Based on the study of the isotropic loading test, the Cam-clay model has been established as the simplest elastoplastic model to describe the stress-strain relationships of normally consolidated clay in triaxial compression test, which is the basis to propose other models. According to the difference in loading modes and fabric characteristics, elastoplastic models describing stress-strain relationships under loading modes related to stress state, stress history, stress paths, loading time etc. are summarized. And elastoplastic models describing behaviors of soil structure, anisotropy and particle crushing etc. are summed up as well. Also, the transformed stress method representing the three dimensional property of soils, over-consolidated clay model describing the stress history effect and the asymptotic state model simulating asymptotic state path are introduced in detail.

Silty clay is a typical soft soil and characterized with its coagulation structure. In the field, it is very difficult to directly determine the shape and size of a grain in the silty clay by eyes. Some colorful photographs of the silty clay were captured by a commercial camera and transformed into grayscale images. To these grayscale images, the six histogram-based parameters, including mean, standard deviation, smoothness, third order moment, energy and entropy, were thereafter obtained. Considering the spatial relations of grayscale intensity in an image, five parameters, including angularity second order moment, contrast, correlation, inverse difference moment and entropy, are also obtained based on a gray co-occurrence matrix. Furthermore, the regression technique was used to estimate the relations between the texture parameters and the traditional engineering properties of silty clays. It is shown that these relations are much satisfactory and may be used in quickly examining the engineering properties of silty clay. The method developed is referable to the geotechnical design in soft grounds.

Aiming at brittle failure of rock with structural plane, single structure plane controlling effect under three-dimensional stress is studied and verified by true triaxial experiments. The mechanical characteristics, structure controlling laws and acoustic emission (AE) characteristics of rock specimens with single structural plane is studied systematically, simulating the excavating and supporting stress path in engineering practice. The research indicates: (1) Single structure plane controlling effect under three-dimensional stress can describe the structure controlling laws, unloading and supporting effect of engineering rock well. True triaxial experiment results conform to the theory. (2) Under excavating and supporting stress path, the failure mode, unloading and supporting effect are all connected with stress condition, supporting strength and structural parameters. Therefore, methods as engineering orientation arrangement and proper support can be taken to prevent structure controlling failure. (3) The AE features and energy release laws are similar with intact specimens. However, the existence of structure reduces the strength and energy storage capability. Also, 95 % of the elastic strain energy is released during failure stage. The research can guide the excavation and supporting of engineering rock mass.

Based on similar principles, two large-scale bridge models were established and carried out. It is the first time artificial simulated the effect on bridges under activities of ground-fissure; and strain gauges were laid on the bridge decks’ up and down surfaces. The test results show that the different construction bridge decks have different damage forms under the activities of ground-fissure. simply-supported bridge due to unbound, the bridge stress and strain mostly caused by the load on the bridge deck, and the additional stress caused by the activities of ground-fissure is very small; so the possible type of damage is off the beam or off the deck, as for this type of bridge, the most important measure is monitoring the bridge during the activities of ground-fissure to forecast the damage situation before the bridge destroyed by the activities of ground-fissure. While the fixed bridge due to be bound, big additional stress such as pressure, shear and tensile stress maybe be caused by the activities of ground-fissure and turns to damage of the bridge construction. At last, it is pointed out that the simply supported bridge is more suitable than the fixed-bridge over the regional of ground-fissure.

Through investigating the property of structure damping, material viscous damping of soil and the radiation damping of foundation considering translation and rocking, the coupling damping ratio and the damping reduction factor of the soil-structure- interaction system are deduced. Based on studying of the relationship between damping reduction factor and seismic influence coefficient , it is shown that it will improve the damping property and earthquake-resistant capability, and reduce the earthquake action of the SSI system, so as to provide a theoretical basis for the aseismatic researches and aseismic designs.

Strength variation and acoustic emission characteristics of skarn under uniaxial cyclic loading and unloading test are studied by using MTS equipment and PAC acoustic emission acquisition system. The results indicate that: in the loading and unloading processes, if there is no remarkably local failure in the loading process, then the cyclic loading and unloading processes might strengthen the rock sample，and Young’s Modulus increases gradually with the increasing of cyclic times; and if the local failure happens and the nonrenewable cracks appears in the loading process, then the cyclic loading and unloading processes will facilitate the slippage of planes of cracks and accelerate the breakdown rate. Meanwhile, the results also indicate that: the uniaxial compression curve of skarn can be generally divided into four stages: pressure consolidation, elastic, plastic, peak post which with different acoustic emission characteristics. In addition, skarn has the anti-Kaiser effect under cyclic loading and unloading; and the Felicity ratio decrease with the increasing of cyclic times. Acoustic emission also exists in the unloading process.

For the warping clay consolidation of blanket crack of clay, under the situation of continuity and equilibrium of solid and liquid phases, a differential equation with the void ratio as a control variable is deduced. Based on the permeation induced consolidation test of highly plastic clay and general clay, the relation among the void ratio, permeability coefficient and the effective stress is determined. The pdepe of Matlab function library is used to solve the differential equations and the temporal-spatial distribution of void ratio is obtained. The calculation results are verified by the model test and the site warping test. The void ratio distributions come from the calculation and the test have the same pattern and tend towards the consistence with the ansolidation, The results provide a scientific basis to research the consolidation of warping clay in blanket crack for soil dam.

