The deformation and failure process of natural soil under loading can be obtained by research on structured clay ,on which the design of construction and soil improvement can be based when the structural influence is considered. With the construction of high, deep and great buildings, the research on the structured soil has recently become more and more important. In this paper, the researches of structured clay on micro deformation mechanism, artificial preparation, civil engineering behavior and numerical models are introduced. Processing in situ test, artificial preparation of structured soil, measuring methods of meso-structural parameters,numerical methods considering meso-structure and establishing macro-constitutive models considering micro- deformation mechanism are the important problems of study on the structured soil.

Since non-associated flow rule cannot be derived theoretically from Drucker’s postulate in classical plasticity, the basic principles of thermo-mechanics in continua are applied to establish the elastic/plastic clay model. According to the theory of rate-independent plasticity, multiple yield criteria are constructed from the known multiple rate independent dissipation functions and it is proved that the number of yielding functions is equal to the number of independent dissipation functions. The influence of dissipation functions on yielding criterions and flow rule is studied. A new set of functions for clay are considered taking into account associated flow rule and non-associated flow rule, Gibbs free energy and multiple dissipation functions and experimental data. The empirically derived function from the present study will include the double yielding function plastic model provided by Yin Zong-ze. These new clay models can provide better physical meaning as well as including non-associated flow rule into the formulation. The parameters of the new model are determined by laboratory tests on clay. It is demonstrated that the new clay models can simulate the constitutive relation of clay with multiple yielding functions by comparing the theoretical stress-strain curve with the experiment stress-strain results.

Through describing the character, application and engineering properties of lightweight mixed soil, the paper demonstrates that its physico-mechanical characteristics are varied with different mixing proportions. It possesses the engineering characteristics of light weight and high strength and has a broad future of application in the field of geotechnical engineering.

A catastrophe model of support and surrounding rock interaction is established. Catastrophe instability of surrounding rock is studied by using support stiffness and softening stiffness modulus of surrounding rock. The model gives rational theoretical basis of new Austrian tunnelling method. The key point of catastrophe instability is quantified. Support and surrounding rock become discrete material when its displacement get the key point. The key point is determined by internal cause rather than external cause of support and surrounding rock.

Based on stress-strain relationship of soil, the proof is made for that s-t curve appears “S” shape when the load is increased linearly, which is similar to construction process. A new model of forecasting the relation of settlement-time is presented. Case history shows the rationality of the method.

Effects of positions of material imperfection at right edge of rock specimen under plane strain compression on initiation and evolution of shear bands as well as stress-strain curves of rock specimen were modeled numerically by FLAC. Two material imperfections were introduced in the form of null element at left and right edges of specimen, respectively. The material imperfection at left edge was fixed; however, the positions of material imperfection at right edge were different for different schemes. The adopted failure criterion was a composite Mohr-Coulomb criterion with tension cut-off and post-peak constitutive relation of rock was linear strain-softening. Only one shear band bisecting specimen through two imperfections is formed and only full development of shear band below right material imperfection is permitted due to end restraint at top of specimen when right imperfection is close to the top. When right imperfection is not close to the top, shear bands are initiated in the vicinity of material imperfections and propagate along their inherent directions so that patterns of shear bands are very complex. Stress-strain curve beyond the peak strength exhibits steeper behavior when the number of shear bands intersecting specimen is lower. Otherwise, strain-softening branch of stress-strain curve undergoes ductile behavior. In the process of shear band propagation, when the tip of shear band head-on approaches two triangular regions affected by strong restraint at top or base of specimen, direction of shear band has to be changed. If the tip is very closer to the symmetrical line in vertical direction of specimen, direction of shear band will be slightly changed (the phenomenon is called shear band refraction). However, if the tip is not very closer to the symmetrical line, the direction will be changed greatly (the phenomenon is called shear band reflection).

The water has an effect on anchoring performance of resin cable bolts. In some case, water could lead to the failure of cable bolts reinforcement. Based on the cable bolts pull-out tests and long cable bolts installation tests in laboratory, the anchoring capability is studied systematically. The research result shows that water can reduce the cable bond strength about 7 %, reduce the anchoring body uniaxial compression strength about 12 %, and shorten the effective anchoring length about 10 %. The achievement is valuable to the design of roadways cable bolts supporting parameters and the evaluation of reinforced rock masses’ safety.

Static method of slope stability analysis is simple and play a distinctive role in slope seismic stability. Sliding mass is traditionally divided by vertical slice. Errors should be induced in calculating horizontal seismic inertial force and anti-sliding moment according to vertical slice. Considering horizontal seismic inertial force in foundation, safety factor is uncertain. The cause of errors and uncertain is analyzed, and an improved method is put forward. Calculating sample shows the improved method is reasonable.

