Research on penetration model of rock is one of the most important subjects in coupled hydro-mechanical research. Penetration property of rock is controlled by pores and evolving cracks before the full coalescence of micro-cracks. The former penetration models of rock are set up just based on either crack or pore, so penetration property in the process of cracks spreading can not be properly depicted by them. In allusion to this problem, statistical penetration model is set up with rock damage evolution considered in this paper. The model regards the penetration property in the process of crack spreading as a nonlinear dynamic process, in which effects of both spreading cracks and pores in rock are jointly considered. Therefore, penetration property in the process of crack spreading can be perfectly expressed.

It has been well recognized for a long time that one of major mechanisms for stabilizing soil due to lateral movements by passive piles is soil arching effect, which is a phenomenon of transfer of stresses from a yielding mass of soil onto the adjoining stationary part of soil. The finite element analysis software package, Plaxis 8.1, is used to study soil arching effects in passive piles and the effects of factors on the behavior of soil arching effect such as soil properties, piles spacing ratio, interface of soil-pile and piles arrangement are discussed in detail. It is shown that the ratio of pile spacing to pile diameter is the most important factor affecting soil arching effect.

Rigid pile composite foundations are getting more and more application to construction engineering. However, the research on their response under dynamic loading, especially under earthquake loading, is quite limited. Now the seismic response analysis in time domain is performed with 3-D finite element method, taking into account of the interactions among soil, pile and the superstructure. The differences between rigid pile composite foundation and pile foundation in seismic response are analyzed. Some parameters influencing the anti-seismic behavior of rigid pile composite foundation are studied. Based on these analyses, some conclusions which may be of some value for anti-seismic design of this type of composite foundations are drawn.

It is unreasonable to study the large deformation of soft rock with classic linear deformation theory. In this paper it is stated that the right analysis way of soft rock large deformation should use the finite deformation mechanics. Based on the finite deformation mechanics, an engineering case analysis is given to simulate the failure mechanism and the process of large deformation of the soft surrounding rock of the roadway by using FLAC technique.

Based on the measuring water temperatures and weather temperatures, the regression models of water temperatures and weather temperatures in different seasons were proposed. By making use of finite element method, the temperature fields of concrete dam in different seasons were investigated, and then the changes of stress fields of concrete dam were analyzed because the weather temperature changes seriously with seasons in the cold regions. The research shows that the first principal stress of concrete dam near downstream surface can be over the tensile strength of concrete, and bring about freezing and thawing deterioration in concrete dam. The numerically computational results demonstrate that the simulating values with finite element method can approach to in-situ prospecting values.

For the saturated silty soft clay, dynamic consolidation experiments, which reveal the dynamic stress, the dynamic properties of pore water pressure, axial strain of soft clay under impact loading, have been carried out. Additionally, the compacted effects of soft clay under impact loading have been also analyzed by the result of triaxial compression tests. The conclusions of experiments are propitious to perfecting the theory of dynamic consolidation.

Local point interpolation method is a new type meshless method. Because its shape functions for displacements and pore water pressures possess delta function property, the essential boundary conditions can be imposed easily. After the basic theory is introduced and the main equations for solving Biot’s consolidation problem are developed, the consolidation and settlement of one multi-layer soft ground subjected to heaped loadings are calculated with it. Furthermore, the famous Duncan-Chang model is adopted in consideration of nonlinear properties of soil, and the uniform point distribution mode is selected. At last, comparisons with the results of one-dimensional consolidation method and FEM show that this method is more accurate and satisfying.

Based on the hierarchical block element method presented earlier, a new concept of subordinate cover and a method to simulate the tension crack in rocky block are proposed. In the new method, each block and its covering element are conceptually divided into many cells that are called as the subordinate covers. The smeared crack model is introduced to the cracked cell and the cracking is regarded as a viscoplastic flow procedure. The out-of-balanced or residual forces arisen in cracking are transferred and the structures will get to equilibrium through the iteration. Thus, both the structural discontinuities and the tension crack propagation of rocky block can be effectively taken into account. Numerical examples show that the proposed method can give reasonable results.