Based on the limit equilibrium method, the failure patterns of undrained saturated foundation under combined loading are investigated by virtue of the finite element software ABAQUS in detail. The conclusion shows that the vertical loading V can control the extent of depth of the sliding surface, the horizontal loading H and the moment loading M make the failure envelope of foundation asymmetry; the forward-tilted scoop failure mode and the backward-tilted scoop failure mode, which are given in this paper, can interpret properly the asymmetry of failure envelope in H-M loading space. Finally, the relationship between the different failure patterns and the loading compound modes in H-M loading space is given; moreover, the discrimination equation of appearance of maximum moment Mmax is given.

Using the adsorption equation of coalbed gas desorption, the heat energy equation and the stress equation of coal framework when taking ultrasound into consideration, a liquid-solid dynamic coupling numerical modeling of ultrasound enhanced coalbed gas desorption and flow including stress, temperature and pressure fields is presented; the desorbing-diffusing- flowing mechanism of methane on coal beds by numerical simulating is discussed. The results show that the ultrasound field enhances temperature of the system of coal and gas, increases porosity and penetratability, depresses stress of coalbed. Moreover, ultrasound attenuation forms vibrating and heating; the spread distance of vibrating equal to ultrasound attenuating, another, the bound of ultrasound heating effecting the deep distance in coalbed.

The flow characters of caved ore and rock is important for reducing ore lose and ore dilution. Firstly, the effected reasons of flow characters for caved ore and rock are analyzed. Secondly, experiments are carried out to study the granular flow characters considering the size of drawing hole, size of grain and type of material by index grain method. The relationship among the moving border, size of drawing hole, size of grain, type of grain and the height of grain is studied. The relationship between the size of drawing hole and the released quantity is studied by plane pattern and stereo pattern. The main experimental results are as follows: (1) the moving border is related with the size of grain, size of drawing hole and type of material. However, the piling height of grain has little effect on the moving border; (2) the flow speed of grain is effected by size of grain and size of drawing hole. Based on the experimental results, a method of determining the mining design parameters is put forward.

Combined with a mountain tunnel project in Hunan province and based on the practical geological analysis and monitoring data, the basic failure mode of surrounding rock is established firstly by key block theory and the discontinuous deformation analysis(DDA) according to the real joint occurrence in the jointed and serious collapse section of the tunnel; and then based on the collapse mode by DDA, the surrounding rock stability is analyzed; and an evaluation for designed reinforcement scheme is made by continuous medium analysis program FLAC; it indicated that the main failure mode of surrounding rock is limited to local block instability controlled by joints and with no possibility of large deformation, which is in accordance with the practice very well so as to provide the assurance for the safety construction. The proposed method of combining discontinuous deformation analysis and continuous medium method for the collapse problem analysis, has acquired satisfying results so as to provide a good reference for other similar projects.

It is usually directly to test seepage quantity in the laboratory, which is difficult to accurately measure for low permeability rocks. In this paper, the volume change method has been used with the new equipment called high pressure permeability testing apparatus in lab. This method can exactly measure the seepage water volume change quantity（the least effective test precision is 0.03ml）. When the seepage water pressure difference is unchangeable, the stable penetration flow phase can be ascertained according to the linear relationship between seepage water volume change quantity and time, which can be considered satisfying the Darcy’s law; and the Darcy’s formula can be used. Using this method, even the ultra-low permeability rocks, whose permeability coefficient less than 10-9 cm/s, when the whole seepage section was formed, the test time was just more than ten minutes or several minutes. This method can save the test time greatly and improve the precision. Test results demonstrate it is an effective permeability test method.

The three-dimensional layered ground model is established based on the construction of expressway. Dynamic responses of rigid pavement and flexible pavement resting on layered ground are studied respectively. By employing transfer matrix method, the integrated rigid matrix of layered ground is obtained. Vehicle loads are considered as rectangular harmonic moving loads; and the analytical solution of the pavement and layered ground interaction is deduced with Fourier transform. Numerical results are derived through the inverse fast Fourier transform method (FFT) and used to analyze the influence of different loads and different ground media properties on dynamic responses. The calculation results are consistent with ones of laboratory model tests. Reference is made to analyze of the pavement design and dynamic response of expressways.

The method of structural mechanics that bridge used in multi-row piles is introduced to the double-row anti-sliding piles. But it is different, that above the slide surface there exists sliding soil body; however above the scour-line of bridge doesn’t consider the influence that the soil body’s existence on the “m” method . In this paper, two new “m” methods are proposed which consider the existence of sliding soil body. At the same time, the soil pressure on the piles of front-row and back-row aroused by the soil body above slide surface are researched with tests and theoretical analysis; the calculation formulas are proposed. At the same time, the finite staff element method is used to analyze the influence of beam rigidity; and the two new methods proposed are used to analyze the influence of connect way between piles and beam; and the conclusion is obtained that the rigidity ratio between beam and piles being 0.48 is appropriate; the continuative increase of the rigidity ratio is not significant; the worst condition is that connecting way between piles and beam is hinged; the best condition is that connecting way between piles and beam is rigid. Whether is single-row pile or are double-row piles, when the front of single-row pile or the front of the front-row pile(in the double-row piles) needed excavation, it is supposed to that ought to be carefulness to excavate, because it is that the engineering cost increased greatly. And it was considered that the double-row piles cost saving and had strong capability of resisting deformation; it is worthy of research and extensive application to engineering.

