The creep behavior of saturated sands is studied by uniaxial compression tests. The samples were taken from the aquifers of Changzhou in Jiangsu Province. Based on the test results, the relationship of stress-strain-time for saturated sands is obtained; and it could be expressed as power functions. The test results show that the strains for sands depend not only on the stresses exerted on them but also the time elapsed. That is to say that the sands have characteristics of nonlinear creep. The conclusion is very helpful to study the land subsidence due to extracting groundwater.

The soil stress, anchoring segment stress and foundation pit side displacement are researched by large-scale indoor model test during construction process of a foundation pit. The result indicates that when the foundation pit is excavated, the soil stress state near the foundation pit wall changes obviously; the stress of anchoring segment of bolt appears distribution of nonlinearly decreasing gradually; The side displacement of foundation pit takes on the tendency increased with going on of construction process. On the basis of model test, anchoring and deformation mechanism of soil bolt are discussed. The conclusion is that an integral mechanical model which includes the soil around the foundation pit and bolt etc., should be established with considering construction process. Thus the stress field and displacement field surrounding the foundation pit can be calculated accurately.

At present, the safety factors are improved little with circular failure analysis method stated in the criterion(Technical standard for applications of geosynthetics, GB50290-98) for preventing deep sliding of reinforced underlying layer of embankment with geofabric, which doesn’t agree with the actual effects. It shows that the circular arc analysis method doesn’t reflect the whole effects of reinforced geofabric. By analyzing interactional mechanism between soil and geofabric in detail, it considers that geofabric with middle tensile strength and modulus will exhibit the intercross sliding resistance mechanism of shearing resistance, of pulling-out resistance and of tension resistance, when embankment and its foundation achieve the state of limit equilibrium as the height of filling soil increases. By comparing the full scale test of embankment without reinforced underlying layer with the other two sections being provided with one or two reinforced underlying layers, the sliding resistance and reinforcement effects are revealed. Considering the above sliding resistance mechanism respectively, the minimum safety factors of the embankment with one reinforced underlying layer are worked out with circular failure analysis method. They also show the sliding resistance and reinforcement effects. It should be pointed out that in practice there is a leading sliding resistance mechanism. Further, making use of the data of the full scale test, a new circular sliding surface passing the point of maximum vertical settlement, which is the center point of interface between embankment and geofabric, is put forward. The computed safety factors of the embankment without or with one or two reinforced underlying layers are improved obviously with the new sliding surface and more closer to actual situation than the old one

The mechanical characteristics are analysed based on compression test,shear test,tensile test,extraction test of soft soil reinforced by geogrid. Through laboratory model tests, the following studies are performed: the lateral and vertical displacement of the variation with depth,displacement field, stress field, strain field of the foundation reinforced and non-reinforced by geogrid. The results show that it is feasible to change and to resist the formation and development of plastic zone; the influence of reinforced cushion to spread and even up distribute stress of soft soil of substratum, and as well the role of geogrid, to control plastic deformation, to strengthen ductility and stiffness, to decrease lateral and vertical displacements, to strengthen shear strength of soft soil foundation, to improve the stability of the foundation and bearing capacity of reinforced soft soil; the study provides reliable basis for engineering applications.

The incremental linear elastic model with modulus of deformation E and poisson’s ratio is very popular in numerical analyses of soil engineering. To research and understand the effects of E and on calculation of FEM is helpful to analysis of calculation results. Firstly, one parameter was simply assumed to keep a constant and effects of variation of another parameter were analyzed. Secondly, when the stability of slope was evaluated with FEM, the effect of E and had already been considered in strength reduction technique. The following three conditions are jointly used as a criteria to assess stability failure of slope, the contour lines of ? xy formed a sliding surface stress levels S in elements on sliding surface equaled to l and the displacement at a certain node increased suddenly. Thirdly, relationships between E and were discussed by means of strength parameters, the greater the E, the greater is the strength and the less is the of soil.

The identification and classification of expansive soils is the problems that should be firstly solved in construction in expansive soil region. The existing approach to identification and classification of expansive soils has been evaluated. The indices that can reflect and characterize swell-shrink mechanism and property were analyzed. The analysis indicates that 5 indices such as liquid limit, plastic limit , clay particles, free swell ratio, swell-shrink total ratio can reflect and characterize swell-shrink mechanism and property; hereby these 5 indices have been suggested as identification and classification indices of expansive soils; and a new approach of 5- indices including liquid limit , plastic limit , clay particles, free swell ratio, swell-shrink total ratio, for identification and classification of expansive soils has been established. The new approach to identification and classification of expansive soils has been validated and it has been shown that the new approach is easy and reliable.