The kinetic model for desorption of bio-refractory organic pollutants in soil is established with theories of transport of solute in porous media and hydraulics; and the analytical solution of the kinetic model is given. And the kinetic model is verified using data of experiments and parameters. The results show that the kinetic model is true in describing the desorption process of bio-refractory organic pollutants in soil and the change of bio-refractory organic pollutants concentration in water phase. In addition , the theory evidence is provided for forecasting diffusion of contaminants in soil, avoiding recontamination and pollution control.

A p-version adaptive error estimator for 3D steady seepage analysis is developed. By the fully exploring of the advantages of less preprocessing, higher accuracy and rapid convergence of p-version FEM, a serial of technical problems for solving 3D steady seepage problem by p-version FEM are studied; and an adaptive strategy is put forward. The influences on free surface caused by order of elements and mesh size are analyzed. An example shows that the 3D p-version FEM proposed is feasible for seepage analysis.

The interpolation of 3D finite element displacement field is researched. The method of secondly subdivision meshes is proposed; it is based on Delaunay triangulation. According to this method, unitary model and partial remeshed model are firstly set up, the initial stress and displacement fields of unitary model are obtained by using FEM and back analysis. Consequently based on Delaunay triangulation, the method interpolates 3D finite element displacement field of unitary model. Then the interpolating results act as boundary displacement of partial model, based on which partial remeshed model performs finite element analyses. At last, this method is used in practical project; that proves that it can improve computational efficiency and it is feasible.

The multi-arch retaining structure composed of borehole cast-in-place piles is a type of combined section in which large diameter reinforced concrete bored piles and small diameter bored piles are arranged in the shape of an arch. In this structure the bending moment and the shearing force are converted into the axial pressure along the arch axis. It shows a reasonable bearing ability, has a better section efficiency, and performances larger strength and rigidity than the pile (wall) structure with same quality. The top is connected with reinforced concrete periphery beam, then, without anchoring and poling it can also support a deeper foundation pit than pile (wall) structure. If the excavation depth is too deep, we can lay reinforced concrete rib stiffeners in a proper distance in the direction of the depth. Briefly, this is a new type of retaining structure, and the economic benefit is notable.

There is essential difference between fluid flow in fractured rock and that in conventional porous media; it is presented as the structure heterogeneities over a broad range of scales. The mainly difficulties for simulating fluid flow in fractured rock are the characterization of that heterogeneities. Conceptual models of present day, including equivalent continuum models, discrete fracture network models and hybrid models, use different techniques to predict flow and transport in fractured geological media. Based on different assumptions and conceptual frameworks, these models have respectively different advantages and disadvantages; the selection for application of them should be dependent on the in-situ speciality and the requiring of concerned problems. Besides, the conceptual models for fluid flow in single fracture are also discussed.

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 (SIF), which is an important mechanical parameter for fracture toughness calculation, is still in question. In authors previous paper, the new and more accurate wide range calibration values, listed as tables, are obtained by using a new slice synthesis method combined with finite element method. In order to guarantee the consistency of the table with ISRM, linear regression is adopted to obtain the lists of calibration with exponent function. The results show that the error of the new formula, compared with the values of calibration, is very small; and that it allows application for a wide range of specimen dimensions and further theoretical analysis. Based on this new formula of dimensionless stress intensity factor, size effect law of rock fracture toughness test is further discussed. The result of analysis with application of the new formula is proved to be reliable.

Study on settlement of organic substance degradation is very important for municipal solid waste（MSW）landfills. The long-term settlement of MSW landfill resulting from decomposition will usually represent the major proportion of total settlement, and it is likely to continue for many years. A large settlement may lead to breakage of the geomembrane and damage of the cover system in a modern MSW landfill. It is a very complex task to calculate the settlement because the waste material exhibits heterogeneous engineering properties that vary over locations and time with a landfill. Now a new degradation settlement model of organic substance of MSW landfill is presented based on the testing data. The model has less parameter. The degradation settlement of Tianziling MSW landfill is predicted by applying the model.

With the development of the highway, the slope engineering is increasingly manifold in many different ways. For the sake of recognizing the characters of excavation engineering rock mass in nature, authors, who are based on the factors influencing the slope, the deformation and destruction characters and discussed, the methods of rock mass mechanical analysis and the numerical simulation of the slope engineering rock mass are proposed and carrieded. Some results are achieved in research. The characters of deformation and destruction of the slope is not alike that of the regular loading rock action, but according to unloading rock mass mechanics action. The stability analysis of slope rock mass must attach importance to hydraulics and unloading effect, at the same time, some essential measures such as in time reinforcing, avoiding watery process should be considered. It is helpful to promote the information design of the slope engineering.