The current criterion doesn’t consider the effect of supporting structure in computing the box foundation settlement, which makes the error between academic settlement and practical settlement. In order to exploring the settlement mechanism of box foundation, a series of tests were accomplished. The influence of profile friction on box-foundation settlement is studied under the condition of the different wall materials, wall thicknesses and inserting depth ratios. The test results show that the friction force is very important to the settlement of the box foundation, and the force is correlated with the friction factor, the interface between the wall and the soil. And the FLAC3D numerical code is adopted to simulate the box foundation settlement under these conditions. Based on the results of the physical model test and numerical simulation, a new box foundation settlement calculation method considering the influence of profile friction is put forward. The results indicate that the method is more feasible and can be used for reference to revise codes.

Under some hypothesis, the Drucker-Prager(D-P) criterions can be used approximately instead of Mohr-Coulomb(M-C) criterion. The foundation of transformation methods from M-C to D-P from energy view is firstly set forth; and then emphasis is given to investigate the square error of distortion energy density, which are needed for reaching M-C yield and D-P yield respectively, provided the same Lode angle in ? plane. Based on the least square method, the relations of parameters for M-C and D-P are obtained providing minimum of the square error of distortion energy density. The result obtained in the approach is according to the equivalent area’s approach, the interpretation in energy view for the transformation method in equivalent area’s approach is presented.

A series of static and cyclic-static consolidated-undrained triaxial compression tests on remolded silty clay samples under three different confining pressures are carried out; and then the post-cyclic loading undrained strength, the pore pressure and the cyclic strain are obtained under various cyclic loading stress conditions. By the non-dimensional analyses of post-cyclic loading strength, pore pressure and cyclic strain, the relationships between the post-cyclic loading strength ratio and the cyclic strain ratio or the pore pressure ratio are established. From test data, it is shown that the post-cyclic loading undrained strength degradation of silty clay depends on the pore pressure ratio and the cyclic strain ratio caused by cyclic loading. The post-cyclic loading strength hardly decreases when the cyclic strain ratio is smaller than 0.1 while the pore pressure ratio begins to rapidly increase. And it decreases in a great deal when the cyclic strain ratio is larger than 0.1 and the pore pressure ratio increases slowly. The degree of post-cyclic loading strength degradation is about 55 % when the cyclic strain ratio is close to 1 and the pore pressure ratio is 0.9

The un-drained shearing strength of saturated loess will degenerate under cyclic loading. This degeneration is attributed to two reasons, the first one is the reduction of effective pressure due to the increment of super pore pressure; another one is the change of soil’s structure attribute to the cumulated of plastic shearing strain. Firstly, on the basis of the undrained shearing tests results, two formulations are given which include undrained strength ratio versus overconsolidation ratio and undrained strength ratio versus initial shearing strain. Then, the quasi-overconsolidation ratio is introduced to consider the effect of super pore pressure; and the fitting formulation is applied to consider the influence of shearing strain. The degenerated formulation of undrained strength of saturated loess is deduced at last; and its reasonableness is proved by the test results.

Based on the cement-solidification of sludge using bentonite as additive, the wet and dry test was conducted to measure the parameters of relative mass loss, volume change, water content and unconfined compression strength(UCS) under the condition of violent water changes, in order to evaluate the wet and dry durability of the solidified sludge. The results show that the cement plays the major role in improving the wet and dry durability of solidified sludge; and the results are achieved at the enough cement content. Bentonite can also improve the wet and dry durability of solidified sludge at the appropriate range of adding content, however exceeding the range, can reduce the wet and dry durability. At cement content below 0.4, UCS of solidified sludge increases after wet and dry cycles relative to control samples but volume of solidified sludge decreases remarkably; at cement content larger than 0.4, UCS decreases relative to control samples and volume varies little.

In the re-pressed tests with jacked pipe piles in soft clay, it was observed that the re-pressed starting pressure can reach to more than 2.5 times the final pressure for 25 days after finishing the installation; and it increased more rapidly in early period than later. It is reasonable to use start pressure as the ultimate bearing capacity of jacked pile by theoretical analyses and test results, and the changes of bearing capacity in short term can be found, which is a effective method to study the time effect. The increase of the bearing capacity mainly resulted from the development of clay shear strength around pile. The increase curves of pile lateral resistance per unit area in clay are confirmed by modification; and three forecasting formulas are derived by regression analysis. By contrast, it is more acceptable to adopt logarithm expression as the formula to forecast bearing capacity of jacked piles.

Creep property is the key factor effecting long-term behavior of geogrid-reinforced earth retaining structures. Contrast test is adopted for creep property of geogrids under different temperatures in the indoor test. The result indicates as follows: creep property of plastic geogrids is totally different with different temperatures. When extensibility is approaching 14 % after 1 000 hours at 20 ℃, the deformation is still not becoming stability under 60 percent of max-pressure. However, under the circumstance of -20 ℃, when the extensibility falls short of 2.5 % after only 100 hours, the deformation reaches stability. So temperature has a great influence on creep property of geogrids. The lower the temperature is, the smaller the creep is.

