Jinping II Hydropower Station, located in Liangshan Autonomous Prefecture of Sichuan Province, is a highest water head and biggest capacity one at the in Yalong River. The underground powerhouse, the core of the project, is situated in right bank of V-shaped valley of the Yalong River. It meets the complicated groundwater seepage environment. For the safety of underground caverns, a reasonable layout of impermeable layer and discharge outlet is put forward based on the new design principle which is ponding first and discharge second, free drainage of high head wall, pumping of low head water, separating out water and inner water. Based on the result of 3D seepage numerical calculation of powerhouse region, the parameters of layer and discharge outlet system are also decided, which considers a rational safety scope. Practice of excavation of caverns proves that the design of seepage control and drainage system is reliable.

Along with the vigorous development of hydropower resources, many super high arch dams are constructing in Southwest region of China. The stability of these arch dams is a key and important problem in the process of design and construction. As for those arch dams constructed in high ground stress valley, foundation excavation may lead to geostress release and unloading of rock mass, and then causes shallow stability problem, which has few successful example for us to learn how to design and reinforce foundation for super high arch dam under these geo-condition. To this problem, unsuitable concept may bring about wrong calculation or numerical simulation, and then lead error to occur during design process. A detailed discussion is conducted focusing on the characters and mechanism of shallow unloading of excavated foundation surface of super high arch dam. Based on the Xiaowan Arch Dam, the calculation method of unbalance force of abutment and surface factor of safety of dam interface are proposed. By employing maximum-minimum principle, the stability of foundation interface of Xiaowan Arch Dam was analyzed and evaluated for supervising the design. The analysis results show that the proposed method is effective to supervise design for those super high arch dams similar to Xiaowan Arch Dam.

With 3D nonlinear finite difference method , the influences of deformation, stress, corrosive rock masses and loose strips on dam safety are researched. The result indicates the surface safety degree of bedding is low due to the great water pressure and the bedrock loose effect; the tension plastic zone of dam heel rock masses is closed to the impervious certain, which must be regarded and such measurement is necessary. Elastic and elastoplastic model are adopted respectively on dam material in the overload analysis; Xiaowan arch dam’s safety degree caused by upstream overloading water pressure is 6.5 and 3.5 respectively. So the global safety degree is 3.5 and controlled by the dam strength. Through the distribution and spread process of plastic zone, the rock masses between the elevations 1 160 m and 1 190 m are in transfixing plastic due to the existing of deepl valley and corrosive when the overload coefficient reached 5.0.

The seismic mechanical behavior of lining structure of deep-embedded cylindrical surge-shaft with multifork tunnel is analyzed by using 3D nonlinear FEM. Combined with the elastoplastic constitutive relations of rock mass, the implicit bolt element and anchorage cable element, a calculation method of excavations, supports and lining cracks of complex surge-shaft structure is presented. The stress and distortion characteristics of lining under seismic wave is calculated by using wave field pseudo-static method, also the calculation formula for the lining crack width and structural reinforcement is provided. By an actual engineering computation, the distortion characteristics and stress distribution rules of the dimensional multifork surge-shaft lining structure under seismic action are revealed, which verifies the rationality and feasibility of this method; and that provides a new idea and reference for the complex surge-shaft design and construction in meizoseismal area.

The Xilongchi pumped storage power station, located in Wutai county, Shanxi province, has total installed capacity of 1 200 MW with a rated generating head of 640 m. The three dimensions of its powerhouse are 149.3 m, 23.5 m and 49.0 m. The strata in the powerhouse area are composed of argillaceous oolitic limestone, thin banded limestone and thin quartz siltstone with almost horizontal occurrence. The axis of the powerhouse intersects the main faults and fissures with large angles. Displacement and anchor bar stress of the surrounding rock are characterized by obvious anisotropy, and the surrounding rock displacement (mean 3.0 mm) and the anchor bar stress (mean 45 MPa) are relatively small.

The Jinping II hydropower plant is made up of low sluice gate, long tunnel and powerhouse arranged at the end of the power tunnel, and the geological conditions at the powerhouse is quite complicated. II, III and IV surrounding rocks coexist in the area of powerhouse at the end of power tunnel. Considering the complicated engineering geological environment, engineering geological condition, hydraulic condition, stability of surrounding rock project, investment and so on are analyzed; the advantages of choosing powerhouse longitudinal axis of N35°E and the reasonabilities of canceling tailrace surge chamber and using two-cavern scheme are discussed. Constructing practice proves that the layout scheme not only can meet the criterion of cavern stability and operation safety of generating units, but also can save engineering cost and shorten the construction time.

There are many coupling effects in rock and soil engineering; seepage field and stress coupling is important in the water resources and hydropower engineering. Taking a hydraulic project foundation pit excavation as engineering background, Biot’s consolidation theory as theoretical basis, and Mohr-Coulomb’s principle as soil yield criterion, hydro-mechanical coupling of foundation pit is simulated in the process of excavation. The results indicate that the stress of backfill is larger than that of excavation, and there is a certain degree stress concentration near the open caisson. There is little yield region before and after backfill; so yield failure of soil is not a major problem in the engineering. Because of large coefficient of permeability of soil and high level of groundwater in the region of powerhouse, seepage discharge is very large in the process of excavation. Open caisson and impervious soleplate laid on the floor of the foundation pit have obvious effect on reducing seepage discharge. In conclusion, permeability-reducing and drainage are the key problem in the process of excavation of the engineering.

By use of the ANSYS, the software of finite element structure analysis, a finite element analysis model is set up for slope excavation, and the landform and geological condition and excavation process of Silin Hydropower Station’s navigation lock are simulated in detail. The stress, displacement and factor of safety of slope stability are analyzed under different conditions such as the natural condition, excavation step by step and reinforcement by anchor rod etc. Based on the definition of local factor of safety of element, the distribution of factor of safety of slope stability is obtained for before and after reinforcement during excavation. According to the calculation result, it is shown that the slope is stable under the designed engineering measure and without other reinforcement measure.

RCC gravity dam with incised transverse joint is a whole structure approximately due to joint effect of incised transverse joint. When RCC gravity dam encounters strong earthquake, aseismic safety of dam is mutative with different cracked degrees. During aseismic analysis by using FEM, considering structure characteristic of tru-cut transverse joint, joined mesh and incised mesh of incised transverse joint can be simulated by living mesh and killed mesh; and cracked degree can be equaled to discount elasticity moduli of the whole joined mesh of incised transverse joint. In the end, the aseismic safety of left bank dam monoliths of Jinanqiao Hydropower Station using above methods are analyzed. The results indicate while left bank dam monoliths of Jinaoqiao Hydropower Station encounters M9 earthquake, cracking of incised transverse joint has little influence on aseismic safety of individual dam monolith and dam monolith, and dam is safe. This indicates Jinanqiao Hydropower Station RCC gravity dam can withstand the design earthquake with the reasonable design.

The rheological behavior of adjacent rock is one of the important factors that influence the deformation and long-term stability of underground cavern. Under long-term load，the rheological behavior of rock mass occurred，and the rheological phenomenon of weak intercalation becomees more obvious. As an engineering example，a large-scale underground cavern of hydropower station is studied, in which there are reciprocal chiasmata with several weak intercalations. Based on the visicoelasto-plastic rheological model of rock，the rheological characters of the surrounding rock mass are simulated by using FLAC3D software. Through the analyzing of the calculated results，the long-term stability of underground cavern is estimated by studying displacement，displacement velocity，stress and plastic zone. The results show that the rheological effect of underground cavern is very remarkable. As for several weak intercalations are adjacent to the underground cavern，the deformation of intercross between cavern and weak intercalations is large, which has someing influence on the long-term stability of underground cavern. It is very important to consider rheological effect for long-term stability estimation of underground cavern.

