The changing process of stress Mohr circle in simple shear is analyzed in detail. In the analysis, the process is regard as a components of some incremental step in equal; and two variables are difined: one is the difference between two minor principal stresses corresponding to a random shear stress state and the initial state, another is the difference between two major principal stresses corresponding to a random shear stress state and the initial state; Then the ratio value of the two variables is proved to be constant, which can be got by the Mohr circle in initial state and failure state. Furthermore, expressions of the principal stresses and the corresponding axis directions related to a random shear stress in simple shear are deduced. The influence of soil character parameters and normal stress on the principal stress axis directions is discussed. The relationship between principal stress and shear stress is also evaluated. Studying shows that under the same soil character parameters, the direction of principal stress axis are only decided by the stress ratio; for constant normal stress and shear stress, the rotation angle of principal stress axis increases with the decrement of internal friction angle of the soil, the principal stresses change slowly at the beginning of shearing, change sharply with the increament of shear stress, and keep constant in the failure state.

Corresponding to design method of highrise building aseismic design, the request of three levels aseismic fortification design and the design way of two stages are proposed for the slope protected by soil nailing. Considering seismic excitation property, soil property and slope height, occurring shear displacement under horizontal excitation, a simplified dynamic calculation model of soil nailing protected structures for the slope is proposed. Based on the hypothesis that the lateral displacement of the stability soil and instability soil is nearly in phase and the lateral interaction between them is ignored under horizontal excitation, the instability soil and the facing are treated as study object. Because the facing is flexible, its lateral displacement depends on the lateral displacement of instability soil. The soil nailing is served as the elastic supports. Under the condition of horizontal earthquake excitation the equation of vibration is established in accordance with being mentioned ahead; the analytical solutions are obtained for simple harmonic vibration. The soil nailing axial force response in the neighborhood of failure surface and elastic lateral displacement history can be obtained by this method. The method is applied to a case record for illustration of its capability; in order to verify the method 3-D nonlinear FEM (ADINA) is used to analyze the seismic performance of this case; the comparison of results, using the proposed approach and FEM shows good agreement. This method can be used the first stage aseismic fortification design and analysis of the slope protected by soil nailing.

The deformation characteristic for loess subgrade filler is an important calculated parameter of loess foundation engineering, slope engineering and underground engineering because it directly related to subgrade settlement and slope angle. Based on one-dimensional consolidation tests, the deformation characteristic of compacted loess is analyzed.Introducing the concept of the compression deformation coefficient, the relation between physico indices (water content,compaction degree) and deformation indices (compression deformation coefficient, compression coefficient) is discussed, and the compression deformation curves is expressed with stress-strain method. Adopting the secant modulous parameter of nonlinear stress-strain relation, the loading constitutive model and moistening (drying) deformation model for compacted loess are studied. The results show that the physico-machanical indices of compacted loess influence greatly on the deformation characteristic. The stress-strain curves of compacted loess can be expressed with the power function . Finally, the loading constitutive model and moistening (drying) deformation model are obtained. The reliability of the model is testified. It provides powerful reference for studying the settlement characteristics of loess subgrade.

Elastoplasticity response of fluid saturated rocks with endochronic theory is analyzed according to the multilevel cyclic loading experimental data of fluid saturated marbles and sandstones. In the procedure of multilevel cyclic loading, the stress-strain curve displays cusped hysteresis loop, which moves toward the direction of strain increasing with time and strain amplitude increasing, indicating the generation of plastic strain continuously. According to the stress and strain values at the reversal points of hysteresis loops, the corresponding parameters in the endochronic equations can be determined by the method of least square fitting. Analysis demonstrates that plastic strain is small relative to elastic strain, and getting smaller in the total strain with cyclic number. Viscoelastic and microplastic strain components affect rock stiffness by time and strain amplitude respectively. At intermediate strain level, due to presence of microplastic strain component, hysteresis modulus of saturated marble and sandstone decreases with increase of strain amplitude, and is influenced by the type of pore fluid of rock. Hysteresis modulus of rock saturated with oil is larger than that of rock saturated with water, which has perhaps mainly relation with the viscosity of pore fluid within the rock.

The research works on effective stress is firstly reviewed in the paper. Physical mechanism and influencing factors on the effective stress coefficient for rock/soil-like porous media are investigated, based on which equivalent connectivity index is proposed to denote the meso-scaled structure of these media. The equivalent connectivity index, relying on the meso-scaled structure of porous media and the property of liquid, denoted the connectivity of the pore in representative element area (REA). Then a general expression describing the relation between effective stress coefficient tensor and equivalent connectivity tensor of pore is proposed; and the expression can be applied to isotropic media and also to anisotropic media. Based on the effective stress test of marble and sandstone under plastic deformation, the main factors influencing the effective stress coefficient was analyzed; and we found that the main factor is the equivalent connectivity index under the plastic condition. The relation between the equivalent connectivity index and the strain is deduced through fitting of the results of experiment; and then the relation between the effective stress coefficient and strain is obtained. The results can provide an important theoretical support to improve the coupled hydro-mechanical research under elastoplastic condition.

In order to study the shallow landslide hazard of soil slope during the spring melt period in seasonal frozen areas, considering that the freezing point of the brine is lower than pure water, a simulated test method of the internal freezing and thawing interface of soil slope is designed. The critical slip surface depths after freeze-thaw circles in different water contents are compared in the test; and the failure modes of the internal freezing and thawing interface of soil slope are verified. Then the sliding face depth damage model of the soil slope is put forward according to the experimental data. The results demonstrate that with the increasing water content and freeze-thaw circle times, the value of critical slip surface depth decreases gradually after freeze-thaw circles; the damage model which is obtained from the experimental data fitting, would present more reference of the slope design in the seasonal frozen area.

