Based on the analysis of fractural mechanism of brittle materials, the concept of the radial plane maximum stress (RPMS) is presented. Under plane-strain condition, the stress distribution near the crack-tip is analyzed for mixed loading mode with different composite stress ratios in which the effect of Poisson’s ratio is taken into account. Afterwards, the maximum Mises stress on the radial plane is taken as the key factor which governs the fracture behavior and crack initiation and the mixed fracture criterion on the basis of the radial plane maximum stress is proposed to consider the effect of three-dimensional stresses. As a result, the expression of crack initiation orientation is given. The results computed by the proposed method are compared with solution obtained by the conventional fracture theory and experimental data. It is shown that the proposed solution can give a good understanding of fractural mechanism and behavior of brittle materials under combined loading pattern.

A concrete diaphragm wall is always used to prevent the seepage through the deep alluvium deposit for conerete face rockfill dam built on it. The tensile stress distributed the zones near by the both riversides and the top zone of the concrete diaphragm wall are usually big and sometimes are even larger than the tensile strength of concrete, that usually leads to cracking of diaphragm wall which decreases the safety of diaphragm wall and dam. In order to solve this complex problem, a new idea— arc type diaphragm wall is suggested. Comparison between the stress-deformation behavior of arc type diaphragm wall and that of plane type diaphragm wall has been made by using three-dimensional finite element method numerical analysis. The calculation result shows that the tensile stress of arc type diaphragm wall is much less than that of plane type diaphragm wall although the compression stress of arc type diaphragm wall is a little larger. Since the tensile strength of concrete is only less than 10 percent of compression strength, tensile stress is the main control factor of diaphragm wall. So the arc type diaphragm wall is probably reasonable especially for concrete face rockfill dam built on a deep alluvium deposit.

By introducing scalar potential functions, Helmholtz decomposition theorem and Fourier transform technique, the three dimensional transmission of vibrations over the surface of the ground, due to a harmonic rectangular moving load, is investigated theoretically; and it is accordant with the practice. The material of subgrade, obeying Biot’s dynamic poroelastic theory, is idealized as a uniform, fully saturated poroelastic layer of soil stratum. The analytical solutions of stress, displacement and pore pressure are obtained in the form of integral. Numerical results are obtained by inversing the Fourier transform and are used to analyze the influence of the moving load velocity on the vertical displacement on the surface of the ground and the distribution of pore pressure along the arbitrary depth of ground. It is shown that the displacement amplitude increases with the increasing of the load velocity and there is great difference for the distribution of the pore pressure along the depth of the foundation at different point of rectangular moving load.

By using wave function expansion method, a series solution of surface motion amplification due to underground group cavities in half-space for incident plane SH waves was given,; and effects of parameters such as the frequency of the incident waves, the angle of incident waves, the distance between the two cavities, etc. on the surface motion amplification were analyzed. The results show that the underground group cavities significantly amplify the surface motion: the surface motion for twin cavities can be 1.6 times of that for single cavity, andor 3.5 times of that for no cavity. It is suggested that the effect of subways on ground motion should be considered when the subways are planned and designed.

Based on the stress-strain relation of structural loess, the structural parameter with the shear strain, water content and consolidation pressure is explored and described by a mathematical formula. The formula can give the curve between the structural parameter and axial strain with a peak-value in which the coefficients are also determined by the experiment results. Further the structural parameter is applied to analyze stress-strain behaviors; and a structural stress-strain relation is set up. The rationality of structural parameter and its stress-strain relation is verified by comparing the calculating curves by the formulas with the testing curves.

Decomposition of organic matter is an important and complex process in deformation analysis of wastes. Tests of decomposition and settlement of waste column had been performed under the conditions of nearly unchanged temperature and moisture, zero pressure and bearing water content. During decomposition volume of leach was measured. The behavior of decomposition and its rate was analyzed. Decomposition law including three conclusions was identified. Mathematical expression of the decomposition quantity with time and the method to determine the three parameters in the expression were presented. Calculation result of the decomposition is consistent with the test. The waste column test was simulated by using the decomposition test result. The settlement of the waste column was calculated by considering secondary compression and decomposition separately. It is found that the calculated settlement is in good agreement with the waste column test; and the settlement from decomposition is an more important factor than the secondary compression.