The behavior of pile under lateral load is a very complex process of pile-soil interaction. The interaction behavior of laterally loaded PHC piles (pre-stressed pipe pile with super high strength) in soft subsoil is analyzed by field test. The internal force and deformation of piles, the critical bearing capacity, and lateral modulus of subgrade reaction can be obtained from the test results. These experiment results are useful for the practical engineering and analysis of PHC piles in same areas.

The passive earth pressure of rigid wall due to various wall movement was simulated by particle flow code(PFC)2D, which is based on DEM. PFC2D model for this problem was founded by the laboratory model test. The rigid wall translated toward the soils, or rotated about its own top or bottom。Then the horizontal and vertical stresses along the back of the wall were measured. These results were compared with that of the model tests; and it is shown that the PFC2D can simulate the distribution of the earth pressure along the back of the rigid wall conveniently and satisfactorily.

The CT real time testing on meso-damage propagation mechanism of cracked-sandstone containing one crack under uniaxial compression loading using the CT loading system application in rock and soil media has been accomplished. The CT images, CT number and variance of CT number in different stages such as crack birthing, developing, macro-crack birthing and sample failure are contained. Comparison to the noncracked-rock sample, it shows that the pre-crack can seriously affect the location of new crack birthing and the formation of connectivity macro-crack. Because of the pre-cracked existing, the volume expansion values of the cracked-rock sample under uniaxial compression are large than the noncracked-rock sample.

Testing method is adopted in the codes when the foundation in mucky-acid soil is stabilized by cememt deep mixing method. Based on the test of cement-soil strength test for Yingtian River Project by deep cement mixing method, this paper analyzed the influencing factors of cement-soil strength and took improved measures to solve it. The test results and practice show that the cement-soil strength is increased by high grade cement and admixture.

In geopolymer reinforced soil structure, the behavior between the soil and geopolymer is very important to inner stabilization of reinforced soil structure, so the index between the soil and geopolymer is a crucial index. In this paper, systematic directtests and pullout tests were carried out between high liquid limit clay and two kinds of geopolymers. Based on the test result, stress-strain relationship is studied. Some useful conclusions and opinions which can be used to supervise the research and design are also presented. That is, the shear stress between the clay and the geopolymer increases with the normal stress increase, but the increase is not unlimited, and the increase ratio of shear stress will decreases. So the high-point of shear stress exists between clay and geopolymer. Due to sample preparation for pullout test, the scraggy interface between clay and geopolymer will generate anchor effect which leads to the friction coefficient and cohesion gained from pullout test more larger than that gained from direct shear test. But in practical engineering, the pullout test can better reflect the truth.

Multi-DEM approach, which is based on borehole data, is flexible, speediness and effective for sedimentary formation; but it is not suited for stratigraphic system controlled by fluvial erosion and aggrading action. To solve this problem, a significant improvement over the previous workflow is presented. Considering fluvial erosion action, interpolation and adjusting of horizon elevations were done two times; so it is natural and reasonable to the pinching of strata around boreholes. The effectiveness and flexibility of the approach are proved by a case study.

Cement-flyash-gravel CFG, piles are found more and more application to soft clay ground improvement in expressway engineering in China. The load transfer mechanism and design calculation theory are conducted empirically in most cases, this resulting in the higher cost compared with other columns. This study focuses on the dynamic method in determining bearing capacity and shaft resistance. The testing site is typically selected in Lianyungang, where the soft marine clay is well known. Finally, the CFG pile design parameters are recommended.

Tests with the static-dynamic dual purpose triaxial compression test apparatus which was manufactured by Hohai University and Japan Round Well Company have been completed. Through the dynamic torsional shear undrained tests on empty heart column body samples, the dynamic undrained response of the same relative density in different consolidation confining pressures is known. Effect of initial mean effective stress on the behavior is examined by tests under undrained cyclic loading at several initial confining stresses with the same stress rations. The results indicate that the stress path is not affected by changing the initial effective mean stress if the shear stress ratio remains the same.

According to specificities for jointed rock mass, multiple sliding failure of a jointed rock mass is presented, due to accumulation of stress along bedded plane of rock mass and destruction of remnant intact rock bridges between bedded planes and joints. And rock triaxial serve testing system is used, through model test involving bedded planes and a set of joint normal to the bedded planes in rock mass, effects of properties of joints and confining pressure on multiple sliding failure are analyzed; the condition triggered multiple sliding failure and characteristic of failure plane is given, under the co-action of inclination of connective joints (bedded planes), interlocking conditions of critical joints, and confining pressure. At last, data are compared with predecessors’ones, and on the basis of it reliable results are given; and the results are hoped to supply guidelines for assessing probable modes of failure of a jointed rock mass for future practice.

By using image processing system made by our own lab, microstructure changes in compressive procedure can be quantitatively studied and correlative characteristic parameters can be extracted and analysed; thus making it feasible to study the quantitative relation between compressive deformation and microstructure changes of clayey soils.