Monte Carlo (MC) simulation has been widely applied to the slope reliability analysis and is accepted as a precise method, which is applicable for complex problems and its error is only affected by standard deviation and sample size. But its precision is affected so much by the reliability of sampling and the simulation times. Based on the limit equilibrium method, the Latin hypercube sampling(LHS) technique is employed instead of the MC method to analyze the slope reliability accounting for the parameters variances and correlations. Then the slope reliability index and failure probability can be computed. The methods for computation of the reliability index in LHS or MC method are discussed, and failure probability together with mean and standard deviation of factor of safety are recommended as evaluation index. The results of example problems show that LHS method is more efficient than MC simulation, which can strongly improves the representation of soil parameters and tends to convergence within relative few simulation times. Hence, the LHS method should be extended in practical slope reliability analysis. The uniform design and orthogonal design are applied to slope stability analysis. The results of orthogonal design is close to FOSM but results of uniform design are unreliable.

The thermodynamic based expression of suction for unsaturated soils was presented. This expression can consider the temperature effects on suction for both surface tension and wetting coefficients. On contrast of expressions by experimental data fitting, its theoretical basis was more strict, and hence it had broader applicability. By adopting the van Genuchten expression of soil-water characteristic curve, a new model considering the temperature effects was established. Based on the experiments of MX-80 bentonite and loess, model predictions were compared with the experimental results; it is shown that the model agreed well with the existing data.

Through researching variation of soft clay microstructure in creep condition, we can deeply understand internal mechanism of creep characteristics. According to the micro quantitative technology and different creep tests of soft clay in Zhangzhou area, comparison between micropores of intact soil sample and soil sample in the creep condition is made for purpose of explaining creep mechanism from microcosm. Research shows that micropore size change follows theory of homogeneity, complexity and directionality decrease; pore figure trends oblate after soil occur screep deformation. Parameters of micropore have different sensitivities of creep deformation in different creep tests. It is suggested that the different micro parameters should be adopted in different creep tests for description of microstructure characteristics. Research reveals soft clay creep phenomenon is caused by soil internal structure change constantly and self-adjustment and reconstruction. Through studying the fundamental factors of soft clay creep characteristics, it is possible to interpret macroscopic phenomenon and provide evidence for reasonable constitutive relation for giving important suggestions to engineering design.

A part of sliding mass of fording landslide submerges the water level with the operation of reservoir; and the stability factor of landslide has close connection with water pressure of slices below the water level when the transmission coefficient method is used to calculate the stability of landslide. Based on analysis of calculation methods about water pressure and seepage force above water level of limit equilibrium method, the water pressure acting on triangle slice and quadrangle slice below the water level is calculated; and the calculation methods about sliding resistances and sliding forces of slice below water level are discussed. It is concluded that sliding resistances and sliding forces of slice below water level only have connection with slice gravity calculated through buoyancy unit weight, and have no connection with vertical distance between the slice and reservoir water level. The results make the calculation of water pressure easier, and have reference significance for the calculation of stability of sliding mass below the reservoir water level.

A simple and practical analytical solution is presented for the analysis of settlement of the large group piles embedded in layered ground under vertical load. The approach is based on the shear displacement method and ‘restrain action’ among piles in group is considered. On the basis of displacement integral equation of a single pile, the relationship between pile head displacement and the axial force is deduced, and so does the relation of pile tip displacement and the axial force. Then, considering the interaction between piles, a flexibility matrix that can be used to compute the settlement of group piles is obtained. On the process of the deducing, the group piles is arbitrarily divided into n segments; thus the presented method can be used to calculate the settlement of group piles in arbitrary layered ground. A case history indicateds that the settlements of group piles computed by the presented method agree reasonably well with those by the hybrid layer method and boundary element method (BEM).

The fundamental mechanisms responsible for drying/wetting hysteresis in the relationship between metric suction and water content, and relevant computational method were studied. The difference between drying and wetting contact angles was considered as the principal factor in terms of microscopic view. Then, based on thermodynamic principle and the assumption that the meniscus among soil particles is a crown face, the iteration relation of filling angles was deduced by studying geometrical properties and taking into account the factors such as radius ratio of soil particles and wetting/drying contact angles. And the relationship between suction and volume of filled water among soil particles with different radii was developed by introducing formulas which solve intensity of pressure on meniscus and volume of filled water. The soil-water characteristic curves (SWCCs) of single meniscus and soil particles with different accumulation styles were solved; the results indicate that: the change of contact angles will cause the hysteresis of SWCCs; filling the pore between particles will raise the water content in lower suction status; and it is more remarkable for loose particles, in which the water content can be enlarged by 90%; the influence of accumulation style and graduation of soil particles on hysteresis is paltry comparatively. Besides, the hysteresis loop of SWCCs can not be interpreted only by hysteresis of contact angles, the relevant theory still under developing.

By the computerized tomography (CT), a series of unloading confining pressure tests were done on the condition of suction control to test the inside structural evolution of unsaturated loess Q3. The tests have proved that the relation between stress and strain of unsaturated loess Q3 becomes hardening as hyperbola, that is, the breakage of the specimen is plastic; the yielding stress of the specimen can be educed easily from the CT data and enforced deviator stress during the tests to see clearly the accretion of yielding stress with the increase of suction and confining pressure；compared with the test result of immovable confining pressure and accreting deviator stress, the strength parameter of unsaturated loess Q3 with unloading confining pressure CT-triaxial shear tests is lower on account of the different stress path. The equation of the unsaturated loess Q3 structural evolution has been set up by the definition of structure parameter.

