The thermal conductivity of soils is a key parameter in analysis of soil heat transfer in geotechnical engineering. This paper intends to develop a generalized thermal conductivity model for unsaturated unfrozen and frozen soils based on the concept of normalized thermal conductivity with respect to dry and saturated states of soils. 328 groups of experimental results for unfrozen and frozen soils, such as gravels, sands, silts, clays and peat, available from the literature were analyzed to develop the general relationship between the normalized thermal conductivity of soils and the degree of saturation. A unique normalized thermal conductivity and degree of saturation (normalized water content) relationship is obtained for the soils with different porosity and different thermal conductivity and water content relationships. There is a strong linear relationship between the inverse of normalized thermal conductivity (1/kr) and the inverse of degree of saturation (1/Sr) with lines passing through the coordinate (1,1). The soil types control the slope of the 1/kr-1/Sr lines. Accordingly, the model integrating the effects of soil types, density (or porosity) and water content (or degree of saturation) on the thermal conductivity of unfrozen and frozen soils is proposed. Method and parameters for calculating the thermal conductivity of dry and unfrozen or frozen saturated soils are given. The model generally predicts the thermal conductivity within an error of 20% for all kinds of (unfrozen and frozen) soils studied.

With the development of geomechanics and the requirements of many large-scale engineering projects, especially in road, water conservancy, etc., the soil and rock aggregate mixture has been regarded as a special type of soil and rock material which attracts more and more attention for geotechnical engineers. Based on three dimensional particle flow code PFC3D, the direct shear test model of soil and rock aggregate mixture is established; and the simulation with different rock contents and different rock properties is carried out. According to the simulation results, the rock content and properties control the shear strength to a large extent. The friction angle of hard soil and rock aggregate mixture is 6°-7°larger than that of soft soil and rock aggregate mixture; and the largest friction angle occurs under about 60%-80% rock content. The shear surface of soil and rock aggregate mixture is no longer a flat surface; and the surface band increases with the increase of rock content. In the shear process, the soft rock mixture exhibits dilatancy under low normal stress, shear contraction under high normal stress and strain softening; while the hard rock mixture displays dilatancy and plasticity. The energies are mainly kinetic energy and strain energy for soft rock mixture; while the energies are mainly friction energy and kinetic energy for hard rock mixture.

By combining destroyed land in mining areas, evaluation indices and indices’ status, and using extension theory and correlation function, we quantitatively described the influence of each index on land destruction extent in mining areas. The land destruction extent in chozen mining area has been figured out. The areas of destroyed lands with different destruction extents were calculated using Arcmap. We have utilized set-valued statistics and determined the weights of matter-element characteristic; and therefore the accuracy of evaluation was improved. The demand of dividing evaluation units is determined scientifically; so the evaluation results can give a better guidance for practice use. The results provide a basis of reasonable use of destruction land in mining areas and indicate that the extension theory is feasible for evaluation of land destruction in mining areas.

It has been confirmed from completely undrained tests that flow failure is triggered only in saturated contractive sands, while strain hardening or cyclic mobility happened in saturated dilative sands during an application of post-liquefaction monotonic or cyclic shearing. In practice, however, there exist different conditions of drainage in shearing, such as partial drainage and even water absorption initiated in saturated sands under pre- and post-liquefaction loading. Experimental facts show that the large flow deformation can be induced in dilative sands during a post-liquefaction shearing application, only when sufficient magnitude of water-absorption in shearing takes place. The occurrence of large flow deformation is found to depend mainly on a constraint requirement for developments and variations in three kinds of volumetric strain components of saturated sands. Such a constraint condition is also verified to govern different post-liquefaction stress-strain responses of dilative sands.

In order to obtain distribution of bending moment along PCC pile under lateral load, full-scale model tests were carried out using large test tank developed by Hohai University. The three-dimensional elastoplastic finite element method was used to study the behavior of PCC pile and homalographic solid circular pile as well as PCC pile composite foundation and homalographic solid circular pile composite foundation under lateral load. The effects of different design parameters of PCC pile composite foundation on distribution of bending moment and deflection along pile were obtained. The study results show that the internal forces and deflection along pile decrease with the increment of vertical load, thickness of cushion, depth of foundation, and replacement ratio. It is concluded that the internal forces of pile can be reduced to ensure the safety of the pile by the appropriate adjustment of the main design parameters in the design of PCC pile composite foundation.

Clay minerals play important roles in hydration process, while the role was lack of quantitative evaluation at present. Therefore, SEM and X-ray powder diffractometry technology were used to analyze the microstructure, components and contents of clay minerals, and the change of microstructures in dry condition and different wetting times. At the same time, expansion experiments in different conditions were performed to study the variation of mass and the structure during the hydration process. These experiments show that: (1) The inner factors affected the hydration process are the contents of clay minerals such as montmorillonite, kaolinite, chlorite and illite in shales and slates. (2) Water-weakening effect is more distinctive when clay minerals array in order than in disorder. (3) Hydration progress of shales and slates happens in a gradual course. That is to say, clay minerals on the surface absorbed water and expanded firstly, which made the shale and slate fallen；then fluids filtered into the rock inside along the layer surfaces or cracks with time prolonged, and the inner minerals expanded, which made the fall occurred when without confining pressures. (4) During hydration progress, addition of inorganic chemical components in slurry and pressure increase will constrain the water-weakening effect; while the temperature will accelerate the water-weakening rate.

Based on the fiber Bragg grating (FBG) sensing system, heat pulse method is proposed for concentrated leakage monitoring in core rockfill dam. Model experiment was carried out with monitoring system composed of sensing-heating unit, regulated power supply, booster and FBG demodulator. At first, the aggregate was in dry and moist condition respectively. The experimental results show that it is difficult for temperature rise to make an exact identification to leakage state, so two dimensionless distinguishing indices ? and ? were defined; where ? was related to seepage velocity and ? was related to water table gradient. Then, two cases with various leakage flow rates were carried out and the leakage state was identified by ? and ? respectively. The results show that both ? and ? can locate the leakage position exactly and can reflect leakage intensity qualitatively. The identification effects by using ? as distinguishing index are better than ?

