Through investigation and in-situ measurement of crustal stress in tunnel location, rather large tectonic stress is ascertained in the tunnel region at first. Because of core sample break, only stress of disturbed area is measured in the tunnel. In the process of 3-dimension numerical modeling, the course of vertical erosion by the Wujiang River is modeled in order to reflect the effect of topographic form on crustal stress. And using the method of pilot calculation to adjust coefficient of horizontal pressure, then appropriate initial stress is determined. Making calculated results coincide with the data measured in-situ, the rational coefficient and crustal stress is obtained. Numerical calculation covers the shortage of in-situ measurement. The research results show that crustal stress of tunnel axis varies with embedded depth and topographic features; and the section K42 is of very high stress. The results provide a scientific foundation for analyzing excavation, support and stability of tunnel.

The effects of hydraulic characteristics play an important role in many landslide hazards; accordingly the variation of matric suction and seepage are considerable factors to evaluate the stability of unsaturated soil slopes. This paper investigates the difference between finite element method with shear strength reduction technique (SSRFEM) and limit equilibrium method (LEM) which are applied to evaluate the stability of unsaturated riverbank in steady and transient seepage flow state. The results show that the effective shear strength equations for saturated soils which are introduced by Bishop and Fredlund are the same in essence. Besides, it is shown that the SSRFEM is more applicable to evaluating global stability of slopes than LEM from the slope stability analysis results in transient seepage flow state. Moreover, the factor of matric suction can be replaced by the relative degree of saturation when the degree of saturation is comparatively high; therefore the approach which is adopted by Bishop can evaluate unsaturated soil slope stability more conveniently, especially in rainfall or water level variation situation.

Based on the theory of particle flow code (PFC), one of the discrete element methods, a series of biaxial tests are simulated to establish the relationship between micro parameters and macro mechanical properties. A numerical model of similar soil slope with weak intercalated layer is constituted by adopting the parallel-bond model of PFC. The progressive failure process of slope is simulated and fissures in slope are monitored during excavation. The simulation results show that the failure experiences a process of fissures formed, grew lager, and developed until large scale landslide occurs. The fissures form from the toe of the slope and weak intercalated layer at first, then expanded until slide occurs, which behaves as a typical progressive failure process; soil structure is seriously damaged and bearing capacity decline after slide occurs. The simulated failure process and numerical results fit the site condition well. It is shown that the proposed method can be used to study the similar soil slope’s failure process and its mechanism.

Geddes stress solution is widely applied to settlement calculation of pile foundation. In order to find the solution, pile skin friction is simplified as concentrated force; however the influence of changing diameter and length of pile additional stress in the ground due to skin friction can not be taken into account. The actual calculated results of the short pile with low ratio of length to diameter are quite different from the results of vertical stress factor by Geddes stress solution. Using the numerical integral function of NIntegrate in Mathematica software, a numerical method of calculating the vertical component of Y-shaped pile skin friction acting at any point in the ground is obtained. One loading case of the skin friction is rectangular distribution from top to bottom along the pile body and uniform distribution in circumference; the other one is triangular distribution from top to bottom along the pile body and uniform distribution in circumference of Y-shaped section. The influences of four independent variables R, , s, , of Y-shaped section on additional stress factor due to skin friction and errors produced by Geddes stress solution are analysed; and the influences of pile length and calculating depth on errors are also analysed. Some significant conclusions are obtained.

Model tests of piled raft are performed, the high quality digital pictures of displacements of soil and piled raft under each vertical load increment are taken during testing process. The axial forces of piles are measured. The detailed displacement fields of soil and piles are obtained by analyzing the digital pictures. Based on this, the failure mode and deformation behavior of the piled raft are studied. The effect of pile spacing and pile length on the settlement beneath pile tip and shaft resistance of pile is analyzed. Test results show that pile spacing is the major factor which has significant effect on the slip at the interface of pile shaft and surrounding soil. The piled foundation with bigger pile spacing produces larger pile – soil slip and pile tip penetration. The central pile under comparatively flexible raft can produce larger pile – soil slip and pile tip penetration than that of edge piles when pile spacing is large enough. The pile tip penetration accounts for most part of the settlement of piled raft with larger pile spacing. This implies that it’s necessary to construct a theory, where the pile tip penetration should be taken into account, to calculate the settlement of piled raft with large pile spacing. By laying a layer of sand cushion, compressible block, or simply a gap between raft and pile head to make it possible for the soil beneath raft to carry load first, the soil beneath the raft can be compacted before piles begin to carry load significantly and thus can reduce the pile-soil slip and pile tip penetration and even change the failure mode.