An elastoplastic anisotropic damage numerical model for rock is established by adopting Mohr-Coulomb criterion as the shearing yield condition, ultimate strain as the shearing damage criterion, and maximal tensile stress as the tension damage criterion. The staged damage evolution of underground stope is emphatically numerically studied in the construction process with supporting structure and without supporting structure; and the deformation field of underground stope is also numerically calculated on the supposing that rock as an elastic material. The numerical test reproduces the staged damage evolution of underground stope in the construction process; and it provides a means to optimize the design and construction process of underground stope, to effectively prevent and control some engineering accidents such as collapse.

An attempt is made to simulate the layer separation in overburden by using the finite element numerical modeling; and the numerical modeling together with similarity simulation is adopted to investigate the surface movement and the breakage of the overburden during the abandoned stope treatment of the section #143 in Mujia Hill. It has been found from this research that the range of surface movement increases moderately with the collapse of jambs and the increase of the roof span. The subsidence area ranges from 1.5 times to 1.7 times of the roof span and the subsidence curves are symmetrical to the vertical line through the point with maximum subsidence. The horizontal movement, however, is not symmetrical and its impacting area is larger than the range of subsidence, with its maximum value equal to 40 % of the maximum subsidence. In addition, the layer separation exists in the end of span of overburden if the subsidence happens in whole overburden，which is resulted from the shear failure of the bedding plane.

The authors pointed out that the formula existed for more than 40 years to calculate the tensile strength of rock in Brazilian test is based on 2D elastic theory; and the formula is not suitable for the practical condition which is a 3D problem. In order to obtain 3D stress distribution within the specimen, we adopted software package Marc to carry out a 3D finite element analysis. It is found that the tensile stress distribution at a cross-section of a solid specimen is similar to that of 2D disk. However, the tensile stress at a cross-section varies with the thickness of the specimen. The nearer the cross-section closes to the end of the specimen, the higher the horizontal tensile stress is. When the height-to-diameter ratio of the specimen is 1 and Poisson’s ratio is 0.25, the tensile strength calculated by the classical 2D solution is 23.3% less than the real value.

Based on the saturated porous medium’s theory, the inertia force of both the soil and the water is considered; the stable vibration problem of transversely isotropic saturated soils is studied. Hankel transform is used to obtain the displacement, stress and porewater pressure in integral form. The numerical inversion of Hankel transform is used to obtain some numerical results. Finally, the effect of the type and degree of soils anisotropy on the vertical amplitude of displacement is investigated.

Primary parametric resonance of a parametrically excited simply supported thin rectangular plate on nonlinear elastic foundation is analyzed. The nonlinear vibration equation that has the form of a Mathieu-Duffing’s equation is derived from the Von Karman equation and Galerkin’s method. The method of multiple scales is used to find the averaged equation. Numerical results are presented to illustrate the effect of various parameters including damping parameter, foundation coefficient as well as geometry parameter.

In practical engineering blast, the water decoupling hole is very common. The decoupling coefficient is one of the key factors influencing explosion effects, and its different values will induce different propagation mechanisms of stress-waves and variable destructive ranges in the surrounding mediums. Previous studies mainly focus on analytical solutions and model tests. This paper uses the large-scale nonlinear dynamic analysis software, LS-DYNA, and with famous concrete damage constitutive model Johnson-Holmquist-Concrete to numerically simulate the wave-induced damage properties of concrete by adopting different radial decoupling coefficients Kd for water decoupling blast in infinite concrete medium. The relationships between the damage distribution zones around blasting hole and the pressure, acceleration, velocity of point on hole-wall with the different values of Kd are analyzed. The results obtained in this paper may be useful in engineering blast.

The shear strength parameters of soils are conventionally obtained by soil triaxial compression tests in laboratory. However, the soils in engineering practice are not always in axisymmetric stress state as in conventional triaxial compression tests. Therefore, it is important to examine the inter-relationship between strength parameters under different stress states. Based on the spatial mobilization plane failure criterion proposed by Matsuoka and Nakai, the strength parameters for different intermediate principal stresses are generally compared. It is demonstrated that the intermediate principal stress ratio has a considerable effect on shear strength parameters of soils; and the effect will be the most significant under plane-strain condition.