The structaral characteristics is of great importance to unsaturated soils; soils compacted with different initial dry densities have different structural characteristics. A series of triaxial tests were undertaken on a remolded unsaturated expansive soil. It appears that the strength of unsaturated soils increases with net confining pressure and suction, but the tendency to dilate diminishes with them. Soils with higher initial dry density have higher strength and more tendency to dilate when shearing.

On the basis of field survey of slate phyllite and siltstone along Wu-Guang Railway, the mineral components and the properties of enduring collapse are discussed. Then, combining the strength of weathered soft rock and the results of compaction test, the feasibility of filled subgrade with weathered soft rock are judged. Furthermore, the judging principle and method of feasibility of filled subgrade with weathered soft rock are set up.

Negative skin friction resistance most possibly exists in piles engineering. Technology of PCC pile is a new ground improvement technology developed independently by Hohai University. Study on negative skin friction of PCC pile hasn’t been carried out. Combined with the previous results and the property of PCC pile, based on Terzaghi consolidation theory, mechanism of negative skin friction of PCC pile has been studied. The results indicated that the negative skin friction doesn’t exist on plug and outside negative friciton can be calculated by previous methods. Differential equation is concluded but it is needed to be proved by tests.

By modeling vacuum preloading and surcharge preloading in different depths of the soil using the laboratory test; then soil properties before and after test, axial settlements, volume changes of two methods are analyzed. And some useful conclusions are drawn; soil properties are improved and penetrability after vacuum preloading is better than the one after surcharge preloading, while compressibility after surcharge preloading is better than the one after vacuum preloading. Settlement after surcharge preloading is much bigger than the one after vacuum preloading, and it is constringed more slowly than the one of vacuum preloading. Volume change after vacuum preloading is 1.8 times more than the one after surcharge preloading, and volume change of shallow soil is more than the one of deep soil after vacuum and surcharge preloading.

Through theoretical discussion of the cross-hole ultrasonic testing method and combining the engineering case, the quality of pile body concrete and the possible positions of pile defects are detected by ultrasonic curve; and used the PSD criteria as aided analysis, the nature and range of pile defects are estimated. Practice shows that the cross-hole ultrasonic method for quality inspection of cast-in-place concrete pile can give visual and reliable results. Thus, it is an effective inspection method for the quality of pile body concrete.

A series of laboratory tests about dynamic strength of gangue were performed, which reveals the influences of different initial consolidation ratios on dynamic strength and dynamic strength envelope. Then the dynamic characteristics and dynamic strength envelope characteristics of gangue are preliminary obtained. So do its curve fitting between dynamic strength and vibration number when failure and its mathematical expression. Based on Mohr strength envelope characteristics, the dynamic strength parameter of gangue is analyzed. All these provide reference for engineering.

Based on the Biot’s dynamic equations, the vertical vibration of a rigid strip foundation resting on partially saturated soil subgrade which is composed of a dry elastic layer and a saturated substratum is studied. The analysis relied on the use of Fourier integral transform techniques and a pair of dual integral equations governing the vertical vibration of the rigid foundation is listed under the consideration of mixed boundary value condition and the continuity condition. The results are reduced to the case for saturated half-space. The set of dual integral equations are converted to linear equations by means of infinite series of orthogonal functions—the Jacobi polynomials. Consequently, the dynamic compliance Cv for partially saturated soils versus the dimensionless frequency b0 is evaluated. Numerical results indicate that: the thickness has great effect on the dynamic coefficient, and as the thickness of the elastic stratum is less than the tenth half width of the strip foundation, the curve of the dynamic compliance versus the dimensionless frequency basically match together with the saturated half-space; and the saturated half space is the special case of the partially saturated soil subgrade(the thickness of the superimposed elastic soil Hn is equal to 0 ).

An approach to calculate land subsidence due to withdrawal of groundwater is presented. This approach is based on the theory of groundwater flow in saturated and unsaturated media. The proposed approach calculates the land subsidence in 3D condition. In the calculation the compressibility of ground was considered. The proposed method was employed to analyze the consolidation of soft clay layer and compared with the result by Terzaghi’s theoretical solution and odometer test. The results show that the difference is less than 2 %. The proposed method was applied to analyse the subsidence around a well of an aquitard layer due to withdrawal of confined groundwater from an aquifer under the aquitard layer. The method was also applied to calculate the subsidence behind an impervious wall, which cut the aquifer with steady flow under an aquitard.

The natural packing structure of sand grains under gravity within cylindrical and cuboidal container has been simulated using Monte Carlo method. First, a loose packing structure is generated using reference lattice method. Secondly, Monte Carlo algorithm was launched, i.e. random displacements are imposed on sand grains; as a result, a new configuration was obtained. If overlapping exists between grains and between grains and boundaries, the new configuration is deserted. The potential energy change of particles and Metropolis law employed to identify whether the new configuration is accepted or not. The final dense packing configuration is reached by repeating the above-mentioned process. The contact detection algorithm advised by Schinner was used to identify contacts between particles, and the contact detection algorithm between particles and boundaries was also introduced in detail. The simulation results indicate Monte Carlo method is very valid for simulating sand particles packing under gravity. The simulating results can provide initial configuration for simulating flow and compaction of sand materials.

