The experimental study on soft rock (analogized with mortar) under dynamic uniaxial compression at the strain rates from 10-5 to 101 s-1 has been carried out. It is indicated that the compressive strength of the soft rock increases with the increasing strain rate; and the rising rates are higher than that of hard rock. The Young’s modulus and Poisson’s ratio of the soft rock increase with the increasing strain rate, but the rising rates are less than that of compressive strength. In addition, based on the SEM results, the mechanism of the strain rate effect of the soft rock is primarily analyzed.

The mechanical characteristics of natural soils are affected by its structure significantly. The special mechanical behavior of natural soils and the influence of stress path on natural soils are disclosed through the comparison of multiple stress paths experimental results between natural soils and reconstituted soils. The characteristics of structure and incomplete consolidation of natural soils are shown in the normal consolidation experiment. The damage of the structure of the incomplete consolidation natural soils caused by the increment of volumetrical strain is more significant than that of shear strain. The influence of the structure on the strength of natural soils is mainly expressed as the increase of internal friction angle. At small strain, natural soils different from the reconstituted soils markedly, such as high stiffness, obvious nonlinearity. Through the comparison of experimental results of natural soils derived from different directions, the anisotropy of natural soils, which is more obvious as the decrease of strain, is illustrated.

An energy-injecting virtual-mass (EIVM) resonant column system was employed to investigate the small strain behavior of dry sand; and the effects of effective mean normal stress, density of soil samples, amplitude of shear strain, as well as number of loading cycles on shear modulus and damping ratio are studied. The test results show that the shear modulus increases with effective mean normal stress and soil density, while the damping ratio exhibits the opposite response. Moreover, the effects of effective mean normal stress on the small strain behavior of dry sand are more than those of soil density. As the shear strain increases, the shear modulus become smaller; but the damping ratio become larger. The number of loading cycles has no significant effects on shear modulus, but it influences the damping ratio to a quite extent.

For foundation pits retaining with soil nails, an incremental calculation method of soil nail forces is presented. The results indicate that the soil nail forces calculated by this method can fit the engineering practice better.

Based on one-dimensional consolidation theory, that the settlement-time curve appears “S” shape under linear loading or nearly linear loading is proved strictly.

For simplified analytic model of rockburst in narrow coal pillar, the catastrophe model of rockburst in narrow coal pillar belongs to the fold catastrophe model and can be educed by equilibrium relation of work-energy increment from energy conservation principle. All characteristics, demonstrated by the equilibrium equation and its equilibrium path of the catastrophe model, can describe all behaviors including system's stability of failure process in coal pillar by form of rockburst and gradual damage one by one correspondingly. The curve of elastic energy changing rate of rock beam, which includes abundant information, is given for the first time; it has great significance in understanding the behavior and law of rock beam- coal pillar's system in each phase. Parlance and expression, given in the article, that energy importing rate J = 0 is system destabilization critical condition implicates Cook stiffness criterion, so it's a dynamic generalization of Cook criterion in the form of energy. Using energy importing rate, understanding in the stability of rock-coal system under ultimate state can be improved from qualitative understanding to quantitative description; and the expression of the stability of rock-coal system is also endue with a new form.

From the united constitutive law of geo-material elastoplastic model, the problem of model identification among one model type is transformed to a problem of parameter identification. So, using the new bionics algorithm, immune evolutionary programming (IEP), proposed by authors recently, the elastoplastic model identification among one model type is studied; and a new model identification method is proposed. At last, this method is verified by a numerical example. The results show that this method can get the suitable geo-material model when only displacements are known.

Fully considering the speciality of soil nailing, a rather precise method of stability analysis of soil nailing based on general fracture surface is presented. The optimization numerical models for inner and exterior stability analysis are firstly proposed, and then a coupling algorithm of simulated annealing algorithm and random disposal-method of points is introduced for solving the model. Such a coupling algorithm is mainly based on the combination of merits of two kinds of optimization method. Several practical examples have been used to testify the efficiency and ability of the proposed method. Not only the effectiveness of it is demonstrated, but also several important conclusions being able to be referred in the stability analysis of soil nailing are simultaneously drawn.