Subcritical crack growth is one of the main causes of time-dependent behavior in rocks. Applied the constant displacement relaxation method, subcritical crack growth in specimens made of marble and granite which were in dry and water-saturated environments was studied in double torsion test. The relations of the stress intensity factor versus the subcritical crack growth velocity V were obtained under the two different environments. The behavior of subcritical crack growth was analyzed. The threshold values of subcritical crack growth in rocks were obtained under the two different environments —— dry environment: marble =1.365, granite =2.305; water-saturated environment: marble =1.118, granite =1.490. The results showed: the relations between and accorded with linear rules; but it were discrete because of inhomogenous mineral composition, etc, it was more discrete under water-saturated environment; water can accelerate the subcritical crack growth; the effect degree was different in different rocks; the threshold values were reduced by water; the reduction was different in different rocks.

Cracked chevron notched brazilian disc (CCNBD) specimen configuration has been used to test the mode I fracture toughness of muddy sandstone according to the ISRM d suggested testing method in 1995. A new cutting procedure of CCNBD specimen is given. Specific rock fracture characteristics have been observed. The valid size range and fracture mechanism of this specimen type have been discussed. Then the advantages and disadvantages of CCNBD method are pointed out. It can be concluded as follows: (1) Derived fracture toughness values are sensitive to the variation of CCNBD specimen diameters; and more consistent fracture toughness values can be derived by the specimen with larger diameter than the ISRM suggested “minimum effective diameter 75 mm”. (2) Fracture mechanism of CCNBD specimen is mode I crack growth type under the synthetic stresses of the dominant tensile stress (indirect tensile) and the in-ligament shear stress. (3) CCNBD method has advantages with simple sample preparation, bearing a greater critical load and generating compatible KIC values. But this method has not considered the nonlinearity of fracture process zone (FPZ); and it is lack of the nonlinearity calibration procedure. It is advised to develop nonlinearity calibration procedure for the CCNBD method in order to generate more accurate testing results.

Permeability is one of the key factors in hydro-mechanical coupling study for underground engineering. A series of cyclic triaxial compression tests were conducted with red porous sandstones; the axial permeability was calculated according to Darcy’s law during the failure process. Based on the mechanical and permeability results, the influences of mean stress and stress cycles on permeability were investigated according to stress-strain curves and deformation modulus evolutions. Some conclusions are drawn: (1) With the increase of axial strain, permeability is consistently decreased in initial compaction and elastic deformation stages; during the plastic deformation stage, the reduction ratio of permeability is gradually decreased; in the end, permeability is even increased under low confining pressure. (2) The skeleton grain compaction causes porosity decrease, consequently permeability decreases; an empirical function is proposed to describe the relationship between permeability and mean stress. (3) During the stress cycles, the irreversible permeability behavior is induced by the irreversible deformation of skeleton grains. (4) There is a weak augment of permeability in post-peak stage, which shows the effect of induced cracks corresponds with the one of pore, the augment extent has a negative correlation with confining pressure, for porous sandstone.

Aimed at the lack in traditional analysis method used in soil-cement wall stability, when it is applied to stability analysis of MC composite support structure, a new computing way for anti-overturning stability was developed based on the limit equilibrium theory in combination with the characteristics of MC piles. According to the new method, various factors affected anti-overturning stability of MC piles were analyzed. The results indicate that, C pile is reasonably located in front side of the composite support structure; and the rotation point of overturning is reasonably located above on the end of C pile. Furthermore, the length and width of M pile, length of C pile can be properly increased to enhance the stability of MC piles. Finally, some advices on designing parameters of MC piles are given in terms of the conclusions of analysis and actual experiences in practices.

The stability of dam slope during rapid drawdown of reservoir water level was computed using limit equilibrium method and limit equilibrium method based on finite element analysis according to unsaturated soil shear strength theory in combination with a specific reservoir. In this computing process, the dissipating process of pore-water pressure was simulated using unsaturated-unsteady seepage theory and the impact of matric suction on shear strength of soil body was taken into consideration, each step of seepage corresponding to a stable situation of the dam. Finally, the comparison between both of stability analysis methods was made. It is found that the rapid drawdown of reservoir water level easily results in the dam slope slipping; the stability of dam slope is enhanced with the dissipating process of water pressure in the dam body; and the matric suction increases the shear strength in this dissipating process.

The soil-cement deep mixing column with different cross-sections is a kind of newly soft soil foundation treatment methods. Since special modifications have been made towards those drawbacks which exist in traditional deep mixing columns, the the soil-cement deep mixing column with different cross-sections exhibits good foundation treatment effect and thus has been gradually popularized in China recently. Based on in-situ static load tests in subsoil of Huzhou, the bearing capacity and load transfer mechanism of long soil-cement deep mixing columns with different cross-sections are studied. The result shows that load transfer is limited to a certain range due to soil-cement strength of column body. Stress concentration appears at the position of cross-section variation. Axial force decreases with depth. The maximum lateral friction resistance occurs at the top of column. The lateral friction resistance below varied cross-section decreases sharply due to the end resistance effect of the varied cross-section. But the lateral friction resistance of the lower part of the column is improved. The base resistance below varied cross-section increases with total load. Compared with the value of lateral friction, base resistance is less. So this column is a type of friction column with base resistance below varied cross-section. Based on three failure models of single column, the ultimate bearing capacity calculation of long soil-cement deep mixing columns with different cross-sections parts is proposed.