Based on finite element theoretical scheme of unified elastoplastic constitutive model, and according to the UMAT interface requirement of ABAQUS, the corresponding UMAT codes are programmed, which will be called by the main analytical module of ABAQUS. Adopting degenerative model of the unified strength ( ，Mohr-Coulomb model) and the built-in Mohr-Coulomb model of ABAQUS, the uniaxial tests and circular chamber are analyzed to verify the correctness and efficiency of the developed material subroutine. Finally, considering the general situation form of unified elastoplastic constitutive model ( ) and hard condition of yield surface, which are not available in ABAQUS software, circular chamber is simulated and variational discipline of stress field is obtained. The provided basic procedures and programming essentials of the UMAT redefining in ABAQUS are universal and can offer a reference for other developers.

The established method of Herle and Kolymbas’s (HK’s) clay hypoplastic constitutive model is described. Several shortcomings of HK model are listed in detail by analyzing clay behavior and response envelope line; then three parameters in HK equation are modified to develop a modified HK hypoplastic formulation and determine parameters. The modified model has advantage of a few parameters which are easy to determine and a simple formulation. Meanwhile, modified HK model not only are based on rigorous mathematics and mechanics, but can be applied to practice.

The transient pressure pulse permeability test method is often used for low permeability rocks test. But this method can not truly simulate the high pore water pressure and low hydraulic gradient geological environment; and the test result is not accurate, either. Therefore, we developed a new high pressure permeability testing machine. The sample seepage outlet water flow velocity can be manually controlled at will with pipe filter and speed control valve; and the seepage quantity can be assured by accurate measurement of the effusion water change quantity. When the inlet water pressure of the sample is sure stable, the controlled water flow velocity will be balance with the sample seepage velocity; and the stable water pressure in the seepage outlet can be formed. It can truly simulate the rock stress and high hydraulic gradient environment. Not only the cylinder but also the cubic sample permeability can be measured with this machine. It has been proved by the test that this method can be used.

Based on the damage theory, a nonlinear damage constitutive model of unsaturated undisturbed loess was developed. The model can describe the complex mechanical behaviors of unsaturated loess. There are 13 parameters in the constitutive model which can be determined from the test. The model revealed some inherent law in the stress-strain behavior of unsaturated loess. The above research develops the constitutive model of unsaturated loess to a new level.

The scope of this paper is to investigate shearing behavior of landfill composite liner by using ring simple shear apparatus to conduct integrated shearing test for the composite liner system. The composite liner used in the tests consists of sand layer, nonwoven geotextile, geonet, HDPE geomembrane and compacted clay. From the test results, it can be found that the relationship between shear stress and displacement of a composite liner does not show a softening behavior under a low normal pressure and however, it shows a hardening behavior under a high normal pressure. The critical failure interface with the largest displacement in a composite liner is not fixed at a single interface, and it can shift from one to another with changes of normal pressure. Thus, the conventional research method for the composite liner systems, which is to conduct liner interface test separately to find a single weakest interface, cannot simulate the true shearing behavior for a composite liner system in landfill. The strength envelop of a composite liner can be simulated by a hyperbolic model.

A series of large-scale triaxial tests under different stress paths are performed, including the conventional triaxial tests, constant p tests and constant stress ratio tests. Based on the comparison of test results, the stress-strain, deformation and strength characteristics of a coarse-grained material under different stress paths are investigated. Meanwhile, the phenomena of the volume-contraction in unloading is discussed. The test results indicate that the stress path has obvious influence on the stress-strain and deformation characteristics of the coarse-grained material, but little influence on strength characteristics. The volume-contraction in unloading of the coarse-grained material is caused by the change of deviatoric stress ratio and is related to stress path of test.

The soil static and dynamic universal triaxial and torsional shear apparatus facilized in Dalian University of Technology was employed to perform different types of experimental test of undisturbed saturated soft marine clay in the yangtze estuary. The samples were subjected to undrained cyclic vertical and torsional coupling shear and cyclic torsional shear under three-directional anisotropic consolidation conditions with different initial consolidation parameters. The effects of initial orientation angle of maximum principal stress, initial ratio of deviatoric stress , initial coefficient of intermediate principal stress and stress mode of cyclic shear on the threshold cyclic stress ratio were investigated. It is found that the effects of initial orientation angle of maximum principal stress and initial ratio of deviatoric stress on the threshold cyclic stress ratio are remarkable under three-directional anisotropic consolidation; the threshold cyclic stress ratio decreases obviously with increasing initial orientation angle of maximum principal stress and initial ratio of deviatoric stress. However, the initial coefficient of intermediate principal stress has almost no effect on the threshold cyclic stress ratio. It is also shown that the stress mode of cyclic shear has significant effect on the threshold cyclic stress ratio; the values of the threshold cyclic stress ratio determined by the cyclic vertical and torsional coupling shear tests are smaller than those determined by the cyclic torsional shear tests.

By using improved triaxial seepage test equipment, a series of seepage tests during shear deformation were performed on clay samples. The permeable behavior of clayey soil during the process of large shear deformation was investigated; and the effects of confining pressure, seepage pressure and seepage directions were discussed. It is shown that the permeability of clayey soil reduced rapidly in initial shear process, and then it changed more and more slowly with increasing axial strain, finally it tended to steady. The permeability is mainly affected by axial strain, confining pressure and seepage pressure.

In order to investigate the water-sensitivity of laterite clays stabilized by dynamic consolidation, the compression characteristics of compacted samples (unsaturated or saturated) are studied by laboratory tests. Furthermore, the shear characteristics of laterite samples (unsaturated and saturated) are also tested respectively by direct shear apparatus and triaxial apparatus. The studies show that the compression deformations of compacted specimens are very small, and after inundation of specimen, the deformation of specimens increase slightly. The stress-strain curves of undisturbed specimens in direct shear tests take on softening characteristics. The shear strengths of unsaturated specimens are greater than those of remolded specimens; it is shown that the inundation effect of laterite clays on its shear strength is obvious.