The geological conditions and characteristics of rock masses of columnar jointed basalt in valley slope of dam site in Baihetan hydropower station are introduced in detail; the proper distinct element model of Baihetan river valley is established; and the river valley evolvement is simulated under several engineering cases taking into account the possible rock masses qualities of the key stratum of P2?3. Based on the simulation results, we have thoroughly investigated the basic law of stress distribution, deformation situation, yield zone and stability factor of Baihetan river slope nowadays under all cases; and the comprehensive contrast studies are carried out between simulation results and the actual geological status of river valley nowadays. Finally, the methodology of gradation by the information of similar degree is introduced to evaluate the rock masses level of key stratum P2?3; and we conclude that the global quality of Baihetan jointed basalt P2?3 can be marked as the level of III1 to evaluate its engineering properties and to determine relevant mechanical parameters at the phase of feasibility investigation; simultaneously the engineering properties of rock masses in valley slope of dam site can be evaluated according to the relevant simulation results.

Geological conditions are the basis for surface subsidence. In mines with complicated geological conditions, the displacement and subsidence angles are often forecasted inaccurately, which leads to disastrous consequences. Taking a typical complicated geological mine as the background engineering, and based on the results of surface deformation monitoring for many years, mechanism of surface deformation and rock movement caused by underground mining is analyzed. Results obtained indicate that underground mining is the direct cause of rock deformation, which is significantly influenced by hydrostatic and hydrodynamic pressures of groundwater existing in rock masses. Joint fissures are the foundation of rock deformation. The tectonic stress is the main factor which causes greater movement and deformation. At the beginning of mining, surface subsidence is mainly caused by groundwater drainage. After the formation of large-scale surface subsidence, expansion of gob is the main reason for surface subsidence; but the special engineering geological and hydrogeological conditions have an important influence on the expansion speed of surface subsidence.

Groundwater plays a significant role in the stability of reservoir slopes. However, there are no general formulas for the calculation of phreatic line. A conceptual model is established based on the reservoir slopes with inclined impervious bed; and the approximate analytic solutions of phreatic line caused by reservoir water level fluctuation and rainfall are derived with the initial value calculated in steady flow condition. The seep/w program of Geo-Slope analysis software is used to verify the approximate analytic solutions; and the results show that the phreatic lines calculated by approximate analytic solution are consistent with the simulation ones in different combination conditions of rainfall and reservoir water level fluctuation. Applying the approximate analytic solutions in the research of phreatic lines in Zhaoshuling Landslide, the effect is satisfactory. The analytic solution has been verified by measured phreatic line and then it is used to predict the different phreatic lines under the conditions of rapid reservior impounding, rapid reservior impounding together with rainstorm, rapid reservior flushing and rapid reservior flushing together with rainstorm (fluctuation range of water level is 145 m to 175 m). The reasons which caused the error of approximate analytic solutions are analyzed thoroughly; and it would provide a basis for better use of approximate analytic solutions of phreatic line in practice.

In order to reflect zone characteristics of karst for highway construction, the authors proposes principle and index system and establish evaluation model for karst environmental zoning for highway engineering on the basis of case study in Guizhou Province. Meanwhile, the zoning map of karst for highway is made with the analytic hierarchy process (AHP) and GIS technology. It divides Guizhou Province into four influenced zones, namely, western region as the high-median influenced zone, northeastern region as the median-high influenced zone, central region as median influenced zone and low influenced zone. After comprehensively analyzing highway network and evaluation results, it is found that 6 265 km of 12 462 km long provincial highways are located in high influenced zone while 567 km of 1 587 km long expressways completed and in progress are also located in high influenced zone. The zoning results could be used as guidelines for highway planning, construction and management in Guizhou Province.

It is studied profoundly that the compound 3D visualization modeling system can be built up with the open-sourced graphic libraries PYOpenGL and VTK. In this process, the computational models written by Python and other models written by C or C++ can be invoked successfully when we use the python language as a kind of adhesive and wxPython as GUI with the help of swig. Moreover, a kind of data structure is implemented using the Quad-edge data structure as prototype, which makes the topology more compact and queries more efficient. Then based-on this data structure, spatial discrete points Delaunay triangulation in any plane is accomplished through the setting of projection plane. Taking full advantage of the topology characteristic, a kind of algorithm which can search interrelated triangles, segments and vertexes efficiently is obtained; and the object of inserting any constraint is reached. Up to now, the function of loading geometry data and other information stored in the format of DXF, Excel or TXT files or access and SQL Server DB is made reality. Also in the system, many general 3D modeling functions as interpolations of inverse distance, Kriging and cubic spline, Delaunay triangulation, constraints insertion, intersections with two TIN and so on are accomplished.

In the analysis of pile response due to tunneling under two different displacement boundary conditions, a displacement controlled method (DCM) based on ground loss is used. The first stage, the transformation of soil displacement field around tunnel is introduced to simulate the process of actual tunneling. Then the second stage, free soil displacement field is loaded to group piles(2×2) to analyze the response(including settlement and force); the results from the presented approach by DCM are compared with ones from other papers; the good agreement is obtained.