The rheological test results and the rheological model of rockfills in Gongboxia Concrete Faced Rockfill Dam(CFRD)were introduced summarily. The 3-D finite element method was used to calculated the stress-strain of Gongboxia CFRD. By contrasting the results from taking into account the rheological effects with that from without taking account of rheological effects of rockfills, the influence of rheological behaviors of rockfills on deformations in dam, on stress and deformation of face slab and on the deformation of the peripheral joint were analyzed and studied.

The creep property of artificial frozen soil curtain wall is obvious. In the calculating model which is based on the tunnel crossing the bottom plate of using station in Shanghai subway，it is considered that the frozen soil curtain wall is made up of creep media, both soil in tunnel and upper structure are elastic materials, outside soil of the frozen soil curtain wall and structure of station are soil spring. Analysis of time-space effect on excavation and support in frozen soil curtain wall of tunnel is made by 3D FEM- MARC. The calculation results are in good agreement with the test values; so it shows that it is reasonable and creditable to analyze the time-space effects of frozen soil curtain wall by 3D FEM. Moreover, the stabilities of the bottom plate of station, frozen soil curtain wall and the structure of support are increased by decreasing the exposed time of the frozen soil curtain wall and applying the way of step-by-step excavation.

The accurate prediction of soft ground settlement after construction is very important to evaluate the treatment method and promote treatment quality. Flat dilatometer test (DMT) can get soft soil property quickly and exactly. A settlement calculation formula of sand and common soil was given by Matchetti; but it is not fit to structural soft soil in the beginning loading. After treatment, soft ground settlement tends to stable; and DMT data and Marchetti formula can be used to predict settlement after construction. A conclusion is drawn from the comparison with several other ordinary methods that DMT can predict soft ground settlement after construction more exactly.

Static piling is the procedure of steady penetration which leads to great compression and large deformation of the soil adjacent to the pile. And it is reasonable that there are errors between the real penetration and the finite element analysis according to traditional small deformation. so new finite element method used to analyze large deformation during piling is presented. The method is based on updated Lagrangian formation (ULF), considering the contract between pile and soil, regarding soil as the Mohr-Coulomb model. The numerical results show that the method can realize the numerical simulation of static piling.

Based on analyzing performances of pile-side soil, a new load-transfer function considering the softening is presented. The shapes of the model curve with three parameters a and b in the model are presented. The new transfer function is applied to simulate the behavior of single pile. The results from softening function are compared with those from conventional load-transfer function; and some conclusions are drawn.

Based on the consolidation theory of unsaturated soils, the numerical simulation of deformation of expansive soil roadbed under the condition of rain infiltration is made. The development of plastic zone is studied. The results show that the shallow slide of expansive roadbed generally happens; and its instability cause is different from ones of common saturated soils.

Landslide was caused by liquefaction in submarine sandy or silty slope due to earthquake. Based on effective stress finite element method and Newmark’s sliding block theory, simplified approach was developed for evaluating lateral slide displacements induced by liquefaction due to earthquake on submerged gentle slope (≤5o). Wave loads were simplified as constant pressure and initial excess pore pressure. Viscosity of seawater was ignored during dynamic analysis. Liquefaction analysis was conducted using improved Seed’s pore pressure model. According to Newmark’s model, accumulated lateral displacements of submerged slope were achieved during earthquake. By examples, effects of slope angle and sea depth were studied and the validity of the new analysis was confirmed. The method can be used to predict earthquake-induced submarine geological damages in offshore engineering fields.

Based on Biot’s consolidation theory, the effects of the performance of waterproof-wall in deep foundation-pit on surrounding environment are analyzed. The subject investigated deals with the effectiveness of the burying depth of waterproof-wall, the influence of water leakage in enclosed structures of waterproof-wall on ground water table and foundation displacement, etc. For purpose of convenience, the excavated soil is treated as the idealized air element in FEM programming. The results show that in the case of thick pervious subsoil, the increase of the burying depth of waterproof-wall can hardly decrease the effects of foundation-pit on surrounding environment. The dense contours of seepage potential around the location of leakage are found with high seepage velocity, liable to induce expanded destruction. The water leakage occurred in the perpendicularly enclosed waterproof-wall will lead to the outstanding increase of the magnitude of foundation settlement around pit margin and ground lateral-displacement, as well as the rapid drawdown, etc. The conclusions could be provided for the appraisal and solution strategies for the effects of water leakage on surrounding environment.

Knothe time function is used to forecast surface subsidence, but the Knothe time function cannot simulate the subsidence rate and acceleration. According to the limitation of Knothe time function, the improved time function of surface subsidence, time function of surface subsidence based on Logistic growth model, is presented. Logistic time function can describe the whole process of surface subsidence and simulate the subsidence rate and acceleration according to the measured data of mine. The results indicate that the method is effective and applicable.