Three groups of soft soil foundation embankment centrifugal model tests, separately with different types of cushion were designed to master the effect of reinforced cushion on the pressure at the bottom of embankment and the tensile force in reinforced cushion. Test results show as follows. (1) With the enhancement of reinforced cushion’s structural performance, the pressure at the center of embankment bottom decreases gradually and the distribution of the pressure at the bottom of embankment changes from convex curve which is large in the middle section but small at the two ends to concave curve which is small in the middle section and large at the two ends. (2) With the reduce of reinforced cushion’s structural performance, embankment changes from quiescent stable state to active limit state. (3) With the increase of embankment load, foundation changes from elastic state to elastoplastic state and up to plastic state. the distribution of tensile force in reinforced cushion changes from the shape of saddle with two peak to the shape of parabola with one peak.

The immersion strength and residual strength of lime-loess is an operation frequently encountered in subsequent projects, reconstruction projects and analyzing the engineering accident. So there will be an important engineering significance if we work for it. The conventional triaxial test was conducted with forty samples of loess-lime of Lanzhou in China, the immersion strength and residual strength of lime-loess were discussed specially. From these tests results it was found that the residual strength ? R with the confining pressure? 3 appears a linear relationship. This law is similar to rock, because the lime-loess was broken into masses in the period of the residual strength, and the friction effect on the crack face was so similar to the rock.; the strength will decrease after the lime-loess was immersed; but the strength will appear up after a few times immersion; and the strength will remain on a constant volume which is not more than its original strength. In addition,we can't define it brittle materials simply. It is found that the lime'-loess fragility is depended on confining pressure and water content; the loess-lime' fragility will be more evident when the confining pressure become more high. It will be fragility when the water content decrease to a certain value.

For purpose of solving the problem of durability for conventional steel lined reinforced concrete penstock, steel fiber concrete and steel fiber reinforced self-stressing concrete were adopted to control crack width of out packed reinforced concrete. Based the prototype of penstocks of a hydropower station, two 1:10 reduced scale test members were produced to investigate the structural behavior of steel lined reinforced concrete penstock. Test results show that steel fiber reinforced concrete penstock presented very excellent properties of crack resistance, the initial cracking loads of penstocks increased and the concrete cracking significantly decreased. For steel fiber reinforced self-stressing concrete penstock, the initial cracking loads remarkably improved and the strength of steel material was fully used. The test results also show that both high-performance concrete provided good future in application of steel lined reinforced concrete penstock.

A hollow cylinder apparatus was used to study failure criteria for Hangzhou intact soft clay under undrained shear stress path with fixed principal stress direction; then the impacts of coefficient of intermediate principal stress, angle of large principal stress direction and pore pressure accumulation on shear strength of clay were emphatically discussed; and shear failure criterion of intact soft clay was proposed. Test results revealed that the coefficient of intermediate principal stress did not affect the variable pattern between stress and strain and stress path; and with the increase of coefficient of intermediate principal stress, the change of shear strength of clay did not show some regularity. The impact of angle of large principal stress direction on the strength of intact soft clay reflected that inherent anisotropy controlled the shear strength of clay. Pore pressure remarkably accumulated in the late period of shearing, which impacted on the performance of the strength of clay. Considering the influencing factors such as coefficient of intermediate principal stress, we used the maximum of generalized shear stress as shear failure criterion of intact soft clay by analyzing changes of generalized shear stress–strain curves.

A new kind of true triaxial apparatus is introduced. To simulate the loading process of core wall element under the dam construction process, true triaxial tests on clay mixed with gravel soil were carried out under complex stress state, which can simulate the practical stress path to some extent. It was found that even for single axial load applied from the major principal stress direction, because of the influence of initial complex stress state, the stress induced anisotropy effects are remarkable. There are different relationships between stress and strain in different principal stresses directions. Based on the testing results, it is suggested that when carrying out the numerical analysis of dam, the stress induced anisotropy should be taken into consideration, so as to reasonably describe the practical behaviors of the core and the whole dam body under three dimensional complex stress states.

The direct shear strength tests of Fujian standard sand with 16 normal stress levels and 5 series of shear rate were carried out by using the super-high-pressure direct and residual shear testing system DRS1. The test results indicate that the shear strength of sand is influenced by both normal stress level and shear rate; and it has a close relation with particle crushing degree and particle rearrangement/reorientation state after particle crushing (coordinate number Nc). Shear rate has no influence on shear strength of sand under small normal stress; and the Mohr failure envelops are almost same to each other. But when normal stress is relatively large, the shear strength with faster shear rate become smaller; and the Mohr failure envelops show “deflexibility-rise” fluctuation cycle; so the shear rate should be considered in the strength analysis of sand under high normal stress condition.

The action mechanism of low-grade backfill with three kinds of different filling height on the stability of mining environment structure was analyzed by ADINA finite element analysis code. The results show that the stability of a layer structure with the increasing of filling height has some rules as follows. (1) The highest value of tension stress of artificial top pillar decreases gradually, and stress conditions has been improved. (2) The tension stress status in artificial pillar transforms into the compressive stress status, and the value of compressive increases gradually; and the carrying capacity has been improved gradually; however the filling height is beyond a certain height, the carrying capacity of the artificial pillar grows very slowly; and It is not too much significance to improve the carrying capacity only by the action of low-grade backfill. (3) The squeezing action on the artificial bottom pillar from artificial pillar transforms to the artificial bottom pillar into gravity action from the low-grade backfill, the largest value of tension stress of the artificial bottom pillar appeares the change rule that increasing at the beginning then reducing. Considering the economic, security and other factors, low-grade backfill has the most reasonable height (2.8 m) in the filling scope. This study provides the basis foundation for the safety construction of the mining environment reconstruction structure.

