An experimental program to investigate the behavior of pedestal pile under combinatorial loads in dense sand is put forward through 1oading test and centrifuge test. The work focused on evaluating the shape of failure envelope surface of combinatorial loaded pile. The measured data and phenomenon are discussed. As a result, the following behaviors have been clarified: The failure curve on M=H h plane is an ellipse approximately, which can roughly estimated by an equation from Vm , Hm , and Um. The failure curve on M-H plane also was an ellipse approximately; this ellipse can be determined by results of two laterally loaded pile tests. If Um, Vm , Hm and Mm are known or assumed, the failure envelope surface can be obtained by the equation. The interaction among vertical, lateral and bending load must be considered in the design of pile foundation.

The effects of shearing strain rate on mechanical behavior of Zhanjiang strong structured clay have been investigated systematically by means of triaxial test. It is discovered that the strong structured clay has special mechanical effect of shearing strain rate; and the CU shear strength increases at first then decreases with the increase of strain rate, and a critical rate exists. The effect of strain rate on pore pressure is not so significant under the low confining pressure condition, whereas with the increase of confining pressure, the effect gradually becomes significant. Furthermore, the cohesion and internal friction angle entirely decreases and increases with the increase of strain rate, respectively, which show turning points when the strain rate increases to a certain value, but the latter lags behind to the former. The above-mentioned phenomena are resulted from the breakage behavior of clay structure related to the strong and weak structure of soil, which provides a help to understand the engineering properties of structured clay further.

Strain localization and macroscopically mechanical behaviors of rock specimen with and without material imperfection in plane strain compression were modeled numerically by FLAC. The adopted failure criterion was a composite Mohr-Coulomb criterion with tension cut-off and the post-peak constitutive relation of rock was linear strain-softening. For ideal specimen without any material imperfection, the deformation of the specimen is symmetrical with respect to the vertical axis of the specimen. If an imperfection is introduced in the form of a null element at one lateral edge, then the deformation no longer remains symmetrical. Shear strain localization is mainly initiated in the vicinity of the imperfection. For imperfect specimen, the onset of strain localization is earlier than that of ideal specimen. When the imperfection approaches to the middle of left edge of the specimen, multiple shear bands are formed so that the relatively ductile shear failure modes are expected and the post-peak stress-axial deformation curve and stress-lateral strain curve of the specimen tend to be less brittle. If the imperfection is closer to the top and base of the specimen, only a shear band is formed, going through the two lateral edges of the specimen, and the macroscopically mechanical behaviors of the specimen tend to be more brittle at post-peak. Migration or jump of shear band and competition between the two shear bands are observed. For ideal specimen, the peak strength is higher than those of imperfect specimens. When the imperfection moves away from the fixed end (base of the specimen), the peak strength decreases and finally approaches to a constant.

Compared with uniaxial experimental study on creep and relaxation properties of rock, multi-axial experiment study is very few, which makes 3-D creep and relaxation model of rock to be just simply extension without enough experiment verification. For gathering useful data and prompting development of multi-axial creep and relaxation model of rock, the following experiments were done with the red sandstone obtained from somewhere in Guangdong Province, China: (1) creep and relaxation properties of rock under different confining pressure; (2) creep and relaxation properties of rock subjected to pressures from two directions; (3) comparison of creep and relaxation properties between air-dried and saturation samples under multi-axial pressure. By analyzing experimental results, some features or phenomena are found on creep and relaxation properties of the red sandstone, for example, when axial pressures are the same, the higher confining pressure is, the smaller creep is, when confining pressures and relaxation time are the same, the higher is, the larger relaxation of is; etc.. All these are of some significance to theoretical study of rock mechanics and the design and construction of practical engineering.

