It has been clarified that the time-dependent behavior of soil results from both rheological properties of soft soils and consolidation of foundations which display a certain nonlinear characteristics and will play an important role in performance of major structures on soft soil grounds. In this paper, the time-dependent effects of soil deformation on interaction behavior of piled rafts and soil are considered. In the proposed procedure, the Biot’s fully coupled equations of consolidation are numerically solved by finite element method; and an elasto-viscoplastic (EVP) model of soils is employed to consider the rheology of soils. The variations with time and distribution in space of excess pore pressures in foundation soil underlying the piled raft and reactions as well as deformations or settlements of raft and piles during loading are examined through numerical analysis. It is shown that the coupled behaviour of rheology and consolidation of soils remarkably affect time-dependent performance of interaction of piled rafts and soils and the dissipation of excess pore pressures not only displays the Mandel-Cryer effects, but also is intimately associated with rheological deformation of ground especially in poor drainage condition. The pore-water pressure predicted considering rheological effect in addition to consolidation displays different patterns from those obtained by conventional consolidation analysis without consideration of soil rheology. While both effects of rheology and consolidation are taken account, the rigidity of piled raft plays a significant role in governing variation modes of reactions and deformations of piled raft with time. Furthermore, the edge pile displays different time-dependent behavior of internal forces and deformations from those of the central piles. The skin friction of pile may also display the nature of time-dependency. During loading, negative skin friction may occur in the pile segments near ground surface under soft soil condition and cannot be negligible in engineering design. The coupled analysis of rheology and consolidation gives rise a more rational evaluation of overall performance of interaction of piled raft and subsoil and conventional analyses which overlooks time-dependency of soil deformation may cause a certain inaccuracy in evaluation of interaction behavior and unreliability in design of structures on piled raft and foundation.

The dissolving mechanism of rock salt with and without stress is same, but difference between them is the variation of the dissolved surface. Dissolving model of rock salt without stress is set up based on the analysis of dissolving mechanism. By way of analyzing the difference of dissolving mechanism of rock salt with and without stress, equivalent dissolving coefficient is proposed to describe the macro-dissolving speed of rock salt under the stress, based on which dissolving model of rock salt under the stress is set up. The method to calculate the equivalent dissolving coefficient is proposed based on the uniaxial meso-mechanical test data under the coupled mechanical-dissolving effect, and the relationship among axial plastic strain, dissolving time and equivalent dissolving coefficient is obtained. The results can provide an important basis for the further analysis of coupled mechanical-dissolving mechanism of rock salt.

Based on the variational principle, the total potential energy of a general group of laterally loaded barrettes is established. By using the Gauss double numerical integration method, it is expanded to a simple equation of matrix form, in which a finite series is used to denote the lateral displacement of barrette shaft, Mindlin’s point-to-point displacement solution is applied to describe the force-displacement relationship of ground soils; and allowance is made for the nonuniform distributions, of both the lateral soil resistance at the front of and the lateral shaft resistance on the sides of the barrette shaft, along the perimeter of the barrette. In light of the principle of minimum potential energy, an explicit solution is obtained for the load-displacement relationship of laterally loaded barrette groups. The proposed solution is verified from the comparisons of the calculated results made with the three-dimensional finite element method.

Based on Mohr-Coulomb yield criterion , the Formula of Intermediate principal stress at failure of Mohr-Coulomb material in plane strain state was obtained by analyzing the Lode angle parameter and the general Mises yield criterion matched Mohr-Coulomb yield criterion in plane strain state, which helps to study the strain-stress of geotechnical materials and the strength effect of intermediate principal stress and also helps to modify Mohr-Coulomb yield criterion. Second, the relation of intermediate principal stress at failure in plane strain state between Mohr-Coulomb material and SMP material is put forward. Finally, a foundation under plane strain condition was analyzed by FEM; and the computational results shows that the formula is correct.

In terms of Biot's dynamic theory and elastic wave theory, the method of functions of complex variable and multi-polar coordinate is used to solve the problem of scattering around a circular lining in saturated poroelastic half-space under harmonic plane dilatational waves. Here, a circular cavity with large radius is used to replace the straight boundary of the saturated poroelastic half space. The equations of the Biot wave motion for poroelastic and the equations of the isotropic elastic wave motion for lining are decoupled to Helmholtz equations by introducing potential functions. The general solution of Helmholtz equations is given by means of the complex series expansion technology. Utilizing the general solution of the potential functions, the expressions of the displacements, stresses and pore pressures of saturated soil and those of the displacements and stresses of lining structure can be obtained by using the boundary conditions and continuous conditons. Then the variations of the coefficients of dynamic stress concentration and the pore water pressures concentration on boundaries of the lining structure are discussed for different parameter conditions. The results of the given numerical example indicate that the method is useful and efficient to the scattering of lining in poroelastic half-space.