The principle and algorithm of composite element method (CEM) are briefly described. The major merits of the method are the preprocessing work load and difficulty can be reduced remarkably; and it can be coupled with finite element method (FEM) system very well. Then the physical model overloading test for Baozhusi Gravity Dam is illustrated. The overloading cases of numerical tests are carried out by three dimensional elasto-viscoplastic FEM and three dimensional elasto-viscoplastic CEM separately for the dam. The computational results are compared with the results from the model test. The comparison shows the displacements of the key points match closely. The whole displacements and stresses of two numerical methods also agree each other well. This research shows the validation of the CEM, and the main advantage of the algorithm: simple in preprocessing and accurate as FEM. Meanwhile, it is proved that CEM is an effective way to solve the deformation and destroy problems for the gravity dam on complicated rock base.

At present the design concept of high earth core dams in China is on the base of experience of building dams such as Xiaolangdi Dam; and there are some reference data only for 200 m level. In order to study the 300m level high earth core dams with thick overburden layer which is in the most advanced world level the whole filling and water storage process is simulated by FEM, and the 3D stress and deformation characteristics of dam body and earth core are analyzed. The results show that the defromations and stresses of 300m level high earth core dams are in the allowable scope; therefore, it is feasible theoretically.

The deformation and stability of dam abutment have great influence on stress states of arch dam under complicated geological conditions. It is necessary to consider the interaction between arch dam and dam abutment. In order to built three- dimensional finite element model easier and describe complicated geological conditions better, arch dam finite element model and dam abutment finite element model are built respectively and the iterative calculation method is adopted to simulate the interaction between them. Based on the theory of unloading rock mass mechanics, the stress-strain state of dam abutment rock mass is studied under thrust force of arch dam after excavation unloading. The results show that the displacements of abutment slot both upstream and downstream are not remarkable. The effect of the dam thrust against the slope displacement can not be neglected.

By the technique of decoupling with two-field iteration, a numerical analysis model is set up for solving the coupled problem of stress-seepage interaction by element-free method. The distribution laws of displacement, stress and seepage piezometric head of dam body and its foundation are analyzed in detail under the normal water level with and without when considering the stress-seepage interaction. It is shown that the displacement of dam under coupled condition is smaller than that of the not one, but their distributions are same. Meanwhile, the distributions of horizontal normal stress are different, and the vertical normal stress and shear stress and seepage equipotential lines are obviously different though their distributions are same too. The seepage flow can result in disadvantageous effect on stress of dam body under coupling condition. The calculation results accord with the general law.

Earthquake disaster of embankment dams will lead to serious results. At present embankment dams located at seismic area are all dynamically analyzed during aseismic design. Credible dynamic parameters of dam materials obtained from indoor tests are the key to the accuracy of dynamical analysis. Shuiniujia Core Embankment Dam is over 100 meters high and its earthquake fortify intensity is nine. Dynamic characteristics of core cohesive soil and damfoundation gravel are studied through the dynamic triaxial tests. And the dynamic modulus, damping ratio and their influencing factors are analyzed. The results show that the method of using one sample to finish the tests of three different confining pressures ?3c and three different consolidation ratios Kc is feasible, and has accuracy and regularity comparing with the method suggested by “Soil Mechanics Laboratory Regulations”. There are many factors affecting dynamic modulus “Ed” and damping ratio “D”, such as dynamic strain level, confining pressure, consolidated stress ratio and porosity ratio, etc.; “Ed” decreases and “D” increases very rapidly with strain level. And “Ed” increases while “D” decreases with confining pressure. Both “Ed” and “D” increases with consolidated stress ratio. Dynamic modulus and damping ratio are different due to different soils. And dynamic modulus of core cohesive soil of Shuiniujia Embankment Dam are high while its damping ratio is much lower; so it is not easy to suffer the dynamic destroy.

Iandslide in a certain reservoir area is chosen as the engineering background. According to the saturated-unsaturated seepage equation, the dynamic response of pore water pressure in the landslide influenced by the fluctuation of water level is studied when considering the infiltration characteristics and the fluctuation velocity of water level. The analysis results show that (1) when the water level fluctuates, the saturated permeability coefficient has great impact on the initial water level under the same infiltration condition; with the increase of the saturated permeability coefficient, the water level becomes lower, and the water level line becomes more smooth, which has smaller impact on the dynamic and static pore water pressure, and is good to the slope stability; (2) with the increase of fluctuation velocity of water level, the response of water level lags behind, the water level line becomes steeper, which causes greater dynamic pore water pressure to the slope, and is worse to the slope stability.

For constructing dam on the deep overburden foundation, it is very important for dam body and foundation to control seepage stability and seepage discharge. In view of the deep overburden foundation, inferred two-dimensional seepage form with the finite element method; compiled procedure to compute the project example. The computed result shows: when the permeability coefficient of overburden foundation is bigger, it will not achieve good anti-seepage results until the cut-off wall Inserts into the relatively impermeable stratum; the waterproof blanket cannot be relied on to effectively control seepage discharge when the permeability coefficient is bigger; The permeability coefficient of overburden foundation controls seepage discharge before cut-off wall inserts into the relatively impermeable stratum.

Geological defects always exist in natural foundation more or less. The foundation treatment is a significant component in dam construction. Based on three-dimensional finite element method, the failure process of dam foundation with weak interlayer is studied with overload method and strength reduction method respectively; the quantitative results of the foundation safety are gotten by comparing with before and after foundation treatment to show the treatment effect. Comparing the treatment effect of each design scheme, the optimum design scheme is obtained. The calculation results show that the quantitative results of the foundation safety can be computed by the finite element method; and the approach has obvious advantages.

In order to simulate the infinite domain, a special boundary condition should be used in the dynamic analysis of rockfill dam with the finite element method. A series of dynamic analyses are performed in time domain by using viscous and rigid boundary respectively and compared with dynamic analysis results in frequency domain. The results show that, with the increase of the height of rockfill dam, the influence of viscous boundary become increasingly obvious. The acceleration of dam top calculated with viscous boundary is lower 10% ~20% than that with rigid boundary for homogeneous dam. For the Shuangjiangkou Clay Core Rockfill Dam, the acceleration of dam top calculated with viscous boundary is lower 30 % than that with rigid boundary.

Based on the related rockfill material tests, the particle flow code computer simulation technology was used to simulate the particle breakage characteristics of rockfill. 2 574 particle clusters were used in the simulation. The result of numerical simulation with the selected micro parameters was in agreement well with the result of plane strain laboratory test. So the numerical test can capture the micro phenomenon of particle breakage properly. Compared with the laboratory tests, the numerical simulation can also expose the regularity of evolution of particle breakage microscopically; and the location of the breakage zone. It can be used as the parameters and theoretical basis for the further study of building a rockfill dam model; and then observing the process of particle breakage during the expounding of the reservoir and during earthquakes. And also the displacements of the dam due to the particle breakage and the location of the breakage zone; and the influence on the strength of the rockfill can be researched furthermore.

Using rock-fill dam’ adaptable predominance over topographical condition, a concrete-face rockfill dam (CFRD) designed to build on the strip dorsum is filled fitting the natural side; and it makes the original massif be parts of the dam body; thus a fairly rare CFRD was achieved, which is called fitting-slope CFRD. The widespread Duncan-Chang E-B model is applied to analyze simulatively the stress and deformation of one fitting-slope CFRD for construction and operation periods respectively by using User Subroutine of ABAQUS. The result indicates that the fitting-slope CFRD differs from ordinary CFRD in deformation; the fitting-slope CFRD shows small settlement and horizontal displacement and deformation of concrete face, which is affected by ledge excavation; convex angle of plane of foundation of echelonment exists obviousl stress concentration, where the stress level are high. The result of calculation can supply rational advices and effective measures for optimizing design.

Arch dam is an important type of dams due to its beautiful body and lower cost and so on. But it has a high requirement to the rock mass of dam abutment. The three-dimensional stability analysis of arch dam-dam abutment is done by using FLAC large deformation software in order to know the safe property.The three-dimensional geological visualization model is done by combined using Auto CAD and ANSYS due to the preprocessing shortage of FLAC software.The basic data information is processed by using Auto CAD, the element model is obtained by reprocessing the basic data information by using ANSYS software.The element model is turned into FLAC to do numerical calculation.Some useful conclusions are obtained by numeration analysis.