Based on the twin shear unified strength theory, and using vertical displacements equality, lateral deformation compatibility and continuum between gravel column and surrounding column soil in the composite foundation, stress-strain state of the composite foundation with gravel columns is analyzed by the elastoplastic theory under vertical load. Ascertaining methods for weight coefficient b are established. Influences of weight coefficient b on bearing and deformation character of the composite foundation are discussed. A series of analytical formulae, for example, between load exerted on the composite foundation or share load of gravel column or compression value of the reinforcement area and plastic area radius of surrounding pile soil, are drived. Design idea of double control on bearing capacity and settlement is suggested for the composite foundation with gravel columns. To make sure feasibility proposed method, results of model tests are compared with those of calculation; the comparison indicates that the proposed method has guidance significance for the composite foundation design with gravel columns.

Based on the principle of semi-analytical method and the assumption of transversely isotropic material of composite foundation, a semi-analytical element method has been presented to calculate the settlement of composite foundation. Vertical displacement is discretized as polynomial expressions, and horizontal displacements are modeled by means of displacement functions in two directions to simulate infinite field. For one direction discrete and two directions analytical, this method can simplify 3-dimensional computation of displacements into one dimension, it can save computation time dramatically for its quick convergence. Furthermore it can simulate infinite soil field and acquire precise results for avoiding introduce redundant boundary condition compared with FEM, An example has been calculated with semi-analytical element method by changing substitution ratio, improved depth and modulus ratio of pile to soil of composite foundation. The results indicate that the substitution ratio and the modulus ratio of pile to soil have little effect on reducing displacement; while increasing improved depth can affect settlement obviously. So it is reasonable to increase improved depth to reduce composite foundation settlement under the circumstance that the optimum design is controlled by ground settlement.

Aiming at the random non-homogeneous media thermoelastic axisymmetric problem, and under the random Weibull and exponential distributions, a new method to solving the random probability distribution using the expression of continuous function is provided; and the analytical solutions are attained in the plane strain and plane stress model. The numerical experiment, discussing the change rule of thermal stress random distribution parameter m, indicates that there is distinct difference between non-homogeneous media themal stress and homogeneous media thermal stress in Weibull, but little difference in exponential distribution.

The stability of the jointed rock slopes is analyzed by means of the universal distinct element code(UDEC) in which the strength reduction method is included. In the analysis, the cohesion and internal friction angle of the rock and joint plane are reduced by a reduction factor. The reduction factor becomes the factor of safety(FOS) when the slope can not reach equilibrium by decreasing the strength parameters. In addition, the slip surface and failure mode of the slope can be determined by the velocity vector of the blocks. Numerical results presented in the paper indicate that the strength reduction method combined with UDEC is reliable and powerful alternative against traditional limited equilibrium method and that it will be a new approach to obtaining the slip surface and FOS of jointed rock slope.

Based on the numerical modeling constitutive law of rock and soil, the stress-strain relations of expansive soil of the Linhuaigang Dam in Anhui Province with different water content were established; and the three dimensional surface of stress-strain relation in the whole stress field (p, q) were drawn through visualization. By comparison, it is found that the effect of different water content on the constitutive relation of expansive soil is obvious. The theory of plastic potential is not used in this paper, in the numerical modeling not only the difficult of seeking analytical expression of plastic potential is overcome, but also the initial condition, such as water content can be chosen freely. Therefore, the deformation of expansive soil could be really described by using the constitutive model provided by the numerical modeling.

Permeable experiments on complete stress-strain course of limestone and sandstone were carried out in servo-controlled testing machine. The relation between axial strain and permeability of rock specimen during the course of deformation and failure is made by a detailed investigation. The effect law of lateral strain on the permeability of rock specimen is analyzed. At the same time, the variance relation of permeable pressure head with time before and after the deformation and failure of rock specimen is also discussed. The result shows that the permeability of rock specimen is closely related with the stress state; and the peak value of permeability comes out nearby the peak value of stress-strain, which has a close relation with the property of rock material. There are the same variance tendency between permeability-lateral strain curve and permeability-axial strain curve. However, the lateral deformation of rock can reflect more sensitively the evolution law of permeability than the axial deformation. The permeable pressure head complies with negative exponential relation with time during the course of deformation and failure of rock specimen. In the end, the permeable mechanism is made with a detailed discussion during the course of deformation and failure of rock specimen.