Based on the dynamic test of the pile in soft soil area, the interaction of pile and soil is analyzed by finite element method. Commonly used equivalent linear model is chosen to consider the nonlinerity of soil, material damping of pile is considered and the changing-status nonlinearity of soil-structure interface is considered by contact element. Parameters of pile and soil influenced on pile’s displacement were analyzed. The results show, there is some influences on pile top’s displacement as a result of a change of pile’s modulus of elasticity and material damping; and the pile’s displacement become smaller with the pile’s modulus of compressibility and material damping increasing.

The geometric nonlinear finite element method is used to analyze the impact mechanism of dynamic compaction. Damping of P wave and S wave are introduced to illuminate the material characters of the soil in the model. The improved artificial boundary conditions are applied to simulate wave propagation at the boundary. Two evaluation criterions (velocity criterion and acceleration criterion) are used to estimate the vibration influence to obtain the safe vibration range. The trench is an effective method of vibration isolation; and various influencing factors of trench are studied to give valuable reference for the engineering practice.

The dispiacement of transversely isotropic foundation under the level strip uniformly distributed load are analyzed. The rules of displacement with the different ratios of modulus of elasticity are drawn. The approximate solution for dispiacements of transversely isotropic foundation under the level strip uniformly distributed load is proposed.

In combination with the real geological engineering conditions and the design parameters of the tunnel layout, numerical analysis is performed to analyze the rock mass stability for two different supporting structures, the ordinary concrete lining with thickness of 500 mm and the wet-sprayed polypropylene fiber reinforced concrete lining with the thickness of 200 mm respectively. The tunnel rock mass stability is analyzed for the stress, displacement and plastic zone distribution. The numerical simulation shows that the lining structure using the polypropylene fiber reinforced concrete is stable.

The design of cushion is the key to the design of a composite foundation. Through the finite element analysis, the relationship of the settlements of the pile and soil with the load is found. And the influence laws of the cushion thickness and its compression modulus on the stress ratio of pile-soil and the settlements of pile and soil are obtained. The research results will provide a theoretical evidence for the suitable selection of the cushion thickness and its materials and will be beneficial to the optimum design of composite foundations.

The rigid ultimate equilibrium method is the common calculating method for rock-bolt crane girder design. A main shortcoming of this calculating method is that the common calculating method cannot consider the deformation of the structure and the action between the rock-bolt crane girder and rock wall. Based on the analysis of the common calculating method of rock-bolt crane girder, some problems of the design methods are identified; and a new calculating method for rock-bolt crane girder which has involved deformation of rock wall, deformation of rock bolt and displacement of the crane girder is established. Meanwhile, a method for determining the coefficient of elastic counter force of rock wall is suggested. And a formula for calculating the level elastic stiffness coefficient of rock bolt is also set up by utilizing numerical method to simulating the pull-out test for rock bolts. In the last part, three examples are calculated using the normal method and the new one; and the results are compared with those from the numerical method.

The stability calculation of overlength piles is a very important problem. In this paper the soil resistance mode with two parts in the lateral side of pile is proposed. The m-method mode is for shallow soil and the constant method mode is for deep soil. Rely-Ritz method is applied to analyze the stability of overlength piles. The critical load formula for overlength piles is obtained. The variation law of length coefficient of overlength piles is researched so as to provide a theoretical reference for overlength piles in engineering practice.

According to the experimental data in soft soil foundation pit in Shanghai, this paper presents the variation of calculating earth pressure based on the different shear strength parameters. Considering national codes, technical specifications and local code, combined with the practical and local experiences, the applicability of different shear strength parameters are analyzed. In the design of supporting structure for foundation pit, this paper suggests that shear strength parameters of consolidated undrained experiment should be used to calculate earth pressure; and that shear strength parameters of consolidated quick direct shear test may be used to calculate earth pressure when with credible experiences.

The protection of two existed tunnels which are right under the Longpan tunnel’s excavation located in Nanjing Railway Station’s Square is presented. Due to the combining use of piles retaining and strips of excavation, the existed shield tunnel’s upwarping during the excavation is controlled successfully. The analysis and calculation of existed tunnel’s upwarping, the piles retaining’s design and the deformation’s supervision during the construction are also analyzed in detail. This excavation made a good example for the future similar engineering.

For the slant problem of large diameter cylinder piers on the sea due to remained mud interlayer between the enrockment bedding and bedrock, a new remedy method is put forward and designed. It is extruded sand-gravel column with sleeve valve grouting, formed by pouring sand-gravel into boring hole, aiguille extruding them into the soft clay interlayer and enrockment, then grouting with sleeve valve. The inspection results after construction indicate that the diameter of pure sand-gravel column in mud and silt reaches 55 to 82 cm, the boring core sample strength of grouting column reaches 4.3 to 11.4 MPa at 28 days. Now the remedy project is completed for 1 year, the good state of large diameter piers shows that the suggested method is very successful.