Based on a macroscopic analysis of geological characteristics of landslides and indoor experiments, the lithology, grain ingredients, mineral components, microstructure, physico-mechanical behaviors and deformation under the reservoir backwater condition of soil in sliding zone in No.Ⅰ riverside landslide soil of Huangtupo landslide are analyzed. The results show that the indispensable conditions for the soil in sliding zone to be easily water-saturated and softened include a high content of clay or powder, rather obvious polished surfaces and scratches under the influence of deep creeps and hydrophilic clay minerals and soil with a sheet structure; the creep deformation of slumped mass is a vital consequence of mechanical strength decrease of soil in sliding zone being water-saturated.

Debris flow is caused by many factors; it is not only related to external factors such as topographical features, characteristics of rainfall, earthquake and human activity, but also to internal factors; for example, clay minerals, grain size distribution, chemical composition, soil dispersion degree and groundwater. Indoor experiments are carried out including clay minerals analysis, grain size distribution analysis, chemical composition quantitative analysis, dispersion degree and exchangeable sodium percentage (ESP) test, ground water analysis. As a result, it is found that the Illite is the main clay mineral in the soil mass of Jiangjia Ravine (occupied 30 percent of the soil mass); the chemical composition of soil mass in Jiangjia Ravine is similar to Illite, it’s average value of ESP and dispersion degree are 24.6 % and 59.1 %, respectively; it is high dispersive soil and barren; the structure and stability of rock and soil mass in Jiangjia Ravine is destroyed by the high salinity and high hardness groundwater; a large number of loose material is produced and a wealth of source material for debris flow is provided.

For risk analysis of slope, present study field is focused on the case of parameters of rock and soil material itself being random variables. The influence of natural multi-random factors is considered little. Only a few of scholars have done preliminary research on the risk of slope under random water level and horizontal earthquake force. But in hydrological risk analysis, just the failure risk caused by hydrostatic pressure was considered. The risk caused by seepage was ignored. In view of this shortage and on the basis of previous study, seepage factor is introduced and the risk of dam slope is evaluated under external random multi-loadings. As a typical example, the means is applied to downstream slope of Gouhou dam. In this project, the influence of permeated deformation and earthquake force are coupled and slope risk is evaluated under natural multi-random factors.

The method of conformal mapping between complex planes is used to solve the problem of the scattering around a poroelatic liner of arbitrary shape in saturated soil under harmonic plane dilatational waves. The equations of the Biot wave motion for saturated soil and liner are decoupled to Helmholtz equations and given by introducing potential function. Utilizing the polar angle transform, the expressions of the displacements, stresses and pore pressures of saturated soil and those of the liner in the mapping plane can be obtained. Based upon this, the dynamic response around the liner can be obtained by transform the boundary conditions of liner of arbitrary shape in the preimage plane into those of the cirque in the mapping plane. Some results and rules are presented with different incident angle and parameter conditions of the liner.

In view of the influence of completely and intensively weathered stratum in the shallow surface of slope and fault fracture belt on the initial geostress field in dam zone of Dagangshan hydropower station, the 3D initial geostress regression analysis model is established based on the measured geostress data and geologic structure as well as topography features of V-shaped river valley. The optimal geostress regression coefficients have been achieved through 3D multivariate regression numerical analysis and the initial geostress field in dam zone of Dagangshan hydropower station is exactly simulated. The calculation results show that the initial geostress field in dam zone is a medium to high stress field composed of tectonic stress and dead-weight stress. The tectonic stress is prominent at shallow level and the dead-weight stress is prominent at deep level, which provides important reference basis for excavating simulation and long-term stability analysis of slope.

Piled bridge abutment on the soft clay may be loaded considerable lateral earth pressure due to soil movements generated by the high embankment on the back of bridge abutment. How to calculate lateral earth pressure reasonably is still a difficult problem for designing piled high bridge abutment on the soft clay. Methods of ultimate earth pressure are brought forward to solve lateral earth pressure on the pile; mechanical model of bridge abutment-pile interaction is built, which can take multilayer soil, the parameters of the soil and piles and lateral earth pressure into account. The new method for analyzing bridge abutment and pile’s internal force and displacement is deduced. This method mainly relates to multiplication of transfer matrixs and is suitable for programming. Compared with the general theoretical methods and the complicated finite element method, it is more simple and needs less parameters; so it has better practical value. Based on engineering example, force and displacement program of piled bridge abutment is compiled by means of programming language Matlab. Results verify that this method is accurate and reliable; so it can be a good reference for design of piled bridge abutment on the clay soft .

The simplified method for slope reliability analysis ignores the spatial variability and use same strength parameters during every computation. The probabilistic characterization of soil properties are obtained through discrete sample test; thus can only represent point variability. The stability of slopes is often controlled by the average shear strength within a zone of influence, hence the average properties in the slope domain should be accounted. The unconfined random field ignores the samples’ location information and may lead to higher variability especially when the variability of soil is high. The constraint random field (CRF) is proposed and implemented utilizing random field theory and regionalized variable theory of geostatistics to ensure that the random field realizations match the parameters at the sample locations exactly; and slope reliability analysis is performed by Monte-Carlo random FEM (RFEM) and shear strength reduction technique. The computation results show that the CRF can significantly reduce variance of the random field simulation and get lower probability of failure when the soil variability is high. The comparison of RFEM and simplified method also shows that the simplified method will not always overestimate the probability of failure. The scale effect in slope reliability analysis is highlighted through RFEM; and the applicability of simplified method is discussed.