It is an issue to choose an appropriate capillary pressure-saturation curve in the research of unsaturated fractured mass. Based on the characteristic of the unsaturated fractured mass, the research on the capillary pressure-saturation curve in an unsaturated fractured mass is summarized. It can be seen that seepage in an unsaturated fractured mass has some special characteristics including capillary flow, film flow, preferential flow and facture-matrix interaction; three methods to establish the capillary pressure-saturation curve, including physical laboratory, numerical simulation and mathematical computation; and all the results of these methods are also summarized. Finally, according to the characteristics of the seepage in an unsaturated rock mass and all these result of the capillary pressure-saturation curve, the following results can be concluded: (1) there is no capillary pressure-saturation curve which can reflect the other characters of the seepage in unsaturated rock mass except the capillary flow; (2) it is a convenient method to build the capillary pressure-saturation curve by numerical simulation and mathematical computation; (3) the capillary pressure-saturation curve simulated by Brooks-Corey(BC) model is better than by van Genuchten(VG) at initial stage during drainage, but worse at the last stage.

The common numerical solution method of the moisture and heat coupling for the soft rock in cold region tunnels is introduced. The temperature field and moisture field in the surrounding rock of Dabanshan tunnel at its exit kl06+025 in the cold region is numerically simulated by software Femlab; the law of moisture-heat coupling transfer in the soft rock tunnel is analyzed. The frozen circle will be thinner when taking into account the moisture field and be much thinner if the seepage coefficient be increased. The moisture field influences the redistributing of temperature field greatly. The simulating result shows that the frozen depth of vault is the deepest; the below of vault’s is deeper and the side wall rock’s is the thinnest and the result is similar to the engineering experience. The software Femlab is proved to be applied to provide some reference for the engineering design if the necessary data is collected through the simulating example.

At present, BP neural network has been widely used in back analysis of material parameters and initial stress field of rock masses in geomechanics. However, BP neural network is prone to over-being-trained, slow in convergence, not global minimum but local ones obtained and number of neurons in hidden layer hard to be determined. Authors using RBF neural network and BP neural network respectively identified mechanical parameters and initial stresses according to measured normal stresses of some specific points. Direct computations based on fast Lagrangian analysis of continuum (FLAC) were performed to get enough training samples for RBF neural network and BP neural network. An example shows that combination of RBF neural network with FLAC is more effective and rapid than application of BP neural network.

Uniaxial and triaxial creep tests have been performed on rock salt of Jintan Salt Mine on high temperature and high pressure triaxial rheological device; the creep characteristics of rock salt are investigated and the effect of stress state and temperature of rock salt are analyzed; and then the creep characteristic curve and parameters are obtained. Based on the character of creep curve of rock salt, a creep constitutive model of rock salt is established by using viscoelasto-plastic theory. Through the test results, it is shown that the steady state creep strain rate is a nonlinear function of diviatoric stress and temperature; a steady state creep constitutive model of rock salt is established. The patameters of constitutive equation are obtained by fitting test data; the theoretic results is proved well by comparison with the experimental results.

Based on the case study of Banqiao River left levee, a feasible approach to risk analysis for seepage failure in levees with deterministic seepage FEM was proposed, according to which risk analysis of seepage failure was carried out, and an evaluation of seepage stability was made. The proposed approach could avail itself of the advantage of FEM, and calculate the downstream hydraulic gradient more accurately while considering the soil distribution more actually than those conventional approaches. With the theory of extreme point combination-monotonicity and “3?” Rule, the critical hydraulic gradient, critical risk coefficient of seepage failure and alarm water level for flood prevention in flood season for Banqiao River levee were set up by the failure case in 1995; that are of great significance to seepage stability evaluation. The analytical approach and the results will be practical and helpful in practice of seepage stability evaluation for flood control engineering.

In order to explain the failure and breakage mechanisms of structural geological materials ,the plane strain compression tests of the samples of prism-like structural bodies assembled in three patterns are conducted under unloading conditions. In the process of reducing the lateral stress, it is found experimentally that the structural bodies will be broken after some relative movement and the main failure modes of structural bodies are splitting and shear failure; while the samples assembling of prism-like structural bodies are broken gradually, the strain hardening or strain softening can be observed and breakage bands are macroscopically formed in the end; the volume strain of the samples is always contractive but the lateral contractive strain turns to be the lateral extensive gradually.