A three-dimensional numerical model of the underground powerhouse of the Shuibuya project was firstly established based on the results of geological investigation. Then, the detailed construction processes, including the replacement of soft rock, excavation as well as support, were numerically simulated. The distribution and evolution of stresses and displacements around the underground powerhouse with and without support system are compared and discussed. The further analyses demonstrate that the results from the numerical simulation agree fairly well with the in situ monitoring data; and the underground powerhouse with the designed support system is globally stable. This paper provides some significant results for the dynamic design optimization of the construction and support scheme of the underground powerhouse of the Shuibuya project.

Clay blanket and the underlying soft layer will be settling, even cracking, after storage of reservoir. A calculation method for settlement of soft earth layer in course of drainage consolidation is proposed; and the possibility of cracking is estimated. Finally, the measures to accelerate and decelerate the settlement of clay blanket are discussed.

The impact toughness and the uneven extent of destroyed sample are the practical indexes of impact properties of frozen clay. The impact penetrant specific energy of frozen soil indicates the work of chiseling the frozen soil per unit volume, and reflects the ability to impact frozen soil. The frozen clay of the certain frozen shaft is regarded as the experimental soil sample. The impact experiments of frozen clay are made in order to measure these indexes in different temperatures and different impact energies. The impact penetrant specific energy experiment of frozen soil is conducted with the chiseling tool. Through analyzing the test results, it is shown that the impact toughness of frozen clay will increase with temperature decreasing and the impact energy increasing, and the uneven extent of sample may increase with the temperature decreasing, and the range of unevenness in the plane is ±3mm or so. With the decrease of temperature the hardness of frozen soil is bigger and bigger, the chiseling depth is more and more shallow, the drilling extent is more and more difficult. The relation formula between impact toughness and impact penetrant specific energy of frozen clay has been regressed. The impact toughness of frozen clay has a good relation to impact penetrant specific energy. The impact penetrant specific energy of frozen soil could be estimated by measuring its impact toughness.

The shortcomings of error back-propagation (BP) neural network and the characteristics of genetic algorithm (GA) are analyzed. Based on GA and BP algorithm, the prediction model of vertical ultimate bearing capacity of single pile is built. Real example research shows that the prediction model which based on GA and BP algorithm owns good quality, high precision and is easy to deal with. The method is feasible, effective and has wide applied prospects as well.

Aiming at the safe thickness of the bridge pile end's support rock mass in karst and mining region, the determination method had been comprehensively probed by a thorough analysis of the distortion characteristics and the destroyed mechanism of rock mass at the end of the bridge pile. A series of economic, reasonable and safety formulas have been proposed; and they are easy to apply in engineering. Finally, the problems such as the formula's using range, notices, influencing factor and the reasonable selection of the safety factor have been discussed.

According to Biot’s consolidation theory and pore water continuous principle, the basic seepage field’s and stress field’s finite element equations and boundary condition are established respectively. By Galerkin theory and pore water pressure, differential coefficient equations are discrelc distributed on space and time domains, then the coupling finite element equations of the seepage field and stress field are established. The conclusions can be of some base for further research and reference value for prevention and cure on slope engineering.

By combining genetic algorithm and artificial neural network, an evolutionary neural network model is established for the suction prediction of unsaturated soil. In the model, total density, initial water content, pressure preconsolidated and void ratio are considered. The predicted results, which were obtained through the created model, indicate that this model is well in accord with the test data. It provides a new approach for the research of predicting the shear strength of unsaturated soils.

