological characteristics of rock specimens in undersea tunnel project, a series of triaxial compression rheological experiments were carried out on the rock servo-controlling rheology testing machine. Results show that creep characteristics of intensely weathered granite is more obvious than full weathered granite; and that creep deformation of rock greatly depends on the confining pressure. With increase of confining pressure, creep deformation of rock will decrease. By analysis of stress-strain relation, creep deformation has few effects on damage of rock during elastic stage; whereas viscoplasticity deformation has more effects on damage of rock during plastic stage. In order to keep stability of tunnel, confining pressure should be increased to improve yield strength of surround rocks and decrease rheological deformation by strengthening supporting structure.

ALPHA model is modified based on subloading surface theory; and the initial anisotropy induced by settlement is also considered. Considering the characters of the modified model, a semi-implicit constitutive integration algorithm is proposed. In terms of the algorithm, a user material subroutine is developed in the framework of general-purpose finite element code ABAQUS. Using the subroutine, simulations for triaxial tests are performed; and the results have been compared with the published studies. The comparison shows that the presented algorithms are capable of the numerically implementing of complicated constitutive model; and the modified ALPHA model, which overcomes the deficiencies of modified Cam-Clay model, such as predicting higher peak strength for over consolidated clay and assuming elastic deformation inside the initial yield surface, can depict the nonlinear and nonrecoverable deformation before yielding. Through varying model parameters, more complicated deformation behaviors can be simulated by the modified model.

The geological condition of Gonghe tunnel is very complex. There are many difficulties when the tunnel is being constructed. There are many vertical cracks in the primary support after the tunnel is excavated. The surrounding rock of the cracking position is shale, which is easy weathered, more hydrophilic, water-weakening and creeping and has identified beddings and joints. These properties of the shale have an important impact on the primary support and the long-term stability and reliability of the tunnel. So the creep test of shale is carried out. The strain-time relation curves of different stress levels are obtained by series of tests. The creep model is built and the parameters of it are got. Based on these, the constructing process of the Gonghe tunnel’s cracked segment is studied by DEM. The possible broken mode of the surrounding rock and the force situation of the supporting structure in tunnel are analyzed. The research achievements provide important support for the new supporting structure scheme of the cracked segment in the Gonghe tunnel. So this engineering problem is successfully solved.

As a kind of material for cutoff walls, cement-bentonite slurry was widely used in vertical anti-seepage system of landfills in the US and some European countries. The application and research of cement-bentonite slurry haven’t been well developed in China. Several different mixing ratios of slurry were prepared for study. The hydraulic conductivities of hardened slurry were tested using a permeameter. The influences of cement and betonite on the hydraulic conductivity of hardened slurry were explored. The results show that the influences of cement and bentonite on hydraulic conductivity of hardened slurry are interdependent. Only the participated amount of cement should reach a certain degree, the increase of bentonite used in the slurry can effectively decrease the permeability of hardened slurry. The hydraulic conductivities of hardened slurry also decrease evidently with curing time.

Free piston thin wall samplers were employed to obtain undisturbed specimens of natural sedimentary soils from ground surface to the depth of 30 m. One-dimensional consolidation compression tests performed on the undisturbed samples, and in-situ piezocone penetration test?CPTU, were adopted to investigate the physical and mechanical behavior of the Yangtze River backswamp soils. And then, intrinsic compression line (ICL) and intrinsic strength line (ISuL) of reconstituted clays were used as a basic frame of reference for describing the corresponding characteristics of natural sedimentary clays. The above results indicate that the Yangtze River backswamp soils have a high level of soil structure; consolidation coefficient Cv shows a rapid decrease after yielding and has obvious features of stages. Another conclusion could be drawn that the consolidation yield pressure and structural strength of natural sedimentary soils have more notable effects on engineering characteristics under lower static load level of the low embankment. Moreover, it's of practical value to decrease the construction disturbance of natural soil and make full use of the structural strength in engineering application.

In order to obtain the distributed rule of the earth pressure for unsaturated loess Q3 at the original state and its rules of changes during the process of excavating or saturating, an in-site test was done on an 18 m high slope, which included displacement, earth pressure, suction and the process of collapse. Meanwhile, a series of indoor triaxial shear tests on unsaturated loess Q3 at the original state were also conducted. The outcome as follows: ①For the unsaturated loess Q3 at the original state, the relation between the apparent cohesion and suction is nonlinear, between the effective friction angle and suction is nonlinear too. ②The earth pressure of unsaturated loess Q3 at the original state increases with the excavating depth, which results in the shape of triangle at the end of excavation, high in the middle, low at the two ends; and the maximum earth pressure at the 1/3 height of the slope. Compared with the calculated result from Rankine’s theory, the tested earth pressure is relatively lower, whereas it increases rapidly on the condition of saturation. In short, saturation is the direct cause of the slope collapse.