The deposit features of Jiangsu marine soft soils was investigated based on Holocene epoch marine geomophology characteristics; the sediment history of Jiangsu marine soft soils is about 6000 years. The depth of embedment and thickness of soil layer of Jiangsu marine soft soils are of fluctuant varying because of effect of many times of transgressions and regressions. Through analysis and research of laboratory and field test data, Jiangsu marine soft soils are of features of high water content, high compression, high void ratio, high liquid limit, low bearing capacity and sensitive warp clay. Otherwise, we present some suggestion for ground improvement methods of design and construction.

Based on the settlement measurement of flood control wall along the bund in Shanghai, the structural settlement of the flood control wall was predicted with viscoelstic FEM back analysis. In order to calculate and predict the structural settlement, authors arranged and analyzed the measurement data of structural settlement from 1993 during the construction of the flood control wall to 2002, selected the typical section and measurement points, and then drew the curves of settlement with the development of time. With the help of two-dimensional finite element analysis, determined the soil layer that influence the settlement mostly, and then gained the equivalent elastic modulus of this layer with FEM back analysis so as to predict the development of the settlement in the future. The results can be good reference to the construction and technical management of flood control walls in Shanghai.

In order to clarify the dynamic behaviors and the damage mechanism of the subway structure, a series of shaking table tests and dynamic finite element analyses of Dakai subway station damaged in 1995 Hyogoken-nanbu earthquake were performed. The mechanism of the seismic soil pressure acting on the structure, the effects of the input directions of the sinusoidal and random waves, the embedded depth of the subway structure and the shear modulus ratio between the structure and the surrounding ground were investigated. Moreover, from the nonlinear seismic response analysis，the seismic soil pressure in the limit state of the surrounding ground were evaluated. It was resulted that the seismic soil pressure would reach a peak value; and the seismic soil pressure consists of dynamic component and static one caused by residual strain of the ground due to strong earthquake motions. The foundation is provided for amending the calculation method of seismic soil pressure and improving the anti-earthquake designing level of underground structure.

Based on practical measuring data in engineering, the hyperbola-shaped constitutive model which has three parameters and reflects the law of creep deformation after construction for high rockfill embankment is firstly proposed by combing the mechanism of settlement with the features of engineering; and the back-analysis way that the model’s parameters are determined has been brought forward with introduction of genetic algorithm and finite element method. Afterwards，the computational means of the settlement after construction for high rockfill embankment is deeply discussed using finite element method for creep; and the relevant analytic software is developed. Finally, the application for the constitutive model proposed in this paper and the computational method of the settlement for high rockfill embankment is deeply probed by combining with the practices of engineering. It is indicated by analysis of the example of practical engineering that both the constitutive model for creep deformation and the computational means of settlement after construction are simple and reach the request of engineering practice, and a new computational method for the after-construction settlement of high rockfill embankment which is elementarily established

Some questions such as disqualification dam, many cracks in developing dam body, disperse-impregnation in the downstream slope of dam, forming ascending spring owing to marshization in dam back, wadding educts coming from drainage ditch and rearing pond and a lot of seepage amount were occurred. These abnormal phenomena were brought by the seepages in the body and foundation of dam. On the circumstances of describing the dam body, foundation geological and hydrogeological conditions, cause of formation of the dam seepage and seepage stability of the dam were analyzed. It is pointed out that the actual saturation line and seepage amount of dam body were abnomal. Especially, the reservoir level was beyond 194 m after 1987, that compared with beforetime, it was abnomal that the identical reservoir level tended to go up. The actual seepage quantity of the dam foundation was unconventional, there were the questions of piping of the highly permeable layer and contact erosion, especially, the reservoir level was under 193.84 m, sand boil in ascending spring behind dam appears. Therefore, the seepage of dam was dangerous. The reasons of formation of dispersed-impregnation and exudates in dam, ascending spring, marshization, the seepage of shoulder and by-pass dam were analyzed.

Blasting vibration can induce some adverse influence on grouted rockbolt. The stress wave theory and wave function expansion method are adopted to analyze the interaction between stress wave and rockbolt. The distribution of stress and peak particle velocity around grout under the blasting vibration is derived; influences of stress wave in different frequencies on grouted rockbolt are compared; the safe peak particle velocity range in the grouted rockbolt is derived with stress waves of different frequencies. The result shows that the higher the frequency of incident wave is, the bigger the safe peak vibration velocity for grouted rockbolt is.