How to treat dredged clayey soils with high initial water contents is an important issue in engineering practice. A new solidification method by adding cement and phosphogypsum synchronously is proposed based on traditional cement-treatment method. A series of laboratory tests were performed on the treated soils. The experimental results show that the unconfined compressive strength of solidified soils increases remarkably by adding cement and phosphogypsum synchronously compared with those treated only by cement. There is an optimum addition content of phosphogypsum for solidification treatment. The optimum addition content increases with the increase of initial water content of dredged clays. The stress-strain curves of solidified soils indicated the range of the failure strain about 2%-3%. The relationship between E50 and strength is nearly linear.

Dredged sediment sedimentation and consolidation progress in the storage yard directly affects the subsequent disposal method and cost. This research relying on the east line of South-to-North Water Transfer Project, the fine sediments were dredged from Baima Lake to the nearer storage basin with a cutter suction dredger. The rules of water contents changing with the deposit time, space and the depth of the storage yard ware studied. Results showed that the water content of the dredged sediment was reduced gradually with time and increased with the distance. The water content in the entrance was 20%-50% after 130 days; after 160 days, 100%-150% at 100 m away from the entrance, and 100%-170% at 200 m away from the entrance. The water content of the dredged sediment was reduced gradually by the depth of the storage yard, the water content was achieve to 140% when the depth of the dredged sediment was 40 cm. The clay content of dredged sediment was increased with the distance of the entrance and reduced by the depth of the storage yard. The permeahility coefficient of the dredged sediment was reduced with the distance of the entrance and increased with the depth of the storage yard.

The change law of congealing time that water glass—calcium carbonic acid grouting material corresponding with the change of calcium carbonic acid is researched. The congealing time of sol increases as the reduction of quality of calcium carbonic acid. However it does not increase evenly with reduction of calcium carbonic acid. There is up-rush point of congealing time when the calcium carbonic acid is reduced to a certain amount. It is difficult to control congealing time accurately, as solution has very sensitive to putting into amount of the calcium carbonic acid. Calcium carbonic acid as alkaline reaction in the whole reaction system, react by H+ of system with solution. The pH value of sol is raised and vitriolic concentration is reduced. So the sol congealing time is changed. The suitable congealing time of colloid is chosen to test their own intensity and corresponding firm sand intensity. The change laws of two kinds of intensity is obtained Under the condition of fixedness of vitriolic consumption. The pure colloidal intensity increases as the increase of the calcium carbonic acid generally. But after adding to a certain amount, its intensity no longer increases. It is not obvious that the intensity of firm-sand body varies with calcium carbonic acid. The slurry of more excellent proportion is chosen to be new grouting material, and according to the performance of the slurry, the corresponding grouting craft is proposed. It has done better preparative work for the subsequent project application.

In order to reflect the characteristics of strength and deformation of stratified rock mass under true triaxial compression, the calculation model is founded by numerical analysis method to obtain the stress and deformation responses of rock samples with different structure plane inclinations ?. The analysis results show that: (1) in the initial loading phase, the initial elastic modulus for samples with ? = 0° and ? = 90° are larger; with the increase of sample deformation, the elastic modulus of rock samples with ? = 90°, 60°, 0° decrease gradually; the brittle characteristics of samples with ? =90° and ? =0° of structure plane are obvious; (2) with the increase of surrounding stress ? 3 =? 2, the compressive strength ? 1 increases correspondingly; the surrounding stress does not have great effect on the location where the peak strength occurs; (3) for the situation of minor principal stress parallel to the structure plane strike, with the increase of intermediate principal stress ? 2, the compressive strength of rock samples shows the trend of first increase then decrease; with the increase of the minor principal stress ? 3, ? 1 increases gradually; when ? 3 is small, their relationship meets in the linear way; but with the increase of ? 3 their relationship transfers to the nonlinear way; and the rock sample with the failure model of slipping along structure plane shows the more obvious nonlinear characteristic; (4) for the situation of minor principal stress perpendicular to the structure plane strike, the compressive strength of stratified rock mass shows the obvious linear relationship with intermediate principal stress and minor principal stress.

Considering the nonlinear interaction between soil and supporting－structure in soil layers for deep excavation designs, p-y curves of supporting pile and soil was proposed according to concentrated force spring model. Based on piles shaft deflection differential equation of the general elastic foundation beam and considering that the deformation of anchor is compatible with the anti-slide pile’s deformation, a differential equation of the piles with prestressed anchor cables considering the nonlinear interaction is derived. Adopting finite difference method to calculate internal force and deflection of supporting piles. Finally, in comparison with the other methods, the calculated results of engineering example indicate that this paper is satisfied for engineering calculation.

Bending failure is a normal damage model of pile foundation in earthquake. An important reason of this model is the deficiency of pile’s flexural stiffness. To a certain length, the flexural stiffness is immediately relate to pile’s slenderness ratio. But in the pile foundation criterion, there has no limitation for friction pile’s slenderness ratio like end bearing ones. On the base of structural dynamic model of saturated loess, the finite-infinite element model of single friction pile-soil-structure system and end-bearing pile-soil-structure in loess area are established by finite element program. The influence of slenderness ratio on the system’s dynamic characteristics was studied; and the regulations were as follows. Firstly, when other conditions are the same, no matter end bearing pile or friction ones, the slenderness ratio has a little influence on the distributions of pile section’s shearing stress and pile’s horizontal acceleration. But along with the increase of slenderness ratio, the shearing stress reduces while the horizontal acceleration increase. Secondly, along with the increase of slenderness ratio, the pile’s deformation type transits from normal flexure model to contraflexure model gradually. Accordingly, the pile’s damage model transits from shearing failure to bending failure. Thirdly, the end bearing pile’s deformation curve is more likely to behave as contraflexure model than friction ones. But when the slenderness ratio arrives at a certain value, the friction pile also can behave as contraflexure model. In the aspect of seismic resistance, the appropriate limitation of friction pile’s slenderness ratio is which can make the pile’s deformation curve behaves as normal flexure model. The conclusions can give instruction for engineering practice in the future.