According to the characteristics of the geology and structure, a sub-model which contains the mechanical characters of the underground continuous wall is built. Based on ABAQUS software, Mohr-Coulomb failure criterion and non-associated flow rule are used to simulate the course of construction. The stresses and displacements of the structure are analyzed amply. Meanwhile, based on the strength reduction method, the stability of the structure is studied. The results show that the constructing method of the groundsill using underground continuous wall is reasonable and feasible. So, the underground continuous wall can satisfy the requirement of engineering.

In accordance with composite soil nailing technology for deep excavation, the FLAC3D is used to simulate the process of construction by composite cement-soil nailing wall. During the simulation Mohr-Coulomb model is used and contact elements are applied to the interfaces between the soil nailing and soil. This simulation offers the axial force of soil nailing along nails length distribution, the horizontal displacements of soil, the settlements of ground, the uplifts in the bottom of the pit and the potential slip surface foundation pit in every step. The comparative results show that the FLAC3D results are basically consistent with data of field test. The FLAC3D results are worth use for reference in practical applications and design too. Furthermore, the agreement shows that FLAC3D model and analytical method are reliable. And the results of FLAC3D numerical simulations can satisfy the need of engineering, so it can be well applied to analyze and predict practical engineering.

The problem of back analysis of initial seepage field is solved by direct method based on orthogonal test and ν-SVR. By orthogonal test, the general information of initial seepage field is obtained; ν-SVR is used to study the relationship between water level and parameters; the connotative expression between them is established and used to substitute for FEM program; finally, optimal initial seepage field is obtained. Through engineering example study it, is proved that the method is efficient and suitable for solving nonlinear complicated problems of rock and soil.

In order to ensure the structure safety on the anchored beam of Xiluodu Hydropower Station, and to study the effectiveness and reasonableness of comprehensive temperature measures to prevent cracking, a 3-D finite-element analysis is used to simulate the construction process and the temperature control measures. Based on analyzing the distritutions of thermal field, stress field and their variation laws are compared each other. The results of the temperature control in initial stage has important engineering significance for construction.

The seepage fields and stability of concrete face rockfill dam(CFRD) in Jinchuan Hydropower Station are calculated by FEM, when vertical joints and seal failure x occurred in the face plate. Two-dimensional plane element without thickness simulating the vertical joints and the sealing peripheral fractures is adopted; meanwhile, Signorini’s variational inequality is adopted to solve the problem. This method can locate the frozen points and the saturation line accurately. The results show that the saturation line and equipotential line are affected by the position and the width of the vertical joints and the sealing peripheral joints. Some references will be given for designing the joints of CFRD.

According to the initial stress field of the Linxi River rock masses, and based on the multiveariate linear regression method, the initial stress field of rock mass is obtained; its loading is and carried out in the software of ABAQUS. Considering the batholithic joint, the interface element functional element program is developed based on ABAQUS-UEL. Nonlinear finite element analysis is used to simulate the excavation unloading．Variations of displacement and stress field in different stages as well as the deformation regularity of different parts of rock masses in different material parameters are discussed．The results of FEA show that the rock stability can be kept in the process of excavation.

Dam material and overburden dynamic parameters are inversed on the basis of strong earthquake monitoring data of Yele Dam. Then three-dimensional nonlinear finite element analysis is carried out to analyze the dynamic acceleration responses of the dam subjected to its largest earthquake so far(4 earthquake). Liquefaction of the foundation overburden is evaluated in accordance with the results by finite element analysis. Seismic safety of the dam suffered by earthquake is evaluated finally. Rockfill and overburden material models used in static calculation are Duncan E-B model, and Hardin model in dynamic calculation.3D nonlinear finite element earthquake response analysis applies equivalent linearization method.

The abutment slope at Dagangshan Hydropower Project has complex geological conditions with faults, dikes, unloading crack intensive belt, deep unloading belt and developed joint fissures. In order to analyse the stress and deformation of the slope during the slope excavation and support, 3D elastoplastic finite element simulation is performed with elastoplastic finite element method by the elasto-viscoplastic finite element software EVP3D, the possible failure location of the slope can be revealed, and the effectiveness of a suggested construction procedure can be evaluated. A suggestion for the supporting scheme is proposed.

The Dos-based DDA program originally developed by Dr. Shi has been upgraded into the Windows-based version by China Institute of Water Resources and Hydropower Research (IWHR) recently. In this new version of DDA program, user-friendly pre-processing and post-processing are developed, and the process of slope excavation can be simulated. An application of the new program to analyze the stability against sliding of Xiangjiaba gravity dam is presented.

The whole construction process of the intake chamber of Qincaosha water source site is modeled by 3D finite element codes Plaxis-3D Foundation; the influence on the intake chamber of the dike and management services is also analyzed; the measures to control settlement of the intake chamber are presented; the strain and stress of the intake chamber are given under 2 controlling conditions. The results provided valuable reference to design and construction.

High excess pore water pressure will rise in the core wall of the earth dam during the construction period. For the high earth dam, the excess pore water pressure produced in the core wall of the earth dam during construction can not be effectively dissipated, which influences the stability and safety of the project. So the dam interior will possibly present the high pore water pressure. The influences of water content and construction progress on the pore water pressure are analyzed, based on monitored data. So，strengthening the pore water pressure monitoring and analysis during the construction period is important to the construction and design guidance and the safty of the dam.

Accordance to the practice of underground powerhouse of Pushihe Pumped Storage Power Station , and by using 3-D nonlinear finite element back analysis method,and considering effect of geological structure, topography and measured stress, back analysis of 3-D initial geostress is carried out. The results show that the method can reflect the impact of geological structure, topography on initial geostress, and it can also reflect the characteristics of stress distribution near measured points. The initial geostress as of The Pushihe Pumped Storage Power Station are middle-and lower geoshtress and mainly of tectonic stresses.

The arching effect of core-wall of ShuangJiangkou earth-rockfill dam of three different design schemes is analyzed by using three-dimensional finite element method. The effects of Poisson’s ratio, Young’s modulus of core and shell on arching effect are studied. The arching effect coefficient that can reflect the core arching effect is defined; and it is used to investigate the arching effect coefficients of different zones of the dam. The results indicate that the core-wall arching effects of the three schemes are similar; and the arching effect is stronger at the abutments, three quarter of the dam and core wall bottom.

Applying viscoelastic artificial boundary to dynamic response analysis of Shuangjiangkou rock-fill dam, the effect degree concerning earth-rock dam dynamic response based on viscoelastic artificial boundary and the radiation damping effect of foundation is evaluated. The result shows that comparing with traditional solid boundary massless foundation the method decreases the dynamic response result of acceleration by 15%~30%. It should be taken into account in the dynamic response analysis with regard to the rock-fill dam.

With the large-scale triaxial apparatus, triaxial tests of gravel soil for a 300m high embankment dam were carried out; the highest confining pressure is to 5 MPa. The experimental results show that the stress-strain curve of gravel soil is a hyperbolic one; and that shear strength envelope of gravel soil is nonlinear. According to physical meaning of Duncan-Chang model, initial modulus Ei should be obtained in the area of minimum value of axial strain εa; and ultimate principal stress difference (σ1－σ3 )ult from a bigger range of εa; so propose that Ei is obtained in the area of εa=0%-3% and (σ1－σ3 )ult in the area of εa=5%-15%. The proposed method is more reasonable than the traditional method because the actual strain of high earth dam is about 1%,. As the confining pressure of the triaxial test is in a large range, confining pressure is divided into three parts, such as 0.2-1.0 MPa, 1.5-3 .0 MPa, 3.5-5.0 MPa; and the tangent modulus in each range of confining pressures are gained respectively. It is proved to be reliable by the comparison between test data and computing data.

The method for selecting of anti-uplift and waterproof water level of on land construction is reviewed; and then the selection of anti-uplift water level and waterproof water level of artificial island is advanced through the study of Jidong Nanbu Oilfield artificial island No.2; the factors influencing the selection is also analyzed. For permanent structures on artificial island, the anti-uplift water level should be equal to the elevation of artificial island; for temporary structures, the anti-uplift water level should be select as 0.5-1.0 m below the elevation of artificial island. The factors influencing the anti-uplift water level and waterproof water level of artificial island are its elevation and rainfall.