The post-grouting technology could improve the bearing capacity of bored cast-in-place piles; and the reinforcing mechanism of the post-grouting technology differs in different soil strata. In soft soils, the improvement of bearing capacity of long piles is mainly derived from increase in frictional resistance. The testing results of static loads and shaft stress are analyzed; and the relationships between frictional resistance and relative displacement are revised in consideration of deformation caused by soil continuity; and they are fitted by transfer functions. Based on transfer functions, the ultimate values of frictional resistance are calculated so as to reflect the real distribution regulations of frictional resistance along the shaft .

The impact process of a large-sized high-speed landslide against the mountain body is analyzed theoretically with mechanical principles. A then the expression of average velocity and moving direction of the landslide rock-mass after impact are obtained. Through the impact experiments, the effect of acceleration motion of partial rock mass after impact is also studied. Finally, the volumetric distribution law of various segments with different velocities after impact is obtained. The results will be useful for reducing and preventing disasters.

Based on conventional experiment results, a simplified constitutive model is given to simulate the strain-softening and shear dilating characters of soils. By using elastoplastic theory and volume-balance equation, an analytical solution to cavity expansion of saturated clays is established with Tresca yield criterion. The regularities of cavity expansion in saturated clays are analyzed under undrained condition. The results have practical significances for analyzing engineering problems such as static piling in clays.

Numerical simulation software FLAC2D is used to simulate the failure mechanism of slender coal pillars (which are of much lower width to height ratios) during high wall mining of thick seam. The results reproduce the whole process from the initiation of pillar failure, propagation, to plastic zone being joined together. The characteristics of stress distribution and failure mechanism of coal pillars are discussed by the numerically obtained stress yield during pillar deformation and failure process.

Based on plenty of achievements of loess test with single-track method and bilinear method, a practical method of moistening deformation is put forward with secant modulus when loess is dampened from some moisture to another one, which can be used to calculate both the most and any possible hydro compaction potential.

The high-water-content and quick-setting materials are a new kind of cement with many unique properties: 1. high water content; 2. quick setting and strengthening; 3. long pumpability time; 4. good plasticity; 5. the property of re-developing strength after ultimate loading. Although having been widely used in coal and metallurgy systems with remarkable technological and economical benefits, the materials have not yet been applied to geotechnical engineering. In order to explore the foreground of applying the materials to the soft soil foundation, the study on the microstructure of the soft soil with the materials is conducted by SEM. The results show that there only exists the geometrical drift of sedentary minerals without firm connection among the pure soil particles. However, the soil structure completely changed with materials added to it. In the consolidated soft soil-materials, the principal structure is the “spatial cellular structure” of calcium crystal. The supplementary structure is the micro-crystal and gel structure which is formed among the soil particles in alkaline environment through ion exchange, aggregation and carbonation. Thus, the materials may have a good foreground of application to ground treatment.

Based on the elastic differential equation of flexural slumping rock layer in layered dip rocky slope and its accurate solution, the critical length expression of flexural slumping rock layer is established with energy method; and the major influencing factors are summarized and their first and secondary relationships are analyzed through predominance analysis. The results show that in significant order the thickness of a single rock layer, the physical properties, the slope angle and the elastic modulus of rock mass are the major influencing factors to the critical length of flexural slumping rock layer .

The fractal characteristics of size distribution of bulky rock material in dumping site of mines are studied by using fractal geometry theory. The quantitative equations reflecting the relation between fractal dimensions and shear strength parameters are also put forward. It is found that there is an excellent fractal structure of size distribution of bulky rock material in waste dump, the value of fractal dimension increases with the increasing height of waste pile, but it is not over 3. The results also show that if the scope of measuring scale is unvaried, the contents of fine grain increases and the average grain-size decreases with the increasing value of fractal dimension. The correlation between the value of fractal dimension and the friction angle which is the shear strength parameter is negative exponential. The value of fractal dimension can be used in predicting shear strength and as a kind of measure in the size statistical analysis of bulky rock material in waste dump.