The single borehole multiple anchor cables have been widely used in the fields such as slope protection and landslide remedial projects in these years. Based on the in-situ pull-out test of anchor cables in a landslide, this paper pays attention to how to test both the stress of anchorage segments and the loss of prestressing force. Accordingly, a new method is put forward and introduced in detail; the basic principle of the method is mainly accomplished by testing the stress of individual steel strands of anchor cables, whose feasibility is demonstrated in the engineering practice. Finally, the forces of individual steel strands which are located in different position along the borehole are successfully tested; the results provide direct proofs for the anchor cables design and construction in the condition of in-situ engineering geology, and have practical engineering applicative values.

A new harmony search method is presented in the location of non-circular slip surface of soil slopes. It differs from the basic harmony search method in the flowing two aspects. Firstly, a kind of two-point search strategy rather than random search strategy is adopted to take full advantage of the accumulated information in the harmony memory. Secondly, a correcting strategy is substituted for the penalty strategy to render the inadmissible slip surfaces to be acceptable. The stability analyses of two soil slopes are evaluated by the new harmony search method. Comparisons between the existed results and the results from the new harmony search method indicate that the proposed strategies are valid and rational.

The pile-soil stress ratio is an important parameter depicting the work state of composite foundation. Lots of theoretical researches were carried out in recent years; but they were usually deduced on the condition of laying sand cushion. Under the load from embankment, the capping plate is set at the top of grouting pile. Based on this especial condition, a proper theoretical model is brought forward. Furthermore, limit equilibrium theory and elastic theory are adopted to deduce the formula of pile-soil stress ratio of grouting gravel pile composite foundation under embankment load; and it is validated by project actual measurement and instruct the design of grouting gravel pile composite foundation.

In layerwise summation method, e-lgp is superior to av and e-p method; the reason is that it can be in consideration of the influence of soil stress history. But it is a pity that e-lgp method is rarely used in practical engineering because the related parameters are difficult to be determined. One thought to consider the influences of soil stress history in av and e-p method is given when lack of high pressure consolidation test data; and the corresponding concept of correction coefficient Ms is put forward. Besides, the approximate spans of Ms for different status soils are analyzed. Then, the calculated formula is developed. It is found that the results of av and e-p methods which are rectified with the correction coefficient are more accuracy and more closed to the e-lgp method. This method can be reference for engineers.

Based on the heterogeneous characteristics of rock at mesoscopic level, the thermal-stress-damage coupled action during the failure process of rock subjected to thermal stress is described with elastic damage mechanics and thermal-elastic theory. A mesoscopic thermal-mechanical-damage coupling model, implemented in rock failure process system, RFPA2D, is proposed. The RFPA2D is used to simulate the stress distribution and failure patterns in homogeneous and heterogeneous specimen subjected to thermal loading. The numerical results coincide well with the corresponding mathematic resolution and experimental results; so it is proved that the proposed model as well as the numerical system (RFPA2D) are reasonable and effective in investigating the failure of heterogeneous materials under thermal stress.

In the conventional allowable stress design approach for driven piles, the safety factor is highly dependent on the accuracy of pile bearing capacity determination methods. However, the empirical safety factors may not be on a reliability basis. This paper proposes a procedure to investigate the effect of pile bearing capacity determination methods on the safety factors of driven piles, and provides a theoretical basis to verify and support existing empirical safety factor used to account for the effect of pile capacity determination methods. The procedure is formalized in the Bayesian framework. In particular, how the safety factor can be reduced based on on-site dynamic pile tests are addressed. Seven design methods for driven piles are investigated to illustrate the proposed procedure. The results indicate that the required safety factors obtained from this study are consistent with the existing empirical values. The required safety factors can be reduced considerably using more accurate pile capacity determination methods, which depends on design methods, pile capacity determination methods, and the level of pile capacity verification implemented. After sufficient pile capacity determination, the required safety factors for different design methods are not sensitive to the accuracy of the individual design methods.