A full probability method is presented to statistically evaluate the variation of geomechanics numerical simulation results subject to multi-random parameters. Taking the interested results as stochastic implicit response variables, firstly the expectations of some special functions of response variables are determined by the high performance multidimensional numerical integration. Then the full probability distribution function of the interested numerical simulation results is obtained to quantitatively analyze the variation effect using two proposed method including numerical probability analysis method based on fast Fourier transform (FFT) and the maximum entropy distribution solver software developed by the authors. The numerical examples show that this method has higher accuracy and the computational effort is reduced.

Based on assumed pendular state of isolated pore water, general thermodynamics theory, numerical and statistical methods, the former analytical procedure proposed in literatures is employed to study diverse suctions in state B, compact accumulation model composed of ball-shaped particles with discontinuous water and continuous air (DWCA) in its void. Development law of the three types of suctions as well as corresponding equivalent suctions with increasing saturation degree, and expression for suction ratio with contact angle and saturation degree or saturation radius as the two parameters are derived for unsaturated material in state B. The results of numerical method show that suction ratio is less than 1 in state B; and that is very different from that in state A, the incompact accumulation model composed of ball-shaped particles with DWCA. Therefore, it can be concluded that effect of tension suction on shear strength and deformation of unsaturated granular materials, usually unsaturated soils, will fall down to a certain extent comparing with that of matric suction with increase of compactness. With change of saturation degree, variation trend of the three types of suctions, especially the three equivalent suctions in state B is basically coincident with that in state A. Both in state B and in state A, logarithmic suction ratio is distinctly linear to saturation radius. Furthermore, relationship between suction ration and saturation degree in state B is linear too; but this is very different from that in state A.

Based on dynamic triaxial test data of asphalt concrete, a dynamic constitutive model is suggested. By 3-D dynamic effective stress analysis method, combining with an asphalt concrete core rockfill dam to be built, seismic responses of acceleration, dynamic stress, seism-induced permanent deformation and seism-induced sand’s liquefaction are analyzed by using TSDA program. The dam is safe because of well aseismatic performance of asphalt concrete core, third-layer sand in the alluvium may be liquefied and need be reinforced.The conclusion could be referred to the analogous engineering.

Dense and mudium dense sands dilate under drained conditions and develop negative excess pore water pressure when sheared under undrained conditions. There exists a phase transformation line for dense and medium dense sand which characters the state from contractive to dilative. In the proposed model, the state parameter which makes the phase transformation line as reference line is introduced into the stress-dilatancy equation and the plastic hardening modulus expression to develop a new constitutive model for dilatant sand, 9 model parameters which are convenient to be calibrated are involved. The numerical simulation is in good agreement with the data of triaxial compression tests.

Damage should be controlled in order to ensure the safety of bedrock under blasting excavation in nuclear power plant. For this case, blasting vibration, sonic wave test and numerical simulation are employed to study the wave attenuation in rock mass and blasting induced damage under blasting excavation at Ling’ao Nuclear Power Station (LNPS) in Guangdong Province of China. The relationship between damage characteristic and peak particle velocity (PPV) at a certain distance from the charge are suggested. The method and the vibration safety threshold to control the damage depth for bedrock under blasting excavation are then presented. It is reported that when the PPV at 30 m from charge is not beyond the safety threshold of 5 cm/s, the damage depth of the bedrock will not exceed 2 m. The method and the safety threshold presented can ensure the safety of bedrock under blasting excavation in the project.

Based on the existing research on damage softening statistical constitutive model for rocks, firstly, the analytical expressions for the model parameters and confining pressure are established for specific confining pressures by discussing the relationship between the model parameters and characteristic parameters (the stress and corresponding strain at the peak point in the complete stress-strain curve). Then, by using the Mohr-Coulomb strength criterion, the relation between the peak stress and confining pressure is developed under different confining pressures. Thirdly, the formula with general significance for the peak strain in different confining pressures is deduced through investigating the correlation between the strain at the peak point and confining pressure for different rocks. Thus, a new method to determine the model parameters is presented, and a unified damage softening statistical constitutive model for rocks which is applicable to different confining pressures is then proposed. This constitutive model has fewer parameters and the method of determining its parameters is also easy. Finally, the rationality of the new method and the proposed model is verified through comparative analysis between the theoretical and experimental results.

Based on the characters of ground failure under eccentric loads, the discontinuous stress fields and discontinuous velocity fields are constructed. The characters of discontinuous lines of stress and velocity are analyzed. By upper and lower bound theorems, the model of calculation and the method for bearing capacity are given. The stress fields and the corresponding mobile fields are obtained by the numerical calculation to solve three kinds of boundary value problems. The stress fields satisfied with all velocity boundaries are found. The rigorous solution of bearing capacity under eccentric loads is solved. The computation results show that the method proposed to solve the limit equilibrium problem is available.