The experiment process and application of extrusion-sidewall in rock fill dam with face slab upstream bedding plane at Siping Hydropower Station are introduced. The place of overfilling, manual and mechanical slope cutting, roller compaction and protection of slope in traditional way are taken by extrusion-sidewall. The construction characteristics of extrusion-sidewall are illustrated, and its technical criteria and construction methods are introduced. It may simplify construction procedures and enhance construction safety.

The depth of overburden layer is large in dam site of Suwalong Water Power Station, and its components are complex, which cause many difficulties to obtain the undisturbed specimen from every layer respectively. Combined with the test results outside, the test results from the lower buried layer from which the undisturbed specimen is easily obtained are analyzed. It is found that the overburden layer does not exist sand liquefaction. The result can be referred to similar engineering。

The research status of hydraulic fracturing in core of earth-rockfill dam is briefly reviewed, and the mechanisms, the conditions and the influence factors of hydraulic fracturing are induced.

The high geostress has important influence on deep-buried tunnels during the phases of design and construction. As the natural test project of western route of South to North water transfer project in China, the deep-buried water transfer tunnel of Yindajihuang Project faces the problems of rockburst in hard rock and plastic deformation in soft rock under high geostress. Representative physico-mechanical properties are studied out according to the survey data. ANSYS finite element analysis procedure is applied to the stability analysis of tunnel rock. The distribution characteristics of deformation, the maximum tensile the maximum, stress, possible rockburst area, plastic deformation zone and shear failure zone are studied under different conditions, gravity geostress field, full geostress field, and calculated according to linear elastic method and elastoplastic method. Analysis result is applied to Yindajihuang Project, and the importance of checking in time in the course of construction is pointed out.

In the course of double-arch tunnel construction, the variations of stress and deformations of wall-rock are complex. It is difficult to construct double-arch tunnel, and it is necessary to perform some technological guidances to assure the of construction safety. Numerical analysis is used to calculate and analyze the stress and deformation of the fractured mountain body. The result shows that in the course of construction, the wall-rock can maintain stable. A theoretical direction and reference is offered to practical performance. And a new method is also offered.

Due to the diversity of the wet-sprayed fiber reinforced concrete lining structure physico-mechanical parameters and the difficulty of the explicit expression of limit state failure function for concrete strength, the reliability analysis for the wet-sprayed concrete lining structure is difficult to perform. The response surface method is proposed to calculate the reliability of the wet-sprayed concrete lining structure. The calculation process is given.In the determination calculation of the rockmass and tunnel lining structure, the nonlinear finite element method is used while the second order response method is used in the reliability analysis. As a case study, the wet-sprayed fiber reinforced concrete tunnel lining structure for Ganzhou-Longyan Jinhuashan Railway tunnel in soft and weak rockmass, the reliability analysis for the tunnel lining structure is performed using the method proposed. The numerical analysis result shows that the reliability index for the wet-sprayed concrete tunnel lining structure is higher and the tunnel lining structure is in safe state.

High pressure groundwater environment becomes one of the key problems for tunnel construction under complicated hydro-geological conditions in China. The seepage field of surrounding rock is coupled with stress field. According to the failure course of surrounding rock, the coupling mode is divided into 2 types: deformation mode and failure mode. In the course of excavation, if ignoring the failure, the seepage-stress coupling mode includes fill compressed mode in filled crack, wall touching mode in crack without filling, time-depending mode and grout-filled mode. If considering failure, the seepage-stress coupling mode includes failure mode caused by excavation and failure mode under high water pressure. Different geological and hydro-geological conditions and different excavation courses will lead to different coupling courses, the establishment of coupling mode will provide concept model and support for design, construction and disaster prevention.

According to study on coupled thermo-mechanical creep properties of bedded rock salt, it is shown that the deformation within bedded rock salt is out of line; it leads to multiple shearing destruction and becoming grid between the interlayer of bedded rock salt; meanwhile, the pores and fissures are increased; the gas permeability is augmented and it raised 5 orders of magnitude than not disturbance; so natural gas must leak when gas storage cavern under long-term running. The experimental study of gas permeability of bedded rock salt at rheodestruction shows that the relation between gas permeability and effective volume stress is . A mathematical model for long-term running permeability of gas storage cavern in bedded rock salt is established; and the numerical simulation for Jintan Gas Storage Cavern is carried out; the results are as follows: the fissures between the interlayer of bedded rock salt is main aisles of gas permeability; it has strong gas permeability; gas permeability within interlayer is delayed the fissure between interlayer; the speed of gas permeability is decreased with time; at last, it reaches stable state. So the salt-mudstone interlayer has a great impact on permeability of long-term running gas storage cavern of surrounding rock; reasonable running pressure is the important condition to the gas storage cavern without leaking. The results can offer some frame of reference to natural gas permeability research of long-term running storage cavern.

The geological conditions of Baozhen Tunnel are complex, such as high geostress, deep-buried, rich groundwater, very weak and cracked rock masses and bias pressure along the rock seam. During construction, intense deformation and serious failure happened very often. Monitoring data showed that deformation is rapid with long duration, at the same time the deformation presented asymmetric and uneven features. Comparing and analyzing with the monitoring data of surrounding rock and geologic sketch of the work face, the weak intercalation is the key factor of provoking intense deformation and serious failure for sandy shale (whose strength is higher) or macker (whose strength is lower). So combined with the conclusion of triaxial test on different rocks in Baozhen Tunnel; some mechanical models are established according to different composite srructures between weak intercalation and surrounding rock to discuss the evolutionary process. The results show that the deformation and destabilization mechanism of surrounding rock provoked by the weak intercalation.

During the development of hydropower stations in Southwest China, more and more attentions have been paid to the engineering mechanical properties of columnar joints rock mass. As dam foundation of Baihetan Hydropower Station is composed of columnar joints basalt, of which the magnitude of RQD is widely lower and integrity is poor; and the mechanical indices such as deformation modulus, is relatively lower. Meanwhile, the rock mass significantly shows anisotropy. Therefore, it has imposed a certain impacts on the deformation of arch dam, and the stability of abutment, high slope, and underground rock caverns; it has become one of the key technical issues of Baihetan Hydropower Station. As we know, the researches on columnar joints rock mass and related engineering experiences at home and abroad are few. Therefore, in order to obtain the first-hand observation data reflecting mechanical properties of columnar joints rock mass, we plan to develop the large-scale columnar joints experimental cavity. The geologic origin and characteristics of columnar basalt and the design proposal of experimental cavity are introduced here; the combination of in situ experiment and numerical experiment is discussed. Then anisotropic constitutive is use to simulate the excavation and in-situ experiment and the representation sites are appraised.

The basic characteristics, analysis peculiarity and constitutive model of software FLAC3D are introduced. The simulated project is set up based on analyzing the geological conditions and utilizing the hydro-geological model of half infinite space. According to the specific geological and engineering conditions of a certain subsea tunnel, the use of the soft FLAC3D in water inflow computation by taking nine typical profiles as examples is explained. Based on the analysis and comparing the calculation results between analytical method and numerical simulation, the applicable work conditions of the software are summarized. At the same time, some beneficial conclusions are summarized which can be references for tunnel construction organization design and drainage design.

With the comprehensive effect of structure, stress distribution, groundwater, opening mode, etc., displacement time series of the deep buried tunnels’ wall-rock display monotone increasing characteristics and nonlinearity. Based on the responding composition model, the displacement of tunnels’ wall-rock is decomposed into trend item and random item. The trend and random items of displacement time series are predicted by Grey-ENN model, which combines the advantages of GM(1,1) and ANN model. GM(1,1) can forecast the trend of increasing sequence, and ANN model can reduce error by self-adapting of network. Thus the correctness of prediction is assured due to avoiding the problem that forecast result is far away from real one by using GM(1,1) only. The Grey-ENN model is applied to predict the short-term convergence displacement of wall-rock in Baozhen Tunnel based on the in-situ displacement data. The reasonable convergence rule of tunnels wall-rock is achieved, which provides eference for choosing opportunity to do the second support.