The technique of low-energy dynamic consolidation method combined with dewatering for strengthening the disturbed soft soils underlying the hydraulic silty and fine sands is introduced. The foundation after treatment can meet the requirement. The effectiveness is also discussed. All the results given are of great practical value for similar soils improvement in the future.

Large deformation was induced in soils of a certain reservoir bottom during the first water impounding, and resulted in cracks in the asphalt concrete impervious face. In order to study the possibility of further settlement and the influence on asphalt concrete face under further water impounding, back analysis of ground soil layers of the reservoir bottom is carried out; and then finite element analysis of the foundation is performed to predict further deformation of foundation and assess the possibility of cracking of the asphalt concrete face.

Finite element analysis incorporated with a highly nonlinear 3-D anisotropic elastic viscoplastic (EVP) model is performed for a deep cement mixing (DCM) column improved marine clay foundation. The 3-D anisotropic EVP model is used for the unimproved soft marine clay (MC); and a hyperbolic model is used for DCM soil column before and after local failure. A simple yet workable method is presented for finite element solution to local failure induced strain softening of DCM soil column. The measured and predicted settlements and pore water pressures are compared, interpreted and discussed. Numerical results are in good agreement with measured data.

The cement-soil mixing piles are widely used in expressway engineerings, so it is urgent that the behavior of cement-soil mixing piles composite foundation is deeply comprehended. And the FEM numerical analysis is an important method. The three-dimension FEM easily leads to the big scale matrix, long calculation time and bad convergence; so the planar simplified method is necessary. During simplification, the transformation of parameters is the key problem. The paper brings forward a parameter transformation method by characteristics of the composite foundation and theoretical analysis. Finally, the method is validated by the observed data of Lian-Yan Expressway.

This paper has deduced the effected diameter of a closed large diameter pipe pile on sand ground as well as the horizontal resistance (or moment) acting on the rigid large diameter pipe pile. And, it provides the theoretically optimal design for the similar case; and by using the MATLAB program to analyze the axial stiffness of single pile, the relationships of stiffness of single pile, and the equivalent stiffness modulus of the soil beside the pile for unit depth, the equivalent stiffness modulus of the soil at the bottom of the pile, the thickness of the steel pipe pile, as well as its diameter, length and the elastic modulus for the used material are now much more clear. Based on this idea, the corresponding axial force can be calculated by using the load transfer hyperbolic function for known or assumed compressive deformation of the pile body.

Considering the case that there exist two bearing strata in soil and low settlement of foundation is required, based on the controlling settlement principle, the design philosophy of long-short piles foundation is presented. The long piles are to control the settlement and short piles to provide bearing capacity. Finite element model of long-short piles foundation is established to analyze a practical engineering. The results show that long-short piles foundation demands fewer long piles and can control the average settlement and differential settlement effectively.

Based on shear stress-relative displacement curve between soil nail and soil, the force transferring mechanism is analyzed. A mechanical model of stress transfer is built. The formulas of stress distribution and deformation along the soil nail are given according to equilibrium conditions of the section. The law of stress transferring between soil nail and surrounding soil is analyzed theoretically; the results of the model are agreed with engineering data very well.

The damages to Dakai subway station in 1995 Hyogoken-nanbu earthquake are analyzed in detail. The earthquake response of Dakai subway station is modeled by the 2-D substructuring methods (program SASSI2000, developed by John Lysmer et al.) with ground motions inputted in different directions. In this method, the dynamic soil-structure interaction is considered; and the effect of soil nonlinear dynamic property is considered by equivalent linearization model (program SHAKE91, developed by Schnabel et al.). The soils above the subway are considered as an affiliated structure of subway. The results prove that the model used is validation and the collapse of the columns in Dakai station was induced by both of the horizontal and vertical vibrations. The dynamic response of Dakai subway station calculated in this paper accorded well to all kinds of damages caused by the 1995 Hyogoken-nanbu earthquake.

According to the control settlement theory, making use of the method of enlarging the distance of piles, PTC piles have been designed and applied in the profundity soft soil ground treatment of a highway. The spot tests of PTC pile with cap composite foundation have been done in order to investigate working mechanism, and study the mechanical behavior of the settlement deformation, load-bearing capacity, load transfer, pile-soil stress ratio and pile-soil interaction of it at two kinds of different soil conditions. At last, there are some useful results by the experiment. The test results can provide useful information for engineers in study the theory of PTC pile composite foundation, and may be a guide to design PTC pile composite foundation under flexible foundation. The working principle study on PTC with cap control settlement and sparse piles composite foundation should be enhanced in future.

Based on the application of cast-in-place thin-wall concrete pile (PCC) in Yan-Tong Expressway, a series of field experiments and monitoring are conducted. The characteristics of load sharing, settlement and differential settlement and embankment stability are discussed.