The stability of surrounding rock mass of underground cavern is computed by using discrete element method software 3DEC. Firstly, the destroy type of rock mass is judged; secondly, the model is built and the random discontinuities are simulated; and at last the instability blocks are discovered after computation.The method and result can give reference to the similar engineering.

The hydraulic factors caused by the fluctuation flow and the filter mechanism of the geotextile filter of sea embankment are researched. There will be an adhesion force existing among the grains that have a diameter less than 0.6mm. Meanwhile, the soil grains are subjected to the shear stress developed by the flow because the filter and the embankment body have different seepage velocity.After the shear stress developed by the flow that make the soil grains deformed; the submit stress around the soil grains, the wave pressure etc. are analyzed. Therefore, based on the principle of balance, the retention criterion of the geotextile filter is proposed.

The complexity of geotechnical engineering makes that there must be deviation in the 3D numerical analytical result from the reality. We analyze those deviations, feed back the 3D model with the coupling data and get the parameters adjusted. That is to say that we adjust the easily adjusted factors which result in the inaccuracy for the uneasily adjusted ones; and make the inaccuracy of 3D numerical analytical result to the minimum. We can use the adjusted parameters in the next analytical model, and will get the more accurate numerical analytical result.

Vacuity and pore-water pressure are two different conceptions, the vacuity measured by vacuum meter in the soft soil is different from the difference of pore-water pressure measured by piezometer; but there is an immanent relation between them. The theoretical formula about vacuity in vacuum tube and pore-water pressure at the observation point was obtained in this paper by using equation of gas state and equilibrium equation. When the observation point is above the groundwater surface, the vacuity is the same as the difference of pore-water pressure. When the observation point is under the groundwater surface, the vacuity is less than the difference of pore-water pressure, but they can be calculated each other by using the theoretical formula. The test results explain the relations between the vacuity and the pore-water pressure and show that the theoretical formula is correct.

Composite material soil-nail, a new kind of bar made of fiberglass and epoxy resin, is used as substitute for general steel soil-nail in foundation pit supporting. It shows a variety of properties: high strength, flexibility of designing, cheapness and environmental protection. Samples with a diameter of 21 mm are made; and tension tests are carried out with these samples. Some important characters are observed from the tension tests. The finite element method is then used to analyze and contrast the deformation and failure of foundation pits supported separately by general steel soil-nail, composite material soil-nail and prestressed composite material soil-nail. Three results are revealed：(1) Difference is obvious among the deformation of pits supported by composite material soil-nail, general steel soil-nail and prestressed composite material soil-nail ; (2) The deformation of pit supported by prestressed composite material soil-nail is near to the deformation of the pit supported by general steel soil-nail when depth of pit is 10 m or less；(3) The settlement have no much difference when the pits are supported separately by composite material soil-nail, general steel soil-nail and prestressed composite material soil-nail.

In order to solve the problem of slope stability under rainfall infiltration, this paper presents a flow-deformation coupled finite element analysis model of unsaturated soil which considers hydraulic conductivity curve, soil-water characteristic curve, modified Mohr-Coulomb failure criterion; and the process of infiltration into an unsaturated slope under rainfall and its effect on soil slope behavior are examined using this analysis model. Some important conclusions are drawn after analyzing the stress field and deformation field of unsaturated soil slopes. This paper provides a basis for stability analysis of unsaturated soil slopes under rainfall infiltration.

In order to investigate the regulation of pore water pressure of silty soils, a series of dynamic cyclic tests on saturated and disturbed silt were carried out in a new universal triaxial torsional shear apparatus of Hohai University. The special was that the tests didn’t complete when the initial liquefaction appeared until the pore water pressure had been in a smoothly way, which could simulate the severity of liquefaction after liquefaction and also describe the whole process of pore water pressure generation. It is found that the regulation of pore water pressure curve can be fitted by an improved exponential function. The function can fit much achievements of other scholars and also make up the limitation that pore water pressure is larger than confining pressure. Both theoretical analysis and test data validation indicate the applicability of the pore water pressure expression.