The screw pile body and pitch of screw is chosen as the subject investigated of the pull-out screw pile foundation under inclined load; and the subgrade reaction by the pile-soil interactivity were put on surfaces of pile body and pitch of screw by the formal load; at the same time, the moving coordinates were introduced in the analysis. So the used problem of superposition theorem for large deformation material system, for instance soil-pile, could be transferred the small deformation & elastic mass for screw pile body and pitch of screw. The failure model of pull-out screw pile under inclined load was analyzed; and the calculation of ultimate load for a pile and pile group were given; and calculations of ultimate inclined load of screw pile group was 93.3% to the average determined value from field pull-out tests under inclined load. It is shown that the research technique, the failure model and the calculation formulas are consistent with the practical characteristics of the pull-out screw pile group under inclined load on the whole; and these research results can guide the designing and analysis of pull-out screw pile foundation under inclined load.

Lateral soil movement due to surcharge loads and pit excavation often occurs in urban construction. The lateral soil movement may generate additional internal forces and deformation in pile foundation of adjacent buildings, and may lead to the damage of adjacent pile foundation and engineering accidents. Based on the Winkler’s foundation model and deformation compatibility condition of pile and soil, the horizontal displacement control equation of a single pile is established. According to the differential relations between the internal forces and displacements, the two-stage method is adopted to solve the equations. With the typical engineering accident, the influence of lateral soil movements on adjacent pile foundation is investigated by parametric analysis of the pile bearing capacity. The analysis shows that the stability of retaining wall and the excavation depth have an important impact on the safety of adjacent pile foundation. One of possible causes resulting in the collapse accident of a high-rise building in Shanghai is obtained from the analysis.

Suppose the constitutive relation of soil to satisfy the hyperbola model. By assuming that the decrease of the hydraulic conductivity is proportional to the decrease of the compression conductivity and the distribution of initial effective pressure doesn’t vary with depth, the one-dimensional nonlinear partial differential consolidation equation which is under random time-depending loading is deduced. According to the idiographic initial conditions and the boundary conditions, the equation is solved using the variable separation method. The general solution of the effective stress is achieved; and then the general solution of the excess pore pressure, the general solution of the average consolidation degree defined according to the settlement and the general solution of the average consolidation degree defined according to the excess pore pressure are achieved. Finally, the solutions under trapezium low-frequency cyclic loading are achieved using the general solutions; and the factors which influence the consolidation characters are found. Based on the solutions under low-frequency cyclic loading, the relevant computer program is developed using FORTRAN language. Using this program, the consolidation characters and the influences of the parameters E and n which reflect the constitutive relation on the consolidation characters are analyzed. The computing results show that the average consolidation degree defined according to the settlement is a little bigger than the average consolidation degree defined according to the excess pore pressure; the closer to the drainage plane, the more obviously the mode of the loading influence the additional effective stress; the influences of E and n on the average consolidation degree defined according to the settlement are so small that can be ignored; however, the influences of E and n on the average consolidation degree defined according to the excess pore pressure and the additional effective stress are bigger, so that they can not be ignored.

The 3-D scattering of plane P waves by circular arc alluvial valleys is studied. The circular surface assumption is used to simulate half-space surface; and the wave function expansion method is used to give the analytical solution in frequency domain. Based on the solution, the effects of the incident frequency and incident angle of plane P waves on the dynamic response of circular arc alluvial valley are discussed. The numerical results show that the surface displacement amplitudes significantly depend on the incident angle and the incident frequency of the incident P waves.

