Firstly the momentum equilibrium equation, the continuity equation for water, the energy balance equation and the elastoplastic matrix are established. Secondly by using the Galerkin method all the governing equations are discretized in the space domain and time domain respectively, then a two dimensional FEM code for coupled thermo-hydro-mechanical elastoplastic analysis of saturated porous media is developed tentatively. Through two computational examples the use try of the code is made.

The circular chamber rockburst under uniform confined pressure occurs and ends by the phase of the plastically deforming localization of rock ring in softening zone on the traditional meaning. The carrying force in the concentration zone of plastic deformation reduces under limiting state, but comparatively intact part in rock ring unloads by way of elasticity. The rockburst occurs when the elastic energy released by latter is more than the dissipated energy by former in plastically deforming form. The catastrophe model of tunnel rockburst is established forthright by the relationship between equivalent stress and equivalent strain , and state variable is expressed by softening zone radius R. Analysis shows: The occurrence condition of rockburst has relations with the product of the rock’s ratio of elastic modulus to descending modulus and crack growth degree of rocks. To rock with specific rockburst tendency, there is corresponding critical depth of softening zone, , i.e. rockburst occurs when softening zone depth reaches . The amount of earthquake energy that released by rockburst has also relations with the deepening degree of softening zone.

It is very important to reasonably estimate parameters of rockfill in study and analysis of rockfill dams. Back analysis of parameters of rockfill according to in-situ measurement is one kind of new method to effectively estimate the parameters. Metropolis accepting rule of simulated annealing algorithm and system identification are applied to improve genetic algorithm during the processing. Applying this improved genetic algorithm to back analyzing parameters of rockfill, the result shows that the algorithm has advantages of higher accuracy, quick convergence etc.. This method is deserved to be popularized for parameters optimization in this filed.

Considering the fact that the creep properties of geogrids are fundamental and important factors on the long-term behavior of geogrid-reinforced earth structures, a series of comparative experimental tests of the creep properties of geogrids are conducted in the laboratory under different combinations of externally-applied load and environmental temperature. Based on the experimental results, comparative analyses are made to examine characteristics of isochronous load-strain curves, creep curves and relaxation curves of geogrids. Furthermore, a constitutive model based on viscoelasticity is proposed for geogrids and a rational procedure based on experimental tests is presented for defining the relevant parameters of the model. The proposed model is verified by comparing the prediction of the model and experimental results. It is shown that the viscoelasticity creep model can mainly display long-term behavior of geogrids.

An evaluation approach to slope stability based on case-based reasoning integrated with neural network is presented. And in view of the complex and uncertainty of the information of slope stability evaluation, a model indexing slope base case with neural network is set up. In this model, the relationship of similarity between the slope base cases is established by the neural network through training based on case-based reasoning; and the most similar base case to the slope target case in the base cases of slope is found out. Finally, the slope stability of target case is evaluated. It is shown from examples that the result of stability evaluation of the slope is the same as the its practical state; and the approach is simple, practical, and convenient to use.

Based on the increasing mode of pore pressure and the liquefaction mechanism of saturated loess, a model to analyze the dynamic stability of infinite slopes of saturated loess is established. By the model, the failures of this kind of slopes are classified into two modes: one due to liquefaction and another due to sliding. The analytical results indicate that the yield seismic coefficient, which decreases with time, is strongly affected by some soil parameters, i.e. the effective cohesion and initial pore pressure ratio. In addition, it is validated that the value of permanent displacement computed by the model, in which the pore pressure build-up is considered, is greater than by the conventional Newmark method.

In order to study on gradual breakage action of red sandstone in different water contents, rock microcosmic loading apparatus is configured with digital microcosmic observation system. And it can carry out several angles real-time whole and local magnifying monitoring to crack of specimen surface with monitor. Moreover monitored images can be recorded and collected automatically with computer. By this system, red sandstone of Hongshanyao Hydraulic Project in water state. The uniaxial compression experiment is carried out. Images of crack engendering and developing are analyzed by digital image technique for discussing the intrinsic relation between crack process and nonlinear deformational responses. In order to obtain quantitative description of crack development, two physical quantities of damage tensor and crack degree are proposed, which can appraise quantitatively gradual breakage properties of red sandstone in water state and furthermore analyze the law of rock crack damage evolution under uniaxial compression.