Long distance pipeline engineering of natural gas and oil faces the difficulty of traversing loess gully, which has a bad effect on the pipeline construction and operation safety. Based on Duncan-Chang nonlinear constitutive model, mechanical behaviors of slope and soil around inclined shaft have been studied systematically through numerical simulation method, when inclined shaft excavation method is taken to traverse loess gullies. The results indicate that: on the premise of that inclined shaft position is designed outside the most dangerous slide plane of slope, the distance between slope shoulder and inclined shaft entrance at slope top is closer, and the stability of slope and shaft excavated is superior. Aiming at probable situation of vault collapse in inclined shaft, based on numerical simulation analysis results under multiple work conditions, prediction formula for depth of vault yield zone is established by using response surface methods; which has good correlativity and can be used in support design of inclined shaft traversing loess gully or steep slope.

Gezhenpu tunnel is the vital construction project in Liaoning Province, its geoligical condition is complex, and there is cataclastic section exists, the conventional method can not reflect the mechanical behavior. Aiming at above problem, according to without supporting, primary supporting and secondary supporting, geotechnical engineering software FLAC3D is adopted; and large scale numerical grid is constructed, the 3D numerical simulation for dynamic construction process is carried out with 4 meters each step and upper and lower steps. Through simulating and analyzing the stress field, displacement field and plastic zones, the complex mechanical behaviors of excavation and supporting are analyzed. Calculation result shows that the displacement is in accordance with monitoring data, the original secondary supporting scheme can guarantee the stability of surrounding rock.The result of numerical simulation has guiding meaning to the tunnel construction.

Wumeng mountain second tunnel is secondary Line from Liupanshui to Zhanyi of Guiyang-Kunming Railway reconstruction. Banuokuai Railway Station situated gate region was extended to the tunnel about 547 m, which is a large span station for 4 lines. It is the largest span (24.13 m) tunnel in Asia at present. The excavation process of the super-large span station is numerically simulated by three dimensional fast Lagrangian analysis of continua (FLAC3D) to research rationality of the design and construction. And, on the calculation results, the study was focused on secondary stress field, deformation and the plastic area. It should serve as a valuable reference for security of recommendatory construction method and removing scheme of temporary support.

The elastoplastic nonlinear softening-cracking area of surrounding rock model is analyzed. According to the entire theory, the relationship between equivalent stress and strain is deduced from uniaxial compression. Analytic formula of stress distribution and displacement in cracking area of surrounding rock. plastic softened zone and elastic zone are derived. The critical pressure that leads to yield caused by inner pressure is obtained. The analytic formula is applied x widely; and the solutions of Kastner and fully brittle medium based on ideal plastic medium are special cases.

In slurry shield, the working face is supported by the pressed slurry. So it is very important to build up a filter-cake to protect the working face, especially in highly permeable ground where the slurry is easy to penetrate the ground without allowing to build up the required support pressure. The function and quality estimate indices of filter-cake were expounded. A series of filter-cake building up tests were carried out for the Nanjing Yangtze River Tunnel with the apparatus which was developed just for the research—the influence of slurry property on filter-cake quality on the working face of slurry shield. In these tests, the ranges of grain size distribution and density of the slurries were same. As shown in the results, if the viscosity is high and the stability is good, the filter-cake will be easy to build up; it will be thin and compact; and the discharged water will be little. The result of this research is significant in the slurry shield construction.

The stratum of Nanjing Yangtze River Tunnel is mainly fine sand, of which the grain composition is good. If the excavated fine sand is discharged directly, the environment near the piling position is easily polluted; and it is also resources waste without reuse. Based on the above consideration, the main subject of research is that how the discharged fine sand can be reused in the aspect of back grouting, and after the reuse of the fine sand, the back grouting recipe should be regulated in time with the change of grain compostion of excavated fine sand. The results show that the excavated fine sand can be reused in the back grouting substituted for the purchased sand, which can save money groatly.

Based on Visual C # 2008.NET development environment, using AutoCAD ActiveX technology, a redevelopment on AutoCAD2008 is carried out; and an object-oriented program which can rapidly establish 3-D finite element model of initial stress field back calculation. is also developed. The program can automatically calculate the grid nodes’ ground elevations to a certain extension that could be applied to change ground-lines for finite element model. This avoids trivial artificial reading on CAD relief maps to get the surface elevations which would make big errors, thus greatly enhance the efficiency and accuracy. It’s rapid and convenient. The program can rapidly and automatically establish the finite element mesh model used to the initial stress field back calculation and the model could better simulate the state of ups and downs of the topography so as to provide a better base condition for the finite element calculation.

Nondestructive examination to first lining of tunnel is a fast accuracy effective method and an important part of tunnel construction. Although the ground penetrating rader(GPR) has been used for a long time in tunnel detection, the operators are scarce of enough experience so that they are unable to judge and analyze the collected pictures exactly.The principles and judgment of GPR are introduced systematically as an example of first lining detection of road tunnel of Shandong Expreessway, such as cavity, non-compact, lining thickness, distance of steel wed and steel arc. It is important to give experiences and references for operators of GPR.

Combined with the electromagnetic wave propagation characteristics in multi-medium, the different influencing factors of electromagnetic wave propagation characteristics in rock and soil mass medium are analyzed. The waveform graph which is received through the receiving antenna is obtained. It can be seen that ground penetrating radar can detect the less dense and the cavity area intuitively and clearly through the application of ground penetrating radar to detect the grouting effect of the air-raid shelter. The application of ground penetrating radar is well, but it is a developing detection technique. A lot of practical experiences should be accumulated to deal with all kind of questions in probing process correctly and to obtain the exact results.

Landslide is easy to occur at the tunnel portal due to the engineering geological condition, hydrogeological condition and some human activities. Taking into account the landslide formation feature, the geological condition as well as hydrogeological condition of Matou tunnel of Baoji-Tianshui Expressway, the landslide of tunnel portal is analyzed by using nonlinear finite element method. The deformation characteristics and the distribution of plastic zones are obtained, and the sliding surface position is decided. Finally, the reinforcement scheme is proposed. This study can offer a reference for similar engineerings.landslide of tunnel portal; slope stability analysis; finite elements;

Research methods for excavation face stability in shield tunneling are deterministic methods at present. In order to account the variability of soil parameters, reliability method to assess tunnel excavation face stability is proposed. Limit support pressure at excavation face of shield tunneling is studied with numerical simulation. Limit support pressures with different soil parameter samples are forecasted by BP neural network. Then the probability distribution of them is gained. Principle of determining the earth pressure during tunnel excavation by use of earth pressure balance shield machine is discussed theoretically and practically. Limit state equation of excavation face stability in shield tunneling is established. Excavation face stability is calculated with reliability method. The work not only can assess excavation face stability rationally, but also is significance to determine the support pressure scientifically.

A novel upper limit method for rock slope stability analysis is developed. Block element method (BEM) is employed to disperse the computational area and to construct a kinematically admissible velocity field. A nonlinear programming model for the upper limit of safety factor of rock slopes is formulated, in which the velocity field satisfies the constrain conditions including the Mohr-Coulomb yield criterion on the slide surface, the associated flow rule, boundary conditions, as well as the visual work of the block system. The model is solved by the complex shape method. A wedge-block in a rock slope is studied, which verified the efficiency of the method. Finally, its application to the intake slope of Xiaowan Hydropower Station shows the practicability of the method to the slope.

With the construction of high dams with large reservoir in China, the stability problem of slopes lied under atomized rain are serious. Atomized rain usually lasts rather a long time with heavy precipitation, under which it is very difficult to maintain the slope stability. The strength reduction of geomaterial or the load increase under the slope is the mechanism which causes the slope failure. However, the coupling action is less considered. Based on the theoretical analysis, two suggestions are made, the infiltration boundary condition is redefined in seepage analysis; the conception that the matrix suction is not equal with negative pressure of unsaturated zone is formed during the process of stress and strain analysis; and the matrix suction involves in spacing ratio and saturation, etc. As an example, the coupling analysis of seepage and stress is performed with a hydraulic slope under atomized rain.