The adjacent construction of two tube shield tunnels was simulated by centrifugal model test method. The value and the distribution regularities of structural transversal internal forces and their variation with advanced distance of shield machine and the relative positions of two tunnels were studied. The results showed that the inside of top and bottom of lining structure subjected to tension, while the outside of left and right hance subjected to tension; and the largest bending moment occurred on the arch bottom. The whole structure was compressed; and the smaller axial force occurred on the arch crown and arch bottom, while the bigger occurred on the left and right hance. The distribution of structural internal force was symmetrical after the construction of the first tunnel; and the structural internal force of two tunnels changed with their relative position when the second tunnel was constructed. The new tunnel construction had obvious influence on the structural internal force of the existed tunnel; and the corresponding strengthening measures should be taken in the design and construction.

Comparing with horizontal support, the bracing systems of pile and oblique bracing have obvious advantages in big and deep foundation pit. Because the study about the removal of diagonal bracing is rare, the use of this system is limited. The accustomed removal method of the internal supporting is supporting followed removing. Based on the coordinating role of space support systems, according to the minimum potential result, the removing design thinking of supporting followed removing in several sub region and sections is proposed; and the calculation method of the length of sub region is derived. Finally, the feasibility and rationality of the proposed method are verified by the practical engineering. Acoording to the research, the top beam moment and the moment and displacement of the pile are the key factors which decide the length of the sub sections. The concept of the overall process design is came up. All of these can provide reference for this design and construction.

The complex geological conditions in the site of Jinping I Arch Dam made its reinforcement measures a huge project ,which mainly includes the concrete seating replacement ,shearing resistant adit, with the fault f13, f14 in the right bank and fault f5 、f8 and lamprophyre veins in the left bank treated with concrete lattice replacement. By employing nonlinear finite element analysis, this article gives computing results and detailed discusses on the dam stress and deformation characteristics of Jinping I Arch Dam under several operation conditions after the dam foundation reinforced. The dam stress distribution and deformation are also discussed by way of strength reserve method and the water gravity overload method. The results show that during the inpounding period, the overall characteristics of deformation and stress distribution of the dam have been significantly improved; the tensile stresses in the heel of dam are decreased after reinforcement; and the dam has enough global stability storage to completely meet the design requirements. Thus the necessity of the concrete seating replacement is afirmed.

Through the field shear test of highly decomposed hornfels at the site of Lingao Ⅲ nuclear power project in Shenzhen, it is shown that the shear deformation of highly decomposed hornfels has some definite ductility. Its shear strength of highly decomposed hornfels decreases exponentially with the water content increase. The rock shear strength indices c and ? are weakened definitely by water. The natural hornfels has the characteristic of shear-thinning after dilatancy but saturated ones only shear-thinning during the experiment. We introduce the deformation index of shear stiffness to study the deformation characteristics of direct shear test and take the influence of water into account. It is shown that the shear stiffness increases with normal stress increase and decreases with its water content increase, especially in the condition of low normal stress. At the same time we analyse the influences qualitatively to the shear deformation with the changing shear stiffness, which has definite guidance for the slope stability analysis and the prediction of slope displacements.

It is the key step for geotechnical engineering stability evaluation to determine suitable mechanical parameters of rock mass due to random distribution of its parameters. The statistical analysis of 110 data from borehole jack tests conducted from earlier research of a hydropower station shows that the deformation modulus more closely matches the Weibull distribution. Then the cube rock masses of various sizes, each of which comprises a number of cube elements, are simulated numerically. The size of each element is identical with that of bearing plate of borehole jack test instrument; and the deformation modulus of each cube element is given randomly by Weibull distribution. Each of rock masses is simulated by 5000 uniaxial compression tests; and then the change of equivalent deformation modulus with rock mass size is obtained, which determines the REV of equivalent deformation modulus. It is a new attempt to survey the macro parameters of rock mass by combination of in-suit test and probability statistics theory, so as to provide a useful reference for the parameter determination of rock mass in this hydropower station.

Based on analyzing the genesis, essential characteristics and tendencies of ground fissures in Xi’an, the physical model tests with a geometric proportion of 1:5 for active ground fissure and numerical simulation for the effect of active ground fissure on metro tunnel are carried out to study the design parameters of Xi’an metro line 2 tunnel orthogonally passing through the active ground fissure zones. On the basis of the average annual active rate of ground fissures and compared with the historical maximum displacements of ground fissures, the predicted and suggested maximum vertical displacements design values of each active ground fissure along the metro line 2 in the design life of 100 years are put forward. The test and simulation results show that the design width of metro tunnel orthogonally passing through the active ground fissure zone could be 60 m; i.e. 35 m in the hanging wall and 25 m in the footwall of active ground fissure zone. The stratum deformation along the tunnel axis ground fissure appears stepped mutational deformation; and integral descent of the hanging wall of ground fissure could be adopted in the design of tunnel longitudinal structure. Metro tunnel passing through the active ground fissure zones should be segmented by deformation joints to adapt the deformation of active ground fissures; the design length of sectional tunnel in main influence zone is 10 m; and in the minor influence zone that is 10 to 15 m. The conclusions will provide for reference to the design of lining structure of metro tunnel passing through the active ground fissure zones.

The macroscopic regimes under dam, which collected by sensor could reflect anti-seepage effect and its time-variance of dam foundation curtain, but in the procedure of multi-sensor data fusion, some evaluation indices were inconsistent. In order to eliminate this phenomenon, Bayes data fusion theory was utilized; the reliability of each sensor must be calculated before establishing the correct relation matrix. The fuzzy reliability of sensor was given by the statistical method. Based on the fuzzy index, the data fusion of multi-sensor was obtained; analysis of groundwater macroscopic regime under a dam section was carried out by using a decision-making fusion method. As a result, The macroscopic regimes under dam section 13 had the tendency of increasing with time between 2003 and 2008. The anti-seepage performance of the dam foundation curtain was to be weakened locally.