This paper mainly carried out analytical theory for consolidation and its engineering performance of double-layered composite ground with granular columns considering smear effects and stress concentration effects, and discussed possible variational laws considering different cases, also with the common applicability of this analytical theory. Conclusions were made that speed of consolidation depended on drain ratio and horizontal coefficient of permeability and stiffness of pile; draining of bottom did not have efficient influence on consolidation with small drain spacing ratio. whether considering stress concentration effects or not had efficient influence on consolidation.

Casing damage is a difficult technical problem and puzzle oil field for a long period. Large field investigation and theoretical studies show that casing damage is closely related to seepage field changes. Shear failure damage, tensile damage and extrusive damage are all induced by seepage. Based on fluid-solid coupling theory, mechanism of seepage induced casing damage were analyzed; a mathematical model to predict casing damage is established; finally and listed simulation cases are given. It is significant to guide the casing damage prevention and forecast.

Analysis of convex location and concave location as the central section of composite soil nailing wall was normally overcautious or unsafe due to the typical spatial effect at convex and concave locations. Behaviors of deformations at convex and concave locations were analysed accordingly by three-dimensional elastoplastic FEM. The results show that the most dangerous area with maximum deformation is the side near convex location of foundation pit; and deformation of concave location is less than convex location evidently.

In order to investigate the long-term deformation properties of municipal solid waste (MSW), a series of creep- decomposition comparative tests were conducted in the laboratory under different biodegradation conditions. Based on the experimental results, characteristics of strain changing, void ratio changing, settlement rate changing against time, and the relationship between stress and strain of MSW were studied. The logarithmic settlement rate is linear with respect to the logarithmic time considering degradation of MSW. It can be concluded that the creep properties of MSW is not related with stress but also with decomposition of organic fraction by considering the stress-strain curve. Test results have proved that the creep-decomposition experimental test offered a new method for investigating the deformation properties of MSW in laboratory.

Three-dimensional nonlinear elastic finite element method had been developed to study the bending behavior of the passive row piles subjected to surcharge nearby. The influence of the space between the row piles, foundation soft sublayer and the distance between surcharge and row piles on the bending behavior of the passive row piles was studied. The variety law of the bending moment and deflection was posted. Study showed that the positive bending moment of piles was 0.55 times pile-length in the vicinity of surcharge. There was biggish negative bending moment in the top of the piles. The negative bending moment varied from increasing to decreasing as surcharge increased. While surcharge increased to a certain value, the positive bending moment accelerated. The moment increased as the space of row piles. While there was soft sublayer in the ground, the negative moment decreased, moreover, the positive moment increased distinctly.

The mathematical model of binary fractal interpolation is introduced. Based on the statistical self-similarity of rock fracture surface, the concept of improved self-affine fractal interpolation is put forward. By using the method of the improved self-affine fractal interpolation, the rock fracture surface is simulated with the measured data from the rock fracture surface. Compared the surfaces simulated with different number of given data to the practical fracture surface, the simulated precision is obtained. The relationship between the number of given data and the simulated precision obtained and shows the power function law. This means that we not only can obtain the simulated result in the interpolation, but also can get the estimation precision of the simulated result. Using a little amount of given data to simulate unknown surface gives the simulating method from the parts to the whole. This is useful for studying, simulating and displaying the shape of complicated objects intuitively with some little information, such as the topographty, the fault surface and the fracture surface of materials.

FISH functions written are used to calculate axial, lateral and volumetric strains as well as Poisson’s ratio of rock specimen in plane strain compression. Influence of loading rate on shear band (SB) pattern and entire deformational characteristics is investigated numerically using FLAC. In elastic and strain-softening stages, the constitutive relations are linear. A composite Mohr-Coulomb criterion with tension cut-off is used. For lower and moderate loading rates, a SB whose inclination angle and thickness are not influenced by loading rate bisects the specimen, so that the post-peak slopes of stress-axial strain curve and stress-lateral strain curve are not related to loading rate. Higher loading rate leads to the conjugate SBs, resulting in less steep post-peak stress-axial strain curve and stress-lateral strain curve. At the same axial strain, higher loading rate leads to shorter SB. With an increase of loading rate, the precursor to failure is more apparent unless the loading rate is very high. At higher loading rate, the great fluctuation in stress exists so that the axial strain corresponding to the peak stress is estimated inappropriately. In strain-softening stage, higher loading rate results in ductile lateral strain-axial strain curve, Poisson’s ratio-axial strain curve and volumetric strain-axial strain curve as well as higher peak of volumetric strain and the corresponding axial strain.