Based on a lot of laboratory testing records from geotechnical investigation of an expressway located in the central region of Jiangsu province and using random field theory to model soil profile as a random field rather than traditional random variable, a statistical method of variability of soil parameters based on random field theory has been recommended, which can take account of the deterministic spatial trend components at the same time. Based on this, the properties of soil variability of lacustrine soft soil in the central region of Jiangsu province were statistically analyzed and the variability characteristics between laboratory physical index, deformation and strength parameters ware compared. It is indicated that the variability of the laboratory physical index parameters in this region is relatively small; no obvious trends or deterministic components can be observed; and traditional statistical method is effective for them too. Correspondingly, the laboratory deformation and strength parameters have obvious deterministic trends. They have to be destrended by regression analysis before statistical estimation, and then estimated by the recommended method due to random field theory. The conclusions of this paper provide not only a new method for statistical estimation of the properties of soil variability, but also prescriptions for engineering or construction in the central region of Jiangsu province. The third but not the least value of this paper is that it can lay a solid foundation for establishing random field model of regional soft soil properties.

The control of post-construction settlement of subgrade is one of the key problems of railway passenger dedicated line construction; therefore, it is beneficial to design and construction that using the field observation data of railway passenger dedicated line subgrade to find the corresponding settlement laws. The thought of three-point method is introduced into hyperbola model based on analyzing mass data of some high-speed railway subgrade; a three-point method based on hyperbola model for subgrade settlement prediction has been proposed. The concrete method is that three suitable points of the measured settlement curve taken as forecast sample are substituted in hyperbola model to forecast the settlement. The common forecast methods such as hyperbola method, three-point method, Asaoka method, Hushino method and Poisson curve method are used as comparison to check the new method. The research results show that the model of hyperbola based on three-point method agrees better with the measured data, with small errors and high correlated coefficient, so as to provide references for the settlement prediction of laying ballastless track of railway passenger dedicated line.

The whole cross section of a granular columns and soil around pile were regarded as an element to analyze. According to the equivalent relationship of the seepage discharge to the volumetric change, the equations for the consolidation of composite ground with granular columns were derived using the concept of average excess pore water pressure; and the consolidation deformation of pile was considered. Through the initial and boundary conditions of the composite foundation and the assumption of the equal strain, the equations were solved by separation of variables. The average excess pore water pressure and average percent consolidation of granular pile and its surrounding soil were obtained; and the degree of consolidation of the composite foundation was acquired. Finally, an example was given for calculation and analysis. Results drawn from this paper have been compared with the existing references’ results; when the diameter ratio of composite ground with granular columns was large, the results are in good agreement; and the diameter ratio was small, the differences come to obvious.

The research on the stability of surrounding rock is carried out during the construction, as per twin-side heading method, of large section and small clear-distance tunnels under complex geological condition; through the on-site supervision measure of internal displacements of surrounding rock, vault settlement, pressure of surrounding rock and stress of bolt in combination with the engineering practice of Damaoshan tunnels. When the pilot tunnels start excavating, the variation trend, characteristics and displacement field of displacement inside surrounding rock should be clarified, as well as the mutual influence of neighboring pilot tunnels in construction, mutual adjusting mechanism between surrounding rock and retaining structure and the reason of smaller distortion measured by vault settlement than the actual distortion of surrounding rock, the stress state of retaining structure, stress of bolt, variation relation of surrounding rock displacement. The supervision results indicate the feasibility of existing construction technology and retaining parameter adopted for fault zone of V-grade surrounding rock section of large section and small clear distance tunnels because of controllable surrounding rock distortion, strong retaining structure, safe storage and stable surrounding rock. The method, analysis and conclusion of research will be valuable experience and for reference in design, construction, supervision and further theoretical research on tunnel engineering under similar condition.

The influence factors of the interface on the cut-and-fill roadbed are studied; and reducing these to two kinds as a whole, geometrical features and physico-mechanical parameters. The characteristics of interface step and the discrepancy of the filling physico-mechanical parameters are researched; and it is indicated that there are limitations in the imbalanced thrust method, such as in plotting slices and there is error in the count result. So the author illuminates that the imbalanced thrust method is unsuitable to be used in analyzing the stability of cut-and-fill roadbed basing on interface. And the MSarma method which is developed freshly to replace the imbalanced thrust method is recommended. Based on mass of cut-and-fill roadbed interfaces in a highway and combining the orthogonal design, statistic method and MSarma method, the mechanical mechanism analytical method for analyzing the stability of cut-and-fill roadbed interface is formed. This method is used to analyse the stability of cut-and-fill roadbed interface in three different cases; and the sensitivity priority of each factor to stability coefficient of roadbed is also given; the rank top 4 are cohesive force, internal friction angle, interface and roadbed obliquity; and then the selecting principle of filling, interface parameters and the form of roadbed is advanced, which is based on the study of the quantity relation between the four parameters and stability coefficient and comparing the variety trend.