It is needed for dynamic nonlinear analysis of soil structures that to follows the history of the stress-strain and to evaluate the instantaneous tangential modulus of the stress-strain on hysteretic loop. Because the seismic loadings are arbitrariness, it is very complex that the trace of the stress-strain of the soil elements in the actual geotechnical engineering. It is different for this nonlinear analysis that is used the conventional expresses of the constitutive relationship of the soil dynamic behavior based on the skeleton curve and hysteretic loop. In this paper, the scaled memory (SM) model is introduced for dynamic nonlinear analysis of soil structures. The SM translates the nonlinear variation of tangential modules during monotonic loading into a piecewise linear distribution geometrical relationship, which can easily to be modified to simulate hysteretic characteristics of soil during cyclic loadings, it also can simulate the dynamic stress-strain response of arbitrary cyclic loadings. In order to determine the parameters of the SM model. An analysis program of nonlinear least square method is developed. The parameters of the SM model, such as , , , , , , are defined by fitting test results. To compare the dynamic stress-strain relationships between the tests and the calculated results by SM model, it is shown that the SM model is capable and practicable.

The paper chiefly deals with the given method of the characteristic time and fluid boundary condition in the analysis course of the fluid-solid couple, which is applied to analyze the couple of fluid-solid of the cofferdam of Tai’an Pumped Storage Power Station. At the same time, it studies the influence of the foundation excavation on the stability of the cofferdam and the slope of the foundation. For the sake of giving the fluid-flow boundary and the proper characteristic time in the excavating process, the last result makes clear the distinct drop of the pore pressure in the cofferdam and foundation. The reason is, firstly, the enlargement of fluid-flow boundary after the excavation and, secondly, the lengthenment of the fluid-flow time in the computation. Those indicate the importance of the characteristic time and fluid boundary in the course of the fluid-solid couple analysis.

The study of reliability of progressive slope failure is presented considering the variability and correlativity of shear strength parameters of soil. Soil mass above slip surface was divided into n slices according to equal arc length. The safety margin of every slice is assumed to be normal distribution and the safety margin of two next slices is bivariate normal distribution. The probability of progressive slope failure and expected value of leak length on the top of slope are calculated by the probability of propagation of slice failure. The results of an example are discussed.

Grey Correlation Model is employed analyze sensitivities of influencing factors. This model regards sensitive factors as sub-sequences, the corresponding safety factors as primary-sequences, top-difference as transforming method of basic data and correlative degrees as estimating indexes of sensitive factors. The model takes the Xiatudiling landslide which is located at Shuitianba, the area of the Three-Gorges reservoir as an example, and four influencing factors, respectively the cohesion of sliding zone(c), the angle of internal friction of sliding zone(φ), acceleration of earthquake and water level of the reservoir, are selected as sub-sequences and the safety factors, which are calculated by push method, are considered as primary-sequences. It is concluded that the values of C and φ are the most sensitive influencing factors of all of the factors.

Numerical simulations based on 1D or 2D methods are insufficient to integrally describe the consolidation behaviors of sand drained foundations. On the other hand, it is very difficult to simulate the coupled three-dimensional consolidation in the situation that sand drains are dense. However, plane deformation and spatial seepage (PDSS) analysis is sufficient and acceptable. On the basis of symmetry principle and Biot’s consolidation theory, the PDSS modeling proposed is improved. A more reasonable scheme of 3D FEM grid is developed for sand drained ground in which drains are distributed on the pattern of equilateral triangle. Drains are located on nodes instead of elements and the special characteristics of radial drainage are considered. The improved model also is connected to an inverse method and applied to an engineering project to analyze the subsidence of a soft foundation preloaded by combined vacuum and embankment as well as the flux of water discharged by sand drains

The mechanism of dam’s earthquake response to 2 dimensional multi-point input is analyzed in detail; and it is pointed that the inner points, on which the differential force acts are in the finite elements with outer points. With the input of outer points’ horizontal and vertical artificial earthquake waves whose velocity is zeroized, the response of damage value, dynamic shear stress and permanent displacement is analyzed. As for the large-sized dam of 200 meters height, the damage value and dynamic shear stress computed by multi-point input at some position at the bottom of the dam are bigger, while in other parts are obviously smaller than that computed by one-point input; especially in the slope of the dam where is prone to wreck; and the permanent displacement computed by multi-point input is smaller, obviously at the top of the dam. But for the flat dam of 80 meters height or so, dam’s response to multi-point input is tenser than that by one-point input, so multi-point input is necessary in earth-rock dam’s designing.

