On the basis of dynamic equations for seismic analysis derived from system energy, the seismic response of layered foundation-nonlinear structure system is studied by means of asymptotic method (KBM). The analytical formulas of amplitude-frequency and phase-frequency are obtained. A series of calculating results for different values of foundation parameters are presented in seismic resonant area. And then according to corresponding calculating results, the effect of foundation parameters on seismic properties of structure is analyzed; and the nonlinear dynamic characteristics，such as distortion of resonant area, bifurcation and suddenly jumping of amplitude, as well as the path effect , are discussed. It is indicated that the value change of foundation parameters of the same sort causes remarkable influence on structure dynamic properties, and the calculating error by the current Code of seismic design might be obvious for the analysis of layered foundation- nonlinear structure system. The interaction between soil and structure and nonlinear properties must be considered in order that design parameters are more reasonable and optimal.

Based on the laboratory dynamic consolidation tests of saturated oozy soft clay under impact loading, the dynamic response characteristics of pore water pressure were analyzed. The tests considered different combination schemes between hammer weight and dropping height. The relationship between pore water pressure and impact times followed the hyperbola. The rate of increase of pore water pressure is faster with impact number under high confining pressure; and for the pore water pressure of over consolidation soft clay under impact loading, the negative value occurred. The subsidiary stress of impact loading causes the increasing of pore water pressure; and the effective stress is increased because of the dissipating of pore water pressure. It is highly important to control construction quality by monitoring pore water pressure during on-site dynamic consolidation.

The natural normally-consolidated diatomaceous soil deposited in Ohita Prefecture of Japan is a natural strongly structured soil. It has a surprising high strength and high consolidation yield stress although its natural water content is very high. In this study, the mercury intrusion porosimetry (MIP) tests were performed on the natural sedimentary diatomaceous soil to investigate the relationship between the change in entrance pore size distribution and the applied stress level. The microstructure investigation results indicate that the entrance pore size distribution varies little when the stress level is smaller than the consolidation yield stress, but changes significantly when the applied stress is in the vicinity of the consolidation yield stress. When the applied stress is larger than the consolidation yield stress, pore space volume decreases, the maximum pore becomes smaller and the pore size gradually becomes uniform with the increase in applied stress level. The relationship between microstructure and macro-mechanical behavior is also investigated.

A method, using pole system FEM and considering the interaction between the foundation beam and the rock and soils, is proposed to calculate the frame foundation beam with prestressed anchor-cable used in reinforced slopes. Based on the linear elastic Winkler model, the FEM model of the frame foundation beam is analyzed in detail by taking the structural bending and torsion deformation into account respectively. An engineering case is calculated using the method; and the comparison between the computing data and the testing data in situ proves the method is feasible.

The software of ABAQUS, which is developed and supported by HKS Inc., is currently one of the most powerful nonlinear finite element analysis implement in the world. It includes many different kinds of material models. However, the release of ABAQUS currently absents Duncan-Chang constitutive model that has been widely used to simulate some deformation problems in the field of geotechnical engineering. The shortage limits the software’s application scopes in some extents. In this paper, the procedure and outline to develop Duncan-Chang constitutive model in ABAQUS by using User Subroutine were proposed and implemented. Two numerical examples were also solved and compared with conventional triaxial compression test data. All numerical results exhibit that it will be possible to accomplish some complex stress-strain analysis for soil engineering problems by fully making use of the powerful solving platform after ABAQUS is added Duncan-Chang constitutive model. Meanwhile, there are some advantages of faster convergence, higher efficiency, higher precision and more conveniently preprocessing-postprocessing. The programming difficulties to develop soil engineering and workloads of maintenance are also greatly decreased.

Centrifuge modeling technique appears to be a potential experimental tool to study geo-environmental problems. The transport process of light non-aqueous phase liquids (LNAPLs) in unsaturated soils and thereafter soil venting remediation was simulated by use of geotechnical centrifuge. When centrifuge gravity reached the desired g-level, the gasoline released from leaking underground storage tank and migrated in unsaturated soils for a prototype time equivalent to 1 year. Then the compressed air was injected into soil mass for two months and four months respectively to extract contaminants from contaminated soil. The soil samples were analyzed by means of gas chromatograph; and the spatial distribution of contaminants was obtained. Centrifuge tests show that volatile contaminants are remarkably reduced by means of soil venting extraction, which demonstrates it is an effective in-situ soil remediation technology.