Selection of the hyper-parameters is critical to the performance of support vector machines (SVM), directly impacting the generalization and regression efficacy of the SVM. An orthogonal experimental design procedure for hyper-parameter selection (ODPS) is clearly desirable given the intractable problem of exhaustive search methods. The authors' previous work in this area involved analyzing the range value of hyper-parameters for SVM of mixed kernel which has been proved and showed a higher convergence rate and a greater flexibility in learning a problem space than single kernel functions, and determining experimental levels for different parameters in order to guide the hyper-parameter selection process. The method selects hyper-parameters optimal composition in terms of orthogonal and interaction effect of hyper-parameters. The results of the performed engineering experiments for the prediction of two typical landslide deformation time series confirmed the reliability and advantage of the proposed approach.

Based on a dynamic Winkler model, a simplified calculation method of both active and passive piles in the case of multi-layered soils is presented. An advanced method is deduced to compute the lateral dynamic impedance of both single pile and pile groups in multi-layered soils, which takes pile shaft shear deformation and moment of inertia into account. Compared with the already results of experiment and computations, the presented results are more close to the tests. The text result is consistent with a correlative thesis in low frequency, but both difference increases when pile shaft shear modulus decreases. Pile shaft shear modulus and moment of inertia are the reasons to cause the differences. The former plays a greater effect even in low frequency. The latter has a little effect, but an evidence differences appear during the pile impedance in peak value and the frequency is high. Thus pile shaft moment of inertia should be taken into account in high frequency.

Soil anchors are commonly used as foundation systems for structures that require uplift or lateral resistance. Based on the upper bound limit analysis theorem, the linear Mohr-Coulomb failure criterion and associated flow rule, the ultimate pull-out capacity (UPC) of strip anchors is studied by means of the kinematical approach of limit analysis theory. The shear strength parameters (internal friction angle ? and cohesive force c) are treated as variable parameters and two new kinds of knematically admissible failure mechanisms are considered for the calculation schemes. The objective functions of UPC are obtained by equating the work rate of external force to internal dissipation along the velocity discontinuities; and then the upper bound solutions are presented by applying a nonlinear sequential quadratic programming (SQP) algorithm. The calculation results are compared with the available empirical and numerical results presented in the existing literatures, and the validity of present method could be illuminated. From the parameters analysis results, the UPC of new kinds of knematically admissible failure mechanisms is no significant difference. It also can be seen that the density of soil mass, the shear strength parameters (? and c), the embedment ratio and the plate geometric properties have significant effects on UPC and the region of failure modes.

The karst groundwater is one of the most important and active master control factors inducing geohazards such as water outburst and mud gushing, it is of great significance in the evaluation, prediction and control of geohazards. The mechanism of water-rock interaction in karst tunnel has been studied by using theories of karst geology, engineering hydraulics and fracture mechanics, and the effects of such mechanism on water outburst and projecting mud soil during the construction of karst tunnel has been explored; the mechanical mechanism of water gushing process has been analyzed. The research results show that sustaining action of karst water and water pressure on fractured rock mass and the excavation effect lead to water outburst and mud gushing by the way of hydraulic fracture; the mechanical functions of the sustaining action is embodied in four aspects: the softening and scouring mechanical effect of water-rock on fractured rock mass, the hydraulic fracture damage effect of water pressure on fractured rock mass of preventing water, the expanding mechanical behavior of water flow on passageway and the dynamic controlling effect of water pressure on flowing yield. Accordingly, based on fracture mechanics and plastoelasticity, the concept of minimum safety waterproof thickness has been put forward; and the expression of semi-analytical solution has been given; it has been proved by a case study. The reference basis can be provided to study on theory of prevention and cure for the water gushing in the karst area.

Rockburst is one of the main geological hazards during tunnel construction in high geostress zone. The prediction of possibility and classification of rockburst is one of global problems of tunneling engineering. Based on efficacy coefficient method, a new model for predicting the classification of rockburst is established. Considering the key influential factors of rockburst comprehensively, four factors including ?θ /?c, ?c/?t, Wet and Is are selected as evaluation indices. The model is tested by a series of rock projects at home and abroad. The obtained results are consistent with practical classification of rockburst and the results of set pair analysis method and extensional method; so it is shown that the efficacy coefficient method used to classify the rockburst intensity is reasonable and effective. Then, the model is applied to Cangling tunnel. The results are in good agreement with practical situation of rockburst. It is proved that the efficacy coefficient method used to classify rockburst intensity is exact and reliable. The efficacy coefficient method is simple and has very strong operability, which possesses a good prospect of engineering application.