The perturbation in the process of blasting excavation for tunnel construction can be studied by Lamb model belong to elastic kinetics. The case was simulated by photo-elastic experiments, which included the propagation, interaction laws and interception effects of slot obstacle. Some results were obtained as follows: (1) there are Pressure, Shear and Rayleigh waves under the action of impact load, which is similar to the mechanical answers of Lamb model. (2) From the fringe patterns, the effects of inducing fracture and laws of propagation about Pressure and Rayleigh waves are important factors for rock-burst mechanism, which can explain the space relationship between rock burst and face. (3) The slot on model surface can effectively intercept stress waves, especially the important Rayleigh waves. So the method of controlling rock-burst with cutting slot is theoretically feasible.

All of the variational law of density, longitudinal wave velocity and tensile strength of gritstone after high temperature are studied. The results show that the density of gritstone is decreased gradually as the temperature increasing; so that it can be ignored; the longitudinal wave velocity is linearly decreased when the temperature increasing, and decrease rate of it follows the law of conic; R is one temperature point, which makes the law of tensile strength of gritstone after high temperature follows the law of parabola; and the maximal tensile strength appears when the operative temperature is R. After the temperature is higher than 700 ℃, tensile strength is small and change range is small when the temperature is increased. Relation between longitudinal wave velocity and uniaxial tensile strength is quadratic curve after high temperature.

Based on triaxial test, the strength behavior and deformation process of reinforced expansive soil under different reinforced mode, are studied. The triaxial test shows that reinforced mode with nonuniform layers is better to construct reinforced project under low confining pressure and small deformation; but for the reinforced projects under high confining pressure and large deformation, using the reinforced mode with uniform layers will get better effect. The sample deformation process shows that reinforced samples can become multi drum-like with axial pressure increasing, and the deformation of middle soil body is larger than that of the soil body at the end; deformation process can well explain that the middle soil body of soil wall will be swelled with time increasing and out load adding. The result of test can guide the construction of reinforced projects.

The mechanism of the rock bolt is discussed; and the corresponding limit equilibrium method as well as finite element method are recommended. The methods are applied to the study of the rock bolt reinforcement for the gravity dam foundation of Xiaoxi Hydropower Project. This project is influenced by a large regional fault, which causes a cracked zone over 180m in width at the river bed under the dam foundation. The systematic rock bolts are used to improve the stability of the dam foundation. The reliability of the rock bolt reinforcement for the dam foundation is verified by the field test. The calculations using the recommended methods are conducted; based on which the bolting parameters such as the dip angle, the length, and the spacing, are designed. The construction work process is arranged carefully too. The reinforcement has been completed successfully; and the whole project started the normal operation in the January of 2008.

New-built railway line from Zhengzhou to Xi’an is specially used to transport passenger. This line passes through many districts that mostly covered with loess and includes many double-line loess tunnels. These loess tunnels have a cross-section area of more than 160 m2 and a span of more than 15 m. That should be defined to be super large cross-section tunnel. Due to the special property of loess and the increase of tunnel’s span and area, how the wall rock pressure responds to the change in buried depth is unknown. At present, there has no unified opinion on the critical buried depth for large-span loess tunnel. To solve the problem, investigation was firstly done on 12 tunnels to find the relationship between ground surface cracks and buried depth. After analysis of the relationship, critical depth variety was given as follows: less than 11m defined to be super shallow burial; more than 60 m defined to be deep burial; and between 40 m and 60 m defined to be critical depth for shallow burial and deep burial. Shear slippage limit theory is used for check out the analytical conclusion; and a good agreement has been obtained. At the same time, 17 wall rock pressure-measurement cross-sections were intentionally arranged in deferent buried depths to collect a great deal of pressure data. Based on the data analysis, pressure-measurement results are in a good agreement with theoretical calculation; and it is proved that the given critical depth is correct.

Layered rockmass which is always met in underground engineering has obvious anisotropic mechanical properties. Based on the in-situ monitoring of Gonghe Tunnel and numerical simulation, the failure feature of layered rockmass was analyzed; and the results show that the surrounding rock deformation and displacement, contact pressure and fracture zone mainly exist on the right side of the tunnel vault, that is, the side near the river is larger than that near the mountain. The fracture zone of surrounding rock deformation exists in the perpendicular direction of stratification bedding of rockmass rather than in the direction of maximum principal stress. Besides the influence of unsymmetrical pressure of topography, the strata configuration characteristics put more influence on the failure feature of deformation of layered rockmass, that is, it has close relationship with the mechanical properties of layered rockmass. This research can provide some effective evidence for tunnel construction and design.

The selection and research of stability influence factors are very important for stability analysis of solid waste landfills. The sensibility analysis is a method to identify the importance of the factors. In the traditional method of sensibility analysis, only the results caused by changing single affecting factor are considered. Therefore, it is difficult to reveal the real picture of the multi factors simultaneously changed in real case. A method of BP artificial neural network combined with the orthogonal design is presented to study the sensibility of influence factors on translational failure of landfill along the liner system. The comparison between the new and traditional methods is conducted by analyzing a real project. It shows that the sequences of factor sensibility are the same but the maximum difference of safety factors for an influence factor used to determine the sequences are different. The maximum difference of safety factors in the new method are more accurate to reflect the differences of sensibility of the factors because several factors simultaneously changed are considered. In addition, the computing and working time for using the new method is much less than for using the traditional method. The results of sensibility analysis indicate that the major factors to impact landfill stability against translational failure include the smallest interface friction angle in the composite liner and the waste filling slope angle. The results of sensibility analysis can be used to optimize the design, construction, monitoring, and operation management for solid waste landfills.