By way of combined field tests and lab tests, it was studied that the change of moisture of the soil body of the slopes with seasonal temperature, height of slope, varieties of plants on the slope surface, and specific locations of the slope, etc. It is shown that: during freezing of the soil body of the slopes, moisture moves towards the frozen zone; with deeper depth of freezing, change of water content tends to take place at deeper depth too; the herbaceous plants has better moisture absorption function than the grass family on slope surface; the strength of the soil body is affected by variation of water content of the slope and temperature of the soil body. When the temperature of the soil body of the slopes is higher than 0℃, the strength of the soil body is mainly affected by its water content. When the temperature of the soil body of the slopes is lower than 0℃, the strength is mainly affected by temperature. It is proved by triaxial test that: cohesion of the soil body of the slopes increases with increase of water content in the beginning, but starts to decrease with increase of water content when the water content reached a peak. The internal friction angle of the soil body of the slopes generally decreases with increase of water content. This study can provide basis for prevention and treatment of freeze-thaw destabilization of soil road cutting slopes of high-grade highways in seasonally frozen-ground region.

Soil-rock aggregate is a kind of common geomaterial, especially in southwest of China, there are different genetic types and different scales of soil-rock mixed slopes. The stability of these slopes is very important to the slope safety during the construction and the operation of engineering project. In the traditional slope stability analysis, soil-rock mixed slope is always regarded as homogeneous soil slope, and rock blocks are neglected. By this way, the result of slope stability analysis may have large error. Using digital image processing technique, a soil-rock mixed slope is analyzed, and its microstructure model is built. Then, by using FEM shear strength reduction method, the stability of the slope is analyzed based on its real structure. The results indicate that rock blocks make the internal stress field became very heterogeneous, the sliding zone of the soil-rock mixed slope obtained by shear strength reduction method is very zigzag. The stability factor of the soil-rock mixed slope based on its real structure model is higher than that of homogeneous soil slope.

The strength reduction method based on the generalized Hoek-Brown failure criterion is studied. Two basic standards judging the rationality of the strength reduction method are proposed as follows: it coincides with strength reduction method based on the Mohr-Coulomb criterion and represents the real failure characteristics of jointed rock. Based on the two standards, three kinds of strength reduction methods are contrasted by reducing σci and mi , σci and GSI, and mi and GSI with the same factor. Analysis results indicate that the method of reducing mi and GSI with the same factor is more reasonable. Through comparative study of one engineering case, the method of reducing mi and GSI with the same factor can represent real failure characteristic of fractured rock is proved; and then more reliable safety factor during the stability analysis of rock slope is obtained.

Regarding the normal component force acting on the side slope with bedding rock mass as initial defect of structure, buckling behavior of imperfect system in a critical state by using initial post-buckling theory and cusp cata strope model is studied, the mode amplitude equation of equilibrium stability for the side slope with bedding rock mass is established, and a bifurcation neighborhood and the criterion of stability for rock mass slope are derived. The results indicate that the initial defect correction term has determined relation with the ripping factor in cusp catastrophe model; compared with the ideal structure, the critical value for the side slope with bedding rock mass is much larger than its load value at bifurcation point, and is determined by its bifurcation set; the critical value in the real critical sense can be obtained only if the actual defect for side slope with bedding rock mass is considered.

The sliding face and the upside rock body are composed by different mechanical property materials. The upside rock body is elastic medium (called medium 1); the sliding belt medium is strain-softening medium (called medium 2). Damage softening and water softening exist to the medium 2. The shear stress-strain relationship is described by the Weibull’s distribution law. In this way, a swallow-tailed catastrophe model of landslide system is established. Through the analysis, it is discovered that the slope steadily have enormous relatedness with the stiffness ratio λ of medium 1 and medium 2 and the water content of sliding surface medium. Along with the increase of water content the value of ξ0 decreases when slope starts to slide, and the value of sudden jump ξ* decreases when skip occurs. At the same time, the critical value x* increases, the skip quantity △x decreases, and λ increases. It is found that the increase of λ or water content has the same distortion rule to slope. That’s why under the condition of rainfall, the landslide becomes unstable easily.

In order to improve the stability of unsaturated expansive soil slope, the method of covering the slope by geo-membrane is applied. Based on unsaturated seepage theory, a finite element program is used to analyze the wetting-drying cycles caused by rainfall and evaporation on slopes covered by geo-membrane and without geo-membrane. Numerical simulation results are used to analyze the slope stability by limit equilibrium method. It is shown that the slope covered by geo-membrane can maintain the unsaturated state for a long period. The matric suction and safety factor of slope covered by geo-membrane is obviously higher than that of without it. The method of covering the slope by geo-membrane is efficient to improve the stability of unsaturated expansive soil slope.

Slope engineering is a dynamic, fuzzy, open and complicated system, and the factors which control and affect slope stability are random and fuzzy variables. It is difficult to evaluate the stability of complicated slopes by traditional analysis method. Based on the basic theory of fuzzy probability, the fuzzy probability model of stability evaluation of depth cutting slope is proposed. Some main control factors of rock slope, such as slope rock quality coefficient, slope structure coefficient, slope height coefficient, slope angle coefficient and engineering factor effect coefficient etc. are selected. At the same time, the slope stability grades are classified as the very instable, instable, basically stable, stable and very stable in the prediction model. 20 typical slope engineerings are performed by this model. The prediction results agree well with the practical records. It indicates that the fuzzy probability model is reasonable and effective to evaluate the stability of depth cutting slope in rock mass, and provides scientific basis for reducing and preventing of the instability of rock slope.

The prediction of velocity of landslide is a quite complex problem. By using the vertical slice method, the velocity of landslide mass is calculated by the kinematics principle. Then this vertical slice method is applied to a landslide case in Three Gorges Reservoir area. The acceleration and velocity of the landslide mass are analyzed by the vertical slice method. The discontinuous deformation analysis (DDA) is also adopted to simulate the movement process of landslide. The velocities of landslide predicted by the DDA agree well with the ones by the vertical slice method. By using the DDA to simulate the landslide, the initiation of failure and the subsequent kinematics process can be understood clearly.

In order to analyze the deep stability characteristic of bank slopes in new Badong county after reservoir storage, firstly, the Baitu slope whicn is on the medial axis of sector of Badong new county is selected as a typical slope, based on the monitoring data of drilling which is more than 300 meters deep the zonation of deep rock structure is done according to the distribution of weakness zone, rock and integrality, lithologic characteristics. Then, based on the geological strength index GSI, the Hoek-Brown rule is used to estimate the rock strength parameter. Finally, the FLAC numerical simulation is applied to analyze the stability characteristic of the bank slope after reservoir storage. It is concluded that the stability appears to decrease with the rising of water level, but it is not obvious, Baitu slope is in integral stable status. When the strength reduces to limit state, the shear strain increment zones locate in the sixth to tenth weakness zone, when the earthquake effect is considered, the shear strain increment zones expand to the deep part of slope, the potential sliding surface develops consequently to layers.The precondition of failure is the plasticity transfixion of anti-dip part in the front of slope.

In view of deficiencies of the locale bolt-grouting body pullout force test method, by using pressure sensors, displacement sensors, data collection boxes and other electronic components, a new test system is set up. The test system uses data collection box to transform the current signal reflecting the pressure and deformation collected by sensors into digital signal firstly. Then, with corresponding procedures, the data can be dropped chirp and protract test curve at the same time. The test systems implement the data collection and map automatically in the test process, which can help testing persons to predict later situation of the bolt-grouting body, avoiding its tension damage. Taking the distributed stress anchor cable testing condition in Hui-Guan Expressway ZK26+231~ ZK26+520 for example to certificate the utility and reliability of the system.

Based on the analysis of the strength reduction FEM and the finite element iteration method, according to the virtues of two methods, a mixed finite element method for slope stability analysis is proposed, which unites the strength reduction FEM and the finite element iteration method together for slope stability analysis. Firstly, the strength reduction FEM is used to find the position of the possible slip surface, and then, the found slip surface is established in the calculational model; lastly, the stability safety factor of the surface is obtained by the finite element iteration method. The validity and accuracy of the proposed procedure is demonstrated by a numerical example and an engineering practical example.