Based on ABAQUS program, 3-D finite element analysis model is established to simulate the effects of tunnel excavation on underground pipeline, in which different embedments, material properties and stiffnesses of subjacent bed are considered. The results show that the different soil properties and stiffnesses, caliber of pipeline have great influences on its deformation and internal force. Some conclusions are drawn to provide corresponding guidance for subsequent projects.

According to the control settlement and sparse piles theory, the applicability of prestressed concrete(PTC) piles with cap in the profundity soft soil ground treatment of a highway has been discussed. The spot tests of single pile with cap composite foundation and single pile without cap composite foundation have been done in order to master its working mechanism and investigate the mechanical behavior of load-bearing capacity, load transfer, earth pressure beside pile, the skin friction of pile, sharing of load and pile-soil stress ratio of PTC pile with cap composite foundation. The test results have been analyzed and researched deeply; and some useful conclusions are drawn, by the experiment, which can provide reasonable test base for us to study the theory of PTC pile with cap composite foundation and may be a guide to design control settlement and sparse piles composite foundation.

Free swelling ratio is a significant index for classification of expansive soil and identification of swelling potential. Unfortunately it is influenced by many factors, among which the effect of soil sample preparation is discussed. Test researches show that soil sampling mass and test results is of little influence by three funnel bores(4.5, 5, 5.5 mm) and three drop heights (5, 10, 15 mm) while they are much influenced by degree of grinding of soil. The specified standard that soil particle size is less than 0.5 mm is not perfect and the results of free swelling ratio for three soil particle sizes(0.25－0.5, 0.1－0.25, <0.1 mm) is widely variable, it is discovered that the finest soil(<0.1 mm) is reduced by 30 %－45 % and isn’t consistent with other indexes for expansive soil classification. The contrast is studied and mass difference of particle up to 2 g measured by a cup of 10ml is found; the conclusion that the results is influenced by particle mass is established and the changing of structure is a possible reason. At last the particle size between 0.1 mm and 0.5 mm is suggested.

A digital CT image processing based finite element method for 2-D mechanical analysis of geomaterials, is put forward. Digital image processing (DIP) is applied to convert computerized tomography (CT) image into a digital form that can be incorporated into finite element modeling. This CT discrimination based finite element modeling is used to analyze mechanical behavior of asphalt concrete indirect tensile test by taking into account the actual inhomogeneities and microstructures, especially voids distributions. The maxium tension stress appeared on the surface between voids and aggregates and the tension stress distribution along the loading axis of the sample is different.

Digital image processing technique is used to study the Duncan-Chang model parameters based on the triaxial tests. The research has recorded valuable data using the newly developed measurement method. There are great differences between the Duncan-Chang model parameters conducted from the digital image processing technique and traditional measurement methods. The reasons that cause by the different measurement technique and measurement area are analyzed. The influence degree of parameters variety on displacements results is discussed through numerical analysis. As a result of our experiments, we conclud that the parameters K and Kb from digital image processing technique are two to three times higher than the values from traditional method. Furthermore, the displacements are about half of the value calculated from the traditional method.

The Kunlunshan Tunnel is the longest tunnel of Qinghai-Tibet Railway on 550km continuous permafrost. It is the new technical problems met with during construction of tunnel in the area of plateau, cold and low atmospheric pressure. The result of the indoor and field experiments and construction practice showed that when wet concrete shot technology has been used in construction of permafrost tunnel, shot concrete could be felt with frozen wall rock firm and the timbering quality of the tunnel could be assured. It has been proved that wet shot concrete could be used in the construction of tunnel in plateau permafrost.