The geocell reinforced mat on soft clay foundation can be simplified to be a kind of elastic board. Generally, the deformation problem of the board on elastic foundations can be calculated on Winkler's hypothesis. Here, the horizontal resistance is not considered. A biparametric model is put forward to calculate the deformation of the board considering the effect of horizontal resistance. And this model is put to use in practice.

The ultimate bearing capacity of single pile increases with time after pile installation, and it is of great importance to foundation design. Although several methods have been established to study this time-dependent ultimate bearing capacity of single pile, they have different occasions for application, and the deduced results of them may differ greatly. Firstly，the methods for determining time-dependency of single pile are summarized. Four typical types of methods namely: (1) empirical method using logarithm function; (2) empirical method using hyperbolic function; (3) soft method using artificial neural networks; (4) analytical method using consolidation theory, are analyzed in detail. Secondly, three criteria namely: (1) simplicity and parameters physical meaning; (2) theoretical meaning; (3) general applicability; are used to appraise the methods by two case studies. Finally, analytical method using consolidation theory, established by authors, is suggested to be basic method to estimate time-dependent ultimate bearing capacity of single pile.

Composite foundation of CFG piles is a lately developing technique in ground treatment and characterized by great bearing capacity, little settlement in ground treatment, wide scope of application, low cost, convenient construction, etc. The consolidation mechanism and settlement form of composite foundation of CFG piles, are elaborated. Analysis of settlement was discussed in detail including computing thickness, influential factors, modulus of compressibility choice and computation of additional pressure, etc. Although some merits were put forward based on the theory of settlement control while computation of settlement, there are a lot of works to be done.

With the example of maintenance of Ming Dynasty city wall between Jianning Road and Yijiang City Gate in Nanjing, the application of the packaged reinforced soil retaining wall to city wall maintenance is introduced . Its working mechanism and construction art are analyzed. With small site and poor foundation of city wall inner side, this project shows that good maintenance result of the city wall can be obtained by the use of packaged reinforced soil retaining wall.

Nuozhadu dam project is situated in Yunnan province in China, it is the important project in Lanchangjiang river development. The stability of excavated slope of the spillway is the major problem in dam construction. Based on field investigation of the structure of the slope, more than 1400 joints were collected, then, by using the Monte-Carlo simulation method and GSI method, the persistence of the joints and the shear strength index of the slope rock mass were calculated. Furthermore, according to the simulated annealing method, the sliding surface of the slope was determined, the stability of the slope was calculated via improved two dimensional Sarma’s limit equilibrium method. Finally, the method to improve the slope stability was suggested.

Bank failure under lateral erosion is analyzed by numerical method. A method to calculate lateral erosion distance is put forward. With continual lateral erosion seepage and stability of bank have dynamic changes. Mechanism and cause of bank failure under lateral erosion are put forward. The seepage and erosion are primary dynamic influence factors on bank failure; and the soil composition, soil distribution and slope angle of bank are primary internal influence factors on bank failure. Based on mechanism analysis relevant treatment measures to bank stability are presented.

The features of deep geological disposal repositories as a deep underground engineering are firstly summarized. Then the concept, mechanism and categories of multifeild coupling are introduced; and the characteristics and the state-of-the-art of THMC coupling and nuclide transport in HLW geological disposal repositories are analyzed. Finally, issues related to the THMC coupling and nuclide transport for HLW disposal are stated.

Based on the experience in prospecting landslide at Baoquan pumped storage reservoir, the paper studies the feasible problem that the application of TEM and CSAMT to prospecting landslide rapidly. Analytical results show that the TEM and CSAMT can be applied to prospecting landslide rapidly by a small quantity of drilling for design of engineering.

The conventional sampling techniques used in China are presented together with the effects caused by soil disturbance on the engineering design. The design and operation of a high quality continuous sampler, which can obtain undisturbed fine silty sand samples, are introduced. The operation of the continuous sampler was simulated in the laboratory. The effects of sampling on the deformation of soil, the magnitude of push-in force and the change of pore-water pressure have been studied. The results show that high quality soil samples can be obtained from the continuous sampler with high efficiency. It seems that the sampler is an important tool in surveying of strata.

The limit equilibrium methods of slices, the safety factors are computed from force equilibrium, have been widely used for analyzing and designing slope stability. However, because the assumptions regarding the inter-slice forces are different, the solving formulations of every method are different. It does not facilitate the compiling of the program and the understanding among the advantages and disadvantages of different procedures. In this paper, the assumptions for the inter-slice forces made by the existing limit equilibrium methods of slices that the safety factors are computed from force equilibrium are expressed into the unified formulation for the first time; the simple and clear recurrence equation of the inter-slice forces is derived based on force equilibrium. The unified solving formulation for the safety factors based on force equilibrium in the context of conventional methods of slices is developed based on the recurrence equation of the inter-slice forces. It makes the calculating principle to be clearer and the calculating process to be simpler. On this basis, if inter-slice moment equilibrium equation that rigorous Janbu method satisfies is expressed into the assumption regarding the inter-slice forces, rigorous Janbu method can also adopt the unified solving formulation for the safety factor based on force equilibrium.