For the reason of special expansive characteristics of red sandstone, a series of experimental procedure performed in rock mechanics rigidity servo testing system (RMTS815.02) and rock oedometer, developed to determine the swelling behaviour of red sandstone taken from a foundation pit of Hongshanyao Project (HSYP) in Nanjing, is described. Based on the experimental data, an empirical formula of expansive strain with water content was expressed as . It is clear that the curve of expansive strain-water content is a logarithm. In the meantime, the relation of expansive strain with time was studied and the importance of expansive stabilization time was illuminated. The experimental results indicated that the water content has a tremendous effect on peak expansive and steady expansive deformation of swelling red sandstone; and it must be a momentous guide in the engineering design and construction.

Effective stress dynamic analysis method is used to analyze seismic response of super-deep bored-concrete-piles foundation of a bridge across the Yangtze River. By 3-D finite element numerical analysis, dynamic behaviors such as seism-induced permanent deformation, acceleration and vibration pore water pressure of the deep pile foundation are studied. The results show that the earthquake led to large permanent deformation, small vibration pore pressure of pile foundation; and also show that the tip of piles and the rim piles have more large dynamic response than other part, but the pile foundation have better anti-seismic behaviors than natural foundation.

An iteration method of inverse isoparametric mapping for hexahedral elements is presented; it doesn’t need to solve high order equations and avoids nonconvergence for poor initial points. By this method the local coordinates can be acquired quickly by simple iteration.

The theoretical foundations of observational settlement prediction by methods of curve fitting are discussed. The fundamentals and the characteristics of the four methods (exponential, hyperbolic, Asaoka and logistic curves methods) are compared. Based on the observational settlement data of eight practical projects, the advantages and shortcomings of these methods are studied. Finally, several key problems for observational settlement prediction are put forward.

Based on experiments on marble, red sandstone and granite, their ultimate envelope can be averaged as straight lines. With these lines, their slope and bonding stress can be calculated. Two hardening parameters should be decided by data of some points on stress-strain curve before peak strength. According to experiments, the occurrence of failure isn’t far away from phase change, so the phase change parameter can’t be computed by Desai’s method. The authors think that taking a value of a little greater than 2 is appropriate. When back predicting stress-strain curve, the authors proposed a simple and applicable method, regarded the end of initial compression phase as initial condition to calculate initial hardening parameter and trajectory of plastic strains.

A new method to define slippage line under local loading condition is presented based on Hill’s principle of strain bifurcation and the elastoplastic constitutive model of soil. It can tail how slippage line formed and developed, and can reveal process of onset and evolution of slippage point and directions in elastoplastic slope body also. In practice, it is convenience to define the location and movement direction of slippage line in the slope by the elastoplastic continuum with finite element increment numerical method. During each step in elastoplasticity, whether the determinant of acoustic tensor on each Gauss point equals zero or not should be checked, once it equals zero or near to zero, mark the point and the movement direction. With some points are marked and arrayed regularly, the slippage line will be formed.

Present approaches for site effect evaluation are either theoretical or empirical. The ratio of microtremor horizontal to vertical spectra of one station (H/V method or H/V) is empirical. The highest amplitude of H/V is considered to be site amplification and the lowest frequency corresponding to the largest H/V amplitude is considered to be the site predominant frequency. In practical, the H/V method of microtremor measurement provides accurate site amplification and site predominant frequency. However, many engineering scientists considered that the H/V method lacks sufficient theoretical background, because numerous assumptions were introduced in formulating the method. Some assumptions are discussed in this paper. The microtremor spectral ratio method is assumed that the spectra ratio of the horizontal component to the vertical component of microtremors on the rock surface is equal to unit. Is this correct? There is no satisfying theoretical explanation. Microtremors are been divided into body microtremors and surface microtremor. In order to reflect the random of microtremors, body microtremor is considered by superposing inclined P-SV waves under different incident angles. Surface microtremor is assumed to be Rayleigh wave on elastic half space. Expressions of the spectra ratio of the horizontal component to the vertical component of body microtremors on the elastic half rock surface are deduced in this paper. The characteristics of the spectral ratio of the horizontal to vertical spectra on the Poisson rock surface are discussed. It is shown that the H/V is close to unit for body microtremors and approximately 0.68 for surface wave microtremors on the Poisson rock surface.

