The interaction between the soil mass and bucket foundation during the sinking process of a single bucket driven by negative pressure is analyzed. The differential equation for the stress transfer in the sinking process of a bucket is established. The relation of the greatest sinking depth of the bucket by itself weight with the weight of bucket, the vertical load, the geometric parameters of the bucket, and the mechanical properties as well as the frictional strength between soil and bucket is obtained. The effect of percolation during the sinking process is also considered, and the sinking depth and the negative pressure required are determined.

The study of the forecast on rockburst mostly remains at simple statistical study and the forecast of single factor, so the result is not satisfying. This thesis realizes rockburst mathematical model by adopting multilayer forward network and optimization BP algorithm based on genetic simulated annealing algorithm which has been used in the network training perceptrons. This optimization BP algorithm introduces simulated annealing mechanism to genetic algorithm and have it combined with multilayer perceptrons to form a compounding optimization perceptrons. The new perceptrons have both the learning ability of the neural network and robustness, and strong random searching ability of genetic algorithm. At the same time, this thesis makes a contrast study on the parameters of genetic simulated annealing algorithm by the principal performance index of genetic algorithm by using the practical monitoring data of Huafeng Mine rockburst and obtains a set of optimized parameters. By using those parameters, the structure weights and threshold value of the rockburst neural network model is optimized and obtains non-all-connected optimized neural network model. At last, this thesis carries out the short-term maximum magnitude of earthquake on Huafeng Mine rockburst by using this model. The relative error of the forecast is 7.84 % averagely. The forecast effect is comparatively ideal.

The use method of pressure meter test and some special measures for in-situ pressuremeter test for exploration of a bridge which is affected by tide, are described in detail. The principles and treatment methods for intensity parameter. Indexes in the pressure-meter tests are also analyzed; and these methods and principles have been applied to treat intensity parameter indexes of the Sutong Bridge so as to offer design intensity parameters for the bridge design. The results will be for reference of similar projects.

Based on a generalized non-homogeneous shear-beam model[1], for stratified foundations with exponential function shear modulus, closed-form analytical expressions are derived for determining natural frequencies, modal displacements, participation factors and steadystate response function. The orthogonality of the modal displacements is proved for the first time. And then, dynamic response of the stratified foundations to earthquake is studied by the theory of random vibration.Two cases of power spectral intensity function for the earthquake acceleration imput at the base rock are considered: the white noise spectrum and filter white noise spectrum. The numerical calculation results show that 1) under the case that the power spectral density of the earthquake acceleration input at the base rock is the white noise spectrum, the maximum expected response of the soil layer is different from that for the case of the filter white noise spectrum; 2) both the earthquake acceleration input the base rock and the response of the soil layer are stationary random process, which overestimates the random response of the soil layer.

The shear strength of slip soils is one of the prominent, but hard to be determined parameter in the stability analysis and control design of landslides, so 2-dimensional back analysis method is extensively used, which is based on the critical state assumption of slides. However, basically all the landslides are 3 dimensional in shape, and their major sliding direction changes drastically in some cases, thus making it necessary to develop a method for the 3D back analysis of slip soil strength and for the 3D stability analysis of the slide. A back analysis method, which is based on the strength reduction technique, is proposed. That is, the shear strength is obtained by gradually reducing the strength parameters to make the whole slip surface into plastic state (critical state). A case history, the No.1 landslide of Hongjiadu Hydroelectric Project, is examined by the method, with back-analyzed friction angle 4.1? lower than that from 2D analysis. 3D effect of the landslide is demonstrated and the method is thus proved feasible.

Based on the theory of Particle Flow Code (PFC), the biaxial test and shear-band evolution of sand are simulated . The macro stress-strain relation of sand is reproduced by PFC model. The variation rules of macro properties of the sand sample with micro parameters, such as particle size and friction coefficient of particle, are studied. The results of sand shear-band in lab test are compared with PFC model, and the efffect of micro parameters, such as particle size, stiffness and friction coefficient, to the formation and extension process of the shear-band is analyzed. It is shown that the mechanism of sand shear-band can be simulated perfectly by PFC model.

International Society for Rock Mechanics（ISRM）proposed in 1995 a new type of rock fracture toughness specimen—cracked chevron notched Brazilian disc（CCNBD），however，the calibration of the dimensionless stress intensity factor，which is an important mechanical parameter for fracture toughness calculation，is still in question. In order to provide the flexibility for choosing the CCNBD specimen geometrical parameters in experiments，considering the geometrical restrictions suggested by ISRM，the new and more accurate wide range calibration values are obtained by using a new slice synthesis method combined with finite element analysis. The results of the slice synthesis method are proved to be more accurate and reliable than those counterpart methods presently available in the reference.