Based on numerical simulation in combination with field tests and measurements for strengthening works of a slope, as well as numerical experiments by varying the design parameters, mechanical behaviors and sensitivity analysis of frame beam supporting structure with prestressed anchors were studied; moreover, the interaction between the supporting structure system and slope was also discussed. The results show that there are two different stages when this supporting structure system strengthening slope; and they are respectively tension stage and stability stage. One should pay attention to the adverse effects in design that the inner forces of the frame beam and the anchor near slope toe increase during stability stage in work. Furthermore, results of parameter sensitivity analysis show that the prestress, angle, and spacing of the anchor have significant impacts on the inner forces of the supporting structure system and the compression deformation of the reinforced slope.

Owing to the economic advantage, the pipe jacking method has been used widely; the control of surrounding environment has also been promoted. But for the disturbance characteristics it is only researching on the medium and small pipe jacking; and it has no considering the particularity of super large diameter pipe jacking. Based on the in-situ monitoring of the Shanghai Expo Cable Tunnel construction, the curves of soil and water pressure are analyzed. The results show the disturbance characteristics for 5 stages during the propulsion. The engineering experiences show that three key parameters of long distance pipe jacking construction are slurry sleeve, stability control of excavation face and position dynamic adjustment. The slurry sleeve forming process and disturbance characteristics are researched; in the process of slurry injecting, slurry membrane forming and the slurry sleeve completion, the functions of the slurry sleeve are filling, supporting, deadening and lubricating, etc.

Based on the field test data of pavement roughness, the influencing factors on vehicle loads are analyzed considering moving velocity and vibration frequency of dynamic loads. And the reference value of design load is proposed. A simplified three-layer structure of expressway is obtained by adopting the method of Odemark equivalent hypothesis of modulus-thickness. The computation expression of dynamic deformation of subgrade is deduced with elastodynamics theorem and Fourier transform method. Combining the expression of dynamic deformation and the pavement deflection control standard of current specification, the control value of dynamic deformation of subgrade top and the determination method are derived in the contest of compatibility of deformation between pavement and subgrade. According to the control standard, a new design method of subgrade on control deformation is advanced; and three typical asphalt pavement structure are designed for illustration using this method.

Xi’an city wall is an artificial loess slope composed of inner-soil and outer-brick masonry. Strength reduction FEM is an effective method for analyzing the slope stability and calculating the safety factor. But when it is applied to analyze the wall’s stability, such difficulties emerge as the potential fracture face in the outer-brick masonry and the interface between inner-soil and outer-brick masonry. According to the contact condition, a plastic interface constitutive equation considering the softening on shear capacity is developed to analyze the stability of Xi’an city wall by using strength reduction FEM. The results indicate that the potential slip circle could be simplified to a line with the vertex 3 m away from the slope shoulder. And the safety factor along this line can meet the engineering requirements of stability. Furthermore, several principal factors that affect the deformation and damage of the wall are determined, such as the shearing strength of outer-brick masonry and the friction coefficient between inner-soil and outer-brick masonry. So it can serve the stability assessment and renovation of the city wall.

Based on an engineering example, the reason of the sloping prestressed pipe pile (PPP) and the treatment method for the sloping PPP were given. First of all, the sloping condition of each pile should be made clearly, then the damaged position of every pile is clarified with low strain dynamic test; and at last the pertinence treatment measures are brought forward. It can be concluded that for the piles with pile shafts floating upward, they can be re-pressed; for the piles with serious pile top slopes and rupture of the pile shafts, they must be replaced by bored piles; for the piles with smaller pile top slopes and soundness of the pile shafts, they can be directly used after rectification and righting; for the piles with bigger pile top slopes and defect of the pile shafts, the first step is rectification and righting; and then strengthening the pile shafts by placing reinforcement cage and pouring concrete in the cores of the piles; and for the treated piles with lower bearing capacity, the bearing capacity of the bearing platform should be strengthened by adding bored piles. The measured settlement of building is small and uniform, and the maximum settlement is only 9 mm.

Screening multiple factors according to their contribution to the debris flow is carried out based on the principle of stepwise discriminant analysis. And then the weights for screened evaluation factors are determined based on improved analytic hierarchy process; so that judgment matrix can meet the consistency requirements, avoiding the high-subjectivity in adjusting the judgment matrix during post-test. The site-specific debris flow risk is evaluated with example verification based on the screening and weight determining of evaluation factors. The results show that the screened factors actually reflect local debris flow risk; and they are closer to the actual situation comparing to traditional methods.

The engineering properties of Marine soft soil of Tianjin Binhai New Area is difficult to directly meet the requirements of constuction, so need for appropriate treatment and disposal. The effect of solidification of soil-cement adding alkaline agent based on raw materials of tianjin marine soft soil and analysis of filed verification test and microstructure are introduced. The results indicate that alkaline environment has a great role in improving the strength of cement-soil; and also can save the cost of project construction, it is worth to appliying in project practice.

The drain pipes, which were applied to treat the dredger fill by vacuum preloading, were always plugged by fine particles. It is essential to keep out of construction period for delay to improve the efficiency of the dredger fill consolidation. The test of dead-weight sludging drainage plus a combination of vacuum method of drainage in the laboratory was carried out. As vertical drainage channels，the drain pipes were experimentally used during the first-stage called dead-weight sludging drainage. Then the drain pipes were filled with medium-coarse sand to consolidate the dredger fill by vacuum method. The pore water pressure of varied depths and ranges were continuously observed especially to approach the primary-stage consolidation law. On account for the balance equation of water in the soil seepage, the major changes of pore water pressure were dominated. The mechanism of the pore water pressure changes during the first stage was explained accordingly. In order to fine consolidation the equivalence circle diametric was determined by sand drain theory and the pore water pressure curves. So drainpipe spacing to achieve the same desired effect of consolidation was determined under different circumstances whether the soil is near or far from the drain for the actual project design parameters.