Considering tunnel construction steps, contact surface between segments and soil and stress releasing, 2D-FEM are put forward to simulate shield tunnel construction to cover the shortage of the traditional computational methods to understructures and to analyze the contribution of construction to tunnels environments with software of GeoFBA. The conclusion and methods in the paper can provide valuable preference for tunnel linings design and construction.

It is important for many engineering to determine the ultimate bearing capacity of a single pile by using the data of pile field load test below limited load. A group of prediction models that can predict the capacity of a single pile are established by the gray system theory. A practical engineering example verifies that these models can meet the project requirement; moreover the self-modifying GM(1,1) model has the most high accuracy.

A methodology of most dangerous sliding surface search and slope stability analysis is proposed by combining mixed genetic-simulated annealing algorithms with Sweden arc method. Some key problems such as the mathematical model building up, the process constituting, the parameters selecting etc. are discussed. An engineering example is studied; and the results show the validity of the proposed method.

The ground surface settlement due to tunnel excavation and ground surface rising due to squeezing by shield is considered as a stochastic process; and the stochastic medium theory is applied to predicting and analyzing the ground settlement in longitudinal surface due to tunnel construction; and the corresponding calculation formulas are derived. An example of case history shows that the prediction method developed can reach good results and has some practical value.

Instability variation of prestressed force will influence the security of the project, so it is very important to study the fluctuating variation of the force. Based on the monitoring data on site, the variation of the force is studied. And the rule of the variation under influencing factors during the construction phase and rainy season is analyzed. Finally, some construction suggestions are brought forward.

Current situation of determining bearing capacity of composite ground is analyzed. Referring collected data of cement mixing pile static load experiments, ultimate bearing capacity of composite ground is predicted by using hyperbolic model, exponential model and grey model. Predicting models that determine ultimate bearing capacity are contrasted and analyzed; and suitable model is proposed. Predicted value is improved. According to predicted value, the relationship between ultimate bearing capacity and characteristic value of bearing capacity is determined.

Based on the measured settlements of road embankment on soft ground during preloading, a new settlement prediction model is established by the BP network with interference function. Its application to a practical case shows that the proposed model has good extensionality, and can be used to predict future settlements with higher precision by means of measured settlements during a short period of preloading. The proposed model can overcome the defaults of some cure fitting methods and the traditional BP model, and has widely applied foreground in expressway construction.

Based on the results of static loading tests and measurement of axial forces, the load-transferring mechanism and deformation behavior of vertically loaded cast-in-situ piles with expanded branches and plates are investigated and discussed through a pratical project. Further，an equation is developted to calculate the vertical bearing capacity. The results illustrate that the expanded branches or plates support the vertical load in excess of 50 % in post-loading; and the resistance of expanded branches or plates behaves as end-bearing force. The bearing capacity of the new type of pile increases as great as about 60 %-100 % over the common pile with constant cross-section.

Based on offshore drilling practical case, simulation tests on interaction of pile with soil under condition of pile group have been carried out in clay. The problem of interaction of pile with soil and soil stress is analyzed. The results are important to guide offshore design and construction.

As a subtopic of stress and seepage coupling research of fractured rock mass, the hydraulic fracturing research was still in its infancy. The theory study was not being perfect. Nowadays, More and more rock engineering were expanded to underground. The underground structures were usually bearing on high hydro-pressure. The requirement of engineering construction was an impulse to drive the theory and technique research of hydraulic fracturing in rock mass. Hydraulic fracturing, as a technique, was used in petroleum industry to increase output of oil wells initially. In the sequel, it was introduced to stress measurement. Along with the construction of hydro-electricity projects, underground nuclear waste deposited, ground thermal energy exploitation, underground mining and so on, underground structures was faced on wicked hydro-geological conditions, such as high water pressure and deep burying. The effect of hydraulic fracture was being paid more and more intention by engineering rock stability researchers in recent years. A detailed review about rock hydraulic fracture research was done in this paper. Some theories, methods, results and hot points of recent studying were reviewed and being commanded briefly. Finally, some key problems were pointed out which need to be studied emphatically.

The development of urban underground space is playing the more and more important role. A new type urban architecture system taking space, ground surface and underground as 3D integralization is being produced gradually. The treatment of foundation between underground works and surface buildings in this system is a very troublesome problem. In combination with the specific engineering project, an introduction to a new compound arching technology for effectively tackling this type of problems is made. This technology is of generalized value to the urban construction in the future.