The grains of noncohesive soils are classified into three groups: skeleton, movable and clogging based on their movability under seepage. If there are some movable grains in a noncohesive soil, piping is easy to take place. In consideration of the grain-size distribution and the degree of densification of soils, a new method for assessing the piping-typed soil is suggested; and its application to some piping tests illustrates its validity. The calculated results show that the degree of densification has influence on the minimum pore diameter, the fractile diameter, the content of movable grains and that of clogging ones.

The initial stress field is very important in the finite element analysis of geotechnical engineering structure. In the engineering practice, the rock masses are nonlinear. In this paper, a methodology of initial stress back analysis combining the genetic algorithm and finite element theory is proposed. An example is studied, the results show that the proposed method is reliable and can be applied to the engineering practices.

Moisture migration in unsaturated loess considering temperature effect is studied by test. The test data show that the more is the temperature gradient in soil, and the less is the soil density, the more is the soil water content gradient resulting from moisture migration. If the soil primary water content is gradually added from very little value，the value of water content gradient resulted from temperature gradient first is lower，then bigger and finally lower. After analyzing the test data, taking the soil density and moisture content into account, the formula is obtained to determine the water content gradient resulting from the temperature gradient. The test and calculated data verify the reliability of the formula. And the method is got to determine the hydraulic head of unsaturated soil under thermal gradient, in which the temperature gradient, soil density, soil water content and water content gradient all are taken into account.

Based on mechanics media classification and block theory and stereographic projection, a calculation formula of sliding direction was deduced; and an analytical method of stability of surrounding rock of underground stope out area in fissure rock-mass was researched with project example. Stability analysis of surrounding rock for a large underground stope out area in North China’s Hebei Province was finished by above-mentioned method.

Based on the factors of reinforced slope computed with Holland method and Sweden method, the tests of single index and multiple factors were designed according to orthogonality table in the paper. Associated with the example of slope with the height of 20 meters reinforced by geogrids, the sensibilities of the factors influencing on the stability of slope were analysed. In sequence, the sensibilities of factors are as follows in their magnitude order: cohesion, angle of internal friction, seism, unit weight, the reciprocation of number of geogrids layers and space between layers, number and tensile strength of geogrids, slope angle space between geogrids layers, overload in top of slope and underground water level. The discussion laid emphasis on the effects of reinforcement. If possible, backfill with high cohesion and big angle of internal friction should be adopt preferentially. When reinforcements are needed, under the condition of the same total tensile strength of reinforcement, it’s better to install more geogrids with moderate strength than less ones with high strength.

With the growth of traffic volume and axial load, the requirements for pavement performances are higher day by day, thus many types of geosynthetics products used for road have been developed. The laboratory and field test achievements and the theoretically analytical investigations on improving performance of geosynthetic-reinforced asphalt pavement are evaluated. Those design methods of geosynthetics-reinforce asphalt pavement are analyzed. Furthermore, in accordance with the design procedure for asphalt overlay proposed by the Asphalt Institute in the United States of America, a design method for asphalt overlay with geosythentics interlayer on cracked pavement is introduced.

This paper analyzes the site-measured settlement of the Yiluo River alluvial flat soft clay foundation in Henan province using the exponential method and the hyperbolic method; and calculates the final settlement and the consolidation parameters of the foundation. It is found that using the back-calculated permeability coefficient to calculate the settlement by FEA method is more close to the fact than the one calculated using test coefficient. Through analyzing a lot of field test data, the relationship between settlement and embankment height is summarized; and the critical embankment height 2.5 m on soft ground is obtained

Simulating computation for Shaojiwan double-arched tunnel about two different excavating sequences is carried out; and pays attention to strength, displacement and stability of effects under two excavating sequences. The results show that the mid-partition is a key load-carrying member; the nonsymmetrical excavating will bring eccentrically loads on the mid-partition easily. From the computing results, this paper evaluates the excavating, and gives some opinions on excavating procedure of double-arched tunnel.

According to the load distributing and transferring rules and constituents of pile’s settlement under static load, the interaction between piles and earth is analyzed; and a simulating method for analyzing pile’s settlement is put forward on basis of routine surveys and mechanical tests. Therefore, the curve of axial static load and settlement of piles can be accurately determined and demonstrated by an example that shows the effectiveness and correctness of this method.