In this paper the piping and filter, two correlative topics, are stated and the background of studying development is reviewed. Meanwhile our studied results are also given for comparison. This is part I about piping topic which is an important phenomenon of seepage deformation and related to the foundation destroying caused by seepage. Firstly, the inherent meaning of piping and the present studying situation with its developing direction are discussed and criticized. Secondly, our experimental data in past about piping and the studied results with formulas, including the discriminating method of piping soil and non-piping soil and the piping critical gradients for seepage flow upward and horizontal, are introduced. Then the published experimental data in references up to date are cited to verify the writer’s formulas once again that shows reliable after verification. Also it shows that the method of piping study based on the soil grain size grading curve is the latest studying trend. Therefore publishing those past studied results for comparison and discussion is beneficial.

Underground environmental information system, a large information- management system based on GIS technology, is the outcome of the application of information technology to geotechnical engineering. Being built up by theories of geology, geography, computer graphics, computation mathematics, and technologies of data manipulation, C++ programming, OpenGL programming as well as 3D image manipulation, the system is to manage the information of underground environment and to execute model analysis. This article introduces the structure, data, function and manipulation characteristic of the underground environmental information system, and describes some important technical innovation.

The number of exploratory hole is usually limited in geological investigation. The unknown geological properties between exploration holes have to be estimated or interpolated by some special methods. Linear connection between explored points is generally used in practice with its simplicity but sometime low accuracy. How to develop convenient and accurate interpolation methods remains an interesting problem in geosciences. Some commonly used spatial interpolation methods are commented in this paper through principal analysis. The Kriging method is thought to be unique and more reasonable with its best use of geological investigation information. As an application attempt, Kriging method is applied to interpolate the spatial distribution of standard penetration number for a liquefiable sandy stratum. Comprehensive understanding about the geological properties of the stratum is derived from the interpolation.

Based on the introduction of finite layer analysis for three-dimensional Biot’s consolidation with a cross-isotropy elastic soil and the verification using four published results, the influences of cross-isotropy on the immediate settlement, the final settlement and the consolidation behaviour are discussed. It is found that the cross-isotropy has very large influences on the immediate settlement, the final settlement and the consolidation behaviour. The maximum differences are over 33%, 24%, and 40% respectively. In the end, curves or tables of the immediate settlement coefficients, the final settlement coefficients and the average degree of consolidation are obtained and presented in the paper, which is useful for engineering practice.

The displacement measurement method and distribution character for large-scale landslide model are studied with automatic mesh method, in terms of non-touched optical measurement theory. The automatic mesh method is adopted in Shiliushubao landslide model experiment to solve the problem of displacement measurement. The deformation character of Shiliushubao landslide under different water levels are researched.

The collapse of surrounding rock mass is affected by many factors, and the relationship between different collapse types has no distinct boundary, so the problem of recognition of collapse type is fuzzy, nonlinear, small samples and high dimensions. Support vector machine is a new machine learning technology, and there are a lot of successful application in the field of pattern recognition. This paper presents a new method based on support vector machine, and the complicated nonlinear relationship between type of collapse and its affected actors is presented well. The application of true example shows this method is feasible and precise.

Based on the deformable discrete element method(DDEM), the caving law of natural block caving mining method is simulated by numerical method. The results show that the numerical simulation based on DDEM is suitable to analyze the mechanism of natural caving law in block caving method, it not only has function of research on caving mechanism in rock mechanics, but also can easily demonstrate the rock state variation at different times. The comparison with actual state measured in–situ shows that this method has practical accuracy, and can be efficiently used to guide the mining process.