Dam deformation prediction is important for dam safety monitoring and has become a focus of increasing interest in recent years. In this study, on the basis of nonlinear dynamic property analysis of the observations of dam displacements, a novel methodology is proposed to establish dam deformation prediction model with improved prediction precision. Firstly, the dynamic properties of observations of dam displacements are studied by combined wavelet transform with fractal, and the results reveal that dam displacements possess certain low dimensional chaotic character. This provides theoretical foundation and transcendental knowledge for relational establishment of dam deformation prediction model. Moreover, derived from the low dimensional chaotic character, a chaos-optimized neural network model for dam deformation prediction is constructed, which is not only capable of capturing the dynamic properties of observations of dam displacements but also of implementing the model’s structural optimization and dynamic mechanism refreshing. Finally, in the practical application of dam deformation prediction, the model performance is quantificationally assessed by multiple indices. The result demonstrates that chaos-optimized neural network model holds higher prediction precision than the conventional back propagation (BP) neural network and ARMA models; and therefore, it is promising for dam safety monitoring.

Distribution characteristic of thrust force of a slope is analyzed using transfer coefficient method for stability analysis of slopes. Main sliding sect of slope is considered as reinforcing object of the prestressed cable. Considering the resisting force of stopping slide sect and the thrust force of slope upper sect, the calculation formula of prestressed cable hold force and the relationship between prestressed cable design strength and its set distance are developed with the slope safety being satisfied in advance; and a design method of prestressed cable for soil slope is put forward. The method is simple in form and easy in application. It is shown that the design strength and the set distance of prestressed cable is directly made certain using this method; and that the stability coefficient satisfies engineering need automatically. Finally, an engineering project is illustrated, and good results are obtained.

The pretress loss of anchor cable is the key cause induced the anchor structure failure; based on investigating all influencing factors, a method for calculating prestress loss is put forward; the influencing factors of prestress loss of anchor cable under long-term loading are analyzed; the relaxation model of steel strand, rheological model of rock as well as creep damage model of grouted material are put forward respectively; and using these theory to predict the prestress loss of anchor cable. There are the significant- sense to design and manage anchor cables.

The working mechanism of cushion in rigid pile composite ground is analyzed conceptually. Based on that, loading tests were performed on rigid-pile composite ground where pile has very large vertical stiffness to investigate the behavior of cushion of rigid-pile composite ground under vertical load. Gravel cushion with different thicknesses is laid beneath loading plate, while pile head is thus separated from loading plate by the gravel cushion. Pile head was embedded in the cushion for a certain length in one of the tests. Test results show that the bearing capacity of pile even with 100mm thick cushion can hardly be mobilized. The embedment of pile head into cushion can increase the load carried by the pile head; in the meantime reduce the penetration of pile head up into the cushion.

The state-of-art of soil mechanics is briefly discussed; and it is shown that the soil mechanics is still built on the semi-theoretical and semi-empirical foundation. Then some problems with numerical method applications to geotechnical engineering are presented; and how to apply numerical methods to practice is discussed; finally, some measures to deal with the problems are given. From above discussions, some conclusions can be drawn as follows: that soil mechanics is in the infancy of state, and with the development of it and the accumulation of experience on applying soil mechanics and numerical method to practice; numerical methods in geotechnique will be applied to practice more and more; and it will become a powerful tool to deal with geotechnical problems.

Utilizing the secondary development of CAD, the slope stability analysis, is carried out by W. Fellenius method. We can get the safety factor and position of any sliding surface of a slope by the program; and also we can get the most dangerous sliding surface and its safety factor of a slope. The program has a friendly user interface the same as windows style; and also it has an intuitional and visual computational process, briefness output; the program is a new choice of slope stability analysis.

A contact theory governing the discontinuous contacts between arbitrarily shaped polyhedral blocks is a major component of three-dimensional discontinuous deformation analysis method (3D-DDA). An edge-to-edge contact model, which forms a part of the contact theory, is proposed. Details are given including the detection of edge-to-edge contact type, judging of the first entrance faces, and the criteria for inter-penetration. Contact submatrices are derived by vector analysis and the penalty function method. This edge-to-edge contact model has been implemented into a 3D-DDA computer program. Two verification cases demonstrate the validity of the model and the capability of 3D-DDA to deal with large movements and multi-block interaction.