The evaluation of rock mass quality of dam foundation is a complicated decision-making problem，often appearing to be the contradiction between influencing factors and the coexistence of qualitative knowledge and quantitative information. It is necessary to find a new meta-synthesis method which can solve the inconsistent problem of qualitative and quantitative information. Extension theory is used generally to solve such problems. It integrates research objects, evaluation indexes and its value range into a matter element system to research things’ extension nature. Through the application of extension theory, the thought of multiple indexes optimal fusion and matter-element transform, the matter element system of rock quality evaluation of dam foundation is established and the relational degree of the comprehensive evaluation index can be calculated, of which the weight coefficients are determined by using entropy weight method. Then the extension theory based on entropy weight is established. The essay applies the model to evaluate rock mass quality of dam foundation of some hydropower station. The result is highly agreement with the geological report of this hydropower station and precisely reflects the practical engineering.

Excavation under existing highway foundation will cause ground displacement and ground settlement. In order to control the ground settlement during excavating, it is important to solve out the ground displacement and stress quickly and accurately for design and construction. Based on image method and injected with equivalent layer method, the analytical solution of ground displacement and stress caused by shallow buried circular tunnel excavation under existing highway foundation is deduced. The result indicates that the ground displacement and stress law gained through this new solution can reflect the special transfer effect of settlement and stress via the upper harder highway foundation. The displacement and stress at any position in the highway foundation and the substratum and ground settlement can be gained through this solution, so as to provide a new analytical method for the calculation of ground displacement and ground settlement caused by circular tunnel excavation in double-layer ground material.

The implementary Code for Design of Road Tunnel (JTG D70－2004) can’t satisfy the requirement of design and construction sometimes due to no study of soil surrounding rock classification and sub-classification methods. After ascertaining the building foundation of surrounding rock sub-classification standard in road tunnel, it had been constituted through lots of test, numerical calculation and theoretical analysis. The researches show that self-stability span is synthetical reflection of surrounding rock stability, so sub-classification standard can be constituted based on it. Surrounding rock self-stability span can divide into long-term stability span, basic stability span, temporary stability span and instability span. Ⅲ class of Rocky surrounding rock in criterion can divide into two sub-classification according as surrounding rock stability, three for Ⅳ class and two for Ⅴ class. Though soil surrounding rock include clayey surrounding rock, sandy surrounding rock and debris surrounding rock, their stability can be unified. The uniform standard of rocky and soil surrounding rock sub-classification built by self-stability span has rationality and inheritance.

A mathematical model of nuclide migration and its inverse analysis for the dual media consisting of the porosity and the single fracture media, are explored. The nuclide migration model is a coupled parabolic equations with initial and boundary conditions. If the variation of the nuclide concentration has been known at the release point, an analytical solution of the nuclide migration model is obtained by the Laplace transform and its inverse analysis. On the contrary, the solution of the inverse problem of the nuclide migration model, namely the nuclide concentration at the release point, is reconstructed by the principle of superposition of partial differential equations and the quasi-solution method of inverse problems from the measured data of nuclide concentration at one downstream point. Finally, numerical simulations for the forward and inverse problems are given. Numerical results show that the analytical solution of the forward problem can describe the variation of the nuclide migration, and the method proposed for the inverse analysis is also effective to reconstruct the nuclide pollution source.

The transferring equation of the prestressed force from slope surface into slope body in singly anchored soil-like slope is deduced and discussed on the assumption that the slope body is elastomeric. The transferring coefficients of the prestressed force are put forward according to the transferring formula. The conclusions are drawn that the spreading angle of the prestressed force from slope surface into slope body in singly anchored slope is approximate 39º; and that the optimal space between anchors is about 3.2 m. Some centrifugal model tests are carried out according to a strongly weathered granite slope locating at K617 of G232 road. In the centrifugal model tests, earth pressure cells are set at different points of the slope body to monitor the increased earth pressures caused by the prestressed force. And then the transferring discipline of the prestressed force from slope surface into slope body can be brought out. The results drawn out from centrifugal model tests agree in the main with what from theoretical study. The coefficients of the prestressed force obtained from model tests are related to the amount of the prestressed force, while it is apart from the amount of the prestressed force in the theoretical study. The plastic deformations that occur in the model tests but not be considered in the theoretic study are the main reason. Both the theoretical study and the model tests result in that slope surface protection must be taken into consideration because the effect of the reinforcing is indistinctive in the surface layer of about 2 m.