A new computational model for critical height of reinforced slope is presented based on kinematical approach. A rotational failure mechanism is used and the failure surface is assumed to be a log-spiral surface. In this method, The principle of quasi-cohesion and friction-bar theory are both introduced into the limit analysis of reinforced slope. The SQP method is employed in the optimization scheme. Comparing to the previous experimental results, it is found that the critical height with the composite reinforcement mechanism is slightly higher than that with simplex reinforced theory; and it is more close to the experimental values. In order to evaluate the influence of seismic force, a case study is given. Results show that quasi-cohesion theory is more efficient, while friction-bar theory can be omitted. The proposed method will provide some beneficial guidance for critical height design of reinforced slope.

In frigid area, with heaving bottom, slope protection project will be uplifted or pushed by ice force. Thus slope protection project will be damaged. Polystyrene board can protect the soil base from the negative temperature, and improve ground temperature, minish freezing depth, weaken frost heave. Through the test of physico-mechanical and freeze-thaw properties of polystyrene board, the effect of bulk density, water content, thermal conductivity, compressive strength, frost-thaw cycle times on insulation is analyzed. At last, an anti-freezing design method of slope protection project is proposed.

Reservoir bank landslide is a knotty problem for hydraulic engineering. It is very important to find out the reasons, characteristics and laws of the reservoir bank landslide. It is verified by a host of facts that the bank stability of a reservoir is closely related with variations of the groundwater level. Based on a vast amount of on-the-spot monitoring data, an empirical mathematical model of relations between the bank stability of a reservoir and variations of the groundwater level is given. Ways of on-the-spot monitoring for reservoir bank landslide are introduced.

The calculation of sliding velocity of landslide is the basis of surge prediction. On basis of considering the resistance of water, the formulas advised by The American Society of Civil Engineers and movement equation method are improved. Taking the Xiatudiling landslide in the Three Gorges Reservoir of Zigui county for example, the average velocity and each slice’s acceleration, velocity in the process of sliding are calculated; the comparative analysis about the value and change law of acceleration, velocity is made between pre and post considering the water resistance; and then, the height of initial surge evoked by the landslide is calculated. It is concluded that considering the water resistance to slices entering water is more coincident to practical force condition. The water resistance has great influence on the acceleration, velocity of landslide. When the water resistance is not considered, with the increasing of numbers of slices entering water, the acceleration of landslide increases firstly, then it decreases, and the tendency will not rebound. When the water resistance is considered, the value of water resistance is related with velocity of landslide and area of slope surface; under the comprehensive effect of these two factors, the acceleration of landslide may increase after its decreasing tendency.

The Hongshibao landslide lies in Badong bulk plant area, and it is one of the key landslidetreatment engineerings in the Three Gorges Reservior. Based on long-term monitoring and analysis of internal horizontal displacement and seepage pressure, it shows that there is shallow slow deformation in slopeⅠand Ⅱof Hongshibao landslide, which is affected by rainfall; and the deformation is not obvious in deep layer. The landslide is still under stable condition when the Three Gorges Reservoir impounds from June 2003. However, it has a serious threat to the stability of the landslide that reservoir water level continuously raises and frequently changes in different seasons. Therefore, it should strengthen monitoring and pay more attention to dynamic development of landslide for ensuring safty.

The rock mass structure of jointed rock slope dominates the slope deformation and stability. To assure the safety of the layered rock slope, the analysis method combined the rock mechanics theory, nonlinear finite element analysis and strength reduction factor method is proposed to analyze the stability of the jointed rock slope by using soil nailing structure. In the nonlinear finite element modeling for jointed rock slope with dense joints, assuming the joints distribute evenly in the rock, dense distribution jointed rock material model is established based on continuum mechanics theory. The improved safety factor calculation method for jointed rock slope stability using strength reduction method is proposed. It is suggested to calculate the internal forces of rock slope excavation and after supporting by using given rock mass strength parameters. Then the nonlinear finite element analysis is performed for the constructed rock with the slope rock mass strength parameter decreases gradually. Safty coefficient is obtained till the limit state of rock slope is achieved. The stability of the soil nailing support structure for DK409+989.4~DK410+020 of Yuhuai Railway at right side of Meijiang River is performed by using strength reduction method. The result shows that the safety coefficient of jointed rock slope is 2.3, which indicates that the rock slope is in stable state. The potential failure surface for the soil nailing slope is consistent with the measured maximum tensile stress for the soil nailing, which is also the interface between the elastic zone and the plastic zone.

Any minor structural change of slope stability caused by adjacent excavation might result in serious distortion of the above architecture; therefore, slope foundation stability should be put to first priority in bridge construction. In light of the slope excavation under the F ring bridge of the Chongqing Shibanpo Changjiang Bridge, by means of transfer coefficient methods, the influences of adjacent excavation, vehicle centrifugal force and pile anti-slide force on the slope safety factor are analyzed so as to provide judge criterion for safety of the ring bridge.

The subgrade reclamation on expansive clay slope foundation, because of the strength of expansive soil down under water , will become weak intercalation easily and make the whole embankment slide even slumping along slope. The stability of subgrade on general slope foundation and easily coming into weak intercalation is analyzed by finite element method. The result shows that the stability safety factor and sliding surface of the subgrade can be obtained with the strength reduction finite element method without any hypothesis. And also it is an effective method to analyze stability of subgrade on the complicated slope foundation. It is a method deserving popularizing for analyzing stability of subgrades under complicate geologic conditions.

Toppling failure is one of the main failure modes in rock slope failure. At present, the G-B method put forward by Goodman and Bray is the main limit equilibrium method to solve the toppling failure. Although an idealized model is adopted in G-B method, the result of G-B method generally reflects the basic law of toppling failure. The relationships among the stability of rock slope, the dip angle and thickness of strata and the angle of cut slope are mainly discussed.

Set pair analysis (SPA) is a system analysis method for solving of indeterminate problems with connection degree. The concept of fuzzy connection degree is applied to determine the value of discrepancy coefficient. As a result, more information can be utilized, and the results are more accurate and reasonable. This method is applied to assess the stability of loess cutting slope. The results from practical example with other methods show that it is simple and effective.

With the development of expressways, the slope excavation is increasingly manifold. The slope ratio has influence on the design and investment of project. Hence, the study of optimal slope ratio will make a lot of benefit of economy and society. In order to make sure the excavation engineering safe and economical, on the basis of engineering geological condition analysis, the residual thrust method is used to calculate the stability of nature slope. Then according to the economic analysis, the excavation slope ratio which made the excavation and timbering charge lowest is the optimal slope ratio. The example analysis showed that the optimal ratio of Shitanba Slope was 1:0.65 and the stability analysis and optimal design scheme are practical and reasonable.

Expansive soil reinforced with geogrids to construct embankment, or to strengthen and protect the excavated expansive soils and rock slope is successfully applied; and this techonology has significant values both in the prevention of geological disaster and project construction. So a filling soils with dimensions of 600 mm×600 mm×600 mm laminated shear test apparatus is employed to carry out a series of pull-out tests, with HDPE uniaxial geogrid, and the weathered expansive marlite in Xinxiang, the middle route of the South-to-North Water Transfer Project. The factors of test conditions effecting the pull-out behaviors of the interface, such as distance between geogrid and the test box wall, the pull-out velocity, and the upper load are studied. Results show that the peak value of pull-out force, the strength and tangent rigidity of the interface are not evidently effected by the distance between geogrid and wall of the test box under the undrained conditions. The pull-out force increases rapidly with the increase of pull-out velocity, and the peak value of pull-out force and the interface strength is greater. The geogrid deformation and the relative displacement between geogrid and soils differ with the difference of the upper load and pull-out forces. The heterogeneous degree of friction of the interface distribution along the embeded length of geogrid differs with the different upper load; and this can lead to the abnormal behavior that the average friction of the interface is bigger even when the upper load is smaller.