The detection of water-bearing structures and karst-fractured groundwater is the key problem needed to be resolved. Due to its high resolution and sensitivity to the low resistivity body, the DC resistivity method is introduced to predict the water-bearing structures in the front of tunnel face. First, the analytical formula of the spheriform water-bearing structures advanced detection in the whole space is deduced. Based on the analysis of large forward modeling results with finite element numerical simulation method, the apparent resistivity data in 3-D space with tunnel is translated into the data of advanced detection in the whole space with comparison method. The disturbance induced from inhomogeneous resistivity around the MN pole is discussed; and the method to identify and eliminate this disturbance is studied. Then the damped least squares inversion method is designed on the base of the analytical formula of the spheriform structures detection in the whole space. With this method, the inversion for multi-group spheriform water-bearing structures models is done. In addition, the anomaly law of the advanced detection of water-bearing structures with other shape is studied; and concept of equivalent sphere is raised. A fast inversion method is designed on the base of the analytical formula of the spheriform structures detection in the whole space. At last, the result of physical model test verifies the feasibility and effectiveness of finite element numerical method and damping least squares inversion method, which lay a foundation for the advanced detection of water-bearing structures with DC resistivity method in practical engineering.

For the stability analysis of three-dimensional slope with known slip surface, based on the upper-bound theory of plasticity, an elastoplastic finite element iteration method for stability factor is suggested. The contact surface is simulated by rectangle element for plane problems or cubic element for dimensional problems with small thickness; and the Mohr-Coulomb associated flow rule criterion for the stresses is adopted. Based on analyzing the associated flow rule in the incremental elastoplastic theory, it is proven that the direction of the tangential stress on the slip surface and the sliding direction of the slope are consistent when the slope reaches ultimate state; so it is accurate that the tangential stress is regarded as the sliding force. In the process of calculation, the shear strength parameter is reduced step by step based on the iterative method, until the slip slope reaches ultimate state. Not only the stability factor can be got by this method rapidly, but also the tangential stress distribution on the slip surface and the deformation law of the slope can be obtained as well, which provides reference for taking reinforcement measures to the slope. At last two typical problems, i.e. ellipsoid slide and wedge slide, and a project example are given to verify its availability and rightness.

Based on the JHC (Johnson-Holmquist-Cook) model of concrete damage evolution, rock damage and failure mechanism of blast-hole near-field in different air-decking charge structures is studied by numerical simulation. The influence of air-decking ratio and detonating manner on blasting effect is analyzed as well. Result shows different blasting effects can be caused by different air-decking position and ratio, which can be used for different purposes. Air-decking ratio is in inverse proportion to the size of crush-field of blast-hole. With low air-decking ratio, bench blasting can be used; while with high air-decking ratio, re-splitting blasting and smooth blasting is more preferable. For bench blasting, indirect initiation (top-air-decking charge structure) and middle initiation (middle-air-decking charge structure) is more appropriate; the influence of detonating manner on bench blasting is more prominent than on re-splitting blasting and smooth blasting.

An improved ubiquitous-joint model, which can take into account of the transversely isotropic deformation characteristic of the layered rock masses, is established. By using the program’s reserves connection, this new model is implanted into the explicit finite-difference program FLAC3D, and the anisotropy of deformation and strength of the layered rock masses are studied. Then, the deformation and fracture characteristics of the layered rock masses of the Longtan hydropower station underground caverns are studied based on the improved model. The results show that the dominating deformation occurs in the isotropic plane of the rock masses, and the asymmetric deformation of the side wall are controlled by the faults. The main failure of the surrounding rock masses is shear failure which is also controlled by the faults and primarily presents the tensile-shear failure and the compression-shear failure under the moderate and low stress. The joint failure that caused by the excavation process are controlled by the steep dip layered rock mass structure, which primarily presents the shear failure caused by intercalated sliding.

The characteristics of seepage of roadbed’s fissures and the effect of seepage on roadbed engineering are studied. Both the reasons that roadbed produced fissures and the characteristics of roadbed’s fissures are analyzed; the seepage characteristics of soil terrence fissures are studied too. For the instantaneous event model (IEM) and the infinite duration event model(FDEM) of rainfall, the formula of seepage of roadbed with the effect of rainfall is derived. The water content distributation in the subgrade leaded by the seepage of fissures of both in the subgrade and cut is modified, The results of numerical simulation show that the water content of roadbed will be changed to a certain extent with the effect of roadbed’s seepage; and it should be paid much attention in the engineering accordingly.

Penetration rate of TBM is mainly predicted by fully empirical, semi-theoretical, semi-empirical models and artificial intelligence in engineering. The parameters used in these models are all deterministic and their uncertainties are neglected, so it leads to inaccuracy of the results. Because of this, a Monte Carlo-BP network model is proposed and the uncertainty of some important parameters are considered in this model. The importance of each parameter is calculated by rough set. Due to the limit of sample data, stepped empirical distributed function is used when Monte Carlo is used to produce random numbers. If sample data are not from the same type TBM, the TBM performance parameters should be considered and the importance of parameters should be calculated again. It is proved that the calculated results of proposed model are in accordance with measured results.