The numerical simulation result and monitoring data have been integrated so as to study dynamic assessment of induced earthquake in the head area of Three Gorges Reservoir. The technical route was that the results of numerical simulation have been evaluated by professional earthquake model. The findings of the evaluation have been regarded as its background database which has been updated with real-time earthquake monitoring data, groundwater level monitoring data and crustal deformation monitoring data. The risk assessment system of induced earthquake has been studied by simulation tools of FLAC 3D, MAPGIS as its basic platform and VC++ as the developing tool. The research results show that the evaluation indices of numerical simulation model and monitoring data can be integrated by information fusion technique on GIS platform; so that a dynamic assessment of reservoir induced earthquake can be achieved.

In the Three Gorges Reservoir area, there covers thick soils and flourish vegetation on the top of the rocks. The Three Gorges Reservoir area is an area which possesses flourish vegetation and poor lithology information. So it is difficult to classify and recognize the lithology in the Three Gorges Reservoir area, and on this aspect there are still no mature methods. In this paper lithology analysis is conducted focusing on the Three Gorges Reservoir area. Badong County in the Three Gorges Reservoir area is chosen as the study area. The ETM+ remote sensing image shot in May, 2000 is adopted to establish 17 classification factors on the aspects of texture, spectrum and vegetation covering. The remote sensing image is piled up with the geological map; and 1 101 sample points are chosen. Decision tree algorithm C4.5 is adopted to mine the interpretation knowledge of lithology in Badong County. The study precisions of the trees before and after pruning are 96.6% and 95.9% respectively. The precision of the rule extraction is 93.1%; and the confidence values of the rules are very high. By knowledge driving and rule matching, intelligent litology classification is conducted with the classification precision of 90.11%. The classification results are compared with ones of the other 6 methods (IsoData, K-Means, Mahalanobis Distance, Maximum Likelihood, Minimum Distance and Parallelepiped). The experimental results have shown that the decision tree method possesses the best classification results and the highest precision; and it is obviously superior to the other 6 methods.

An algorithm that can simulate the excavation problem in numerical manifold method (NMM) is proposed according to the special cover system of NMM. In this algorithm, the excavation face is considered as a special kind of discontinuity that divides the mesh it crosses into different elements but doesn’t divide the mathematical cover it crosses. Such manner ensures that the elements on both sides of the excavation face are independent while the elements in the same mesh still have the same physical covers. So the algorithm retains the advantage of NMM that a uniform mesh can be competent to any geometrical conditions, and break the limitation of NMM that the excavation face must be treated as real discontinuity, which will result in unavoidable error. After being verified, the algorithm was used in an excavation simulation of a tunnel; and the results prove that the algorithm has a wide range of application.

The upper bound ultimate bearing capacity of shallow rough footing on anisotropic and nonhomogeneous clays has been studied. A slip failure mechanism with mesh-like rigid blocks system has been constructed, in which the velocities changes on radial and tangent directions in transition area are allowable. Thus the more accurate failure modes and plastic velocity field are formed. The objective functions of bearing capacity factor on anisotropic and nonhomogeneous clays were obtained based on upper bound theorem; and the bearing capacity problems were transformed as a nonlinear optimizing problem. And the computer programming was compiled. From the numerical results and comparative analysis, it can be seen that the solutions presented in this paper compared reasonably well with the results presented in the existing literatures; and the proposed method gives better results than other methods. At last, the parameter analysis has been performed to investigate their influences on bearing capacity of footings on anisotropic and nonhomogeneous clays.

Abstract: Not only the strength and stiffness varies with stress level, the volumetric change of rockfills under shearing also depends on the confining pressures. A strain hardening model based on Mohr-Coulomb model is proposed for simulation of the shearing characteristics of rockfills. This model utilizes Mohr-Coulomb yield criterion with full consideration of the stress-dependence of stiffness, shearing strength and dilatancy. The theoretical development and experimental base of Rowe’s dilatancy theory is assessed in details, with its limitation for rockfills highlighted. Modification is then made to derive the mobilized dilatancy angle of rockfills. Compared with large triaxial testing results, it has been demonstrated that this new model is capable of simulating the shearing characterizations of granular soils, specially the volumetric changes, despite of its simplicity.

Based on the theory of fluid-solid coupling and dynamics of fluids in porous media, and incorporated with the Landgem model, Darcy’s law, state equation of gas, principle of effective stress, a seepage-stress fields coupling model of landfill gas transport has been established. Solutions to the coupled model are accomplished by finite element discretization. The numerical visualization simulation on the distribution law of gas pressure has been presented under coupling effect. The quantitative assessment to the effect of deformation media parameter and landfill degradation coefficient on landfill gas production has been analyzed. The results show that the gas pressure and gas yield in coupling action are less than uncoupling action, of which the reason is that the gas movement is blocked by changing of pore structures when pumping. And the production of landfill gas increase by the augmentation of permeability and degradation coefficient. Therefore, the effects of coupling cannot be ignored. The theoretical evidence is provided for forecasting migration and diffusion of landfill gas and preventing secondary-pollution. Moreover, it has important theoretical significance and practical use value for protecting ecological environment and resources utilization of landfill.

The simple method to find empirical formula of the experimental and researched data which plotted on the coordinate paper of related function is not a straight line is described. As examples the relation curves plotted on log-paper semi-log paper and ordinary coordinate paper in hydraulics and soil mechanics are selected. With these typical curves the procedure of simple method to find empirical formula is expounded. Consequently the formulas of drag coefficient for immersed sphere body moving through water, settling velocity for silt and sand, settlement consolidation degree for soft foundation and specific yield are obtained.