The tyaditional unified viscoplasticity constitutive model is only applied for the constitutive analysis of metallic materials. A coupled viscoplasticity damage constitutive model for concrete is developed within the framework of irreversible thermodynamics; and an expression for the Helmholtz free energy function involving the state variables of mix hardening is given. The hardening model of concrete is analyzed; and the flow equation and the evolution equations of the state variables are derived from a non-associated flow potential function including the state variables of kinematic hardening and isotropic hardening. The results of numerical simulation show that the represented model can reproduce the strain-rate sensitive characteristic, inelastic volume dilatancy, softenting-hardening under loading; and strain-softening induced by damages and fractures.

In the area of sandy and silty soil, seepage is the main factor that threatens the safety of foundation pit and surrounding environment. The complex system of foundation pit is composed by soil、water and surroundings, and the factors of seepage failure are complicated. Based on the former analysis of seepage failure of soil, a method for analyzing foundation pit seepage failure model is proposed; the method can considers the influences of seepage, excavation and the deformation of surroundings. The foundation pit seepage failure model in homogeneous soil is gained by this method. According to the finite element numerical simulation results of a practical project, the process of seepage failure is gained. The conclusions of those results show that not only the checking computations of flowing sand and piping should be made, but also the unitary failure of foundation pit system should be considered.

Usher model, as a model for general prediction of petroleum economy and resources, is used to predict roadbed settlement based on the process of roadbed settlement under the linear or approximately linear loading and the characteristics of the Usher curve. Through analyzing the differential equations of the Usher model, it is pointed out that the Logistic model and Gompertz model used for settlement prediction of foundation at present are two simplified patterns, but to the actual condition, the applicability of the Usher model is better. The calculation methods of the parameters in Usher model are expounded; and they are applied to the calculation for an example; the comparison of results between the three models shows a good agreement, which indicates that the Usher model advised in predicting the subsoil settlement is reasonable. The example also indicates that the Usher model has a higher forecast accuracy and may be adopted in engineering practice.

Basing on the Gens-Alonso model describing the constitutive behavior of unsaturated soils presented in reference [1], the softening mechanism of contaminant concentration on preconsolidation pressure presented in reference[2] and the softening mechanism of contaminant concentration on the cohesion, a constitutive model to describe the chemo-hydro-mechanical coupling behavior of unsaturated soil is developed. The governing equation of the coupling problem consisting with the equilibrium equations combined with the chemo-hydro-mechanical constitutive relations, the governing equations for flow of fluids and contaminant transport, are solved numerically using finite elements. The numerical analyses are carried out to simulate the chemo- hydro-mechanical coupling progress of unsaturated soil around tunnel. Three cases mechanical response, chemo-mechanical elastic response, chemo-mechanical elastoplastic response etc. are compared. The increases in the stress state and the strains in the region close to the tunnel and the shrinkage of the tunnel surface are observed due to the presence of chemistry. The numerical results show the feasibility of the present method to simulate the composite coupling behavior of unsaturated soil.

Based on systematic analysis of the composition and mechanism of the debris landslides, this paper first proposes that the monthly rainfall and its change can be selected as the load-unload dynamical parameter, the average displacement velocity and its changes as the dynamical response parameter to load-unload and the displacement load-unload response ratio as the displacement dynamics parameter of debris landslide induced by water in term of the principle of the load-unload response ratio theory. Meanwhile, on the basis of analysis of the data of the displacement and rainfall of the debris landslides in the Three Gorges Reservoirs area, the feasibility and effectiveness of the displacement dynamics parameter are discussed. Finally, the stability of Huanglashi slope in the Three Gorges area before and after the water drainage are evaluated respectively by means of the dynamical parameter of the load-unload response ratio; and the evaluated results are well agreed with the practical stability situation of the slope. Therefore, all results above show that the dynamical parameter of load-unload response ratio proposed is a very effective displacement dynamical parameter in the stability evaluation of debris slopes; and it can be used in the evaluation of the stability of debris landslides induced by water.

A dynamic coupling model of track structure and underlying ground under moving load action is developed by employing the 2.5 dimensional finite element method together with thin layer element method. First, the distribution of dynamic stress in ground due to train traffic loadings at different speeds is computed; then, incorporating Li and Selig’s Method (1996), a computation procedure to evaluate long-term settlement of subgrade ground is proposed. The Swedish high-speed railway X-2 000 running on soft ground in the West Coast is introduced as an illustrative case study to demonstrate the development of long-term settlements with time and its distribution inside ground. Also a parametric study is conducted to consider to influence of train’s running speed on long-term settlement in soft soil ground.