Based on triaxial compression tests of saturated limestone soaked by water-chemical solution, main factors affecting mechanical characteristics of limestone such as pH value, ion concentration and confining pressure are analyzed. The tests show that the elastic modulus and the peak strength of saturated limestone trend to decrease with the increase of acidity-alkalinity for the same solution with the same mol concentration; strength of limestone soaked in Na2SO4 solution, distilled water and CaCl2 solution with the same pH value decreases according to priority; the axial strain when the peak strength reaches, the strength of limestone and plastic deformation increase markedly with the increase of confining pressure. Considering the effect of the chemical solution and the stress path for mechanical property of limestone, an implicit modeling method describing mechanical property of limestone using evolutionary neural network is proposed. The neural network constitutive model trained by learning samples, tested by testing samples, and whose structure are searched by genetic algorithm, can well describe the mechanical properties of the limestone and can be used to simulate the mechanical tests in the similar condition. Correction of simulation is proved by 5 mechanical tests under different lab conditions.

Geologic failure is one of the most important impacts for the safety of lining segments in TBM construction tunnel. A new assessment method is proposed to analyze the risk of segments breakage more quantitatively considering geologic uncertainty. Firstly, probability model of segment type incorrect selection is established after the probability of geologic distribution aligning tunnel is estimated based on Markov process. Secondly, considering the mechanical parameter’s uncertainties of surrounding rock and segments, the breakage probabilities of different segments under a certain rock type are calculated respectively using stochastic finite element method. Then, segment breakage probability aligning tunnel is obtained from the former two probabilities using total probability formula. Finally, the method is applied to a real project. We obtain the segment breakage probability at anywhere along the tunnel, the maximum breakage probability and the related locations under the construction conditions (loads). The results provide a great support to lining structure optimal design, segments type selection and risk prevention during TBM construction.

The mechanical problems of grouting engineering traditionally are pointed out; and the law of grouting fluid movement is analyzed based on the mechanical solutions of the grouting hole. A new grouting method is put forward, for which the position of original split dam body lies in the bottom of earth dam. Based on the project of split grouting engineering in certain dam in Shandong province, the displacements and the stresses are studied after grouting by using 3-D explicit finite difference method. In numerical simulation strain-softening model is suitable for stimulating elastoplastic stress analysis of soil, and embodying the interaction between grouting fabric and embankment. The conclusion of numerical analysis is consistent with the in-situ observations. Some available results are gained, which are useful for the design and construction of grouting in embankment.

Starting from the own characteristics of mortar bolt anchorage body, the research results of reinforcement structures corrosion cracking is used for reference to analysis mortar cracking process caused by bolt corrosion. First, considering the volume expansion process of corroded bolt, the displacement model of mortar inner surface leaded by bolt corrosion is established after the loss of corrosion production is denoted by a filling factor. Second, based on elastic theory, the mortar cracking process is analyzed after the concept of influence coefficient of surrounding rock is introduced in the course of analyzing, and the degree of cracking course affected by surrounding rock parameter is also analyzed; the finite element method is adopted to verify the results. The theoretical result shows that the mortar cracking process is greatly influenced by surrounding rock characteristics; there is a course of stable propagation in mortar after cracking; the max stable propagation radius increases with the rising of surrounding rock influence coefficient, if the coefficient reaches a certain value, cracks can propagate to the mortar outer surface stably. The finite element result is consistent with the theoretical result.

It is important that the compliance design of tunnel boring machine (TBM) is performed to improve the efficiency and reduce the failure accidents when they excavate in the heterogeneous geologic strata. The equivalent excavating model of the heterogeneous geologic strata has been established based on the typical geological structure in the tunnel construction. The load behavior of the individual cutters was discussed. The mathematical description of total torque on the cutterheads is given in terms of the load of cutter and their locations. The correlation between the torque behavior and the rotating angle of cutterheads is investigated. The results show that fluctuation of torque is dependent on the ratio of hard rock and soft soil on the excavating face. When the percentage of the soft soil is 30%, the fluctuant amplitude is maximum, which may lead to the blockage and failure accidents of driving system. It is in agreement with the engineering case in the Shanggongshan tunnel construction. It can be used in the compliance design of the TBM.

In order to study displacement field characteristics and working mechanism of pile raft foundation, a displacement analysis procedure is worked out based on digital image correlation (DIC) method. This procedure is used to study a series of images captured from the model test on pile raft foundation; the whole gradual deformation process of soil around piles is got from this analysis; the failure pattern of pile foundation is also deduced. The study results show that it is viable to analyze the displacement field around piles by the procedure of DIC; and a full displacement field is got from this analysis. Small pile spacing will weaken the single pile bearing capacity. The compressive region is mainly centralized in the soil beneath the pile tip to the pile raft foundation with 3b spacing, which presents a massive deep foundation failure pattern. But to the pile raft foundation with 6b spacing, the compressive region is mainly on the upper part of pile which is about 1/3 of pile length; the displacement influence length evidently smaller than the pile raft foundation with 3b spacing; and it is destroyed by the lateral squeeze of the soil around piles.

Considering the influence of the slope angle on the anti-slide piles spacing, a calculation model is established based on inclined soil-arch effect between piles. Firstly, on the basis of the assumption that arch axis is parabolic, according to the static equilibrium condition and strength condition inside horizontal plane and vertical plane, a calculation formula of piles spacing is derived; and corresponding rational calculation formulas for piles spacing are obtained respectively. Secondly, the calculated process of piles spacing is illustrated through the calculation of concrete engineering examples; and the result is rational; then the relationship between piles spacing and internal friction angle of soil, as well as the relationship between piles spacing and the angle of the slope are analyzed. The results show that the spacing is increasing with increase of internal friction angle of soil behind piles and first increasing then decreasing with increase of slope angle while other effective factors are not varying.

