The fundamental ideas and assumptions and their physical interpretations of subloading surface theory are presented. In order to describe the Massing effect and ratcheting effect of soils under cyclic loading, the conventional ellipse-parabola two-surface model is extended to the subloading surface cyclic plastic model by incorporating the Generalized plasticity and subloading surface theory. It is concluded that the model is capable of describing the deformation behavior of soil under monotonic and cyclic loading.

The calculation methods of earth pressure and water pressure on retaining structure in the conditions of hydrostatic pressure, steady seepage, excess pore water pressure, have been analyzed and summarized. Some examples have been given to explain the difference between the methods of separately or integrally estimating water and earth pressures on retaining wall and the effects of seepage and excess pore water pressure on total pressure on retaining structure. Also the critical state analysis of stability of retaining structure has been emphasized

Winkler’s model is widely used in designing elastic foundation beam and plate, but this model is too simple to reflect the characters of subsoil correctly. A new two-parameter layer model is presented. The model consists of a number of elastic layers, in which the distributions of stress and strain are assumed. Layer stiffness matrix, which expresses the relation of force and displacement on surface of every layer, can be calculated applying integral transformation. Thus, the layer system can be solved through compiling layer stiffness matrixes to form total matrix under the principle of FEM. The model is viewed as an extension of Vlazov model, and proved to be correct comparing with the result gained from Vlazov model. The most important thing is that the result of load embedding in layer model is gained; this means the method presented can be adopted to calculate pile foundations.

Thin-wall pipe pile using cast-in-situ concrete(PCC) with vibrated and steel tube mould technology is a patent for ground improvement invented by the authors. This new style pile is suitable for wide application to soft soil areas which can increase ground bearing capacity and reduce the ground settlement remarkably. The technical principle, soil improvement mechanism, the construction equipment and technology, the design and detection method are introduced in detail. It is concluded that the new style pile overcomes the shortage of traditional one and has following advantages, high bearing capacity, reliable quality and low cost, it is expected to be great applying prospect in ground improvement.

A method of equivalent retaining of arch effect for computing inner force and displacement of circular retaining structure is presented. An equivalent retaining structure of arch effect is got based on the solution of cylinder under uniform distributed loading in Mechanics of Elasticity and then this equivalent retaining structure is applied to an elastic foundation-beams to compute inner forces and displacements of the circular retaining structure. Engineering examples illustrate the feasibility and validity of this method.

Research of settlement and load transfer law on the composite foundation is a very important content in the composite foundation theory; then it isn’t maturity to this kind of composite foundation studying of settlement and load transfer law on theory. In this paper, based on the vertical deformation model[1] and the radial deformation model[2], the control differential equations of pile and pile-surrounding soil are established by the elastic theory and the pile-soil displacement coordination condition. The analytical formulas calculating deformation of pile and pile-surrounding soil in the pile group composite foundation reinforcing area are derived under flexible foundation; at the same time the analytical formulas calculating the pile side shear stress and the vertical stress of pile and pile-surrounding soil are drew. For verifying feasibility of the method , the results acquired by this kind of method are contrast with the finite element method by way of calculating example. And also carrying on the model experiment. All results indicate: this kind of method has enough precision to analyzing load transfer law and deformation of the pile group composite foundation in reinforcing area under flexible foundation , it is simple to calculate, and is easy to engineering application.

In light of the complexity of rock mass structure in mining area, joints, cracks and anisotropic rock masses are regarded as damage rock mass in the paper. And a three dimensional (3D) damage model of finite element analysis is set up for joint-crack rock masses. Concrete formulas of 3D finite element imitation are given in greater detail. The 3D simulating software is completed, which can be carried out in WINDOWS. All kinds of engineering factors can be considered in the software. Case analysis results show that the given way is feasible to deal with complex structure rock masses and the developed software is effective.

Investigates the kinematics in centrifuge modelling which are highly useful for improving the understanding of results from centrifuge modelling tests. Mathematical expressions of the global velocity and acceleration of an arbitrary particle in a centrifuge model, which describe the motion of the particle, are derived. The acceleration is a critical factor in centrifuge modelling because it links kinematics to dynamics through Newton second law. The physical meaning of each term of the derived expression for global acceleration is described. Contributions of the centripetal acceleration in steady flight, the tangential acceleration due to the effect of the angular acceleration, the Coriolis component of acceleration, the radial (the vertical direction at prototype), circumferential and axial (the two horizontal directions at prototype) shaking effects and the elongation effect of the centrifuge arm to the global acceleration of a particle in centrifuge modelling are identified in the expression of the global acceleration. It is found that, for ease of comprehension of test results from dynamic centrifuge modelling by means of uniaxial shaking, the preferred direction of shaking is in the axial direction (parallel to the axis of rotation). In addition, a description of the kinematics in centrifuge modelling proposed by Schofield [1] is critically examined and is found to be confusing.