Rock burst may result in tremendous hazards in coal mining, such as sudden roof falling or even abrupt closing and jamming of roadway. According to the mechanism of roadway destruction by rock burst, a strong-soft-strong (3S) structural model to prevent rock burst from taking place was established and analyzed. The result shows that the 3S structural model has several characters, such as strength character of the structure itself, stress adjustment, wave absorbing, deformation and anti-deformation, energy consuming, etc.. Stress criterion and energy rule of the small inner support structure destroyed by rock burst were deduced. At last, based on the 3S model, the engineering application was theoretically discussed; several techniques such as decreasing shock energy, setting proper soft structure, and improving support strength were put forward to prevent roadway from being destructed by rock burst.

Finite element method with reduced shear strength (SSRFEM) was used to evaluated the base stability of excavations in soft clays under the undrained condition. The influence of clay undrained shear strength, conditions of pit bracing system and pit dimensions on base upheave stability of excavations were studied detailedly. The results from several limit equilibrium analysis methods for evaluating base stability of excavations were compared with the results from FEM. It shows SSRFEM is a reliable and robust method for assessing the safety factor of the base stability of excavations and limit equilibrium analysis methods only can be used on some conditions.

In order to enhance computational efficiency and precision of response surface methods, the global response surface method is improved. Using RBF neural network substitutes BP network as the approximation of implicit performance function, and the response surface is formed in the sphere of hyper-pyramid at iteration step. Compared with other response surface methods, numerical case studies show that the proposed method not only markedly reduces the times of iterations and finite element analysis to shorten the processing time, but also benefits to better accuracy. Moreover, the engineering examples of shallow foundation and retaining wall are analyzed on their structural reliability. The calculation results show that the proposed method may gain reliability index satisfyingly by quicker convergence rate and less machine time, and to be suitable for reliability analysis in geotechnical engineering.

Based on studying the mechanism of deformation and bearing capacity of vibro-replacement stone column foundation, the assumptive conditions are presented. The composite two-dimensional numerical model of stone columns is estabilished; this model considers the couple of stress-strain with Biot consolidation and the reinforced efficiency, the finite element analysis program (analysis program of soil engineering) is developed according to this model. The reliability and validity of APOSE is verified by two simple examples. APOSE can be applied to analyze the consolidation and subsidence of vibro-replacement stone columns and sand well compound foundation, etc..

A series of isotropically consolidated undrained triaxial tests (CU) were conducted on a clean sand and a well-graded silty sand (with 10 % silt content) to investigate the effect of silt, void ratio and confining stress on the instability of saturated sands. The test results show that both clean sand and well-graded silty sand exhibit strain softening characteristics under undrained condition (i.e. instability). Under the same confining pressure, the brittleness index increases with increasing void ratio, but the stress ratio of the instability line decreases with increasing void ratio. If equivalent intergranular void ratio (ege) is used to interpret the critical state data of the silty sand, clean sand and silty sand possess similar critical state line in ege-ln p? plane. Based on the critical state theory and equivalent intergranular void ratio, clean sand and well-graded silty sand exhibits similar instability under the same modified state parameter (?ge).

Utilizing actual rainfall data, transient stability of soil slope is computed and analyzed under condition of one peak of rainfall and 8 different kinds of two peak rainfall schemes at different time intervals according to theory of unsaturated soil mechanics. Moreover, the effect of time and space about stability of slope is explored under the infiltration of rainfall into the slope body. In addition, soil hydraulic property changed by rainfall is presented too. It is found that the time effected once by rainfall is about 12 day, the minimum of safety factor appears after 0.5 day of rainfall, that the most dangerous situations of the soil slope effected by different interval time of twice rainfall happen 0.3-0.8 day later than that of once rainfall, the lasting time effected by rainfall being kept, and that the physical and mechanics characteristics of the soil, the most dangerous slip surface of the slope and its relative safety factor is effected and vibrated with water motion in different parts of the slope.

There are many ruins of ancient earthen sites in Northwest China, which are precious mankinds culturalheritage, and their valuable artistic value is rareworldwide. But the violent processes of the wind erosion caused many ancient earthen sites collapsed. Many investigation indicate that the wind erosion is the main power mechanism and the genesis resulting in destruction of the ancinet earthen ruins. So this paper make the indoor wind-tunnel test and field wind erosion test to study the performance against wind erosion. The experimental result conclude that the bear for wind erosion of the consolidated ancient earthen sites are hugely increased.. The results of the indoor wind-tunnel test indicate that the wind erosion amount is increased with wind speed and with test time. At the same time, the laboratory experiment discovered that even if the wind speed reaches 20 m/ s, the wind erosion amount of the samples reinforced with more than 5 % of PS is less than 20 (kg/m2•h), and the against wind erosion intensity enhances 6~10 times. According to the result of the field wind erosion test, the wall consolidated with 3 % or 5 % of PS is good bear for wind erosion, and the depth of penetration and the amount of PS material directly affect reinforcingt effect. In sum, the key to protecing Ruins is to choosing the suitable consistence PS material and is to enhancing penetrability of PS material So this reinforced method could be effective in scientific protecting the rare ancient earthen sites from rigorous natural conditions in Northwest China.