Based on the construction parameter optimization test of class Ⅴ surrounding rock of Damaoshan Tunnel, through the on-site monitoring work of blasting vibration velocity, acoustic wave velocity of rock mass and internal displacements of surrounding rock, the damage extent and scope of rock mass of a new large cross-section tunnel constructed by double side-wall heading excavation method next to existing tunnel was studied; and then the construction parameters such as single-cycle footage of pilot tunnel ,blasting parameters and so on were optimized. It is shown that the surrounding rock of the tunnel constructed by double side-wall heading excavation method would unavoidably be damaged in a certain degree because of repeating blasting, especially the interlaid rock wall in tunnel groups with closely-spaced. In construction of large cross-section tunnel with double side-wall heading excavation method, it is contradictory to control both damage extent and damage scope. By reducing the single-cycle footage to reduce the blasting velocity, it could only control the damage scope, however, repeated blasting would lead to a greater damage extent, greatly affecting the stability of surrounding rock. On the contrary, through appropriate increasing of the single-cycle footage to control the damage extent, the excessive blasting vibration velocity would lead to greater damage scopes, which greatly affect the safe operation of existing tunnel. Basing on the monitoring result, Therefore, in engineering practices, we should weigh the advantage and disadvantage of both solutions according to the characteristics of the actual project and to determine an optimal compromise. The research method and analysis method of this study could provide reference for the design, construction, monitoring of tunnel project under similar conditions and further theoretical research.

For the traditional pile-raft analysis method, the vertical inhomogeneous soil is calculated through layering the soil; but soil’s inhomogeneity in horizon can’t be considered. An improvement analysis method is presented. After calculating multi survey pores’ Voronoi diagram in horizontal plane, the survey pore’s soil data have been applied to the nearest soil element based on the Voronoi diagram characteristic of the nearest influence domain; and the pile-raft foundation in the horizontal inhomogeneous soil is analyzed. Applying the Bowyer-Watson algorithm to the Delaunay triangle and indirect method Voronoi diagram, the pile-raft analysis program is developed by the C++ program language. Through a pile-raft foundation calculation model, it is contrasted and generalized, that is between the single-pore survey data and multi-pore survey data’s calculating result. It is much difference to the two analysis result, which are foundation settlement, pile force distribution, raft moment and so on. So the Voronoi diagram method for analyzing pile-raft foundation should be taken into calculation for the greatly inhomogeneous soil, applying the entire survey pore’s soil data.

The analysis model of integral stability of cofferdam with geotextile bags on seaside soft foundation is established based on the characteristics of the cofferdam. The effects of the tensile strength of geotextile bags, the cohesion force of filled sand-silt mixture and the depth of geotextile bag on the stability safety factor are investigated when the longitudinal tensile force of bags are taken into consideration. The field observation of long term settlement of the cofferdam is performed. According to the consolidation test and the permeability test of soft foundation, a new model of settlement prediction is proposed by modifying the classical Grey Model. It is found that the integral safety factor increases significantly with the increase of the tensile strength of geotextile bags and the cohesion force of filled sand-silt mixture, and decreases rapidly first and then tends to be stable with the increase of the filled soil depth. The consolidation characteristics of soft soil have influence on the long-term settlement of foundation. Therefore, a reasonable predictive model involving consolidation properties of different soft soils should be chosen to improve the predictive precision.

Many natural gas fields discovered in the west of South China Sea, such as DF1-1, YC13-1 and Ledong, are associated with high concentration of CO2. Considerable amounts of CO2 has to be separated from natural gas stream during the development of these gas fields each year. In order to reduce the emission of CO2 into the atmosphere, geological storage of CO2 in deep saline aquifers has been considered. This study is aimed at selecting saline aquifers in the Yinggehai region, intending to carry out a CO2 storage demonstration project. Five candidate aquifers are selected and their capacities of CO2 storage are estimated based on an accurate method which considers various mechanisms of CO2 storage in aquifers as well as the influence of aquifer structural features on CO2 migration and distribution. The assessment results show that all five aquifers are good candidates for CO2 storage with high storage potential to store all the CO2 expected during the demonstration project, and also can provide storage sites for the man-made CO2 in Hainan and Guangdong provinces in the near future.

In the past the study of squeezing effect during pile driving focused on the single or double pile，but little on the pile group. Based on the model test, soil deformations were analyzed when the pile group were driven; then the soil lateral displacement, vertical deformation and the law of soil surface heave were obtained. It is concluded that as the distance to the pile edge increasing, the soil compaction displacement of the side surface of pile is logarithmicly decaying; the soil horizontal displacement and land surface heave are accumulated continuously; but there are sheltering effects after pressing pile, constructing order of pile plays a key role in the soil displacement; so it should be recognized in actual projects.

During shield tunneling, it is helpful to predict surface settlements near the shield machine for protecting preexisting structures from damage. Gaussian equation is accepted widely by engineers to describe the surface settlements induced by shield tunneling, but ground loss is derived from the engineering experience, so that this method is subjected to limitation in practice. The ground loss is derived by the least square method based on observed surface settlements; the Peck formula is extended to establish a new approach to predict the surface settlements near the shield machine. A visual program is written based on this new approach, which is proved to be dependable by a real example.