By the method of Laplace transform, consolidation of elastic Gibson soils under arbitrary loading is studied. The general solution in the Laplace transform field is got, and the effective stress in the soils under arbitrary loading can be calculated by the Laplace inversion. In addition, according to numerical examples, some characters of consolidation of elastic soils are found.

Underwater explosive ramming is a widely used method to strengthen foundations for docks. The design and implementation of underwater explosive ramming for the second phase dock of Qingzhou Harbor in Guangxi Region, are introduced. It is indicated that the average subsidence of the dock is about 12.7%; and the strengthening effect is quite good. It is also reported that the vibration induced from the explosive ramming for the first phase dock is less than the threshold value, which ensure the safety of the first phase dock. The work presented can be a good reference for similar engineerings.

Baranov formula in frequency domain for transient lateral vibrating piles is derived by the Fourier transform. Expressions of Winkler parameters k and c are derived by the Baranov formula. Because the rigorous expressions are complicated, they are not suitable for calculating transient lateral vibration of piles, and for this reason the simplified expressions of k and c are derived by asymptotic expansion of the Hankel function. Mobility curve and velocity one at pile head, when k and c are calculated by the rigorous expressions, are compared with those calculated by the simplified ones. Good agreement between the two results indicates that the simplified expressions are effective for transient lateral response of piles.

The numerical simulation method of the saturated-unsaturated seepage flow is presented. The pore-water pressure is simulated under rainfall conditions adopted this program. The traditional method handled the rainfall infiltration boundary is conquered, and the real alteration of the rainfall infiltration boundary is taken into consideration to give a good basis for the coupling simulation of the saturated-unsaturated seepage flow and surface overflow. As a result this method is very suitable to the real rainfall process; so It is very helpful to analyzing the reason for rainfall-induced landslides.

The methods of monitoring large-scale land subsidence by static and kinematic differential global positioning system (DGPS) were described in detail. Resulting from different reference planes, the difference between the measured subsidence by GPS and by leveling were investigated. An example of monitoring Tianjin land subsidence by GPS was given. Through analyzing the accuracy of Tianjin land subsidence monitored by GPS in 1999-2002, it was shown that static DGPS can take the place of long-distance precise leveling for monitoring large-scale land subsidence.

Application of info-construction to large landslides ensures the project both safer and more economical. Methods of info-construction focused on tremendous data analysis are studied. The slip plane, slide direction and landslide zonation are determined by method of data visualization of monitoring data. The support vector machine is applied to predicting landslide displacements. The results of intelligent and visual analysis of monitoring data are used in the dynamic optimizing design of landslides. Finally, an engineering example is given to discuss the train of thought of the methods.

The stress relaxation experiments of rocks under the deformation at peak load and load-unload experiments before peak load are carried out. The results of experiments show that the form of the relaxation curves of rocks under the deformation at peak load descends in step form; the stress relaxation of rock under the deformation at peak load is discontinuous, that is, alternant between quickly and slowly, which is the resut of the synthetic action of slip and extension of existing cracks and creation of new cracks; and integrality of rock structure and the performance of store of elastic deformation energy of rock have obvious influence on the number of stress descending steps and stress relaxation time.

Strain softening structural response of rock material in uniaxial compression is investigated analytically based on shear strain rate gradient formation. One dimensional shear strain rate gradient formation of the second order is proposed based on the non-local continuum model. Non-local plastic shear strain rate is dependent on local shear strain rate and its second spatial derivatives. The closed-form analytical solution of the local shear strain rate is straightly obtained by substitution of the non-local plastic shear strain rate into the local one in classical plastic theory, instead of differentiating the local shear strain with respect to time. Relative shear velocity along shear band is calculated by integrating the local shear strain rate. Velocity at the end of rock specimen beyond the peak compressive stress can be divided into two parts. One is elastic part described by Hooke’s law; the other is plastic part dependent on the relative shear velocity. Summing the two parts yields analytical solution of structural response for uniaxial compressive rock specimen subjected to shear failure. It is shown that sudden snap-back instability can occur as internal length parameter (or thickness of shear band) of rock material is decreased. Higher shear softening modulus, lower Poisson’s ratio or inclination angle of shear band can lead to brittle axial response. Based on analogy between specimen and pillar in mines, the brittle axial response of rock specimen means that pillars in mine will lose their stability and pillar bursts will occur. Main advantage of the present analytical process based on strain rate gradient formation is concise.