Based on studying the performance of widely used prestressed grouted rock anchors in water conservancy and hydropower projects, the factors affected on the anchoring load losses such as steel fiber relaxation, rock mass strength and property, construction quality, anchor structure, environment change in long time was discussed, and the mechanism of load losses with factors was put forward. It was observed that the main reasons of load losses versus time are rock mass deformation and construction quality. According to the monitored data of anchoring load losses with the factors, the relativity of the factors and load losses was build up. Furthermore, some engineering controlling methods were taken out. It is believed that the methods discussed in this paper can be used for construction of anchoring engineering in future.

The forepoling bolts are used for major anti-sliding measure in soil nailing retaining and protection of foundation excavation. In the forthcoming design of soil-nailing retaining wall with forepoling bolts, the whole stability is only checked or they are used for safe reserve. This paper applies the theory of earth pressure acting on piles in a row, which had already been derived by Ito and Matsui, to analyze forepoling bolts. The anti-sliding action that the forepoling bolts take in the soil nailing retaining wall is studied. The stability analyzing method for the soil-nailing wall with the forepoling bolts is expounded; and it has been verified by an engineering example. By studying the soil-nailing wall with the forepoling bolts, its design theory will be greatly improved. Meanwhile, engineering cost will be decreased.

The dynamic response of the ground under the action of a rigid circular dynamic loading is studied. Cylindrical solutions are given. Based on the solutions, a practical dynamic ground rigidity is presented. Dynamic rigidity and damping coefficient of the ground and their relation are also discussed qualitatively. A practical method is presented for determination of the dynamic rigidity and damping coefficient.

Soft rock would display the characteristics of elasticity and viscoelasticity under low stress, of elasticity, plasticity and viscoelasticity under higher stress and of elasticity, plasticity, viscoelasticity and viscoplasticity under very high stress .In order to describe these characteristics comprehensively, firstly the paper brought forward two nonlinear components of creep body and plastic cranny body, and combined them with KELVIN body describing the deceleration creep and HOKE body describing the instantaneous elasticity to gain a new multiple rheological model .Then it used the model to simulate the results of the multi-step incremental cycling loading and unloading creep test of soft rock and drew a conclusion that the new model could effectively describe the creep properties of soft rock under different stress level ,especially the properties of the cranny-closed phase and the creep-accelerated phase so that it could be popularly used in engineering practice.

The characteristics of rock socketed pile is mainly decided by rock sockets. Based on shear expansion rule that is supposed to govern the pile-rock interaction, this paper uses load transfer theory to create a new load transfer function and generates a set of formulae suitable for soft rock socketed piles. Through analysis of these formulae and practical test results, it satisfactorily explained the relationship between pile-end resistance and socketed ratio H/D, investigated the effect of rock asperity and bottom quality, etc. on pile settlement and pile-end resistance, and also proposed some useful suggestions for socketed pile design.

Combined with engineering cases, the mechanism of inrush through fault which is water-inconductive in initial geological condition, has been studied. It is found that the fault zone can act as a barrier of excavating-induced stress & deformation under some conditions. The barrier effect may cause intense deformation, high deformation gradient in rockmass within the fault zone, more intense deformation and stress concentration between the excavated space and the fault. All of them may easily arouse rockmass deformation and geological structure slip within and near the fault zone, and furthermore lead to groundwater inrush. The rationality of analyses mentioned above has been confirmed by the specific engineering cases.

By using ANN and its powerful nonlinear mapping ability and combining production of FEM dynamic analysis, a new way to predicting terrane crack depth of complex fire hole is offered. The result has indicated that the ANN can incarnate the connotative nonlinear relation between explosive parameters and terrane crack depth fully. This method has higher fitting precision, and its result coinsides with the result of FEM.

It is important to identify the soil parameters while using finite elements method. Cambridge model is a widely used soil constitutive model in practice, whose parameters always determined by conventional laboratory test results. The expression of extended Cambridge model under triaxial test is presented. And simulation computer program is developed to figure out the optimum parameters. The application to Xiaolangdi project shows the rationality and practicability of this program.

A numerical model calculating displacement of jointed slab on void foundation is established with finite element method. And a method for modulus back analysis of jointed slab is developed based on the theory of system identification. On the ground of above work, this paper has established an iteration method to identify void of rigid pavements using deflection data measured from falling weight deflectometer.