An optimal design method combining the system simulation technology and the multi-object decision technology, which can be used for optimum design of piled rafts, is presented. The objective function for the optimization is defined as the volume of materials of piled rafts, while the variables are raft thickness, pile length, pile spacing and pile location. First using orthogonal test to optimize system input scheme, then applying 3DFEM to calculate system output, at last the multi-object decision technology is adopted to evaluate output and acquire optimal solution. The validity and effectiveness of the proposed method is examined by a numerical example.

The simulation of the subsurface and surface flow is based on easch other under rainfall conditions; a coupling method is used to solve the problem accurately. The subsurface and surface flow coupling equation is formed and its computer program is compiled using the FEM. A method is presented to speed the convergence and to judge the saturation of the surface. The simulation results show that the speed convergence is feasible and very fit for the real phenomenon in the nature. It is helpful to analyze the reason for rainfall-induced landslides.

Based on analyzing mechanism of deformation of cement-soil retaining wall for foundation pit, the effect of the top beam is analyzed; and the effective area and optimal measure of the top beam are further discussed. The results of a practical project show that the top beam is an effective measure to control the deformation of retaining wall.

After detailed analyses and researches on the problem of interface electric resistance in the electro-osmotic process, an assumption called interface voltage drop assumption is made. This assumption has been tested and verified by some experiments. A series of deductions based on this assumption finally led to a succinct formula of interface electric resistance. This will contribute to a more accurate estimation of electric current and energy consumption of electro-osmotic consolidation.

The method of space analysis and calculation of foundation pit’s retaining structure are discussed. The concept of space elastic-reaction method is proposed and the calculation model of space analysis is established. Space elastic-reaction method is applied for three-dimensional calculation of foundation pit’s retaining structure. Analysis is made for various kinds of factors affecting the retaining system’s internal force and deformation. Corresponding conclusions are drawn. These conclusions can be used in practical engineerings.

By dividing the area of the ground, solution of two-dimensional consolidation theory, which is based on Esrig’s one-dimension consolidation theory, is provided and discussed for the three kinds of boundary conditions: anode closed and cathode open; cathode closed and anode open; anode and cathode open. It proves that the ultimate excess pore-water pressure produced by electro-osmosis may be positive or negative, whose maximum is determined by the difference of electric potential between cathode and anode, whose distribution depends on the potential distribution and boundary conditions; and is independent of the initial conditions.

A calculating formula of compression strength for cement-stabilized soil in different sample sizes ratio of height to width (or ratio of height to radius) and surface frictional forces has been derived by twin shear stress yield criterion. The calculation results with the formula are farely coincide with the experimental ones. It is showed that the sample sizes and surface frictional forces influence the compression strengths. The bigger ratio of height to width (or radius) of the sample is, the less is its compression strength. The compression strength of the cement-stabilized soil sample putted on oil is lower than the no oil putted on it.

A large number of pipes are buried on flat soil foundation for supplying water or petrol. Its distribution of base pressure is apparently different from the one when pipes are buried on other foundations. Based on in-situ test data, a base pressure’s distribution law of rigid pipe on flat soil foundation is discussed with analytical method of Winkler elastic foundation. The computation model has been proved reasonable because of computation results tallying with in-situ test data. In-situ test results and the computation model can be used to compute pipes’ settlements and forecast their safety.

The condition of growth, mechanism of development and necessary boundary restriction of Shanxiying rotatory landslide are studied. And the sliding data and developing trend of the rotatory landslide are analyzed. It will be useful for deeply researching rotatory landslide.