Strain localization is a very important subject in rock and soil mechanics. To deal with strain localization problems, some regularization mechanism must be introduced. The main regularization mechanism includes: viscosity effect, Cosserat theory, non-local theory and gradient theory. The development of these kinds of regularization mechanism in strain localization problems is summarized systematically; and the disadvantages of these regularization mechanism are analyzed and discussed. Finally, some primary ideas about the trends of regularization mechanism in strain localization problems are put forward.

Jinping II Hydropower Station is an important cascade hydropower station on the Yalong River in Sichuan Province. The hydropower station region is a typical V-shaped river valley morphology with high grand mountain and deep gorge. Tectogenetic movements, including Indo-China movement, Yanshan movement and Himalayan movement, made the region preserve much horizontal constitution stress. But, the corrosion effect of the Yalong River leads to figure the V-shaped valley and release of constitution stress. For understanding the function of inter dynamical geological process and outer dynamical geological process to current geostress, a new nonlinear initial geostress back analysis method is presented, which integrates the ground abrasion simulation, elastoplastic calculation and neural network inversion. The method takes the constitution order process into account to some extent by elastoplastic calculation and simulates the ground abrasion process by surface excavation. The model is verified by two ways. One is the comparison between measured stress, and inversed stress in the same position; the other is the broken behavior of cavern rock. The results indicate that the method is reasonable.

Due to the change of stress field and the seepage field caused by tunnel excavation, unloading deformation is extremely complicated mechanical process in rich fracture rock. Viscidity elastic fracture and creeping theory are adopted, two-field coupling creep model of tunnel excavation in rich fracture rock is established; and Laplace transformation is applied to educe the expression of radial deformation function, in order to illuminates the influence of stress unloading distributions, seepage force and crevasse distribution on radial deformation. FISH language is used to compiles the FISH function; and FLAC inner model is used to calculate result of tunnel model. Comparing with the measured data, the applicable scope of the model is accounted. The result of the model shows the radial biggest displacement mutative quantities are not in the orientation of the principal stress and in the tunnel crown; mainly affected by geostress distribution, hydraulic pressure and joint distribution. Hence, academic reference for tunnel supporting is offered.

Aiming at the problems occurring in actual projects, using the displacement penetration method, the complete process of successive penetration of jacked pile is simulated with finite element method based on ANSYS. Displacements and stress field in homogeneous soil are compared with which in layered soil in detail. It is shown that the soil’s displacement increases; and radial compression stress changes rapidly and discontinues at the boundary of soft soil and hard soil; and piles driven before are prone to be broken there.The methods for prevention is put forward.

A model of coupling the stress equilibrium and fluid continuity equations is proposed and implemented to solve numerical simulation problem of the hydraulic fracturing propagations. The mechanism of critical stress criterion of crack propagation is also introduced. The pressure descent distribution function on the fracture face along the fracture length is deduced and the corresponding user subroutines are developed and also embedded into ABAQUS. The complex factors of geology such as in-situ stress distribution, mechanical properties, fracturing fluid properties etc. are included in the present model. Several conclusions are drawn from the simulation results. It is viable to solve problems of hydraulic fracturing propagations in the permeable reservoirs with the finite element analysis software(ABAQUS). The concept of critical width is proposed; the critical width can be used to judge a hydraulic fracture is treated as a porous passage or as a fluid flow fracture passage. The obtained conclusions are of much significance for the perforation parameter optimization and design of hydraulic fracturing treatments.

Torsional oscillations of a single pile embedded in isotropic elastic foundation are investigated by means of integral equation methods. Firstly, the fundamental solutions of the isotropic elastic foundation subjected to an embedded harmonic torque are obtained using integral transform methods. Then, based on the fundamental solutions and compatibility conditions, the Fredholm integral equation of the second kind is established. After the numerical solution of the integral equation, the torque, torsional angle and dynamic compliance coefficients of the pile can be obtained and parameterized. The conclusions obtained have some guidelines for the design, calculation and the low strain dynamic torsional wave testing of pile foundations.

In order to solve the similarity relation between the model and the prototype, based on the theorem of E.Buckingham ?, the dimensional analysis method is used. Using deduced similarity relation, the model test of column-net structure is carried out for the design and the manufacture with the field engineering practice. Model test results show that it is feasible for using the dimensional analysis method to deduce the similarity relation between the model and the prototype. The settlement curve of flexible arch likes the shape of net sling. The strain of geogrid increases with the structure heightening and cyclic loading time increasing; and it increases more quickly before the formation of soil arch than after ones.