Silts and silts treated with some additives are studied. These additives include 4 % lime, 2 % cement and 2 % lime, 4 % SEU-2 solidified agent, and 8 % SEU-2 solidified agent, respectively. Unconsolidated undrained triaxial tests and consolidated undrained triaxial tests are used to study characteristics of strength and deformation of silts at various ages and with different additives. Test results show that the stress-strain curves of silts and stabilization silts are primarily softening, and that SEU-2 solidified agent can apparently improve the cohesion of silts. Comparing the strength parameters of stabilization silts treated with different additives, it is considered that adding SEU-2 solidified agent is the most effective method to stabilize silts.

Based on the mathematical model of high pressure injection cement liquid, a formula of pressure distribution is derived in the district with the cement liquid injection and the raw water area , and the pressure in well bottom to fade away as stop injection cement liquid. The pressure in well bottom relation with the time of the injection and the viscosity of cement liquid , and the permeability in the confined aquifer are analyzed. The empirical formula of the injection pressure with the water-cement ratio is established. The formula can consequently guide the engineering; the good fulfillment results are obtained.

Based on the analysis of mechanical tests of core and well logging data, a new method for detecting geo-pressure using rock mechanical parameters is presented. The research includes transition of dynamic and static rock mechanics; the relation between ground pore pressure and rock mechanical parameters; and the determination of basic rock mechanical parameters in pressure traverse, etc. By using the new method and combining with the well logging data, the geo-pressure for a high-geopressure zone is analysed.

Relationship between jointed slab and void of elastic foundation and acoustic features of resonator is studied by acoustic vibration. The vibration frequencies of jointed slab with or without void are calculated and analyzed by finite element method (FEM).The range and size of void, detected by acoustic vibration, prove to be closely associated with the acoustics features. Taking a void pavement slab as the example, by calculating and analyzing, an integrated neural network based on information fusion can be applied to identify the void of rigid pavement slab. Thus it offers theoretical and experiment basis for NDT of the defect like foundation void by means of acoustic features. The method proves to work rapidly, precisely and conveniently in practical application.

A new method based on support vector machine（SVM）model is proposed to predict settlement of road soft foundation. A case study shows that the prediction results accord well with the actual settlement measured data. The new method is also compared with BP artificial neural network model and traditional hyperbola method. The prediction results indicate that the SVM model has a better prediction ability than BP neural network model at the same training set mean-square error. Utilizing the settlement data under multi-stage loading, SVM model has a better reflection for foundation soil deformation trend compared with hyperbola method only using the data under pre-loading. Therefore, settlement prediction based on SVM model can reflect actual settlement process more correctly.

Through analyzing ultimate bearing capacity of square and circular foundations using three equations and two theoretical solutions, it is shown shows that (a) result of equation and theoretical solution is obviously less than the data of load test for sand, (b) result of Vesic’s equation is closer to the data of load test for clayey soil; (c) result of Li’s solution is proper for soft clayed soil, but Zhou’s solution is fit for high strength clayed soil.

There are a few paper discussed establishing permeable coefficient tensor of rock under tensile load until now. In this paper, an anisotropic permeable coefficient tensor of rock under tensile load, thingking about hydraulic pressure, microcrack extending and distortion, is established. The equations of the theories in previous paper and this paper are deduced for rock under axial tensile loading. The presented models are compared with experimental data. The comparative results show that the constitutive model can reflect all phases of stress-strain curve and the character that hydraulic pressure make rock strength lower. The permeable coefficient tensor can reflect the anisotropy and the evolvement of seepage in rock. The permeable coefficient tensor can be applied to rock mass too.

In the engineering of embankment or earth dam, the occurring of piping erosion may cause great changes in seepage fields. Numerical simulation to piping erosion developing process is very important to piping erosion prevention and treatment. A method of embedding erosion tunnel in 3-dimensional blocks is put forward to solve series of difficulties in FEM simulation. After discussion of some operating problems, an example of earth dam piping erosion is studied. With numerical calculations, 3-dimensional characteristics of dam seepage field under developing process of piping erosion are put into analysis; that shows the concentrative seepage status near the developed erosion tunnel. It is concluded that reforming of seepage field is critical method to prevent piping erosion.

Applying object-oriented programming to researching finite element method is a beneficial effort and creativity development. By comparing the conventional procedural programming and object-oriented programming, the advantages of combining the FEM program and object-oriented programming method are discussed; and the progress of object-oriented programming at home and abroad is reviewed. Based on a description of the major characters of object-oriented programming, a 3D brittle-plastic finite element analysis class library is constructed. By combining VC++ with Matlab, a geotechnical FEM software based on Windows98/2000/NT is designed to deal with 3D brittle-plastic problems. The successful application to the stability analysis of an underground excavation of a certain hydropower project proves the validity and practicability of this object-oriented program, which can be of beneficial reference to analogous projects.