Gravel-pile composite foundation has been applied widely to reinforce actual engineering; and the characteristics of its stress and strain have been studied deeply. The consolidation of the reinforced foundation has been researched to a certain extent, but the known analytic formulas are mostly complicated, so they are difficult to be used in engineering. Radial soil around pile is considered as a whole element in this paper, the effect of the coating caused by construction is not necessary to be considered. According to the theory of equivalent of seepage discharge to volume change, a simplified formula for consolidation of double-layered ground reinforced by gravel-piles is derived from the concept of average excess pore water pressure. This method can solve the average excess pore water pressure and average percent consolidation of the gravel pile and its surrounding soil, and the average percent consolidation of the entire reinforced foundation can be also obtained. This formula is laconic and has the advantage of application.

Soil pressure on the shield segment is one of key factors which affect the results of segment design. Because of segment grouting, it’s very difficult to measure soil pressure; and some measured data is unreliable. In the view of the above problems, the back analysis method of soil pressure on shield lining segment has been found. On the basis of comparatively easily measured internal force of segment and optimization method, soil pressure on the lining segment has been obtained. According to the results, soil pressure on the shallow tunnel is different from that on deep tunnel; and it’s different from the hypothetical distribution of design soil pressure.

Cast-in-place tubular pile technology is introduced. Based on the in-situ test data, the engineering property of single pile and composite foundation are specially analyzed. It is found that the cast-in-place tubular pile gives prominence to its vertical bearing capacity. At the same time, the pile can have large diameter which induced thin-shell effect that enable the pile with high horizontal resistance. Finally, the tubular composite pile foundation test indicates that it not only well meet engineering requirement in settlement and bearing capacity, but also has the advantages of good quality, low cost etc..

Based on laboratory dynamic triaxial tests, the dynamic properties of EPS （expanded polystyrene）block under various confining pressures and stress levels are studied. Tests show the dynamic stress-strain relationship of EPS is much different from that of soil. Under low confining pressure and s＜0.5, - relation is linear while it changes to hyperbolic-type under higher confining pressure. The characteristics of and secant dynamic shear modulus Gsec of EPS are also distinct. In the first load cycle, reaches a high value, and increases slowly to be almost constant. As to Gsec, it initially decreases, then increases to be stable. According to test results, 40 kPa is suggested as the optimal confining pressure in application.

So far, the methods of dynamic parameters include method of frequency and method of frequency-muzzle velocity, which could apply to testing the bearing capacity of soil foundations and the pile foundations. Based on the method of frequency, a meliorative method of dynamic parameters is put forward. First, adopting different area of boards and using linear regression, the multiplying value of Cz (the rigidity coefficient of soil foundation) and A (the area of board)could be got. Then, the rigidity coefficient of soil foundation as the area of board of 20 m2 is got by computation. Finally, through correlative criterion, the value of bearing capacity could be got.

Aimed at the characteristic of discreteness of the coal sample, pulse-penetrating method is used to measure the acoustic wave speed and the strength test is finished on MTS815.03 servo-controlled rock mechanical test system. The relationship between acoustic wave velocity and mechanical parameters is obtained through regression analysis. This provides one technical method which can eliminate blind test to a great extent because of the discreteness of rock strength. On this basis, the triaxial compressive test of coal sample is done using MTS815 servo-controlled rock mechanical test system. The results indicate that it is different from the high strength rock such as granite because of the existence of micro holes and cracks in coal. Under the confining pressure, the holes and cracks are compressed and closed; and the elastic modulus increases with the increasing of confining pressure, but it is not linear relative. Additionally, the conclusion that the triaxial strength and residual strength of coal increase with the confining pressure can be used to guide the research on the bolting mechanism of those roadways which are drived in cracked coal mass.

On the base of abundant triaxial experiments and nanometer SiO2-x powder first stabilized as agent of cement-stabilized soil（NCS）, a general three-dimensional failure criterion for nanometer SiO2-x and cement-stabilized soils（NCS）is proposed; and it includes five parameters. From the result of this comparison, it can be seen that the criterion may be applied throughout the stress range from tensile stresses to high compressive stresses.