Based on the mechanical analysis of water jets assisting PDC bit to cut rock, the effects of water jets on the PDC bit forces are investigated. The following results are obtained from the experiments. The bit forces increase with the cutting depth while water jets assisting PDC bits to cut the hard rock. When water jets is directed from the bottom and offset of PDC bit, the bit forces have a great decrease. The force reduction is about 30 % to 52 %. Moreover, the change of cutting depth does not have much influence on this force reduction.

The technique of soil nailing has already got an extensive application to deep foundation pit engineering, but the research of its work mechanism and the calculation method is still not perfect. Now the numerical simulation experiments are prevalent; but it must to do a large numbers of triaxial or true triaxial tests to gain the exact model and other parameters for local soil. So a simple calculation model is founded based on three supposes, the writer also studies on the work mechanism of soil nailing and finds the regulation that Curve of nail stress is “Two half parabola”, and the concerned formulas is deduced. Combining the Pengcheng underground square engineering, the data of displacement for pit are measured. The stresses of soil nailing are also measured; these data verifies the accuracy of the formulas. The analytical algorithm is worth for reference in the similar case.

Taking a frame structure office building for example, a 3D nonlinear constitutive model regarding the building and its foundation with cavern as a whole and taking into account the tunnel-soil-structure interaction is put forward by means of general FEM program ANSYS10.0. Its differential settlement and variation of internal force due to the passage of a shield tunnel is investigated. The result indicates that major settlement of the foundation of the building occurs in the zone where the shield tunnel passes through the building; its transverse obliquity increases along with the shield advance, while its longitudinal obliquity reaches the maximum when the excavation face is close to the centerline of the building; during the passing course the equivalent stress of columns can rise by 20.1 % at most; torque of structural components changes more obviously compared with their bending moment; its deformation and internal force tend to be constant when the excavation face overpasses the building for 20 meters.

The strength reduction FEM (SRFEM) is the most popular method in geotechnical limit analysis FEM. It has been studied and applied in recent years quickly; and significant achievements have been obtained and its feasibility, superiority and practicability in geotechnical engineering have been proved. Several problems about SRFEM are discussed such as the definition of safety factor, utility condition of Mohr-Coulomb criterion and access to calculation parameters after the adequate praise and affirmation of its advantage and characteristics. It is concluded that the application conditions and access to calculation parameters of SRFEM should be carefully considered; the further and probable research might be turned to the safety and stability analysis of geotechnical structure with the emphasis on deformation control; and the development of professional calculation software of multiple methods and functions with the combination & complementation of traditional limit equilibrium method.

Based on the static loading tests on pretensioned high-strength concrete (PHC pile) piles and precast square piles with strain gauges mounted in them which are in the same field, the load transfer mechanism of PHC pipe piles is studied through comparing the load-settlement curves, shaft load distribution, the behaviors of skin resistance and base resistance of two types of piles. It reveals that the behaviors of skin resistance and base resistance of PHC pipe piles is the same as those of precast square piles, however, with nearly the same side surface area, under the maximal load, the development of skin resistance and base resistance of them is different—the average skin resistance of PHC pile is 8.1 % less than the one of the precast square piles while the base resistance of PHC pipe piles is at least 24 % more than that of square piles.

With the increase of salt content of saline soil in inshore, the salt particles are formed in soil, in general, which presenting an appearance of different sections and causing the consistency indices of solidified soil drop gradually. Uniformity coefficient of the solidified soil with lime increases with more salt content and more curing periods. Conductivity of the solidified soil has been increasing with more salt content and increasing hardly with more curing periods. It has been certified that salt has no action in the chemical reaction of lime and soil, salt is still on the surface of soil particles or in the pores of soil, and the solidified soil will be softened because of absorption of water. It has been proved that maximum dry density drops slightly; and optimum water content is hardly change with the increase of salt content on the basis of compaction test; and in situ salt content effects scarcely on compactness of saline soil in inshore with lime.

The formula of elastoplastic matrix for the generalized Hoek-Brown failure criterion used in the finite element analysis, has been deduced. And then, the criterion is used for simulating the construction stages of a cutting rock slope in the elastoplastic finite element analysis. Meanwhile, the strength reduction analysis is also executed by using the equivalent Mohr-Coulomb parameters in order to find out the evolvement of critical failure model during the construction. It is shown that the development rules of the stress and strain, the displacement, the stability and the critical slip during the excavating are coincident with the results gained by using the traditional Mohr-Coulomb failure criterion. However, the results also show that using the equivalent Mohr-Coulomb parameters gained by the Hoek’s formula (2002), may overestimate the stability of slope.