The scattering of P waves by a local nonhomogeneous body of arbitrary shape in a layered half-space is modeled using the indirect boundary element method (IBEM) in the frequency domain. The free-field responses are calculated by using the exact dynamic-stiffness matrix of soil layers to determine the displacements and stresses at the interface of the local nonhomogeneous body; and fictitious distributed loads are then applied at the interface in the free field to calculate the Green’s functions for displacements and stresses. The amplitudes of the fictitious distributed loads are determined from the boundary conditions; and the displacements arising from the waves in the free field and from the fictitious distributed loads are summed to obtain the solution. The effects of width and thickness of the local nonhomogeneous body, and the incident angle and frequency on the surface displacements for P waves are studied. These results are compared with that of one-dimensional model. The local nonhomogeneous body has important influence on the scattering of P waves. The influence of local nonhomogeneous body on determination of design earthquake ground motion parameters should be considered reasonably in evaluation of seismic safety for engineering site.

Based on investigating the construction situation of concrete faced rockfill dams(CFRDs), the weakness to simulate the slab construction in FE analysis is pointed out; then the correct definition to pave upstream slope is given. An algorithm for slope paving is presented for 2D/3D FE analysis. The algorithm will play an important role in the simulation of mechanical characteristics between the concrete slab and special cushion zone by using the contact model with friction; and the paving-slope algorithm in ABAQUS by using User Subroutine are proposed and implemented. The examples show that the algorithm for slope paving is simple and valid; it will speed up the convergence for solving contact problems; and it can keep finite element mesh well. The results of the stress-displacement in slab and in dam will become more precise. The algorithm can provide a foundation for the investigation if there will be a gap between the slab and special cushion zone or not when the creep in rockfill material is considered.

The height of the concrete faced rockfill dam (CFRD) of Shuibuya hydropower Station is up to 233 m. The properties of the cushion material are very important for the dam deformation & seepage control. Based on the CFRD construction experiences of the world and the test results at feasibility study of Shuibuya Projects, the function of the cushion layer and the design requirements for its materials are discussed. The permeability and seepage deformation characteristics are pivotal among the design requirements. A series of seepage deformation tests on cushion material performed further at construction design stage are expounded. Permeability, critical and failure hydraulic gradient from horizontal model tests are higher than those from corresponding vertical model tests. Horizontal models simulate better the situation of filling and flow pattern in the cushion layer of the real dam. So the results from horizontal models approach more closely to the properties of the cushion layer. With different gradation curves and density values, the permeability varies in a large range. It is mainly between 10-4-10-2cm/s as required, but the coarser materials with low density would exceed the upper permeability limit. The critical and failure gradient does not changes so regularly as gradation curve and density varies. The interior structure of the material would not be stable. The results emphasize further the importance to control the material gradation and filling density. The seepage stability of the cushion layer must be supported by the transition zone with efficient filtering and protection.

According to Numerov’s theoretical solution, the additional length of seepage path of upstream slope of dams and levees on impervious strata is direct propotional to the upstream water depth H, and inverse propotional to the ratio of the seepage quantity of unit width to the permeability coefficient q/k. On the basis of the equation of phreatic line in Numerov’s theoretical solution, coefficients and are calculated by Simpson’s numerical integration method. For confined flow, the corresponding additional length of slope is directly propotional to the thickness T of permeable strata only; and not relate to H and q/k, i.e. . In accordence with the calculating results, . Why the additional length is inversely propotional to q/k, the reason is explained. The method of calculating has extended to the condition that under the slope an overburden is located. All the formulae of additional length are analysed and compared each other. Finally, an example is given to relate the process of calculating the seepage flow of dams with the additional length .

The course of seepage deformation in embankment foundation is actually the course of “water in soil” turning into “soil in water”. It is not very appropriate for conventional seepage theory to conduct the analysis with just increasing the permeability coefficient of the piping channel. A more suitable method proposed here is using the pipe flow theory in the piping channel; and conventional seepage theory in the rest. On their common boundary of the two computational domains they share the same water head and equal value of discharge rate with opposite sign. Element free Galerkin method (EFG) is employed to facilitate the computational changeable boundary between the two domains. Example shows this coupling of seepage and pipe flow can simulate the complex process such as the piping channel bypassing the cutoff wall and advancing upstream.

The clogging factors of mat base of inside and outside liner of the Yellow River-crossing tunnel include pressure, concrete slump, concrete pouring time and mixing measures. Model expeiments are used to evaluating the influence of these factors. The results show that the vertical pressure reduces the seepage coefficient to a certain level. The slump and mixing time may make a certain degree of reducements without big difference. Different mixing measures reduce he seepage coefficient to 1or 2 magnitudes down. In order to avoid these influences, a 3-D geotextile net is recommended as the material of mat base of inside and outside liner of the Yellow River-crossing tunnel.