In order to choose rock cover of Xiamen subsea tunnel now, 3D elastoplastic constitutive relation and damage evolution equation for 4 profiles has been done along the longitudinal of the tunnel. The numerical results of stress distribution, displacements, plastic zones and damage zones of rock mass after excavation are got. By means of analysis of stress disturbed area, and comparing rock cover of weak regolith with stress disturbed area at axis and raising or decreasing, it is easy to determine minimal rock cover; similarly, it is satisfying to evaluate stability from the numerical results of stress distribution, displacements, plastic zones and damage zones of rock mass after excavation. Thus, it can be concluded that the tunnel is stable even the rock cover of the subsea tunnel decrease 4m compare to the original design elevation by organic integration of the two.

Restricted by the field condition, many buildings were constructed on high constrictive soft soil. The differential settlement of soft soil may threaten security of constructs. There are so many influential factors, including the differences of loading, structure stiffness and soil layer, etc., of which all affect the differential settlement. Traditional layerwise summation method can’t take all those factors into account. Therefore, it is necessary to improve one effective method to forecast the settlement of buildings. Based on the conception of construct, substratum and foundation interaction, a 3-D numerical simulation model of a brick structure is established and its settlements are analyzed. The result proves that this method can analyze the differential settlement of oblique buildings effectively.

Th anti-side pile engineering design for reservoir landslide is a topic of general interest in engineering domain. It is quite important how to determine rationally design landslide push-force to optimizing design of anti-slide pile. Based on studying thoroughly pushing force curve, aiming at the question existing in "specification" and engineering design, the concept of " fundamental calculation cases" and " control and design calculation cases" are proposed. For down-slide section and slide-resistant section of the landslide, different determining method of design push-force is provided. All these are applied to engineering design of Songjiawuchang landslide; and the enormous economic benefits will be produced.

In order to investigate the sedimentation acceleration of serous fluid of dredger fill under the action of the additive and to find a method which can quickly change the serous fluid of dredger fill to foundation with bearing capacity, settlement test was conducted in the acryl glass vessel to simulate the subsidence and consolidation of serous fluid of dredger fill which was mixed respectively with cement, calcined lime and the mixture of cement and lime. Moreover, the mechanism was analyzed from granulometric composition, mineralogical analysis and microstructure. The basis for quick strengthening of the dredger fill was provided. By the comparison of the test result before and after the treating, it was found that the additive had the ability to accelerate consolidation and strengthen serous fluid of dredger fill.

By using vane shear test, portable sounding test, water content test and direct shear test, the strengthening effect of vegetation on the soil slope of an expressway, i. e. the influence of vegetation on mechanical parameters of slope soil is researched. The tests are done in two kinds of vegetation areas. The result indicates that the vegetation has potential influence on the stability of shallow slope. Through tests the quantitative influence of the vegetation on the shallow slope is analyzed.

There are a lot of stochastic-fuzziness phenomena in earth and rock excavation project. This paper takes them into account and designs a simulation system for earth and rock excavation works. In this paper programming methods of computer simulation for earth and rock are discussed, and how to set up a stochastic-fuzziness model for earth and rock excavation project is emphasized. The simulation model can match well with the progress of earth and rock excavation project ,the simulation system can provide effective analyse method and evaluation reference for optimizing design and decision-making.

Developed during the Chinese national 7th and 8th Five-Year key science and technology research project, geomembrane strain gauge was firstly used in-situ to monitor the strain of waterproof geomembrane in the 2nd-stage upstream cofferdam of the Three Georges Project and their good capability for measuring large strain were verified. All the 18 strain gauges placed in the cofferdam at different elevation had made good performance in measuring the strain of the cofferdam during construction. In section 0+500, all of the 10 gauges had measured large strain up to 11 %-19 %; most of them worked well till the measured value reaching their measuring limits. They only destroyed within 3 months after installated due to quick loading at the construction time. The others worked continually till Oct. 22, 2001 (just before the removal of the cofferdam). Their life-spans were longer than 3 years. Some of the gauges in sections 0+500 and 0+930 reached rapidly to 16 %-20 % during the flood season in the summers of 2000 and 2001; it seems that large strains, even cracks, probably occurred in the soil mass of cofferdam.