In order to research the elastoplastic deformation of sand skeleton under dynamical shear loading some constitutive models are analyzed and built, including the model of the finally or the irreversible deformation in the touched part of particles which maybe crashed; and a method is designed to verify the above model through testing the percent change of masses of different sizes particles before and after sand liquefaction. In order to simulate the nonlinear dynamical volumetric deformation and constitutive relation of shear stress-shear strain during the liquefaction, a time-domain-discrete model of sand diliatancy is suggested; the simplified equation can easily to explain the liquefaction and easily to analyze the dynamical deformations of sand.

A neural network model for diagnosing pile integrity based on reflection wave method is suggested. The model predicts the basic features of pile integrity such as its normality and various defects including partially enlargement or reduction in pile diameter, concrete segregation, cracks and breakages in pile stem and so on. The service ability and efficiency of the neural computing are enhanced by implementation of some elaborated operation technologies. The application of the neural network model in the integrity check of dozens of concrete piles, in soft soils in Tianjin region, tested with reflection wave method yielded a fairly high accuracy of prediction.

The influence of the construction on environment is an important problem, especially in the area packed with buildings. Vibration is one of the key factors that cause nearby buildings’ inclination and cracks. During the construction of driven-and-vibrocast RC piles for treating a barn foundation, it is measured that the peak velocity of vibration acted on the nearby buildings caused by pile construction is 4.92mm per second. According to the regulations, the reasonable threshold velocity is 5.0 mm/s, so the vibration velocity of the buildings is under control. The project has been finished successfully by digging damping channels, and alternative operation of several pile drivers to decrease the vibration subsequently.

The existed technical specification is not particular enough to ensure the quality of expansive soil embankment for highway construction. Based on the embankment build tests with different construction technique parameters, certain reasonable parameters are advanced which will give some instructive reference to quality and progress control for expressway construction.

The subgrade fill of some reaches of Qin-Shen Special Passenger Line consists of clean, round and poorly graded fine sand. For satisfied with “Detailed Rules and Regulations of Qin-Shen Line Railway Subgrade Construction Technology”, on the basis of a vast amount of comparative test, an economical and rational technical plan for improvement of fine sand is determined. According to the material proportion and construction technology, several millions of cubic meters of subgrade construction have been completed. A vast amount of technology data and rich experience for improving fine sand has been accumulated. Through analysis and study for improvement of fine sand, making further improvement on much respects has been found. On the basis of integration of theory with practice, this paper raises a calling in question for necessity of improvement of fine sand fill and control standard with a double targets; beside, reveals and sets forth essence of K30 value of poorly graded fine sand being on the low side and change regularity of fill strength as construction height.

Based on the analytical solution of sphere cavity loaded with instantaneous load in elastic medium, the influence of dynamic unloading of blasting load on the stress distribution in the medium is studied; then the role of dynamic unloading effect in the process of fragmentizing rock by blasting is discussed further. Some phenomena observed in blasting engineering could be explained with the dynamic unloading effect proposed. Finally the necessity of further studying dynamic unloading effect is illustrated.

Time-space dependent effect in process of excavating deep foundation pit is in close relationship with the design of support structure and construction sequence and organization but is mostly dependent on engineering behaviors of soil on site. According to Biot’s consolidation theory and large deformation theory, a coupled model and the method of FEM numerical simulation can be derived with classical variation principle, which is based on Updated Lagrangian formulation of large deformation, As for a real example of engineering, the comparison of the computing results between large deformation and small deformation is shown; and time-space dependent effect of excavating deep foundation pit is analyzed. It is the main conclusion that time-space dependent effect in process of excavation is remarkable and the security of pit using small deformation method is lack.

At present, according to the soil-water retention curve, the matrix suction of soil is mainly obtained by moisture content, which neglects the influence of density on matrix suction. This is imperfect both in theory and in application. Taking the Baqiao Bridge sandy soil for sample, the matrix suction of sandy soil with various densities and moisture contents is tested. After analyzing the test data, the relation between the matrix suction and moisture content in three kinds of densities is got, and taking the density and moisture content both into account, the formula is obtained to determine the matrix suction. The one-dimensional moisture migration test verifies the influence of density on moisture migration. Then this paper finds the changing law that the matrix suction changes obviously with density especially in low moisture content. And with the same moisture content, if the density is gradually added, the value of matrix suction first is lowered, then added and finally lowered, this phenomenon is probed into in this paper.

By monitoring the pore-water pressure in mucky soft soil during dynamic compaction (DC), the laws of the increment and the dissipation of pore water pressure and the variation of pore water pressure with number of passes and lateral distance are studied. In terms of the results of SCPT after DC, the mechanism of improving filled sand above soft soil with DC is analyzed. In addition, effective depth of influence and number of drops per impact point are discussed.