By using homemade shear equipment, the mechanics characteristic of the weak intercalated layers in the slope rock mass are carried out. The shear stress-deformation curves have the obvious proportion limit, submission and peak stress, which indicate that, at the initial stages of the shear deformation, the shear stress-deformation is linear and the shear stiffness don’t change. With the increase of the vertical stress, the peak shear stress increases linearly. After the peak strength, the shear strength changes little with the increase of the shear deformation, and the remnant strength is approximately equal to the peak, the experiment sample subvert, which is the ‘plastic’ subversion type. The shear deformation can be divided into 3 stages, the strength parameters in every stage vary, for the slope engineering, which must have enough safety coefficient, the low strength parameters are recommended. Basing on the experiment results, it is found that the vertical stress-compression displacement curve is the hyperbola, when the vertical displacement is less than 3.4 mm, the experiment result be more close to the theoretical value. The results will guide the stability analysis and the reinforcement programme design of the high slope.

Acoustic emission tests of sandstone specimens under uniaxial compression are carried out; and Kaiser point is determined by parameter method according to the principle of Kaiser effect. First, based on the above testing results, the energy distribution of acoustic emission signals is studied by means of the wavelet packet analysis technique; and regularity of energy distributions for different frequency bands is analyzed. The results show that the energy percentage of dominant frequency band at Kaiser point is significantly higher than other points. Then, relevant fractal dimensions of acoustic emission process are obtained by using G-P algorithm. Results show that the acoustic emission process is of obvious fractal characteristics. And the minimum value of relevant fractal dimension is at Kaiser point. The conclusion can be used to identify the characteristics at Kaiser point by waveform analysis.

Based on a large number of measured data for a deep excavation in-situ, the corresponding bending moments, deformation characteristics and the earth pressure distribution of a double-row piles retaining structure are studied. Some problems are analyzed, including the space effect of deep excavation, the effect of cap beam on earth pressure, the relationship between retaining structure deformation and the earth pressure distribution, and the mechanism of action between retaining structure and soil. The studies show that the earth pressure distributions on the double-row piles retaining structure are quite complicated, and are different from those obtained by the classical Rankine’s or Coulomb’s earth pressure theory, which supply a basis for the design model of double-row piles retaining structure.

According to longtime monitor on residual strain states of two large-diameter rock-socketed cast-in-place piles (dig by hand) before loading, inducing factors and distribution rules of residual strain, and its influence on bearing behaviours of pile are analyzed, some conclusions are obtained as follows: (1) the main factor of inducing residual strain is drying shrinkage of concrete; (2) the residual strain distribution of the two piles are regularly changing with space and curing time, but some construction factors, such as blowing up, groundwater and type of casting pile, will disturb residual strain distribution or soften restricting force which comes from rock beside pile side. (3) local strain of piles can exceed ultimate tensile strain of concrete, which can result in crazing of concrete and losing of capability of protection to reinforcement bar, and the shrinkage of the whole pile will decrease contact force between pile bottom and rock. The foregoing conclusions provide reference to engineering practice.

In light of the importance of vehicle loads and speed in damage of road pavement structure, dynamic responses of road pavement under different vehicle loads and speeds are researched through in-situ experiments on a newly-built freeway. The research results show that the peak values of stress and strain increase with accretion of vehicle loads; but decreases with speed increasing; the increasing range with loads of the landscape orientation strain of front-wheel drive is less than the vertical strain of front-wheel drive; but the increasing range with loads of the landscape orientation strain and vertical strain of rear wheel is close; amplitude change of the dynamic stress and strain by speed is less than by loads; the effect of dynamic stress on pavement by vehicle traffic weaken promptly.

People Square Station of Shanghai Metro No.8 is a parallel transfer station, of which excavation is adjacent to People Square Station of Metro No.1. Monitoring data indicate that the constructed station inclines reversely during adjacent excavation. Through FDM numerical simulation, displacement transfer behavior of excavation is analyzed; and displacement transfer law of excavation adjacent large stiffness underground building, is analyzed. The results show that a large stiffness underground building makes a great difference of displacement that: (1) block effect, which results to minish the displacement of retaining structure; (2) cutting off the path of soil displacement transfer, which changes soil’s displacement and brings on building’s inclination reverse to pit.

Based on the concept of state parameter, the peak stress ratio and dilatancy ratio are regarded as the function of state parameter; and meanwhile the initial modulus changing with confining pressure is considered; then an elastoplastic model for coarse grained soils and its parameter calibration are proposed. The model expression is simple and its concept is clear; it can describe the strain softening and dilatancy over a full range of densities and stress levels and its dependency on physical state and effective confining pressure. The validity of the model is confirmed in predicting triaxial compression test results of coarse grained soils.