It is a very common way to use quicklime to treat soft ground; the calculation of volume expansion of quicklime is a key problem. To study the expansive behaviors of quicklime, the quicklime and the mixture of quicklime and cement are taken as the specimens. In the test these factors influencing quicklime expansion are considered which include grinding rate, mixture ratio and pressure and so on. The quicklime volume expansive pattern is obtained from these test results; the quicklime volume expansive coefficient and pressure always appear following relationship: ; the relationship is obtained for the first time. When this formula is used in the calculation of ground treatment, the expansive coefficient depends on the lateral pressure coefficient , the gravity density and depth , i.e. . This formula can be taken as a basis in the calculation of expansive quantity and provide more accurate design parameter for this type engineering.

This paper describes a solid-oriented 3D strata model base on solid model, and presents the system data structure of it. The model describes the 3D strata integrally. The procedure of the model construction is presented and the strategy of dealing with stratum absence and stratum inversion are discussed. Solid-oriented 3D strata model is superior to other models.

The fatigue behavior of cemented soil is investigated by dynamic loading test of dynamic asymmetric sine wave load. According to the result of the test, the fatigue failure criterion of the cement -stabilized soil stress space is proposed; and a three parameters exponential function model of fatigue life model is established. There are many factors influencing cement-stabilized soil fatigue life; the analysis results show that the he higher cyclic load of the stress level, the shorter the fatigue life of the cement-stabilized soil is; longer on the contrary. Cement-stabilized soil age longer, cement ratio greater, and the fatigue life of the cement-stabilized soil will be longer.

In order to consider the composite impact of mechanical dilation/compaction and pressure solution on fracture aperture, the coupled thermo-hydro-mechanical model for dual-porosity medium established by the first author was improved. Taking a hypothetical nuclear waste repository as a calculation example, three coupled THM cases in which fracture aperture changes with different patterns were simulated numerically by FEM. The variations and distributions of temperatures, pore (fracture) pressures, flow velocities of underground water and normal stresses in the rock mass were investigated. The results show: the temperature fields of three cases are near the same; the forms of seepage fields of three cases are similar; but their quantity values have some differences; the closure degree of fracture apertures under the combined action of stress and pressure solution in case 1 is the maxmium one; so the negative pore pressures in this case are the highest; the liberated heat from vitrified waste changes obviously the horizontal component of gravity stress field of rock mass, but exerts smaller effect on the vertical component.

A three-dimensional finite element model for numerical calculation is established considering rheology. According to particularity of the surrounding rock for underground cavern of Xiangjiaba hydro-power station, stability of surrounding rock is studied based on the indexes of cavern deformation and point safety factor against sliding. It is shown that the rheological speed rate and initial strain decrease gradually with confining pressure increasing. Compared with other rocks, the rheological speed of soft interlayer decreases slowly. Finally rheological displacement of soft interlayer is larger than other states when rheology reaches a lower state. The displacement distribution and change law of surrounding rock of viscoelastic-plasticity and elastoplasticity are uniform; but the calculation displacement of viscoelasto-plasticity is larger. An important influence on rock deformation, stability and support structure is done by rheological effect. At the state of viscoelastic-plasticity, characteristic points’ safety factors against sliding are less than characteristic points’ safety factors of elastoplasticity, point safety factor against sliding of soft interlayer and cavern arch crown. It is also shown that the soft interlayer has an important influence on stability of surrounding rock for underground cavern by studying point safety factor against sliding; accordingly, the displacement analysis results are verified.

The interlamination disturbed belt which gets through Baihetan hydropower station underground caverns, with the characters low-angle dip and perfoliate, is derived from vary top of tuff. In fact, it is a disturbed shear zone blending cataclasite and mudstone under complicated geological process. As its formation process and internal structure are relatively complicated, it is difficult to descript its mechanical behavior. In order to reveal its mechanical properties more intuitively and reasonably, its geological structure is considered as a ‘sandwich biscuit’ which contacts upper and lower and clamps weak belts in the interlayer. Based on field test, FLAC is used to analyze its mechanical properties; and the acquired rules and calculation parameters are used to analyze the surrounding rock of underground caverns. The shear strength margin balance theory is used to analyze the influence of disturbed belt on the surrounding rock of underground caverns in order to provide support method and support parameters for the underground caverns.

Based on blasting vibration monitoring for the second phase for Ling-ao Nuclear Power Station, in Guangdong Province, the wave propagation characteristics under blasting in concave landforms are simulated with UDEC. It is found that the protruding topography can enhance scale of vibration wave of blasting, and the numerical simulation results agree well with that by site monitoring. The numerical results show that, under protruding topography, the amplified coefficient of velocity of vibration wave of blasting does not monotonously increase with the height of terrains. In the definitive energy of the explosion source, it is found that the amplified coefficient increase when the height of protruding topography is below a critical point, but it will decrease if the height of protruding topography exceed the critical point. The amplified coefficient is also relative to the ratio of height to width under condition of isolated protruding topography.

In order to exactly calculate the seepage discharge of groundwater in oversize groundwater sealed oil storage of rock caverns, adopting the calculating analysis method of three-dimensional FDM numerical simulation with solid-fluid coupling of porous continuous medium, the seepage field of underground water was simulated by the site investigation, in-situ test and monitoring, and physical mechanics tests. On the premise of guaranteeing economics and security, considering coupling interaction between stress field of surrounding rock and seepage field of groundwater, and water flow condition, a reasonable method to calculate the seepage discharge of groundwater in oversize groundwater sealed oil storage of rock caverns, is presented, connected with an engineering practice. Compared with the results obtained by the presented method, the empirical method of France expert, Hirishi Oshima empirical equation and Investigation Norm of Railway Engineering Hydrogeology (TB10049-96), the results are comparatively consistent. The research results show as follows. Firstly, the presented method is applicable for calculating the seepage discharge or water inflow of groundwater in oversize groundwater sealed oil storage of rock caverns with the feasibility study phase lacking test data. Secondly, the water inflow of single cavern considering groundwater fluid-solid coupling analysis, may be smaller than that only considering the analysis of groundwater flow. Thirdly, considering fluid-solid coupling interaction, the maximum velocity of groundwater seepage of surrounding rock is smaller than that without considering fluid-solid coupling interaction.