Based on introduction to various methods of reliability analysis for block stability, fuzzy and random characteristics of block stability in caved area are analyzed. The method of fuzzy random reliability analysis and the formula of fuzzy probability measures for block stability are presented based on block theory and fuzzy measures theory. Furthermore, the method has been applied to analyze the block stability of roof in a caved area of Suichang Gold Mine in Zhejiang Province. Results show that the block tends to slide and safe measures should be taken before recovery of residue pillars at the caved area.

A new analytical solution which is about shearing stress of sand layer with underlying substratum and upper covering layer under the suppose of known earthquake intensity or layer displacement, is obtained by Laplace transformation; and a new differentiation method for sand liquefaction is proposed. Additionally, the influence of the soil parameters on sand liquefaction is analyzed by computer programming; from which the possibility of sand liquefaction can be judged under different combination conditions. It is of benefit to practical engineering judgement.

The relationship between the rebound force and the rebound value of the underpinning static pressure piles is discussed quantitatively by using least square method. And the reasons of rebound are analyzed quantitatively through the pile-soil interaction mechanism. The maximum rebound value of the static pressure pile-head is also studied. Meanwhile, the relationship among rebound force, underpinning force, actual rebound value and maximum rebound value, is obtained.

In order to study the creep properties of soft soil, a 1-D consolidation–creep test has been completed. The creep properties are summed up from the test results. The effect of the secondary consolidation on the consolidation process is analyzed by the parameter Cα/Δe100 Taking the saturated soft clay as viscoelastic body, a new method of separation of the secondary consolidation and primary consolidation is proposed. The method can also be used by the data collected at the field. Some interesting conclusions concerning the effect of secondary consolidation are drawn from the test results.

The displacements and long-term stabilization of the old landslides in Three Gorges Area importantly depend on both the decreasing of strength and time-effect of the mechanical characters of sliding zone soils. In order to set up a basis of the further numerical analysis, the drained triaxial compression tests with the constant stress have been carried out. Based on those tests a shear stress-strain-time function, Mesri creep model, in which a hyperbola is adopted for shear stress-strain behaviour and power function for strain-time behaviour , is given.

Meshless method is a new type numerical method of solving the Biot’s consolidation problem. On the basis of treating the essential boundary conditions with penalty method, the system equations of consolidation problem with meshless method are developed. Then the factors which influence the accuracy of nodes displacements, excess pore water pressures including the mode of nodes arrangement in the calculation domain, the shape and size of the influencing domain, the numerical integral scheme and penalty parameter are discussed. By analysis and comparisons, the corresponding value scope or reference suggestion are provided.

Based on the research of mining circumstances and geological conditions of rockburst in Yanshitai coal mine, the influence factors of rockburst are provided. Because of the shortage of traditional methods to forecast rockburst, the method based on the back propagation neural network and genetic algorithm is applied to predict rockburst through reduction training time and instability in network training in Yanshitai coal mine. The results show that it is an effective method to predict rockburst and it can be applied to similar engineerings.

Through indoor testing study on mechanical properties of the jointed rock and in-situ push shear test on the structural plane of rock mass, the strength and deformation properties of the slope rock mass are obtained and analyzed. The results are helpful for slope stability analysis and engineering designs.

Aimed at some limitation of the traditional BP neural network, the radial basic function neural network (RBFNN) is brought forward. On the same convergence condition, RBFNN is compared with the neural network based on the traditional algorithm and the excellence of the former is explained, As an example, on the basis of the nonlinear characteristic of ANN and 3-D seepage flow FEM computation , inversion results of the dam percolation parameter are obtained. The seepage flow field is analyzed by using the inversion results; the forecasted water heads approach to the observed values, which illuminates the result is accurate; RBFNN applied to the back analysis is reliable.

According to the deformation character of expressway foundations, a 3-D Biot consolidation FEM model of soft foundation improved by vacuum combined surcharge preloading method, is proposed. This model can discretise PVD element as its actual factor to avoid the problem of PVD’s simulation in 2-D FEM. A practical engineering of vacuum combined surcharge preloading is computed and analyzed; and the results are satisfied.

The advantages of object modeling technique in developing CAD system are expounded. The modeling techniques of CAD system for geotechnical engineering are analyzed. The general modeling techniques are also discussed. The key program codes are presented for relevant developers’ reference.