Results obtained from CT scanning test of red sandstone under the condition of frost and thaw, different damage extension of four different classical initial water-saturated red sandstones was studied under the condition of frost and thaw. All results especially depended on CT-means and CT-figures in different interested zone in CT scanning plane. The research shows that the degree of damaged extension is determined by initial water-saturated state for the same initial damaged rocks.

The larger spatial variability of soil properties is due to the difference of soil properties for different soils. So it is necessary to establish a model to show the actual mechanism of the variability. The multi-indicator geology statistical model based on the Markov field is introduced. And the analytical expression for the statistics of the soil parameters is derived and the impact of multi-soil on K-L (Karhunen-Loeve) expansion is analyzed. Then the stochastic seepage simulation is conducted with spectral method. The results show the correctness of Gaussian stationary field-Markov field and the validity of spectral model.

P-y curves method is one kind of nonlinear subgrade-reaction methods; it considers the nonlinear character, layer character, different kinds, and load kinds of ground soil. Starting from the concept of spring joint in Newmark method, the contact nonlinear finite element model is established for the pile-soil system. By the formula of P-Y curves of compound foundation reaction method, the formulas of elastic coefficients of nonlinear springs are deduced. The corresponding programs are organized based on Marc. Based on 1st Taylor stochastic finite element concept, the sensitivities of the displacement on the soil level for soil parameters are computed. By comparing the data of testing pile, the numerical results indicate the rationality and the feasibility of the presented method.

The stresses of lime-soil compacted pile are analyzed based on the unified strength theory. The stress of the soil around the hole in the compaction and hole formation process of lime-soil compacted pile is discussed. The elastic solution and elastic limit load are obtained during the hole formation for lime-soil compacted pile; and the relationship between the pressure on the hole wall and the plastic radius is also obtained. This solution considered the intermediate principal stress effect and the strength difference effect in tension and compression. Mohr-Coulomb solution is a special example of this solution obtained. The obtained results have practical value for comprehensively studying the function of the lime-soil compacted piles.

In order to clearly define the underground rock mass structure, such as discontinuous construction face, including fracture, joint, layer and fault, on the platform of Visual Basic 6.0, the second development towards GIS function group parts-MapObjects, on the base of OCX technique was made; and boundary denotation of three-dimension data structure and three-dimension grid structure was harmoniously connected. Three-dimension grid structure as main, we attempt to denote real underground construction in less data. Improved method of three-dimension grip structure realize enlargement, reduction , browse to geological map layer in local plane and formation of underground section as well as multi-format input for analysis of stabilization. By successful utilization of the system, geological model of significant reservoir section in two sides of Zipingpu Key Water-control Project in Sichuan Province was created, which effectively guides landslide disposal and project of changing line in the district; moreover, successful reservation of reservoir is guaranteed.

Based on FEM- load transfer hybric method which was proposed by the authors, base bearing characters of overlength single pile was studied using popular FEM software ABAQUS. The effects of pile length, pile diameter and soil characters on base bearing characters were studied in deal. Longer the pile is, higher the base bearing capacity is; bigger the pile diameter is, lower base bearing capacity unit area is; Young’s modulus and internal friction angle have great effect on base bearing capacity, but cohesive strength have little effect on it. Moreover, how the shaft resistance affect base bearing characters was introduced. Shaft resistance increases the base bearing capacity.

Unifying the extension theory and evaluation methods of tunnel surrounding rock masses stability, the surrounding rock masses stability types are determined synthetically by selecting some synthetical characteristic parameters that can reflect the stability of surrounding rock masses on the basis of the geological documentation of muck and the boring parameters of the tunnel boring machine (TBM) during the tunnel construction of double-shield TBM. The concept of membership degree and one kind of method that can determinate the selected patameters weight introducted, the extension evaluation method of tunnel surrounding rock masses stability classification is set up based on the operation of matter-element theory，extension set and dependent function. The surrounding rock masses stability classification of two sections of tunnels is carried on by applying the method based on the extension theory during the construction of double-shield TBM in the Yellow River Diversion Project of Shanxi province; and the rational result is in conformity with the reality.