Considering the characteristics of parameter inverse problems on unconfined seepage flow such as high computational cost, numerous objective parameters and wide variation ranges of parameters, and based on the study of parameter inverse problems by means of common genetic algorithm, a new hybrid genetic algorithm is proposed to overcome the limitation of common genetic algorithm such as poor local search ability, premature convergent and excessive computational cost. With water heads used as measured data and seepage coefficient scale genes of different fissured groups selected as objective parameters, a typical slope case study is given. The result shows that the method is effective in identifying the seepage parameters of fissured rock masses on the supposition that the parameter bounds are given. And the method breaks through several limitations of traditional optimization method and improves the efficiency. For the sake of comparisons, the results of the same case study with traditional simplex method used are given.

The preliminary study on the effect of pile-soil cooperative work is made at first. Then the condition for formation of rigid pile composite ground and the design method for different pile spacings of composite pile foundation is discussed. When piles are friction ones and end-bearing friction ones, the rigid pile composite ground without cushion is safer and more economical than that with cushion. If the total safety level and settlement of composite pile foundation can be satisfied, design may be carried out in definite stress ratio of pile and soil; and the designed stress ratio of pile and soil is unnecessarily equal to the practical one. Some existing problems in design method of pile foundation with large spacing between piles are discussed, and some proposals of improvement are put forward, too.

For an actual project, the reason of standard ultimate bearing capacity of a single pile less than that of designing value is analyzed. It is suggested that when kaolin included in the soil at the end of piles is softened by water, a plastic shear-sliding plane will be generated. Then the soil will be in shear failure mode under static loading which significantly decreases the soil standard ultimate bearing capacity. For this case, it is not reasonable to determine the soil standard ultimate bearing capacity only by liquid index based on technical code for building pile foundations, the compression modulus and ratio of pore should be added for consideration.

The 3D mechanical interaction model of framed structure and bar-crossed foundation and ground soil is established. The effects of stratum structure and foundation section form on the interaction are analysed by FEM program ANSYS.

The gravity of rock masses and denudation are important factors in the construction of initial stress field. The unit weight got by the conventional back analysis is usually larger than that obtained by the test in-situ. An example is studied to show that such phenomenon results from the earth's surface denudation. Based on the result，some engineering practical problems are explored.

Based on the assumption that all the variables are invariant in circular direction but can vary in the other two directions, FEM formulations are developed with the incremental unknowns for the coupled liquid-solid problem of axisymmetric geotechnical structure due to multi-directional imposed load. In the analysis, the medium is regarded as continuous, anisotropic, saturated, and it is assumed that small deformation occurs and either Darcy’s law or effective stress principle holds true. Finally, a FEM simulation of the consolidated undrained triaxial compression test for a saturated axisymmetric sample are performed which can prove the present method true.

FEA numeric solution of wave equation indicates that deductions must comply with acoustic parameters such as velocity of sound, amplitude, wave shape etc. when inspecting interior flaws of grout of anchor bar. Basing on wavelet packet analysis, energy eigenvector is a flaw vector, which could be regarded as basis in anchors' non-destructive inspection. As a nonlinear dynamical system, artificial neural networks dealing with quality inspection of gray system have been proved efficient.

Great advances have been made in the research on the liquefaction distinguishing; and some methods have been matured. This paper is to probe into the differences among using different methods such as anti-earthquake design specification for architecture structure, anti-earthquake design specification for railway engineering, effective stress method of finite element for free field and effective stress method of finite element taking into account the change of stress status owing to subway tunnel’s construction. Finally, the mechanism for the differences is explained. So the paper is taken as a reference for the survey, design and construction of underground engineerings.

A new elastoplastic model for jointed rock is presented. The structure is divided into block elements and fault elements, which are real joint elements or artificial fault elements. The basic unknown quantities are the rigid displacements and the average strains of the block elements. The constitutive laws of joint material and block material can be fully considered in the model. The cost of computation is low. It is a discontinuous element for displacement. The model is suited to numerical analysis of jointed rock.

The major principal stress arch is studied in the backfill in passive critical state. The curve equations of major principal stress arch and the coefficient of passive earth pressure are given. By using the method of level layer element, the distribution of passive earth pressure is analysed.

The method of taking value for the strength parameter of residual soil slope is discussed. Based on the testing data of a real residual soil slope, the characteristic parameters c and φ in the different position of slope have been analysed statistically. By way of many teams parameter back analysis in the stability analysis of slope, a method of taking value from which the strength parameter has fit to the real state index of the slope, has been put forward.