Bachimen landslide lies in a highway construction site, and hundreds of people are living nearby. In recent years, by human factor and the rainfall, the slide became moving frequently and threatened the residents and workers on it. Rainfall is the key factor leading to the landslide, so study on the relation between rainfall and displacement of landslide is essential to forecast the landslide. Combining genetic algorithm and neural network, a GA-NN model is proposed whose structure is optimized. The relation between the rainfall and the displacement of landslide is mapped by this GA-NN model. The research result has been adopted by the highway construction corporation and certain institutes, and it was very useful for directing the highway construction and ensuring the safety of the residents’ lives and wealth.

A new approach is presented for the safety analysis of structures subjected to bounded but uncertain mechanical parameters of rock material based on convex model theory. An optimization solution of the approach is adopted. First, it defines the uncertain material parameters with a convex model when the amount of information available on the uncertain material parameters is not enough to accurately define. The worst cases are searched over this convex model by using the optimization methods. The safety parameters’ domain of rock material is then got. The approach is reasonable; and the whole process is feasible.

In light of the static and dynamic pile testing on a single casting pile of a project , the limit bearing capacity of a single pile that can not meet the design requirement is analyzed; then the treating measure, i.e. to use flexible deep-mixing pile to remedy the inadequacy of the casting piles bearing capacity, is put forward. The two aspects of rigid pile’s and flexible pile’s force bearing condition and deformation compatibility are analyzed; it is shown that the two piles can act jointly. This treating method not only is lower in cost but also is convenient in construction. The practical engineering treatment result has totally reached the design effect. Our method can be for reference of similar foundation incidents treatment.

Being industrial waste materials, fly ash and quick lime are used to improve soft soils. The dispensing formula indoor tests of fly ash and quick lime were done. According to the different proportions of cement (or quick lime) to fly ash, the samples mixed with soft soil of different water contents. Then unconfined compression strengths of the samples at four different ages were tested. The relationship between improved soil strength and content of quick lime as well as ages was analyzed. Compression coefficient and compression modulus of the soil were also discussed. Improving mechanism of fly ash was studied further more. The conclusion of soft soil strength increase and so on were obtained. The aim is to refer to further study and engineering application.

On the basis of experimental data the socket length, base resistance and shaft resistance of rock-socketed piles have been analyzed. The relationship between share of base resistance and socket length，the relationship between bearing capacity and share of socket, and the influence of different rocks on pile capacity，are discussed; the best socket lengths of different diameter piles in soft soil ground are presented; meanwhile we think there is no longest socket length.

There are hundreds of soil model, but there are no model which can describe the true features of soil because soil is too complex. In order to describe all the characters of soil, we have to join lots of model parameters. However, too many model parameters of soil make the model can not be used in practice. From engineering practice, the best model is that its form including to obtain the parameters is simple, but it can describe the concerning problems. Based on the relationship of e-p curve and e-lgp curve, a simplified calculation method of oedometric modulus of soil is established. And Poisson ratios of different kinds of soils are assumed different constant values. So a simplified soil model, which can describe the settlement and the vertical stress accurately, is presented. The calculated results of engineering case show the rationality of the method.

An analytical solution is given to the problem of calculation of effective stress for a layered ground under one-dimensional upward seepage. The formulas for computing the effective stress are derived. Based on the formulas, the characteristics of effective stress are discussed. The effective stress of seepage has been defined. The effective stress for a layered ground under one-dimensional upward seepage is divided into two parts of both effective stress of weight and effective stress of seepage, the former embodying the effect of hydrostatical pressure is brought about by the weight, and the latter embodying the effect of super hydrostatical pressure is given rise to by the seepage. The effective stress of soil layer is decreased by one-dimensional upward seepage. The effective stress distribution along longitudinal section for a layered ground under one-dimensional upward seepage is linear, and has a turning point on the bedding surface of soil layer. The key to analyzing effective stress for a layered ground under one-dimensional upward seepage is to calculate the effective stress on the bedding surface of soil layer and the head loss of soil layer. an example is given to illustrate the analytical procedure.

Self-balanced method was adopted for three piles static testing; at the same time, the axial forces of the three piles were measured by stress gauge. And the pile-soil load transfer behavior of the three piles tested by this method, is analyzed. Finally, the self-balanced results were converted to equivalent pile head load-settlement curves with both the precise and the approximate methods respectively; and the comparison between them is carried out too.

The mechanism and method of Geogrids in harnessing soft foundation of expressway are analyzed. According to finite element method, the settlement calculation results approach the practical measurement results．The calculation method and construction model are proved to be correct．

According to the sequence of the soil creeping failure time under different loading conditions, a grey forecasting model for the failure time in the course of soil creeping is established. By using the failure time in the condition of heavy-loading, the model can forecasting soil failure time in creeping test in the condition of light-loading, so it can be used in the field of slope failure forecasting, creeping, material mechanical test and so on.