Regarding the Burridge-Knopof (B-K) spring block model as a conceptual model for the physics of earthquakes has attracted much attention among physicists and seismologists. In this paper, the B-K model is used to analyze the slope instability. There are certain characteristics of the B-K model such as deterministic chaos，self-organization，etc., which provide heuristic clues to understanding of the nature of sliding slope and shed light on the instability of slope prediction．

The influence of cushion on loading behavior of the composite foundation with compacted soil-cement pile was studied by static loading in-situ. The result of test shows that the thickness and character of the cushion have an important impact on the loading and deformation characteristics of composite foundation. With increasing of the cushion thickness, the loading ratio of the pile is decreasing, but the ratio of the soil is increasing. The pile-soil stress ratio reduces with the increasing of the cushion thickness. On the other hand, the more the character of the cushion is strong, the greater the ability of adjusting deformation, the thinner the cushion thickness. The test result of different thicknesses and two types of cushion shows that the best thickness is of 0.2-0.3 m.

In order to evaluate and treat the distress of silt subgrade by rainfall of Beijing-Jiulong railway in Yellow-River alluvial plain area, the basic physico-mechanical properties of silt were investigated by a series of laboratory experiments, for varying compactnesses and water contents; the deformation and strength behaviors of compacted silt were studied. Results indicate that the silt is poor graded and difficult to be compacted, even at its maximum dry density, compacted silt also has high volume ratio of air. For specimens at optimum water compactness of 90 %, the deformation character is softening. However, with water content increasing, the deformation character of compacted silt changes to hardening, especially for specimens at high confining pressure and at high water content, the plastic shear deformation is more significant. For specimens at compactness lower than 85 % and water content not less than optimum water content, the deformation character is always hardening. Cohesion of compacted silt descends sharply with compactness decreasing or water content increasing; but internal friction angle reduces insignificant. There is remarkable slaking deformation of compacted silt due to wetted; and compactness plays a very important role in slaking deformation.

It is a key problem that how to determine the most dangerous sliding circular surface and calculate the minimum safety factor in the stability analysis of soil slope. The traditional limiting equilibrium analysis method will be easily immersed in local minimum, so the real most dangerous sliding circle can not be searched out. For the reason, a new approach which is genetic algorithms integrating the traditional method of slices with vertical interface is put forward to analyze the entire stability of soil slope. The stability analysis model of soil slope which can be called object function is established by the methods of slices with vertical interface; and then the most dangerous sliding circular surface will be searched out by the genetic algorithm. So the minimum safety factor of soil slope will be figured out. The analysis process will be performed by the computer program designed by the Microsoft Visual C++ program language. After the search scope of the most dangerous sliding circular arc is determined and input into the program, all the calculation and analysis work will be done by the program algorithm automatically. Genetic algorithm simulates genetic evolutionary process of organisms and avoids the limit of traditional methods successfully. Compared with the minimum safety factor figured out by the area subdivision method and the most dangerous sliding circular arc searched out by the same means, the conclusion can be made that the stability analysis result of soil slope analyzed by the genetic algorithm is much more reliable. Genetic algorithm can successfully solve the problem that how to search the entire extremum of soil slope. The engineering application case indicates that the genetic algorithm is effective to analyze the stability of soil slope, which has extensive prospect and will be widely used in the slope engineering.

Based on nonlinear relationship between permeability and void ratio of intact natural clay, four theoretical permeability models, i.e. model, model, model, and model, are introduced and discussed. The 1-D consolidation and permeability combined tests on eight undisturbed Xiaoshan clay samples are carried out by GDS advanced consolidation testing system. Void ratio and directly-measured permeability coefficient obtained from the test results are analyzed to summarize clay parameters of four permeability models. Experimental results show that the permeability of Xiaoshan clay decreases nonlinearly with consolidation pressure increasing; and the permeability coefficient varies from 8×10-8 to 8×10-9 . It is also shown that all the four nonlinear permeability models are suitable for describing the permeability of Xiaoshan clay.

Based on Kalman filtering theory, an identification method of Winkler foundation’s parameter is put forward. After Mindlin theory is introduced, the differential equations of Mindlin plate on Winkler foundation are derived. Through applying Fourier transformative technology, the corresponding solutions to the pinned plate on Winkler foundation are obtained. Kalman filtering equations of Winkler foundation’s parameter are established ; and the steps of Kalman filtering identification of Winkler foundation’s parameter are studied. Research shows that Winkler foundation’s parameter can be efficiently identified by applying Kalman filtering theory ; and the convergence velocity and precision of Winkler foundation’s parameter are depended on both the initial information of Winkler foundation’s parameter and the measured displacement data at the studied nodes. And this identification method can also be applied to the problem of identification of parameters of other foundation models.