The research outcomes at home and abroad about dynamic pore water pressure developing models are firstly reviewed; then the dynamic triaxial tests which used saturated core cohesive soil and dam foundation gravel of a rockfill dam were performed; and Gu Gan-chen models of these two materials were put forward. And dynamic pore water pressure developing rules of gravel were analyzed in detail. The results of dynamic intensity tests show that with the increasing of vibration times and vibration intensity, dynamic pore water pressure increases. While with the increasing of consolidated stress ratio, dynamic pore water pressure decreases. For cohesive soil, in spite of equivalent-pressure or unequivalent-pressure consolidation, liquefaction phenomenon didn’t appear. For gravel, final dynamic pore water pressure could all reach confining pressure under equivalent-pressure consolidation, and when consolidated stress ratio Kc exceeds or equals to 1.5, whether samples could liquefy lied on that dynamic stress σd could make samples stretch or not. And the effects of consolidated stress ratio Kc on various soils were different.

At first, based on the principle of least squares, the back-analysis method of the average shearing strength of the slip zone soils with multi-sections is discussed. Secondly, a back- analysis method of considering different slip segments with different shearing strength indexes is brought forward according to the difference of the matter components or whether eroded by groundwater in landslides. A practical example is introduced by using the two methods. Meanwhile, the landslide thrusts of a section calculated by utilizing the two kinds of shearing strength indexes are compared and analyzed. The results show that the calculation precision of the former is still comparatively reliable in landslide control and design when landslides are simple and in small scale. However the latter will be more reasonable and reliable in control and design of large or medium scale landslides as well as complicated ones.

To investigate the effect of seismic history on the liquefaction resistance of sand, two groups of centrifuge dynamic tests have been performed on models of saturated sand deposit. The response of excess pore pressure as well as deformation of soil column were monitored and recorded during testing. It was found that small earthquake could bring beneficial effect on the sand resistance to liquefaction by strengthening interlocking between particles and forming a more stable structures. On the other hand, re-liquefaction may occur on a once liquefied site when it is subjected to an earthquake with magnitude less than that causes the first liquefaction, due to the unstable structure formed in the re-sedimentation process. The experimental finding indicates the impact of seismic history on the liquefaction characteristics of sand, as well as the significance of study on microstructure of sand.

As an efficient way to enhance the anchorage performance, anchorage underreaming is widely used in civil engineering. Several underreaming methods have been introduced. A new type of grouting-open soil anchorage with flukes is also presented. This anchor doesn’t need some specific tools to expand the bottom. Grouting pressure is efficiently utilized to expand the bottom and accomplish the grouting procedure consecutively. It has the advantage of convenient operation and high performance in practical use. Through the expansion experiment, it proves that it’s possible to stretch the flukes and expand the bottom with the use of grouting pressure in soft clay zone such as Shanghai.

There are apparent spatial connections between the raw data and drawings of the reconnaissance survey, which may be useful to store, manage, query and deal with these data and drawings. For this reason, computer-technology-based survey information system should play a great role in not only the data acquisition, map drawing, but also in the data management of documents, multimedia, maps and other digital data, according to the inherent relation between them. This article gives illustration of the relations and sets up a practical model on the maps drawing, storing and management base on GIS (geographical information system) and RDB (relational database). The application examples in the Three Gorge reservoir are shown; and it is proved that the model can meet demands of both the operation survey entities and the management departments.

For the soil around soil-cement columns, mechanical properties will change after column installation. The strength and modulus changes of the surrounding Ariake marine clays during and after deep mixing using two different installation methods, jet grouting method (JGM) and cement-slurry mixing (CSM) method, are presented. Field construction tests are conducted on Ariake marine clay to investigate the mechanical changes. The Ariake clay is a structured clay and sensitive to disturbance. The investigated results from field and laboratory test indicate that the degrees of disturbance (DOD) to the clays around the soil-cement columns depend on the method of mixing. For the aforementioned two installation methods, the average strength ratio of the surrounding sensitive clay is for JGM method of 0.42 and for CSM method of 0.68. Thirty days after mixing, about 44 % original strength is regained for JGM method and for CSM method, it is 40 %. The recovery of the surrounding soil modulus is slower than that of the strength.