As a type of multi-dimensional data analytical tool, OLAP (on-line analytical processing) and data warehouse have got a lot of uses in finance and business but had few uses in underground engineering. Some of these applications made a good profit for enterprises. The conception, function, features of data warehouse and OLAP are introduced briefly. A basic OLAP application was built for Xiaowan hydropower plant underground powerhouse. The example shows that OLAP can provide quick, easy and visualized queries from multi-viewpoint, such as observed time, measure point types and construction types, and different stages for top managers. Combining with data warehouse, OLAP will be very useful in safety management for geotechnical engineering. And the future direction of OLAP application to underground engineering is discussed.

Modern 3D scenery modeling and emulation technology has wide application prospects in route selection, construction and operation management of highway engineering. The study of structures emulation modeling and 3D stratum modeling which can reflect the ground surface shape changing before and after construction are important problems in the research of highway informatization. A simple method to extract the geometry information from the surface of structure 3D model with ANSYS is introduced. By combining OpenGL texture mapping technology, the structure emulation model is realized. Because the shape of ground surface will be changed a lot after construction, a clipping method named vertical projection clipping method for surface grids, which makes use of the structure surface data to clip the ground surface grids of 3D stratum model, is put forward. By applying these methods to 3D scenery emulation modeling of a certain high slope in a highway in Guangdong Province of China, it is shown that the emulation model of the slope is lively; and the ground surface shape of the 3D stratum model is very close to the real one after clipping. It proves that these methods are feasible and reasonable.

Xiang’an subsea tunnel is the first subsea tunnel in China; and its geological conditions are complex and unfavorable with enriched groundwater. During the tunnel construction, the deformation of tunnel support is great; and it has brought the bad-effect on the construction of quadric lining; moreover, the large deformation maybe bring on the surrounding rock collapse. It is important to seek for a reasonable countermeasure to restrict the large deformation to ensure safety construction. Focused on Xiang’an subsea tunnel, field monitoring data and construction annel are analyzed and numerical calculation is employed. Some measures and its combination against abnormal deformation during the tunnel construction are taken. The analytical results indicate that, to some extent, the countermeasure including setting locking anchor pipe, enhancing stiffness and intensity of temporary support, constructing continuous wall for groundwater proof, can decrease the displacements of the tunnel support. But the effection of using the combination project is better during constructing the large-span tunnel in the complex geological conditions. For example, after adopting the seventh combination project, arch crown settlement will be reduced 46-60%; and horizontal convergence will be reduced about 30%. The analytical method and result can provide references to the other similar engineering cases.

The prediction and control of ground deformation and displacement resulted from large slurry shield tunneling in complicated environment are important problems to be solved. Combined with Shanghai Yangtze River Tunnel Project, the ground settlement data of test section approach to building areas in uplink tunneling is analyzed. The ground surface movement of test section induced by single tunnel excavation as well as cumulative movement due to two parallel tunnel excavation is accurately predicted by using stochastic medium theory. Based on ground movement prediction, recommended procedures for tunneling in a building areas are presented. The case study shows that the prediction method and measures presented for ground movement control are reasonable and reliable and have some practical value.

The zoning of structural homogeneity of rock mass is carried out according to the project features. In the process of practice, we must choose the elements which have great influence on the project used as the basis of zoning. The author rationally elects the elements and zoning method of structural homogeneity of rock mass in granite, based on the two key problems of the pre-selected area of high level radioactive waste, radionuclide migration and surrounding rock stability. By the applying of the project, the result is comparatively reliable; and the process comes true comparatively easily. So the method has certain extension value.

Through the abundant geological investigation of construction tracing in situ, the intake slope with vertical height of 106 m at a large hydropower station in Southwest China. the deformation of the high rock slope with great gradient is studied under the conditions of complex geology and high in-situ stress. Through systematical study, the basic laws and special characteristics of its deformation responses are acquired and classified as follows: ①During the slope excavation, it is found that there is strong synchronism between the slope deformation and its excavation process. ②The slope deformation is mainly influenced by excavation. ③The slope deformation generally is weakening with the distance between the excavation plane and the monitoring position, whose responding features of ultimate stability have three stages; that is, rapid increase stage of deformation, slow enhancing stage and the stable stage. ④The high slope deformation can be classified into 3 types, the shallow surface relaxation, the harmonized gradual change and rebound fluctuation. The main one is the shallow surface relaxation.