Stress induced anisotropy has important influence on soil’s stress-strain relationship under complex stress state. Traditional constitutive model with isotropic assumption cannot describe this character. Influence of anisotropy on hydraulic fracturing of earth core dams is analyzed herein. A new anisotropic soil constitutive model is applied to the finite element analysis of a high earth core dam. Minor principal stressσ3 got from anisotropic model is larger than that from Duncan E-v model. It is proved that the estimate of the hydraulic fracturing of earth core dams with Duncan E-v model will be more dangerous.

After water impounding, stress and deformation of the soil-rock fill dam become more complicated than that in the construction period. The calculating methods mainly contain total stress method and effective stress method. Total stress method is more simplified and it is reasonable with the macroscopic viewpoint in taking account of total stress and surface force as a big element for core wall, but it is unreasonable for every element of core wall with the microscopic viewpoint. Effective stress method takes account of effective stress and seepage force, in addition, uplift force and equivalent force to the damping deformation of the dam shell and core wall for every element of dam under the saturation line is considered, so that effective stress method is more reasonable not only with the macroscopic viewpoint but with the microscopic viewpoint.

In-situ test is the most objective and reliable method to obtain design parameters of pile foundations and to understand the pile mechanism. Based on the experimental equipment, such as fatigue machine, hoisting jack and so on, we researched a combination equipment of static and dynamic load on pile top, a key problem in the static-dynamic load test of pile has been solved. Static and dynamic load test in the filed of precast static pressure piles have been performed by use of combination equipment of static and dynamic load. Distributive regularities of inner force of pile under static and dynamic load, the change of pile’s side resistance ,and settlement of piles are analyzed by static and dynamic load test. Test results show that the distributive regularities of side resistance of piles are substantial agreement in the process of static and dynamic load. Lateral friction in soft soil of pile stem upside decreases, and lateral friction in bottom soil layer increases; after three hundred thousand times has been vibrated, the side resistance of piles is without changing.

For the quasi-three dimensional ground water model or the three dimensional groundwater model, it is difficult to determine the hydrogeologic parameters for aquitards. The stress-strain diagram method introduced in the paper is an effective method to estimate aquitard parameters. Firstly, the principle of the method is introduced. Then the elastic and inelastic specific storage and vertical hydraulic conductivities in aquitards in Shanghai area are estimated by the method using the subsidence and hydrograph data. The results estimated by stress-strain diagram method provide good start parameters for numerical modeling of land subsidence in Shanghai area. For aquitards, the aquifer test analysis is ineffective; and the laboratory soil test method is also ineffective if there are no soil samples of the aquitards. However, the stress-strain diagram is useful, when the observation data of subsidence and water level of aquitards are available.

Laboratory tests based on the principle of slab probe are undertaken for the measurement of thermal conductivity changing with material selections and mixing design, maintaining time and temperature, and the results are prepared into some curves and analyzed in detail. It has been shown that the bentonite alone has not a good thermal conductivity, but it can be improved by mixing with cement and sand. The thermal conductivity increases as the ratio of water to cement decreases. It is an effective method for increasing the thermal conductivity by adding granular fillers. An increase in sand content will enhance the thermal conductivity nonlinearly in theory.

Pile- soil stress ratio is an important parameter in the design of the composite ground. In this paper, the field measurements of the pile-soil stress ratio of the composite ground with DCM pile under embankment are carried out for Jieyang-Puning Expressway in Guangdong Province. The magnitude of the pile-soil stress ratio and its variation with the load and the consolidation time are measured. The measured results show that the measured pile-soil stress ratio is much more less than that under rigid foundation; it varies with load from decrease to increase first, then in the form of wave. The conclusion drawn can provide valuable preference for the design of the composite ground under embankment.