Air element method is proposed to model drainage holes in seepage analysis. The method is to look drainage holes as some elements filled with air. By defining certain higher permeability coefficient, these elements can be included in the conventional seepage calculation like common elements. It is proved by the engineering example that the method is easy to be applied in the engineering practices.

Reliability of cohesive soil slopes is assessed using the spatial averaging (SE) method. Spatial variability of soil properties is represented by an anisotropic random field. Also a method of landslide hazard spatial prognosis is presented by calculating the minimal reliability index corresponding to the width of potential failure zone.

Preconsolidation Pressure is an index of deciding the stress history of a soil layer; and it is also an important computation parameter in settlement analysis dealing with soils which have different stress histories. It is very significant to determine preconsolidation pressure conveniently and precisely. A new method of determining preconsolidation pressure named as mathematical model method based on theoretical research and test analysis. Results of tests for soil samples taking from Runyang great bridge demonstrated that the application of the method is recommendable.

There are many results about the interface test for geotextile , but the testing result of geogrid is lacking. This paper presents the contents and results of interface tests for uniaxial oriented geogrid and warp knitting geogrid; some useful opinions are provided. The interface friction coefficients between geogrid and sand-gravel and coarse sand and eluvial soil, are evaluated; and then compared with the testing results of the woven geotextile .

The application of gray clustering procedure for classification of expansive soil is described. Taking the middle road scheme of the Water Transfer from South to North Project for example, the authors use gray clustering procedure of gray system to classify expansive soils. The result indicates that using gray clustering procedure of gray system to classify expansive soil is superior in solving the problem that it can’t be classified for cross of index in general multiplefactor classification and making mathematization and quantification for classification.

To improve our understanding of the fundamental mechanism of rain-induced landslides in unsaturated expansive soils, artificial rainfall simulation tests were carried out on an 11 m high cut slope in a typical medium-plastic expansive clay in Hubei of China. The slope was well-instrumented with tensiometers, thermal conductivity suction sensors, moisture probes, earth pressure cells, inclinometers, a tipping bucket rain gauge, a vee-notch flow meter and an evaporimeter. Two artificial rainfall events were created during a month of field investigation and monitoring. Monitored results demonstrate: rainfall infiltration leads to a significant increase in pore-water pressure and water content within the top 2 m soil layer, which may result in a reduction of shear strength due to a decrease in effective stress and wetting-induced softening. On the other hand, rainfall infiltration causes a significant increase in total stress ratio (sh/sv), which may lead to a local passive failure and then trigger a progressive slope failure under a continuous rainfall condition.

A nonlinear viscoelastic constitutive model is adopted to describe the creep properties of soft soil. Finite element model is established to simulate a project where EPS was used as substitutive material. The effect of EPS was computed. Primary consolidation, secondary consolidation and over consolidation are discussed. The causes of large settlement after construction are discussed. The long-term settlement of the project is predicted. The method and principle of designing EPS are discussed.

The measurement of three-dimension relative crustal stress at great depth in the medium-level radioactivity waste disposal field is briefly introduced. The effect of properties difference betweeen the sealing-hole medium and the rock on crustal stress measurement data is analyzed. It is necessary to consider modification of measurement data due to the property difference of the media.

The deep unloaded crack band is located in the high slope of left dam shoulder of Jinping hydopower electrical station; its formation cause and distribution seriously affects the stability and treatment cost. The ANSYS software has been adopted to make analysis of mechanical properties of the high slope by considering the faults and crack band and strata in detail with different loads combination. On the above base a simple mechanical model has been established for the clarification of its formation, the strange stress range is defined.

A method, drainage with plastic board, was used to improve the soft ground by preloading method for a row material site of a certain steel-iron factory at the bank of the Yangtze river; and it has yielded good results. In this paper，FEM of Biot’s consolidation theory is applied to calculate the consolidation of foundation. The plastic board is rationally simplified to equivalent sand-wall. The measured results are favorably coincident with the numerical results; and that verifies feasibility of the computational method.

The hydro-photoelectric pressure gauge,a new patent product, is developed by our institute recently.At first,its technical feature,function and application scope are presented. Secondly,the stress and deformation of pressure transmission cell are simulated by finite element method;and based on the computation results,its structural optimization analysis has been carried out.At last,the method and process of calibration and indoor simulated test of this pressure gauge,as well as analysis of the test results are described.The test results indicate that the new product has good transducing performance,stable behavior and bright application future.