The osmotic pressure is very important for sea wall safety. Analyzing the survey data correctly is a useful way to ensure the safety of sea wall and people who are protected by it. In order to improve the accuracy of sea wall osmotic pressure forecast, the harmonic quantity regression model has been used to fit the osmotic pressure periodicity, and the time series model has been used to analyze the error series. The combined model has been established base on these two kind models. Tests with practical data show that the combined model has very high accuracy to fit and forecast sea wall osmotic pressure. In addition, the equal-dimension new-information model idea has been put into the combined model to achieve the real-time forecast of sea wall osmotic pressure.

More attention has focused on the issue of shallow tunneling across pile foundation. In this paper, a two-stage approach is used to analyze axial forces and displacements of pile caused by shallow tunneling. Free-field tunneling-induced ground moving is estimated based on an analytical solution given by Loganathan and Poulos (1998a). A simplified finite difference formulation is then developed, based on the Winkler model of soil reaction, for computing the pile response induced by the estimated free-field ground movements. Finally, a case history has been studied with both the proposed two-stage approach and a complete finite element analysis. The results obtained by both methods are in fair agreement. Because the simplified method does not need complex model, it can be used well in engineering.

Most natural clays have structural property, so the disturbance of foundation treatment changes engineering property of soft clay ground. Upper and lower limits of compression and settlement characteristics of structured soft clay are analyzed by comparing in-situ compression curve of disturbed soft clay with its experiment curve. Soft clay settlement calculation formula considering influence of disturbance is presented. The examples show that the construction disturbance enlarges settlement of structured soft clay ground between initial void ratio e0 and void ratio 0.42e0. Additional settlement is related to stress level and disturbance degree, whose value is in the range from 0.1 to 0.3 under the general stress level. The influence of disturbance becomes negligible with the increase of stress level finally. Relational conclusions are used for the project.

Based on a new kind of rockfill power function creep constitutive model which can simulate high confining pressure state of rockfill, the stress and deformation simulation analysis with consideration of rockfill creep are performed for Shuibuya concrete face rockfill dam (CFRD). The computation results show that the deformation of dam shows evident increment and stress of dam relax a little. The creep of the rockfill result to some increase of the normal direction deformation and stress of the concrete face. The reasonable creep model is adopted to simulate deformation of rockfill correctly, the results of which can offer some references for the construction process and the decision of the constructing time. It has also very important significance for that the stress and deformation of CFRD can be forecasted according to simulation analysis results.

It is important to analyze sensitivity of landslide factor. The west area in new Wushan County was taken as an experimental area. Logistic model was set up for which independent variables are landform, physiognomy, lithological character and geological structure conditions and dependent variable is historical landslide condition. The sensitivity degree is expected according to Bayesian information criterion. The authors design test method which taken in factor one by one and compared with superior degree on not nested model. The results of sensitivity degree are lithological character, height, distance to effected structure line, gradient, slope direction, slope shape. The experiment provides a new and credible method for evaluating slope stability.

The influence of end conditions on the load transfer behavior of cast-in-place pile is discussed using the load transfer method. The three-stage hyperbolic softening model is present as the load transfer function of pile-side, and tri-linear model is introduced to simulate the characteristics of sediments in pile end. Differential equations are established by dealing with the states of static equilibrium, with the settlements and resistant forces of pile-end as boundary conditions. By transforming the nonlinear differential equations into integral equetions and solving them numerically; variation of the axial force along depth and the load-settlement curve of pile are obtained. The load-settlement curves and distribution of friction on pile-side of pile under different pile-end stiffnesses and thicknesses of sediments are studied by parameter analysis. Analysis of two groups of adjacent test piles shows that this method can well represent the actual character of pile foundations.

The simplified analysis method of single pile subjected to vertical loading combined soil displacement factors matrix in Poulos’s integral equation method with the polynomial linked pile body and pile tip displacement which is deduced from Randolph’s shear displacement method. So the finite difference calculation in integral equation method is out of need herein. The method is more accurate to characterize shear stress allocation than Randolph method. Pile group under vertical loading can also be analyzed with the simplified method. Comparison with Poulos method, Randolph method and Chow’s hybrid method for single pile and pile group analysis show that the simplified method is feasible and accurate.