Seepage and seepage-pressure are important factors which influence the stability of dam foundation. Based on some measured data of gravity dam of Shiban Hydropower Station, taking into account the influence of water, temperature and time on the seepage and seepage-pressure of dam foundation, a statistical regression analysis model for seepage and seepage-pressure has been established by the stepwise regression analysis method. Computing results indicate that the statistical regression data for seepage and seepage-pressure are accordant with measured data; the statistical double correlation coefficients between them are larger; and the estimation standard errors between them are smaller. The statistical regression analysis model efficiently reflects the changing rule and developing trend of seepage and seepage-pressure of dam foundation. This model has provided efficient analysis means for evaluating safety properties of the gravity dam.

The permeability coefficient of the unsaturated soil can be got from the seepage test with the triaxial test instrument for unsaturated soils controlled by stress and strain in the laboratory. Based on this, under the environment of rain and flood we analyze the variability of the seepage field of unsaturated levee slopes in the lower reaches of Yellow River with the finite element method. From this we get the extent influenced by rain or flood infiltration in front of the saturation curve. The extent is about 2 meters. We analyze the co-operated influence of rain and flood infiltration and get that whether the flood infiltration can easily change the seepage field or not is determined by the rainfall intensity and rainfall duration.

Baota landslides are one of the four landslides whose volume is more than 1×108 m3 in Three Gorges reservoir area. Baota landslides are in the sandstone and mudstone alternate layers of Jurassic Penglaizhen formation. The clay gouged intercalation, existing much in Baota landslides, is one of the most important reasons of Baota landslides happened. On the basis of geology analysis, using X-ray diffraction (XRD) test, scanning electron microscopy and energy dispersive X-ray test(SEM-EDX), physical chemistry test and underground water quality analysis test, the composition, the structure, the characters of clay gouged intercalation and its original rock are analyzed contrastively. The reasons of clay gouged intercalation establishment are concluded: the layer structure of sandstone and mudstone alternate layer is the basic reason; the tectonic stress or gravity is the necessary condition; and the long action of underground water is the main reason. The water-rock interaction of clay gouged intercalation establishment is studied on the basis of above conclusion. The study results indicate that hydration, ion exchange, corrosion between underground water and mudstone are promoting each other. These water-rock interactions change the structure, composition and characters of mudstone; then induce the mudstone sludging thoroughly. At last, mudstone is changed into the clay gouged intercalation. Thereby, the establishment mechanism of clay gouged intercalation in Baota landslides is interpreted.

Based on the stochastic finite element method (SFEM), the probability analysis has been done on the seepage failure of embankments. The influences of the variation of the coefficient of permeability, the change of the flood level and the geometry of the embankment on the failure probability of seepage are studied. The failure probability increases with the increasing of the variation of the coefficient of permeability. When the coefficient of variation increases to a certain value, the failure probability would cease to increase and then descend slightly. The failure probability increases with the increasing of the flood level. It also increases with the increasing of the angle of the embankment slope. Particularly, when the slope ratio is greater than 1:2.5 the failure probability increases rapidly.

Sub-river Shield Tunnel for Chongqing Urban Drainage Works is one of the state highlight environmental protection projects and the greatest shield tunnel in the Yangtze River. This sub-river tunnel is constructed with slurry shield machine. Because the main agent structure will bear 0.6 MPa high hydraulic pressure during both construction and operation period, it is significant to study the effects of high hydraulic pressure on shield tunnel. Based on topographic, geological and hydrological conditions in tunnel site, in-situ tracking test for hydraulic pressure on main agent structure of shield tunnel were carried out in construction period to acquire the distribution regularities of external water pressure and provide important parameters for tunnelling control. Thus, profitable references are provided for similar project construction.

In order to explore the processing method of foundation stabilization. Large-scale field tests on a soft ground composed of a 2-5 m thick mucky soil were conducted in Jiangsu province, involving five ground improvement methods, on a soft ground composed of a 2-5 m thick mucky soil. These tests included packed-drain with explosion, plastic-drain with surcharge, cement-jet-pilling at different spacing, and sand mat. During 14 months’ in situ testing, the deformation behavior of the improved soft ground was investigated, and by comparing with the reinforcement scheme, the settlement after completion and economical efficiency of project are also studied. These results are expected to provide the reference value for the selecting of soft ground treatment methods and design parameters of high-speed rails.