The model pile with two plates was through 5 times repeated load-bearing and load-shedding tests under the limit load and 0.75 times of the limit load, in order to studying the project behavior of piles with plates and branches in silty clay. In addition, taking the simple loading test in silty clay for determining the limit bearing capacity. According to the test results, the bearing capacity and deformation characteristics of the pile in the soil are analyzed; and the pile’s characteristics about load transfer in silty clay, characteristic of pressure changing on different places of pile are studied; especially the reason why the skin friction of the soil to the pile would appear complex changing is analyzed; in addition, the situation and reason of the pressure changing of soil different distances away from the plate during the repeated loading are analyzed too. It is shown that the repeated loading of different intensities loads impact obviously to the convergence of settlement deformation; the mutual effect mechanism of the pile and the soil is quite complex, so a lot of studies should be done to understand the project behavior and load transfer mechanism of the pile with plates and branches under repeated loading.

Facing is significantly important for stability of soil-nailing walls and for transferring earth pressure to stabilized soils . It is absolutely sure that the facing bear against water and earth pressure. However present designers of soil-nailing walls consider the facing as accessory structure rather than the main one. Facing isolated and considered as finite beam on winkler foundation simply, solutions of displacement and inner force of soil-nailing walls are gained through analyzing soil-nailing interaction. The results show maximal value of displacement is on the lower side of slope instead of the top. The location moves down with the pit depth. The law is that displacement is larger in the middle than the two sides in agreement with the actual measurement data. Internal friction angle and cohesive strength have large effects on the displacement, so preventing water from flowing to the vacation is very important. The analytic solutions also disclosure characteristics of moment and lateral earth pressure. Facing moment is increased with depth, the gains are small at the top slope and large at bottom of pit, and reaches its maximal value at lower side of slope. The moment is developed into negative one because of passive earth pressure at the bottom of pit. Earth pressures have similar characteristics and behaviors with inner facing displacement. The paper puts forward a method of exploring soil-nailing walls based on precise Elasticity Theory , the results are also referenced by designer and give people throughout comprehension of soil-nailing walls.

Aiming at the measure of expressway slope protection with greensward in China at present, the reinforcement mechanism is analyzed; and the reinforcement effect is studied experimentally. Based on the direct shear test results, the effect of roots content on the two indices of soil shear strength (c, )is studied; and the reinforcement effect formula of roots is deduced so as to use for reference in the design and construction of slope virescence.

Based on the solution of Boussinesq, a model is established; and the model assumes that a cone-shaped load acts on the circinal plane while its radius of a. Then a shield tunnel ground maximum settlement formula during constructions, is derived. The two important parameters are probed into. Then the three results of the Peck method, the formula in this paper and the true value are compared by a real example. Without considering creep of soil, the formula in this paper is closest to the true value.

During pile driving soil adjacent to pile tip comes into the tubular pile thus formed soil plug. The effect of soil plug on the bearing capacity of large-diameter steel pipe pile and new developed large-diameter cast-in-situ tubular pile can not be neglected. Through soil plugging the bearing capacity of open-ended pile will be increased and its settlement decreased. Two different definition of soil plugging were compared, and through which the definition based on the failure mechanism was verified to be more reasonable. Different effects, such as pile diameter, inner friction, vertical bearing capacity of the underlain soils and the lateral stress level, were studied. ICP discriminant of plugging mode for both clay and sand was discussed. This method was proved to be a simple one and cannot embody the real plugging in practice.

The failure model of young concrete lining and its safety vibration velocity under explosive loading are important problems in hydroelectric and railway engineering. According to the characteristics of the propagation of elastic P wave and SV wave, the P wave and SV wave transmitting in folium concrete lining and their approximately research method were analyzed. Based on Mohr-Coulomb strength criterion, limiting tensile stress and limiting tensile strain strength criterion, the failure model and safety vibration velocity of young concrete lining under explosive loading were studied. The results indicate that the incident stress wave and refractive wave in the lining is the most dangerous to the concrete lining. The reflecting wave produced at the lining interface will decrease the stress in the lining and has an uninstall effect. The safety vibration velocity of lining increases with the rise of the concrete age. Under the effect of P wave, the safety vibration velocity increases with the accretion of the angle of incidence, the shear failure is easy to take place at a big angle of incidence, and the tensile failure is easy to take place at a small angle of incidence. Under the effect of SV wave, the shear failure is easy to take place at a small angle, but tensile failure will appear in a big angle. The higher modulus of elasticity of the surrounding rock is, the lower safety vibration velocity of concrete lining is.