The embankment behind the bridge abutment of the high speed railway is different from the general railway in the aspects of padding, construction control and quality supervision. However, there is a little experimental research of the earth pressure behind abutment; and there are a lot of factors influencing the earth pressure also; and the distribution of the earth pressure is not exact predicted through actual earth pressure theories. Therefore, a long-time in-situ observation was practiced to gain the first materials. Based on the experiment results, the changing of the earth pressure with time and the height of embankment, the magnitude and distribution of earth pressures behind the abutment are given. Test results show, the earth pressure behind abutment is nonlinearity with the depth of abutment. To begin with, the earth pressure of abutment increased with the depth of abutment, later, it minished with the depth increasing of abutment. The comparison are made between formula presented with the experimental observations; the points of application of the resultant earth pressures have significantly difference; the height of actual action point of resultant earth pressure is 0.41 of the embankment height.

On the base of the uplift model tests and prototype tests on foundation of transmission line tower, the uplift performance of expansive soil is deeply researched. The regularity of soil displacement, stress distribution, load capacity, failure mechanism were analyzed. The defect of existing uplift theory and calculation in clay is pointed out; this is that the failure of the soil is not only existing in cracking surface, but also existing entire soil body. Thus the composing of uplift bearing capacity is put forward that it is consisted of base weight, earth mass weight above the base, shear strength in the failure soil, and foundation bearing capacity caused by stress re-distribution owing to soil compressed; and then the FEM software is used for the analysis and validation. Finally, scale effect in the model tests is discussed.

A newly developed numerical approach MFPA2D (material failure process analysis)Code is presented to simulate the failure process of brittle material containing single hole or double holes under uniaxial compression. Numerical simulation results show that initial cracks are not always the leading cracks which result in the ultimate macroscopical perforation failure. And brittle materials have a localization characteristic when they damage. It is also shown that nonhomogeneity is the essential reason of brittle material’s local failure. The influence of hole distribution on the material strength and failure mode is studied. Stress-strain curves of failure process for models are provided. The material strength decreases 50% if it contains a single hole or double holes. It is indicated that some hole distribution can increase the stress concentration and some hole distribution can decrease the stress concentration．The numerical simulation results are consistent with the experimental results

For the safety and economy in the aseismic design of structures, not only the collapse of structures must be avoided, but also other failure modes should be controlled. In this situation, the performance-based design method, which is regarded as the main design method in the future in aseismic engineering, is studied by many researchers. A method of how to choose the high dam construction scheme is proposed based on the function of electricity-generating of dams. Economy losses caused by different intensities of earthquakes are analyzed. Through water level, the relationship between dynamic mechanics and economy loss is established. An example is presented to illustrate the feasibility of the proposed method.

It is presented to predict slope splash-erosion for rain drops based on rough neural network. The redundancy information is reducted by the relative dependability between condition attribute and decision attribute of rough sets. The test indexes such as water depth and flux are deleted. The 2−5−1 rough neural network is established in which input parameters are gradient and rain intensity while output parameter is splash-erosion quantity. The frame of neural network is predigested. The train time of neural network is decreased. The reduced sloping field rain drops splash-erosion linear regression correlation coefficient of prediction and experiment is larger than that had not been reduced. The constringency speed is faster than that had not been reduced. The example calculation indicates that the rough neural network is an efficient and feasible algorithm to forecast sloping field rain drops splash-erosion.

On the basis of limit equilibrium equation for thawing settlement of permafrost subgrade, a global optimal algorithm is put forward to calculate the reliability index and failure probability based on genetic algorithm. It can overcome the drawbacks of local optimal wildly existing in classic searching method. By this method, difficulty brought by the transformation of complex performance function can be avoided and nonlinear programming problem can be solved efficiently. Engineering example of Qinghai-Tibet Railway shows that this method is accurate and reliable.

Supporting structure of deep excavation is optimized using genetic algorithm(GA); and limitation of GA such as poor local search ability and premature is largely enhanced. Then crossover operator and mutation operator is improved while considering the adaptive method; also the combination of hill-climbing with GA enables better local search ability in post-evolution. Mathematic model of deep excavation supporting structure is discussed; according to which a GA software system is developed for deep excavation retaining system. An engineering example is studied; and the results show the validity of the amelioration.