To study more and more serious vibrations problem induced by moving train traffic in urban areas, in a residential district near Jing-Guang Railway, field tests of velocity and acceleration vibrations of ground were carried out during train moving; and some conclusions were drawn. It is shown that the vibrations of ground due to moving train rise with train speed or axle load increasing. Generally, when speed of train increases 10 km per hour, the vibrations level raises 3 dB, while at the same speed, vibration induced by freight train is bigger than passenger train because of the difference of axle load. In the test, at speed of 50 km per hour or so, the vertical velocity vibration induced by freight train is about 10 dB bigger than that of passenger train, and as for the difference of lateral velocity vibration, this magnitude is about 5 to 15 dB; moreover, as for the difference of vertical and lateral acceleration vibrations, they are 12 dB and 8 dB respectively. The vertical velocity vibration of ground near the joints of rails is 2 to 6 dB bigger than the other positions far from joints. Ground vibration decreases gradually with increasing in the distance between testing locations and rail; and there is a fluctuated characteristic of the decay process for vertical vibrations; while the lateral vibration decreases monotonically with increasing in the distance between testing locations and rail.

The practices show that “heavy hammer and low fall” and “light hammer and high fall” give different treatment effects. Considering material nonlinearity, geometric nonlinearity, contact nonlinearity, movement nonlinearity and coupling characters of them etc., large deformation dynamic nonlinear FEM based on explicit time integration is applied to simulating the impact process of dynamic compaction. The trace of soil, maximum collision force, collision duration have been obtained at the same single blow energy but with different combination of height and hammer weight. From the analysis, the efficiency coefficient and the influencing degrees of these soil parameters on the treatment effect are obtained. The results show the conclusion of “heavy hammer and low fall is superior to light hammer and high fall” is conditioned.

The model?Ⅰcrack stress intensity factor KⅠ is an important property of rock mass. Before obtaining KⅠ, we should figure the crack geometric impact factor out. According to “modified Feddersen” formula, we argue experimental model and engineering rock mass could share the same . Based on the double exposing holographic interferometry theory, the equations of crack tip stress field, the photoelastic stress-lit law on plane, the standard processing method, a technical line, which could be used to measure model-Ⅰcrack stress intensity factor KⅠof rock mass, is thought out. The method has some special advantages, such as higher precision and more clearly interference fringes.

A laboratory test program was conducted on partially clogged nonwoven geotextiles under pressure. The results of test showed that the presence of soil particles inside the geotextile reduced its compressibility and permittivity, a reduction factor (RF) of equivalent opening size was proposed during filtration. RF of 1.5－2.5 was suggested for the drainage of bank slope. The expression presented by Giroud (1996) demonstrated a satisfactory forecast of coefficient of permeability of non-clogged geotextiles under pressure. Comparison of measured and predicted permeability values for partially clogged geotextile specimens indicated that an expression of equivalent porosity has a better prediction of soil impregnated specimens under pressure.

The experimental research on shear properties of geocell reinforced soil and geocell reinforced cement stabilized soil was carried out by using a large size direct shear equipment (500 mm?500 mm?400 mm, length?width?height) which was developed by South China University of Technology. Through the experiments, the shearing process of geocell reinforced soil was simulated. The shear strength indices and its strengthening theory by mechanics were determined. The experimental results show that the relationship curve of shear stress to shear strain of geocell reinforced soil is nonlinear. In addition, the cohesive force index was increased greatly. The friction angle was increased relatively less. Furthermore, on the purpose of understanding the influences of testing methods, three kinds of shear tests including regular direct shear test, large size direct shear test and triaxial compression test with in-situ soil and 5 % dosage of cement stabilized soil were conducted. The corresponding shear strength indices of different kinds of testing methods are in sequence from less to more as below: Friction angle of soil: triaxial compression test less than large size direct shear test less than regular direct shear test. Cohesive of soil: large size direct shear test is less than triaxial compression test less than regular direct shear test. Friction angle of cement stabilized soil: triaxial compression test is less than large size direct shear test. Cohesive force of cement stabilized soil: triaxial compression test less than large size direct shear test.

As a new type of advanced pile of retaining and protecting for foundation excavation, the squeezed scallop pile mixed expanding admixture is studied experimentally. The intention of this paper is to survey the compaction efficiency against soil around pile, the mechanism, the retaining height, the inner stress distribution and calculation of squeezed scallop pile mixed expanding admixture as retaining and protecting for foundation excavation. Compared with common reinforced concrete retaining piles, the major characteristics of squeezed scallop pile mixed expanding admixture contain: (1) The maximum bending moment is decreased 20 % ? 30 %; (2) The total displacement in top can be reduced 33.5 % on average; and (3) The ground limit load is increased 13 % under regular service conditions. Against the contraction distortion of common reinforced concrete piles, the squeezed scallop pile mixed expanding admixture as retaining and protecting can strengthen the soil around piles effectively.