Dynamic characters of saturated soft clay strata have been studied under unconsolidated undrained condition based on the cyclic torsional shear test results. Stress equivalent failure relationship and strain equivalent failure relationship have been studied under different confining pressures and different stress combinations through cyclic torsional shear tests and cyclic triaxial tests. Analyzing the tests results of different test stress states, it is surprising finding that saturated soft clay followed Mises criterion under static combined cyclic loads as same as under static loads. And the cyclic strength is an invariable on certain static loads and certain number of circles to failure. Further, the pseudo-static elastoplastic cyclic creep relation, that is, the changing law of cyclic accumulate strain with static loads and cyclic loads as well as number of circles to failure is built through cyclic triaxial tests results. And this relation is in harmony with cyclic torsional shear test results. Then we can draw a conclusion that cyclic stress followed Mises criterion and cyclic failure course met pseudo-static elastoplastic cyclic creep for saturated soft clay under unconsolidated undrained condition. These conclusions not related to the testing stress states and confining pressures, it can be popularized in general stress states. It is the basis for research cyclic failure mechanism of saturated soft clay.

Based on the theory of stochastic medium, a new tunnel movement and deformation prediction software code is developed. And it is used to predict the ground surface settlement，inclination，curvature，lateral movement and lateral deformation due to the tunnel excavation. And through modifying the formula, it can be applied to predicting the ground surface movement and deformation of large cross-section tunnel for staged construction. A case study shows that the prediction method developed can reach good results and has some practical value.

The analytical solution is presented to one dimensional viscoelastic consolidation problem of soft clay with impervious boundaries and pervious boundaries under cyclic loading that has been Fourier expanded. The influence of some parameters, such as permeability coefficient, viscosity coefficient and elastic modulus, etc. and different constitutive relation conditions on the consolidation is investigated. It is shown that the effective stress reaches the stabilized state in the end with certain amount of cycles. The rheological feature of saturated clay mainly functions in the intermediate and long-term stage of consolidation.

With the application of new solidifying agent to ground engineering, the influence of solidifying agent on the strength of solidified clay is widely noticed. The variation of unconfined compressive strength of the clay improved with solidifying agent #Ι with different mixing ratios and ages are studied through the laboratory experiment. The data of unconfined compressive strength show that the stabilizing effect of the agent #I Ιis superior to that of cement.A prediction equation is developed for calculating the strength of stabilized clay by analyzing the experimental data.

Based on the engineering tests, the stress, pore water pressure and effective depth range of treating soft foundation with vacuum preloading are analyzed. The analytical results show that: the vacuum preloading brings atmosphere about pressure difference between treating groundsill and its entourage; and brings plus pore water pressure; the mechanical relation is accordant with effective stress principle. The test results of pore water pressure are influenced by atmosphere pressure. Vacuum preloading and surcharge have distinct difference in stress action characteristics, stress treating transfer and effective treating range etc.

As large scale construction of highways in West China, more small spacing tunnels have been adopted due to the limitation of landscape. Because of the complexity of construction techniques，deformation and failure mechanisms of surrounding rock mass during excavation are complicated. Construction sequences and supporting time are important to the stability of rock mass and concrete lining. Effects of release proportion of the load and supporting time on stability of tunnel are studied based on construction characteristics of Qishucao Small Spacing Tunnel which belongs to Shanghai-Chengdu high-way. Numerical simulation results show that, as the lining constructed earlier, linings and anchors bear bigger load and the plastic deformation becomes smaller. Constructing the reinforced concrete lining in time can prominently control the deformation of the rock pillars and improve the stress condition of the surrounding rock mass. Achievements from the study can guide the design and construction of small spacing tunnel with similar conditions.

It has been a focus of debate for a long time how the system bolts act on the loess tunnel. Associating with the large section loess tunnel of the building Zhengzhou-Xi’an high-speed passenger rail lines, we have done many in site contrast testing to evaluate the effect of system bolt. For the good comparability of the testing result, we’d choose the tunnel which has the similar test condition. In this case, we take the Hejiazhang Tunnel as our experimental section in which we set system bolt section and non-system bolt section both for 40 meters. The main contrast experiences are the settlement of the tunnel crown and arch foot, horizontal convergence, surrounding rock pressure, the stress of initial supporting steel framework, axial force of bolt, etc. The testing results indicate: the section with system bolt has more 40% of the settlement in the tunnel crown and more 25 % horizontal convergence than the one without system bolt; there are little difference in the soil pressure and steel framework stress between the two sections; there is less axial force in the bolt and the part of arch is pressed. Through comprehensive analysis, we make the conclusion that there is little improvement of supporting effect in the crown bolt, so we suggest canceling the bolt to induce the construction procedure and quicken the enclosed of the initial supporting section of the tunnel. It will be helpful to control the supporting settlement and deformation and it also reduces the investment cost.