Since the material properties of the pile and the soil surrounding the pile are uncertain, so the responses of pile are uncertain too. Reliability analysis of the responses such as the maximum bending moment in the pile and the pile head displacement were presented. The analyses of responses of pile were obtained by discretizing the pile as beam elements and by using the p-y curve to represent the soil resistance. Reliability analyses of laterally loaded pile were carried out using the first order reliability analysis method by considering the uncertainty in horizontal loading, the soil resistance and the stiffness of pile. Further, the effect of the uncertainty in the probability distribution parameters on the estimated failure probability was investigated using the point estimate method. The numerical results for the considered examples seem to suggest that the influence of the uncertainty in the probability distribution parameters on the estimated reliability is not very significant.

The existence of structural surface in rock mass often makes notable influence on rock mass quality. This paper analyzes the evident shortcoming of the traditional rock mass quality index; and based on the project geological survey of main mine side slope rock mass of Baiyunebo iron mine, the rock mass structural network graphics are drawn by using the Monte Carlo method and the multifractal spectrum of rock mass structural distribution and complexity is calculated and drgwn according to the standpoint of multifractal geometry. The qualitative evaluation and quantitative analysis for rock mass are made. The rock mass quality classification is also made based on multifractal spectrum.

In order to rationally evaluate engineering properties of rock masses in one section of the Three Gorges Reservoir and provide method for harnessing geological hazards, the probable patterns of discontinuities were calculated and joints network were simulated with the aid of the Monte-Carlo method on basis of surveying data of discontinuities. Some technical improvement were proposed. There are cluster analysis for classing discontinuity groups, direct method to form joint random numbers, calculation of generalized RQDt and line connection rate. According to surveyed and simulated results, there are 3 sets preponderant discontinuities in research section, and the average trace length is about 1.45m, line density of discontinuities is 3－6 sets every metre. when t = 0.10 m and 0.70m, the value of RQDt is 90 % and 10 % － 20 % respectively, and the varying of RQDt along different orientations will affect stability of bank slope.

Influence of structural size on axial stress-lateral strain curves due to shear localization is investigated and a new method for determining the axial stress-lateral strain curves is proposed according to the axial stress-strain curves obtained by tests for different sizes. Using the analytical solution of the axial stress-axial strain curve based on gradient-dependent plasticity, linear regressions on the experimental axial stress-axial strain curves in strain-softening regime are carried out to calculate the number of shear band for different widths. After the number is determined, the axial stress-lateral strain curves for different sizes can be obtained according to the analytical solution of axial stress-lateral strain curve depending on the number of shear band and width of specimen. It is found that the ratio of the number of shear band to the width of specimen is a key parameter for describing the axial stress-lateral strain curves. If the ratio remains a constant, then the curves are size-independent. Otherwise, the post-peak curves are dependent on the width of specimen. For a single shear band appears in specimens with different widths, specimen with larger width leads to steeper curves and even exhibits snap-back behavior. The method proposed can also be used to analyze the problem of size effect of axial stress-circumferential strain curves. The reason for the size effect is shear localization, but the case that localization can not cause the size effect is not also impossible.

Genetic algorithm based on natural evolutionism is a good method to resolve complicated geotechnic nonlinear problems. Some classical works on genetic algorithm are introduced and remarked. The settlement of a soft soil foundation often manifests as complicated features at time sequence due to the influence of many factors. In the settlement prediction of a reinforcement and slant rectification, genetic algorithm programme coded by MATLAB predicts the settlement. Calculation result is consistent with the result from actual measurement. It indicates that genetic algorithm has much more superiority than traditional algorithm in global optimization, nonlinear optimization, multiparameter optimization, and so on.

The analyses of sensitivity have been considered to be one main method in the solution to identification of many parameters in civil engineering. At present, during the course of analysis and calculation in underground engineering, Duncan-Chang model is an ideal one. By a lot of nonlinear finite element method calculation, the main parameters, which have much larger influence on the calculated accuracy of embankment settlement, are found out; and then the qualitative relations between every parameter and embankment settlement are also given, and that can be the basis of simple disposal for back analysis of the model parameters in practical engineering.

Based on the characteristics of permafrost in plateau along the Qinghai-Tibet Railway, simulating calculation about the ground temperature during constructing concrete grouting piles is made by finite element program Ansys5.6. The changing rules of the ground temperature field during construction in plateau are analyzed too. According to the results, some problems, which are related to the construction of the pile in permafrost, are discussed. Then, some significant results are presented, which can provide a reference for corresponding engineering.