In order to solve the problem of geotechnical parameters distribution inferring on the condition of small sample and get over the inevitable shortcoming of subjective randomness in those fusion methods based on expert’s experience, the notion of K-L information distance in the information field was introduced; and multi-source information fusion method was proposed on the basis of the credibility of prior distributions. Using K-L information distance as a measurement of distances between parameter distributions, “the rate of prior distribution difference” was defined and the fusion weight was determined. Further, the posterior distribution was obtained by using the Bayes principle; and the fitting probability models of geotechnical parameters were optimized. It is shown in the process of a project case that the method suggested is simple while no subjective factors are included in the statistical inference. The results show that the variance of the suggested fusion distribution is smaller than ones of the existing results, which illuminates that an optimum fitting probabilistic model for parameters in statistical sense can be resulted from the proposed method; and it provides a reference for choosing design values of geotechnical parameters reasonably.

Based on the spatially mobilized plane (SMP) failure criterion of the coherent material, the stress problem for the coal pillar under the three-dimensional stress states was analyzed; and the formula of limit strength of the coal pillar was derived. Through changing the internal friction ? and the cohesion c of the coal, compared with the limit strength of the coal pillar using the Mohr-Coulomb failure criterion and the simplified A. H. Wilson formula, it is shown that because of neglecting the influence of the intermediate principal stress in the Mohr-Coulomb failure criterion and A.H.Wilson formula of the limit strength of coal pillar underestimate the actual limit strength; and it also is shown that limit strength computing of the coal pillar based on the SMP failure criterion of the coherent material has certain practical significance.

On the supposition that the distribution of shearing force in inverted triangular form between anchorage-body and surrounding soil, the displacement of the top of anchorage-body was calculated. Based on the analysis of pull-out bearing mechanism and deformation characteristics of bolt, which is similar with anti-floating pile, a displacement of shear mode between anchorage-body and surrounding soil was used to calculating the displacement of the surrounding soil. Then, a simplified method for calculating the critical anchorage length of bolt was deduced according to the displacement coordination between anchorage-body and surrounding soil. Comparative analysis results of two engineering examples show that the calculated values by the presented method agree well with the measured data. Furthermore, the calculation formula is a simple and easily remembered one and it has a specific value range. And it is appropriated to estimating the critical anchorage length of bolt in engineering design.

Damping ratio testing method of a foundation was studied theoretically and experimentally based on the corresponding Chinese measurement and design codes. It is shown that there is a relatively large difference between numerical results of codes and approximate formulae based on elastic half-space analytical solution. Therefore, six-degree-freedom time histories of the center of mass center of a foundation are calculated from three-component vibration curves of some points on the foundation surface to be selected as the analytical time-history of some dynamic parameters such as compressive stiffness, rotational stiffness, shearing stiffness, torsional stiffness, damping ratio and mass of vibration of subsoil. It is recommended that the vibration sensors should be pre-embedded in some proper positions of the foundation bottom surface to improve the precision of subsoil dynamic parameters measurement.

Slope stability assessment is a geotechnical problem characterized by many sources of uncertainty，random uncertainty and fuzzy uncertainty. Practice has proved that fuzzy uncertainty is more profound than random uncertainty in slope stability evaluation. The article summarized the application of fuzzy analysis to slope stability evaluation. The basic principle, characteristics, advantages and shortcomings of various methods were elaborated. Based on the properties and research status of slope stability and fuzzy theory, the main issues and development trends of application of fuzzy analysis to slope stability evaluation were discussed.

Estimation of earth pressures constitutes an important subject of research in geotechnical engineering. Centrifuge model test provides a powerful tool for the study of earth pressure. A set of centrifuge model test facility for the earth pressure is developed for the study of earth pressure at rest and active side for the rigid retaining wall system. A motor is employed to make the model retaining wall moving slowly and uniformly. Besides, an automatic control system is developed to retain the wall at rest when the centrifuge acceleration increases. Centrifuge model tests are conducted for the rigid retaining wall with horizontal sand backfill. Variation of earth pressure and deformation of backfill with the wall displacement is measured. The test results show a good regularity. Therefore, the facility is verified to be effective for the study of earth pressure at the active side with translational wall displacement.

For the fact that rock mass degradation is not taken into account in the appraisal method for surrounding rock stability and the insufficient norms reference to deformation characteristics of the large underground powerhouse, considering the fact that the actual rock mass properties change in the excavation of underground powerhouse, based on strength reduction method idea, a new stability analysis method of surrounding rock for large underground powerhouse is proposed. At first, yielding approach index is used to appraise the excavation degradation zone of surrounding rock in numerical simulation. Secondly the deformation modulus and cohesive strength are reduced in the degradation damage zone. Then the failure criterion could be determined through the displacement, damage zone and energy release amounts mutation. Meanwhile, the early-warning displacement is analyzed in the process of rock degradation, and it can distinguish the stability of surrounding rock rapidly. At last, by analyzing an example of underground powerhouse, it is shown that the proposed method can provide quantitative basis for underground powerhouse stability; and it meets the need of underground projects fairly.

Because of the complex geological conditions of geotechnical engineering and its increasing project scale, the requirements of the calculation speed for large-scale numerical simulation become more strict. Graphics processing unit (GPU), the core unit of graphics card, can solve this problem with the advantages of parallel computing, high-speed floating-point performance and high memory bandwidth. The hardware architecture differences between GPU and CPU are analyzed firstly. Then the advantages and disadvantages of CPU and GPU are summarized; the development and achievement of general-purpose computation on GPU are described in detail. Finally, an example about application of GPU to stochastic differential equations of permeability is given; the advantage of GPU is displayed and the application of GPU computing to geotechnical engineering is discussed.