With the evolution of many application domains ,which are involved in radioactive waste repositories, sewage infiltration of resulting from refuse filling fields, seawater intrusion and leakage arising from oil pipeline aging, it is requested that theory of solute transport in fractured rocks is developed from the mechanism, experiment and model. Multi-scale conception models of solute transport in fractured rocks system are established. Furthermore, advantages and disadvantages of different mathematical models for solute transport are analyzed in present fractured rocks systems. It provides referential foundation for selecting rational mathematical model to solve concrete problems. Finally, problems needing further research are put forward.

The situation of two tunnels with short distance between them will be encountered in the construction of metro, because of the limitation of topographical conditions, sometimes their spacing is beyond rule of code. In this paper, the ABAQUS program is used to analyze the actual status of the continuous construction of one number line in the second period of time of Shenzhen City Railway Traffic System by numerical simulation and shows the right line construction’s effect on the left line, including the ground surface subsidence, building, stress distributions and liner deformation. Meanwhile, some beneficial conclusions are drawn to offer constructions of tunnels with short distance between them.

This paper presents the numerical simulation of the tunnel project in Pearl Line of Shanghai Metro from South Pudong Station to Nanpu Bridge Station using a 3D nonlinear finite element method. The influence of new tunnel on old tunnel during shield tunneling is studied. Some influential factors affected on the interaction of parallel tunnels are also evaluated. The results show that the relative position and net distance between the runnels have great influence on the interaction.

The mechanical behavior of the horizontal round adits in viscoelastic rock was studied by fractional Kelvin constitutive law. The imcompression of viscoelastic rock is assumed. And the analytical results were compared with those from classical Kelvin model. Therefore a new way to study the related subjects in viscoelastic rocks was proposed. The fractional derivative model can model any viscoelastic rock mass and its relaxation properties, and which have a wider area than classical model.

Based on the main feature of soft ground in mountainous area, taking the measure of multi-type-pile composite foundation to improve is an innovation. In combination with field test, the load transfer behavior of multi-type-pile composite foundation has been analyzed by use of FEM. The results show that there is a zone of negative friction in pile upside and the maximum axial force is below the top of pile. Compared with single-type-pile composite foundation, the multi-type-pile composite foundation is more whole and possess stronger capacity of load transfer. It can satisfy the requirements of load bearing capacity and deformation under special foundation conditions.

The composite support form for shallow excavation of depth H≤7 m has been suggested and widely used in recent years. Basing on the engineering practice, we adopt the elastoplastic model and use plane finite element method to analyze the effect of supporting parameters on the deformation behavior of excavation with composite supporting. The general principle of deformation behavior of different support methods is obtained. When the soil nails and piles are adopted simultaneous as composite support system, they will notably enhance the effect of the support; and the deformation behavior is different from that using soil nail merely, and the maximal displacement of the supporting system will move downwards closely to the bottom of foundation pit. And when the appropriate angle of the slop is used the composite support form will control the displacement of the side of foundation pit more effectively.

Using the finite element method, the paper is mainly focused on the effect of pile group and its effect coefficient of the composite pile foundation. Some influential factors, such as the pile length (L), the ratio of the pile spacing to the pile diameter (Sa /d), the pile number (n) density and soil type etc., are introduced and their effects on the effect of pile group and its effect coefficient, are analyzed, respectively. The results indicate that: the bearing capacity of the single pile (Qu) and the effect coefficient of pile group both increase with the pile length (L), and decrease with pile number (n). While the ratio of the pile spacing to the pile diameter (Sa/d) is a fixed quantity, the Qu and theη will achieve maximum. The effect of pile group and its effect coefficient of the composite pile foundation is correlated with the soil type.

A newly developed composite foundation technique is used in the practical project of soft soil foundation treatment. This kind of composite foundation is made up of two types piles, the rigid one is concrete pile, and the flexible one is mixed-in-place cement pile. The design ideas of the composite foundation are proposed. In order to determine the bearing capacity of composite foundation, the in-site loading tests of an important project were carried out; and the major engineering characteristics of the composite foundation are studied. The stress ratio and the load ratio of pile to soil in the process of loading are analyzed carefully. The results of tests indicate that the rigid pile, the flexible pile and soil can interact on each other very well; and their bearing capacities can be developed reasonably.