Through investigating the data that correlated with the loess, the engineering behaviors of the saturated loess and the soft loess were presented to compare with the loess in Xi’an; and the differences between them are pointed out. At the same time, the rheological model of unsaturated loess loading-volume and its applicable conditions have been described emphatically. Finally, the application of the model is analyzed in detail.

Deformation modulus of subsoil is an indispensable parameter for calculating settlement of foundation based on elastic theory; whereas the deformation modulus of subsoil is usually not provided in geotechnical investigation reports in China. Previous published researches are analyzed in this paper. An approximate method that considers the influencing factors including Poisson ratio, porosity ratio and remolding of soil, is developed based on porous medium theory. It estimates the deformation modulus of subsoil through compression modulus. It has practical significance in both calculating settlement of foundation with elastic theory and making full use of the existing research data.

The suitable grouting parameters for Yuanliangshan tunnel. are verified by analyzing particular karst aquifers within high pressure and rich water zone. And a borehole occluding system is developed by above analysis; the reliability of the system was thoroughly analysed and checked in order to quarantee construction safety. This technology was applied to construction of Yuanliangshan tunnel in Chongqing-Huaihua railway; and anticipatory effects have been obtained in complex karst condition. This technology can be applied to more field under similar conditions.

The test study on the silt of Xu-Su district in Jiangsu Province has been carried out. The results show that the silt of this area is of weak plasticity, low cohesiveness, high dispersion and low strength. The lime, cement adding lime, and stabilizer SEU-2 have been used to stabilize the silt respectively. The data of unconfined compression strength and dry-shrinkage tests show that the stabilizing effect of the stabilizer SEU-2 is the best one.

The field detective results and the laboratory testing results are given for the silty soil foundation of the flood-prevention dyke in Yibin strengthened by dynamic compaction method. The field detective data of the strengthened foundation show that the valid strengthened depth is about 8 meters by the 1600kN•m compacted energy. The test site is compacted with 2 times of full compaction at the space of 5 meters and another low energy compaction at the space of 2 meters. The dry densities of the subsoils are increased and the compression and permeability are decreased through dynamic compaction. The standard penetration numbers are all more than 7 while there are 32.2% of the standard penetration numbers less than 5 for the natural subsoils. The subsoils can meet the need of the requirements in bearing capacity and settlements of the flood-prevention dyke after dynamic compaction. The liquefaction tendency at the 7 degrees of earthquake has been disappeared through the dynamic compaction. The equilateral triangle arrangement of the compacting points is better than the square arrangement of the compacting points through the dynamic penetration tests and standard penetration tests.

A soil foundation composed of silt and silty clay needs to be improved in order to get its bearing capacity of composite foundation reaching 180 kPa. A series of in-situ improvement tests on the foundation were carried out by the methods of dry jet mixing piles (DJMP) combined with quicklime piles and DJMP. The results of the tests indicate that it is cheaper and more efficient by the method of DJMP combined with quicklime piles than the method of DJMP and that the composite foundation is to attain higher bearing capacity by process of DJMP carried out before quicklime pile improvement than DJMP carried out after quicklime pile inprovement. The calculation methods of bearing capacity for composite foundation of DJMP combined with quicklime pile are proposed.

For the disperse impetus dynamoelectric locomotive groups (DIDLG), an experimental study on the dynamic stress-strain impacts of a roadbed-culvert transition section of Shan-Sui multiple tests section in Qin-Shen passenger transport special railway line was conducted by using the method of high capability multicenter parallel data collecting and analyzing system, BY-1 dynamic-static stress sensor, etc.. It is obtained, that the dynamic stress-strain caused by DIDLG is steady comparatively, which is very advantageous for the high speed run of train; In the meantime, the dynamic stress-strain characteristics and the change trend in the direction of railway line of roadbed-culvert transition section are analyzed.

The design concept of composite pile is introduced into foundation treatment using jacked archor pile. The development of foundation bearing capacity and settlement with number of archor piles is also considered. Thus the plan of foundation treatment is optimized.Simuteniously, the load sharing contribution of soil and the whole safety of foundation are discussed. It is shown that the number of piles needed can be reduced, thus the investment can be saved.

According to the consolidation effect of soft soil, the strength increasing regularity of subsoil with consolidation effect is analyzed. The loading scheme of embankment fill is put forward considering consolidation effect. At the same time, based on the site information of Huaihe River waterway to sea, the degree of consolidation and the strength increasing regularity of embankment subsoil are analyzed; and then the way of stage filling is put forward.