In this paper ,the rock and mortar is simulated by solid mass element, the cable is simulated by structural element, the interface is setted between the rock and mortar, and the prestress is applied to the cable according to the new method in FLAC3D program，that is to say , the board in pressure diffusion anchor cable is simulated by structural element rather than the distributed loads gained by the theoretical analysis are applied to the board. And then the numerical simulation model of prestress anchorage is established, After that, the stress nephogram of the interface, rock and mortar mass is analysed; and then the axial stress along cable in rock mass, bond stress distribution between mortar mass cell and membrane, which is affected by pressure diffusion anchor cable are displayed more clearly.

By way of contrast tests for on the new type of ESC mixing piles body with the soil-cement mixing piles body, the mechanism of ESC solidified soil is expounded; and that these mixing piles have higher side friction is proved. Meanwhile, that substituting the ESC solidifying agent for cement can obviously increase the strength of solidified soil in the mixing piles is proved. Therefore this method has naturally solved the following problem, that is, the single use of cement can’t allow full play to the side friction because of low strength of the bodies of mixing pile and low bearing capacity of the single pile.

No explicit result has been achieved on the research of time-effect on uplift bearing capacity of drilled grouting pile in the ground of sandy soil and weathered sandrock. The mechanism of time-effect is analyzed by the data from the test and the construction draft of drilled grouting pile. It is shown that the time-effect of drilled grouting pile on sandy soil is significant under the effect of too thick lateral mud, even strong than cohesive soil. The uplift bearing capacity increases more quickly in the early period than that in the later. In order to make good use of the uplift pulling capacity, it is suggested that the resting phase before the pile test should be lengthened properly.

A device combined with system of gas permeability measurement was designed to investigate the gas permeability of fracture rock under peak stress in mining. Several groups of fracture rock with elevations of ?653 m to ?771 m from Guqiao coal mine were employed as the standard samples of gas permeability testing. By the aid of MTS815, the samples achieved their peak stress, and the gas permeability of them was obtained in that elevations. Furthermore, one-dimensional permeability of non-Darcy flow and the solution of their gas infiltration rates are also analyzed theoretically. It is shown that, even in the deep-seated, the gas infiltration rate of rock of that kind is remarkable larger about 103?104 order than that of integrity rock. Meanwhile, the infiltration rate of fracture sandstone is higher than that of fracture mudstone in the same elevation.

The basic principle of fiber Bragg grating sensor is described. Through engineering application of fiber Bragg grating sensor to monitoring axial forces of anchor bolts for Longtan tunnel of Hu-Rong Expressway West Section, some important aspects of fiber optical sensing technology applications to geotechnical engineering monitoring, which are selection of sensors, installation of sensors, calibration of sensors and embedding of sensors, et al, are discussed. Through local monitoring, the characteristics of axial forces of anchor bolts are obtained. And some useful experiences with application of fiber optical sensing technology to geotechnical engineering are summarized.

Aiming at the rationality and limitation of the Rankine earth pressure theory to the characteristics of bracing for foundation pits and the specific soil conditions, the discussions are carried on. And the insufficiencies in the calculation method of bracing for foundation pits are pointed out. Taking the active limiting equilibrium condition of retained soil stress for example, the rule that the active limiting horizontal displacement along with the depth of retained soil accords with parabolic equation base on the earth deformation regions in foundation excavation is obtained. According to the need in the project, considering the effect of wall displacement, depth of excavation and embedded depth on the calculation method of the Rankine active earth pressure is proposed, under the small displacement condition.

In practical engineering calculation, data transfer between different mesh fields plays an important role in coupled analysis and the method of inverse mapping is required. The paper introduces the available methods of inverse mapping in the literatures and points out the deficiencies of the above methods. Then the method of FEM inverse isoparametric mapping inside the mesh is newly improved and the renewed method of data transfer outside the mesh is introduced. With the detailed introduction of the key problem of programming, the example of the data transfer procedure of temperature field to the stress and strain field in a high arch dam construction process is presented; it is shown that the reliable and accurate results can be achieved with the new method; and this method is simple, efficient and accurate, so as to be used in actual projects conveniently.

The application of optical fiber sensing technology to rock deformation test is studied. The axial and radial strains are tested by sticking fiber Bragg gratings and electric strain gauges on rock surface in the uniaxial compression experiment; and test results are compared. The method of cyclic loading is applied; and the rock damaged at the last time. The small deformation only before damage is tested. By three times of loading, the results show that the testing curves of fiber Bragg gratings accord with electric strain gauges’ ones. It is shown that the fiber Bragg grating sensing technology can be used in deformation test of rock. It has certain meanings to increase the level of rock deformation monitoring.