The non-thickness contact friction element is presented to simulate the mechanical behavior of contact surface between rockfill and concrete retaining wall for Guanyinyan Hydropower Station mixed dam, which makes up of a rockfill dam and a roller compacted concrete gravity dam. The Ducan hyperbola E-B constitutive model is applied to simulate rockfill body and clay core wall’s stress-strain relations. Considering actual construction process and impounding process, sensitivity analysis are performed for varying of configuration shape of concrete connection, which include contact surface slope changing and contact surface rotating to upstream on horizontal plane. Normal stress, contact state and latent water power crack area of contact surface for different configuration shapes of concrete connection can be revealed through sensitivity analysis. So the better configuration shape of concrete connection can be recommended. The three-dimensional nonlinear FEM simulation results show that normal stress on contact surface of clay core wall is all compression stress; the one is smaller when contact surface slope steeper and rotation angle smaller to upstream. In sum the seepage prevention of the fourth design scheme among wrapped connection configuration shape is better than others from a comprehensive consideration, which will be recommended to be the design scheme.

Utilizing seepage coupled slope surface runoff theory, the seepage field of Dishuiya Landslide No.1 affected by the infiltrating process of rainfall is simulated according to the monitoring daily rainfall data in May. Based on generalized limit equilibrium method ( abbreviated. GLE), the safety factor of the landslide is computed by means of unsaturated soil strength theory, respectively utilizing strength parameters under raw or saturated conditions. Simultaneously, its stability is evaluated, which offers a reference for transient stability analysis. Then, transient stability of the landslide is calculated and analyzed by means of calling seepage and runoff results at different rainfall step. Moreover, the time and space effect of the landslide’s stability caused by rainfall infiltrating into the slope body is explored. Meanwhile, soil hydraulic property and slope surface runoff affected by rainfall are presented.

Based on the test results of prestressed high strength concrete(PHC) pipe piles by static and high strain dynamic load testing, Q-s curves of test piles have been achieved; and the relation between the soil resistance and relative displacement between pile and soil is calculated through the stress test. Comparative analysis of the Q-s curves between the dynamic and static load testing is made; and the settlement behavior of PHC pipe piles is discussed. Results show that the settlement of pile calculated by high strain dynamic load testing is higher than that of pile tested by static load testing when load is smaller; and it is smaller than the result of the static load testing when load gets larger. The results also show that the end bearing of the pile can not exert sufficiently when the pile driven into the full efflorescence granite or the higher intensity of the soil in spite of the dynamic or the static load testing; and the Q-s curves of test piles have the character of slow transmutation.

Taking Yuyang coal mine as research base, this paper systematically has carried on experiments of the kinetic parameters of groundwater, the combined structure features of mechanics of overlying strata and the water-insulation character of weathered zone of bedrock. The result indicated: Water-bearing stratum at the bottom of eolian deposit sand strata is strong water-bearing stratum. The intensity of mudstone stronger than sandstone on the main production seam; the porosity, moisture content and tensile compression ratio of sandstone is great; the clay soil content of mudstone and sandstone is low. So it has new damage and excursion character of canonical brittleness,the feebleness capability of resist remolding and the feebleness revival capability of water-stop. It settled the character of dynamic vary of height in breaking of overlying strata in shallow coal seam with a thin bedrock as elements fitting based, and put forward long-wall mining to control blowing out Water and bursting sand. The technique apply in Yuyang colliery successful and put into green technical conservation water of mining. The paper settled foundation for further popularized apply high productive and high efficient mining and protect pysical environment for putting into green technical conservation water of mining for shallow coal seam with a thin bedrock in Yushen coal field in Northern Shaanxi.

In order to research the behaviors of the geogrids reinforced soil retaining wall of wrapped face in the railway main line of China, the tests, including the basement pressure and lateral pressure of the reinforced soil wall, the tensile force of the reinforcement and the lateral deformation in-situ are done. The vertical basement pressure, the distribution of tensile force along reinforcement, the potential slide surface and the lateral earth pressure along height are analyzed. The basement vertical pressure of reinforced soil retaining wall is nonlinear along the reinforcement length, and the maximum value is at the middle of the reinforcement length, moreover the value reduce gradually at former and bottom. The testing lateral pressure of the reinforced soil wall is nonlinear along the height; and the value is less than the active lateral earth pressure. The distribution of tensile strain along reinforcement at the upper wall is single peak value; but the distribution of tensile strain along reinforcement at the lower wall is twin peak values. The potential fracture plane at upper wall is similar to “0.3H” method; but the potential fracture plane at lower wall is near to the active Rankine earth pressure theory. The position of the maxmium lateral displacement of the wall face during construction is at lower wall; moreover the position of the maxmium lateral displacement of the wall face after construction is at top of the wall.

Quaternary period sediment in north side of the Yangtze River estuary (Nantong-Qidong reach) is evaluated by physical property indexes; it has poor properties and belongs to soft soil according to the soil classification system. But evaluated by mechanical properties indexes (a1-2, Es1-2, CPT, SPT etc), the soil has good properties. So it is not all consistent between physical properties indexes and mechanical properties indexes. The phenomenon is analyzed that physical property is poor but mechanical property is good. Now some, new indexes evaluating engineering characteristics of the soil are proposed to solve the inconsistency between physical properties and engineering properties.