Prestressed cable is one of the common ground anchorage forms; and its types become more and more in use. The loading transfer along anchoring section is crucial for controlling cables performances and engineering design. Shear lag theory is applied to analyze loading and load transfer mechanism along anchoring section; and the anchorage mechanism of dispersion-type tensile anchor is discussed. The analytical results indicate that interfacial shear strength of dispersion-type tensile cable gradually increases to peak shear strength (? 0), and then decreases. The analytical model accords with field test result perfectly.

Considering the slope features, location of the tower, size and quantity of potential unstable rock mass on the slope surface, and the size and quantity of the rock blocks at the slope toe, a feasible risk assessment method is put forward based on the energy of the rolling rock block reaching the tower, and the frequency of rockfalls. The velocity of the rock block rolling from a zigzag slope with a steeper segment near the slope toe is larger than that form a concaved slope. The tower located at the concaved side of a hill has more risk than the tower located at the convex side.

Under the mining disturbance the overlying strata will get a great adjustment; and displacements in the vertical and horizontal orientations occur. The characteristics of layers in coal geology overlying strata make the strata slipping displacement not reasonable which gained based on the homogeneous medium or loosening medium theory. So a complex rock beam model is set up to analyze the overlying strata shear slipping; and a numerical simulation for an engineering example is given to demonstrate the correctness of the model. The results show that the model is reasonable and feasible.

A reasonable and simple method is proposed to calculate the active earth pressure on rigid retaining wall under nonlimit state. Based on the unloading stress-strain relationship obtained from the unloading stress path experiment reflecting the stress-strain characters of soil in the active area behind the wall, the relationship between the friction angle and wall movement is established under nonlimit state. The sliding wedge, behind the retaining wall of not reaching the limit displacement, can be divided into numerous differential slices paralleling to the sliding plane. Then, with the force analysis of these differential slices and the relationship mentioned above, equations can be set up and the inclination of the sliding plane is also derived. Thereby, the calculation formula of the nonlimit active earth pressure is obtained. Subsequently, compared with one model test, the value of the calculated earth pressure has a satisfying agreement with the observed at the upper two-third of wall height and a certain deviation at the lower one-third of wall surface. The results show that the proposed method can provide a good prediction of active earth pressures for walls under nonlimit state and has some theoretical significance and engineering reference value.

Physical model of rock and soil mass is built by means of particle flow code software. Based on these, two types of initial calculating condition are designed; one is all discounting from physical model, the other is all beginning with the previous discounting computing result. Each type contains three kinds of discounting method, only discounting cohesion, only discounting internal friction angle and discounting shear strength parameter. Furthermore, each kind embraces five types of discounting rates such as 1.00, 0.5, 0.1, 0.01 and 0.0. Then, evolutional map of slope shape and velocity in x direction of monitoring point are compared and analyzed. It is found that the cohesion does good to uprightness of rock and soil mass, whose failure mode is collapsing and toppling; that the internal friction angle plays an important part in stable slope angle. The failure mode changes from collapsing and toppling mode to slipping step by step mode, when strength parameters is discounting 0.1, cohesion being 10 kPa.

The location of three-dimensional critical slip surfaces of slopes is a very important problem that has not been thoroughly solved. Observing that any point on a critical slip surface is a local maximum point of the equivalent strain in vertical direction, the strength reduction technique is used to bring the slope into the critical state. Then, a set of vertical lines are arranged within a horizontal plane. Finding out the maximum point of the equivalent plastic strain on each of the vertical lines, a group of discrete points on the critical slip surface will be obtained. Last, the discrete points are smoothed by means of the thin-plate smoothing spline; and the position of the critical 3D slip surface is determined. The proposed procedure is confirmed through the applications of the convex slopes, a typical kind of 3D slopes.

The uniaxial tensile test of loess shows that the tensile strength of loess is very small; and under the action of tensile stress, the burst brittle rupture will occur on loess sample, with the coarse fracture plane and the direction vertical to tensile stress. By using the numerical analysis software RFPA, the whole tensile fracture process of loess is simulated; and the expansion and evolution of internal cracks in loess under the action of tensile stress is captured. The results indicate that the tensile fracture course of loess can be divided into two stages, one is the linear deformation stage, and the other is the stage of formation, expansion and evolution of cracks in loess, which can be completed in very short time. So the broken of loess under the action of tensile stress is paroxysmal, which belongs to a brittle fracture. The result of uniaxial tensile test on loess is very consistent with that of the numerical simulation analysis.