The study areas of temperature tracer method are mostly concerned with shallow layer, its temperature is mainly influenced by weather and groundwater. Fluctuation of air temperature can be accurately expressed by Fourier series. How surface temperature and vertical groundwater flow influencing temperature field were demonstrated with a transient analysis model. The analytical solution is obtained by Laplace transform and numerical solution by FEM. The results indicate that shallow ground temperature field also has seasonal fluctuation; but the decay rate of amplitude mitigates singnificantly; and fluctuation of air temperature can influence deeper in groundwater recharge district: while in discharge district, amplitude of temperature waves decays faster. Besides, a transient temperature field near horizontal strong leakage layer is simulated. It is found that because heat transfer ability of convection is much stronger than conduction, the temperature within strong leakage zone is consistent with recharge source quickly and then temperature field in a wider range is changed by conduction. Geologic bodies near low temperature source are cooled faster and changed more, vice versa, slower and less. Therefore, the potential leakage zone can be traced accurately in this way.

Two-dimensional numerical model is built for mining soft coal covered by soft rock under Beizao sea area. Mining process is simulated and roof abutment pressure distribution law is analyzed with the help of finite difference software FLAC3D. The result shows that there are two stress peaks in the abutment pressure and its magnitude and location are affected by the mining. It is also concluded that the abutment pressure distribution is affected by the roof stiffness, coal strength and buried depth. It is significant for the mining under the sea.

In order to set the pipeline out of the hazard zone, the numerical strength reduction method and actual landform simulating method are used to evaluate the position and shape of the landslide of Qianyang loess gully. In the process of simulation, convergence is chosen as the failure criteria. By reducing the strength parameters step by step, the surface of the landslide is decided according to the displacement isoline when the landslide happens. After the parameters of the pipeline traversing the loess gully is designed, the distribution of displacement in the loess around the well while excavation and the stability of the slope after excavation are studied. The results indicate that the method given in for designing the parameters of the pipeline traversing the loess gully can set the pipeline out of the hazard zone effectively; and the construction of the pipeline will affect the safety of the slope little. The change of the safety parameters after exaction is not obvious, which is from 1.162 to 1.156. At last, some reasonable advices for support are given based on the numerical simulation.

With the consideration of dynamic bedrock-structure interaction of nuclear power plant, explicit dynamic finite difference method is used in this paper; therefore, to analyze the characteristics of seismic response of the foundation of those nuclear power plants built on very soft bedrock, less softer bedrock and hard rock respectively, and to study the influence of rock hardness on the acceleration spectrum of the foundation. The research shows that: Seismic response of the foundation of the nuclear power plant increases if bedrock becomes harder and acceleration response spectrum moves to the shorter period (i.e. higher frequency domain) on the period axis with the increase of the rock hardness; In the high frequency domain, acceleration response spectrum of the foundation constructed on the harder rock is higher; for medium frequency domain, softer rock results in higher acceleration response spectrum; and rock hardness has little impact on the acceleration response spectrum in the low frequency domain.

By borehole camera technology, the structural characteristics of rock mass can be obtained. Further, a new method, rock mass integrity index (RMDI), is proposed to describe rock mass integrity. And this method is applied to separation strata boreholes for site investigation of the digital borehole camera project of Tangshan mining area of Kailuan coal mine. The application shows that: (1) The high resolution borehole image gives superior results for evaluating rock mass quality; (2) Integrity index density function (DIDF) can reflect rock mass integrity degree along axial distribution of boreholes well and truly; (3) The use of rock mass integrity index (RMDI) to evaluate rock mass quality is feasible, accurate and effective; (4) RMDI can be used to evaluate rock mass integrity in full or part range of boreholes, and to search for the optimal position with different integrity segment of rock mass in boreholes.

To apply the time domain reflectometry (TDR) to slope monitoring, on the base of brief summary of principle of TDR, and with types of indoor shear tests and situ construction of different cables, reflection waves of types of different cables are studied. Compared with the monitor results by TDR and oblique monitoring result by drilling hole, the follwing conclusions can be drawn, i.e. TDR can be fast applied to determining the sliding plane, economically, safely, and precisely. By the research results, to satisfy different monitoring goal, the application rules of types of TDR are put forward; and TDR is a very useful tool for slope survey.

Monitoring natural landslide hazards in a wide mountainous area has been a worldwide problem for a long time. Differential Synthetic Aperture Radar Interferometry (D-INSAR) technique, which is a main profile of satellite SAR application, has been an important developmental direction of microwave remote sensing in recent years. Although the D-INSAR technique is still under development and there are several bottlenecks that need to be solved; however, because it has an ability to theoretically measure a very small movement of the ground at a centimetre level for a continuous large areas, this technique can be considered as a potentially ideal tool for monitoring and forecasting occurrence of landslides. With the purpose of applying the D-INSAR to landslide hazard monitoring and early warning, this paper firstly introduces the main algorithms, derivation principles and processing method of the D-INSAR technique. Then based on a detailed review for the application studies to this subject so far in the world, the advantages and difficulties concerning the application of this technique to landslide monitoring are concluded. By means of some new developments of monitoring technique, possible solutions for the existing problems to practical application of D-INSAR are proposed. D-INSAR should be synthetically utilized with advanced earth detection and digitization techniques in monitoring landslide, such as permanent scatterers (PS), small baseline subset(SBAS), global positioning system(GPS), linear SAR (LISA) technique. These techniques are suggested to be combined with the D-INSAR technique together to improve an effective monitoring.