By using Mindlin solution and boundary element method, the calculation formulas of superimposed stress of surrounding soil induced by bulkhead pressure and friction force during the propulsion of shield tunneling are deduced. According to the space regularities of distribution of ground loss and by image method theory, the calculation formulas of superimposed stress are deduced. And combining the above three part of stress, the total superimposed stress induced by shield tunneling is obtained. Finally, combined with the practice of subway engineering in Shanghai, the distribution law of the superimposed stress caused by bulkhead pressure, friction, ground loss and their combined effect is analyzed. And the analytical results can provide gist for the protection of surrounding construction during the propulsion of shield tunneling.

Finite element method was used to calculate the additional tensile stress of different layers of the pavement and of steady broken stone-cement layer, which are both caused by the differential settlement between new embankment and old embankment for expressway’s extension project. Based on the results obtained by finite element method, and the requirement of differential settlement of subgrade in code and that of the function and structure of pavement, this paper put forward a control standard of variation range of cross-slope gradient of road bed’s crown after completion, less than or equal to 0.45 %, as the allowable differential settlement for expressway’s extension project on soft soil foundation according to design theory of control settlement. Finite element method was also used to analyze some cross-sections of Foshan-kaiping expressway extension project in China. The extension part of subgrade in this project would be treated by composite foundation of deep mixing pile. Through analyzing composite foundation of deep mixing pile with different construction parameters by FEM, the differential settlement of subgrade were respectively obtained. Combining with the control standard of differential settlement drawn in this paper and the design theory on control settlement, the optimum design parameters of deep mixing piles were obtained, i.e. pile spacing equal to 1.6m, length of pile equal to 8m, diameter of pile equal to 0.5 m. In practice, pile spacing would be 1.5 m, 0.1 m less than the calculation’s result because certain non-concordance happens between piles and soil when bearing load.

The interaction between the resistance at pile end and the resistance of pile is researched through the indoor model test on the rock-socketed pile. The result shows that the rock stratum at the pile end influences the lateral resistance of pile; as the increase of strength of rock at the end, the lateral resistance of pile will increase; but the enhancement effect doesn’t occur at the whole side of pile, only near the end of pile. Inversely a good lateral rock stratum also increases the resistance at pile end. The load-bearing capability of pile will be improved by using the interaction relationship so as to optimize the design method of pile.

Projects of excavation constructions of triple-span arch culvert are simulated using nonlinear finitee element analysis program. After two feasible construction projects are simulated, ground surface settlement, stress change of liner, plastic zone of surrounding soil and so on in the one project are relatively compared with those in the another project. An optimized project is then selected by using fuzzy evaluation after comprehensive consideration. Various risk situations in tunnel excavations are found from the simulation data, which reminds construction unit to adopt relevant provision for the risk area, has achieved high application value and can be used in similar construction for reference.

By considering train load as single linear moving load and rock mass as viscoelastic layered ground, the paper analyzes the dynamical response of the rock below the moving train with the Multi－Layer method. The affecting range of the moving load is obtained , thus the affecting extent of the moving train load on the stability of the underlying highway tunnel can be evaluated. The comparison of theoretical analysis with site monitoring results(mainly about the vibration response of the tunnel) shows that they accord with each other.

The soil parameters that effect phase velocity of Love wave are compared; and it is feasible using phase velocity of Love wave to determine shallow shear wave velocity profile of the site by virtual inversion. The first mode phase velocity of Love wave estimated from three-component microtremor array records is chosen as the object function, the shallow shear wave velocity profile of the practical site is inversed by means of a hybrid approach of genetic algorithm and simplex in two typical conditions and are compared with those determined from PS logging data; and it shows that it is a feasible technique using phase velocity of Love wave estimated from microtremors array to determine the shallow S-wave velocity structure of engineering site.

The first monitoring for surface and deep of surrounding rock was used by high-precision total station instrument and sliding micrometer in large-scale underground caverns in China. According to thirty months monitoring data, the measuring points on rockmass surface of which the displacement are larger distributed on the 5 th and 6 th layers excavation rockmass, the deform ations of deep rockmass is mainly caused by the opened structural plane; and the rockmass of underground caverns is stable during monitoring period. Through monitoring and rapid forecasting, which guide the construction works immediately provide security for the project.

As an all-weather and high precision continuous positioning system, the global positioning system(GPS) is widely applied to engineering measurement and deformation monitoring because of its speediness, agility and operability. In combination with practice, occupation planning, baseline vector calculating, network adjustment results and residential uncertainty of the deformation monitoring network are analyzed and studied in detail. The reliability and accuracy of GPS monitoring for slope deformation are verified.