Based on the differential control equations of the coupled thermo-hydro-mechanical processes of dual media, a three dimensional coupled model of dual media to research coupled thermo-hydro-mechanical(THM) processes of fractured rock masses, is proposed. In coupled model, the values of nodal displacement, water pressure and temperature in different media were solved. A three dimensional FEM code. for analysis of coupled thermo-hydro-mechanical processes of dual media is developed tentatively, in FEM program, 3D jointed elements with 8 nodes were used to simulate the crack elements during the stress analysis of discontinuities; and 2D isoparametric elements with 4 nodes were used to simulate discontinuities during seepage and heat energy analysis of discontinuities. So the different media can exchange water and heat flux, water head, temperature and displacement of nodes which are in the interface between two models were equal. Through the numerical computation for heat extraction in HDR; it is shown: that in the thermo-hydro-mechanical coupling process, discontinuous is in low stress state; the crack width increases nonlinearly with the heat extraction; in transient fluid flow stage, the water head in discontinuities was higher than equivalently continuous rock medinm; in steady fluid flow phase, the dominant effect of discontinuities on fluid flow would unconspicuous. Because of massive heat replenishment, the compact of discontinuities on temperature distribution was indistinctive.

With the increase of traffic and the over-load vehicles, the bearing and deforming behavior of retaining structure is increasingly influenced by traffic loads. According to the prestressed anchor sheet-pile wall, using FLAC3D, the spatial analysis model is established. Combining with the field dynamic strain test, the mechanism of bearing and deforming behavior of retaining structure is studied. The results show that the depth of the traffic loads affected is about 2 meters in both subgrade and retaining wall. Under normal circumstances(fully loaded heavy vehicles, driving on a carriageway), the dynamic earth pressure of prestressed anchor sheet-pile wall is approximately 10% of earth pressure at rest.

A compound method which includes integral site stability analysis, stratum stability analysis of foundation pit boundary and 3D finite elements is proposed to evaluate the feasibility of deep foundation pit project in complex environment. A typical foundation pit project is used to evaluate the feasibility of the compound method. The analysis results indicate that the ground stability analysis is useful to understand the stratum situation of project site and adjacent area. In 3D finite elements, undulate stratum can simulate the supporting system more accurately. The compound method brings a new analysis method for foundation pit project in complex environment and complex geological conditions.

The shape function of the meshless local radial point interpolation method (LRPIM) has the Kronecker delta function properties, and no additional treatment to impose essential boundary conditions. The discretized system equation for moderately thick plates on biparametric elastic foundation is derived using a locally weighted residual method. Bending problems for the raft and moderately thick plates on biparametric elastic foundation with simply supported and clamped boundary conditions are analyzed by the meshless LRPIM. Case studies show that the LRPIM is easy to implement, and very versatile for the bending of the moderately thick plates on biparametric elastic foundation.

The effect of stress states on the earth's surface deformation is investigated. With clay selected as test sample, deformation rules obtained by a series of classical triaxial compression test under different stress paths. Based on the tests, a numerical constitutive model under different stress paths is derived by numerical modeling method. Moreover, the constitutive model is set in FEA program to simulate earth's surface deformation under different stress paths. By comparison of the cases, some conclusions are drawn as follows: ①effects on the earth's surface deformation under different stress paths are different; ②the influences of stress paths should not be neglected in analysis of the earth's surface deformation; ③the constitutive model by numerical modeling method which can reflect the effects of stress paths by using different weights fits for analysis of the earth's surface deformation; ④the maximum volumetric strain of path TC is about 20% lower than path CTC; ⑤Shearing dilatancy field of CTE path is larger than that of CTC path while shearing contraction field is smaller. Maximum relative difference of dilatancy volumetric strain between the two paths is about 17.3% whereas maximum relative difference of contraction volumetric strain is about 98%.

Though bucket foundation used as a new type of foundation in shallow water can have significant advantages over conventional ones, the history of its development is relatively short and the method of design is still not mature. In this situation, the authors obtain the horizontal bearing capacity of bucket foundation based on three-dimensional finite element method and limit equilibrium method. According to the result, a simple formula for evaluating the horizontal bearing capacity of bucket foundation on saturated soft clay ground is given for engineering practice.