This paper presents the test data of field static loading tests of overlength friction piles. The analysis of the data shows that the load transfer performance of overlength piles is similar to that of end-bearing friction piles. The ultimate side soil resistance from the depth of l/3 pile length beneath the ground surface to l/6 pile length is much higher than those recommended by the Specifications, which indicates that the side resistance is strengthened. However, the ultimate side resistance of other parts is in accordance with Specifications. And the base grouting can not only improve the soil bearing capacity under the piles, but also enhance in side soil resistance. Based on the analysis of the performance of overlength pile, a simplified method to calculate the ultimate load bearing capacity of single pile is suggested, which is validated by some pile case.

Based on the triaxial tests of fly ash of Yangzhou Power Plant，some factors affecting the dynamic intensity of fly ash for embankment filling are analyzed. The capability resisting liquefaction of fly ash embankment under saturated condition is also discussed. The research results show that the vibration times, initial static stress level and water content etc. have obvious influence on the dynamic intensity of fly ash; the capability resisting liquefaction of fly ash embankment under saturated condition is related to earthquake peak acceleration and initial static stress level etc..

The load variations of each anchor in coal stratum are recorded with load cells for more than two years. The instantaneous losses of load that occurred during the lock-out operation have been measured. The load changes versus time after lock-out are analyzed. The comparison between measured deformations and calculated displacements at the heads of the anchors is discussed. The gray model, GM (1,1), of load loss is established. The trend of variation is researched. Results show that the gray model has a higher precision. This study is of referential value to construction and design for other similar projects.

At first FEM is used to calculate the deformation of the right abutment of the Danjiang arch dam; and the influence of the fault F1 on the deformation of the abutment is analyzed emphatically. Then the limit stability analysis method is used to calculate the stability factor of safety of the blocks cutting by the fault and bedding layers. The results show that the fault has significant influence on the deformation of the abutment within a certain extent; the blocks can’t meet the stability requirement and reinforcement is required. Finally, on the basis of the results some reinforcement measures are suggested.

A new kind of excavation support technology, pretressed anchor flexible retaining method, is numerically analyzed using nonlinear finite element. The model for prestressed anchor flexible retaining is established to study its mechanical performance. Also, the comparison of two other kinds of different spacings soil nailing is proceeded. The result indicates that the prestressed anchor flexible retaining method can control deformation more effectively for the strict deformation requisition.

Overlength piles have been found abroad application to large bridges and high buildings. Based on an example of an over- length pile foundation, the influences of base strata on the behavior of overlength piles are studied with 3D FEM. Duncan-Chang elastic model is used to simulate the constitutive relation of soils; and linear elastic model is used to simulate the constitutive relation of concrete and rock. Results of analyses indicate that for the different base strata, the scales of tip resistance and side resistance are different, but the behaviors are same; the critical loads are different, but the limit displacements are almost same; the tip resistances are different, but the failure reasons are shearing failure of the soils around piles.

Slope collapse and the slide body come into moving state from stable static state simultaneously, and are accompanied by a dramatic increase in displacement of slide body. Furthermore, the displacement is not a definite value, but an infinite increase. This is the definition of overall collapse of a slope. In finite element model, the slope reaches instability with the strength reduction, value of the nodal displacement just after slope failure has a sudden change compared to the one before failure. This actually means that no stress distribution can be achieved to satisfy both the yield criterion and global equilibrium. Slope failure and numerical non-convergence take place at the same time. An element stress reaching the yield criterion state not always means that infinite “plastic flow” occurred. It is determined by boundary condition. The plastic zone developed from slope toe to top not means the overall collapse occurred. On the other hand, the distribution of plastic zone was influenced by many factors such as Poisson's ratio, flow rule, etc. So non-convergence in finite element program can be taken as a suitable evaluating criterion of slope failure. Through a series of case studies, the applicability of the proposed method was clearly exhibited.