Randomness and fuzziness of plane sliding of slopes are considered comprehensively. Associating with real project condition, probability density function for performance function and membership function of the slope are set up. Then a practical method to calculate fuzzy failure probability and fuzzy reliability of slope’s stability is put forward. At the same time, confidence interval of fuzzy reliability is calculated.

The dynamic plastic response of a simply supported RC beam on a semi-infinite viscoelastic Winkler foundation under low velocity impact is investigated. In calculating RC beam subjected to low velocity impact, the effect of local damage must be taken into account when the integral bending deformation is analyzed. The relationship between local damage and integral bending deformation is established; and the calculating formulae for the elastoplastic impact force and dynamic transverse deflection of the beam have been deduced for low velocity impact at the midpoint of beam.

The factors affected on prestress losses of unloading rock mass such as stress state of rock mass, rock mass property, rheology of rock mass, the time of prestress action, steel fiber relaxation, construction quality, anchor cable structure, environment change in long time are discussed; the mechanism of prestress losses with factors is put forward; and the coupling between different factors and prestress losses is discussed too. The relevant conclusions are drawn.

Firstly, through XRD method, the mineral composition and the contents of different compositions of expansive soil in North Hubei are analyzed by diffraction strength and half depth-width quantitatively. Then through EDX method, the chemical components of expansive soil in North Hubei are measured and analyzed. Finally, the phenomenon of subcutaneous nodes is expounded. The research results have great significance to evaluate the deliquescent character of cleaving stone in expansive soil and disclose the characters and strength formation mechanism of expansive soil and modified expansive soil. We hope to make some theoretical basis for the future study and use of expansive soil.

The significance and feasibility about the database based on SQL and the characteristics of SQL database were analyzed. After a lot of data about engineering tests packed up, the database of physico-mechanical parameters of soil was built up. How to use the database and how to maintain it were presented. An example using it to analyze the relationship between compression index and swelling index was presented. With the improvement of the database, it would be significant to investigate correlations between physical and mechanical parameters of soils.

The influence of cavern’s span on surrounding rock classification is getting more and more recognition along with large span underground working’s increasingly coming forth. The authors analyse the timbering expense of cavern in jointed rock mass, the radius of plastic loosened zone and the size effect of macroscopical mechanical parameters of rock mass. Based on the complexion of depressing of surrounding rock’s stability due to increment of cavern’s span, the authors pinpoint attaching importance to the influence of cavern’s span on surrounding rock classification; and suggest reckoning the factor of cavern’s span in surrounding rock classification scientifically by studying the size effect of rock mass’s physico-mechanical parameters.

Deformation displacement monitoring provides important information for analyzing the landslide’s structure and genesis mechanism, appraising and forecasting the landslide’s stability and development trend. The analysis of slope example shows that the deformation stages of slope can be more accurately judged; the slope’s stability during its construction and use can be appraised and forecasted when combining the deformation displacement monitoring data with the slope failure phenomena.

Considering the characteristic of vehicle loads and the actuality of overloading of vehicle in China, simplifying vehicle loads as equivalent static concentrated load, using Boussinesq solution and layer-wise summation method, the influential depth of vehicle loads and its two important influencing factors, embankment height and overloading degree, were analyzed performed on four actual examples. Results indicate that the influential depth of vehicle loads is about 6.0-14.0 m in the condition of overloading; otherwise it is about 6.0-8.0 m; the influential depth of vehicle loads linearly increased with the decrease of embankment height and parabolic increased with the increase of overloading degree of vehicle.

With that the underground projects are widely used, a new technical problem of consolidating and reforming them are proposed. As the peculiar place of underground projects, the technology of growing bars affect the effect greatly. This article expounds the damage mechanism and damage shape of the standing loads bars and researches different rules and shapes of damage of different ways in bonding bars; and compares the damp and arid environment standing loads bars accepting force and damage form. The conclusion that the process and method of bonding bars under damp environment has great effect on bonding result is drawn.

Aiming at the bearing power of load board in the pre-burying load cell of static load test on single pile, the load board’s intensity and deflection are analyzed by the Reissner bending theory of elastic plane and the ANSYS finite element analysis method that is very important in practice for load-cell’s design. What’s more, under the condition of allowable intensity and deflection, the load board’s thickness is optimized and an optimized result is deduced so as to save materials, reduce test cost of static load test on single pile and raise the productivity.

The Longtan tunnel which is being constructed is the second longest expressway tunnel in China by now. The stratum of the tunnel is complicated. And there are bad geological conditions such as partial press, karst, fault, high in-situ stresses and so on. In the paper, some key technologies are simply introduced; and some measures are presented to solve the possible problems during the progress of construction of the ninth bid. These measures can ensure the quality and the time limit for the project.