Hydraulic conductivity is indispensable for groundwater modeling in fractured rock masses while deformation modulus is required for stability evaluation of rock masses. Unfortunately, the variations in hydraulic conductivity and deformation modulus with depth are usually ignored, which would lead to inaccurate results. The feasibility of estimating hydraulic conductivity and deformation modulus using the rock quality design (RQD) at different depths is discussed. In a granite rock mass, it is found out that the mean RQD would increase with depth, while the mean hydraulic conductivity would decrease with depth. Moreover, there is a high correlation between mean RQD and mean hydraulic conductivity. Therefore, it is practical to estimate depth-dependent hydraulic conductivity using RQD data. Furthermore, based on empirical equations, the deformation modulus is successfully estimated using the variations in mean RQD with depth.

The surface soil permeability is tested on the soil samples taken from a region of 200 m by 100 m in a typical stretch of Yaodi Dyke of Hanjiang River. Taking the test results as samples, both random and structural spatial properties of soil permeability are analyzed. It is shown that the permeability of sandy soil in the research area is horizontally isotropic; and the exponential model can describe its spatial correlation structure. Turning bands method is adopted to simulate the permeability random field. The basic statistics and spatial structure of the simulated results are checked. It is shown that the generated realizations of the turning bands method preserve the statistical properties of the original random field; and the turning bands method has acceptable convergence.

The seepage flow is one of the critical issues to the stability of landslide. In recent years, how to correctly reflect the effect of seepage force during the stability analysis of loose accumulational landslides has been the focus of geotechnical engineering. Certain Chinese design codes, which considered the effect of seepage flow, have a prominent problem in redundant computation of seepage force and pore water pressure. Based on the theory of hydromechanics, this paper has proved that the resultant force of seepage force and buoyant force is identical to that of ambient pore water pressure. Not only in steady seepage, but also unsteady seepage, the equivalent principle is tenable. As a special case, the proof process of this equivalent principle for loose accumulational landslide in seepage flow condition is suggested. This paper also proves the superiority of the calculation method using seepage force in a simple flow net condition, as well as the necessity of concerning the effect of seepage force and buoyant force in the calculation of the sliding force for landslides. This paper has revised the methods of stability analysis and sliding force calculation for the design codes. Furthermore, the impact of the deviation effect for certain design codes have been qualitative and quantitative evaluated. Finally, an engineering example illustrates that the result of the design thrust and the construction cost of landslide support project, which are given by unrevised design codes, is 5 % -or-less higher than necessary.

In order to investigate the influences of design, construction and operation conditions of relief well on its clogging, a series of seepage tests have been carried out for studying the related materials as well as their combinations. Besides conventional seepage tests, a special radial model test device has been developed to simulate site circumstance of groundwater movement around relief well. The possible varieties of foundation sand, gravel filter, plastic screen, removable polyurethane foam filter and inner tube are taken into account respectively or as a whole drainage system. Through the comprehensive analysis of tests both in laboratory and in situ, the mechanical clogging mechanism and its control are summarized. In view of actual hydrodynamic circumstances and operation conditions in Yangtze River dikes, an optimized filter system design for relief wells has been proposed.

The experiment of wave flume model is adopted to study the action of pore water pressure under the sandy seabed induced by both regular and irregular waves. The influences of water depth, wave height and wave period on the pore water pressure are mainly discussed. The rule of pore water pressure responses is achieved. It is shown that the wave period and wave height remain unchanged, the water pore pressure caused by wave decreases as the water depth increases. When the water depth and wave height remain stable, the water pore pressure grows as the wave period lengthens. Under the condition of fixed water depth and wave period, the augmentation of wave height leads to the increase of the water pore pressure.

It is difficult to obtain the seepage field parameters of dam foundation while the seepage characteristic of high arch dam foundation is studied during operation period. According to Ertan arch dam foundation, a back analysis model is proposed with the genetic algorithm theory and the technology of three-dimensional finite elements for solving the seepage field. The typical positions of osmometers are used as the actual measurement points, the permeability coefficient of dam foundation seepage field is retrieved in special time, meanwhile, the parameters are testified by the seepage field at different time points. The analytical results show that the inversion results of the seepage field are reasonable; and the results can be used to study the real behavior of seepage field of high arch dam foundation during operation period.

The hydraulic and mechanical properties of rock fractures are of considerable interest in several areas of rock engineering, such as radioactive waste, dam foundations, excavation of tunnels and caverns, geothermal energy plants, oil and gas production. Coupled shear-flow test is an effective measure researching the Hydro-Mechanical (HM) coupling character of rock joint. The experimental device was designed for a fracture to be subjected to normal loading and shear displacement by placing the fracture in a shear box. In order to retain a water seal between the lower and upper shear boxes and less friction resistance during shear, special rubber loop and silica sealant are installed between the lower and upper shear boxes. Through nice design, the shear box could keep favorably sealed under higher seepage pressure. In the meantime, a whole number-controlled computer control system has been developed to automatically accommodate the change in stress and displacement under CNL, CNV and CNS boundary conditions and also described to present performance of instrument control, data acquisition and storage operations of the novel apparatus. A series of tests using the artificially prepared joint specimens is conducted on the apparatus under different boundary conditions. The results of the conducted shear-fluid tests validate its reliability and practicability.