By shear test of disturbed silty clay at true triaxial apparatus and triaxial apparatus under isotropic consolidation drainage and lateral unloading, the stress-stain curves are obtained. Analysis shows: these curves are nonlinear and strain hardening; curvilinear shape changes from original straight line into curve; stress value of yield point is larger at true triaxial lateral unloading test( constant, is decreased, 0) than at triaxial lateral unloading test; strain value of yield point is smaller at true triaxial lateral unloading test than at triaxial lateral unloading test. Analysis shows: Matsuoka-nakai strength criteria is suitable for sdudy yield property of Wuhan silty clay at lateral unloading.

The theory of super shear stress is briefly introduced, and the influence of the blasting excavation disturbance on the super shear stress is studied, and then, the rock-burst prevention method based on controlling the super shear stress is advised. Then engineering practices are given. The result shows that the sliding of both sides of fractures can be induced by dynamic excavation disturbance under low super shear stress condition and the super shear stress can also be strengthened by dynamic unloading stress wave during blasting excavation. The two conditions can both lead to rock-burst. So the rock-burst prevention can be carried out based on controlling the excavation disturbance. The measurements include the boreholes arrangement, optimization of initiation network and strengthening the supporting.

A study of the effect of acid treatment practice on the geoenvironmental properties of muds in the Ariake Sea tidal mud, is carried out. The results of the field tests undertaken at the Iida tidal flat site and Higashiyoka tidal flat site of the Ariake Sea and the laboratory infiltration test results are presented. It is found that as a consequence of the sea laver acid treatment practice, considerable reduction of salt concentration and pH of the muds has taken place. Furthermore, the measured increased sulfide content of the muds indicates that the acid treatment practice in the tidal flats of the Ariake Sea have produced serious consequences for some benthos inhabiting at the shallow depth of the mud. Finally, the mechanism of the observed change in geoenvironmental properties induced by the sea laver treatment practice is discussed.

In view of geologic origin, the span of saturated degree and matric suction of the gassy sand in Hangzhou metro(MTR) project are analyzed. The shear strength characteristics within the span of matric suction of the gassy sand are determined by GDS unsaturated triaxial system, and the shear strength index of the unsaturated gassy sand is obtained. The results show that the shear strength increases with the increase of matric suction of the gassy sand; and the influence on the shear strength is significant when the moisture content is greater than residual moisture content. The contribution of matric suction to the shear strength is not obvious when the moisture content is less than residual moisture content. The values from shear strength test and from predictive formula are compared and analyzed. Results show that the shear strength formula can be used to describe the strength characteristics of Hangzhou MTR gassy sand reasonably.

The surface’ effective shear stress of closed-crack is introduced into calculating the stress intensity factor (SIF). The value of SIF is calculated when cracks are in different lengths, different angles and different friction coefficients. Introducing isoline, the effective shear stress criterion is developed as follows: (1) the crack grows up along the direction in which the sum of twin shear stress reached minimum on isoline; (2) the crack begins to grow when the crack tip stress intensity factor KII arrived at critical value KIIC. Accordingly, the proposed criterion successfully predicts critical cracking angle of closed-crack. Compared with other criteria in predicting initiation angles , it shows that the effective shear stress criterion is accurate and secure in predicting closed-crack’ fracture.

Under the analysis frozen earth forming process and the fabric premise, embarks from the frozen earth viewing carefully structural feature, regards as the transverse view isotropic solid dielectric which the frozen earth is composed of the ice layer and the dry and hard soil layer caking. According to the theory of composite materials mechanics, in outside the frozen earth isotropic surface and the surface elasticity coefficient and the Poisson’s ratio are obtained. Based on the Tsai-Wu criterion, the transverse isotropic frozen soil strength is perdicted. According to the empirical data, the influence of the different components on the frozen soil elastic constant and strength is analyzed. In the project application, according to the ambient temperature and the soil texture, whether there is the system moisture content supplies, the temperature drop speed and the freeze speed whether synchronization, the frozen soil stress direction and the freeze title page direction special details selects then, thus the indoor and outside test number is reduced largely. Has laid the foundation for the frozen soil project numerical calculation, to further understand that the frozen soil mechanics characteristic so as to provide the theoretical basis.

Researches on factors affecting strength of reinforced soil are performed by using lab triaxial tests. The change law of strength of samples with different reinforced conditions is discussed, and the corresponding factors are tested. The results show that the effect of the reinforced action becomes obviously while the axial strain increases; for the samples with low strength, the strength increases greatly after being reinforced; for the same samples, the higher the strength of reinforced material is, the more obvious the reinforced effect is; for the same reinforced material, the more the reinforced layers are, the smaller the layer spacing is, the more obvious the reinforced effect is; the higher the density of the sample, the more obvious the reinforced effect is.

In order to evaluate more deeply and articularly the deformation and failure mechanism and shear strength parameters of relaxed rock mass structural plane, and to provide reliable evidence for subsequent assessment of consolidation grouting effects of dam foundation and recheck arch dam foundation excavation and design scheme of foundation treatment, the researches on shear resistance of Xiaowan Hydropower Station relaxed rock mass infield and laboratory are carried out.

Using random solid-heat coupled mathematical model and FEM, only considering thermal dilatability and thermal conduction as random variables, plane stain model is adopted to analyze the changes of thermal cracking of rocks caused by thermal stress; and the whole process of thermal cracking of rocks with Gaussian distribution and Weibull distribution laws is simulated. The influences of probability distribution and distributed parameter m on thermal cracking of rocks are pointed out; the relationships between thermal cracking of rocks and time t，the temperature and distributed parameter m, the temperature and time are discussed; the change law of thermal cracking rate between time and temperature is studied.

Based on interpreting the importance of statistical work of soil parameters, uncertainties, the theoretical foundations and superiorities of many statistical methods are analyzed and contrasted. The research results about soil variability are summarized systematically via reviews and collections of the involved literatures at home and abroad, including index parameters, deformation parameters, strength parameters, consolidation parameters of lab tests and the parameters from CPT, VST and SPT. It is shown that the traditional method and the three-sigma rule, which are both based on the random-variable theory, will never overcome defects of model itself in spite of improvements in any case. The random field-based approaches model the soil profiles by superior random field theory and show strong vitality. It will replace the traditional method along with gradually mature of in situ tests finally. The graphical three-sigma rule, converging theoretical advance and applicability, is a worthy recommended method. The results of soil variability show that the variations of laboratory index parameters are small, the laboratory consolidation parameters are big and the other parameters from lab tests and in situ tests are in the middle. The results also show significance for selecting and optimizing parameters and reliability analysis of some important projects.

Aiming at brittle failure of hard rock(taking limestone for example), true triaxial and acoustic emission experiments are adopted to study the mechanical characteristics, deformation and failure mechanisms, characteristics of acoustic emission(AE) activities and law of energy release. The experimental results indicate: (1)Under the unloading stress path, strength of specimens is apparently effected by unloading, and varies in intervals along with the intermediate principal stress. Failure modes of most specimens are splitting. (2)Under the unloading-supporting stress path, the mechanical properties of rock are significantly improved by supporting force. The main failure mode is tensile shear failure. (3) The whole process of AE activity can be divided into 3 active stages (crevasse crack closing stage, unloading damage stage and destruction stage) and 2 relatively quiescence stages (elastic stage and fracture stable development stage). The characterization parameter “absolute energy” of AE can quantitatively describe the brittle failure of hard rock. The results of experiments are similar with rock mass behaviors and support effect in project field so as to provide test basis and guide instruction for engineering practice.

Soft soil has obvious rheological character and it will induce subsidence distortion, landslide etc. serious geotechnical and geologic disasters, and make severe threatening to stability and security of projects. The initializing shear stress and viscosity of sullage soft soil are tested under static load; and the influencing characteristics are analyzed, of which the percentage of clay and water affect the rheological parameters. The mechanism of which the percentage of clay and water affect the rheological parameters are opened out by using the theoretical analysis and technology of structure micrograph. The research results have theoretical and practical significance for us to analyse changing disciplinarian of rheological parameters, reinforce soft soil foundation, raise bearing capacity and whole strength of soft soil.

The exact predication of rockburst is a foundation for the disaster harness of rockburst and engineering measures. An improved calculation model for the predication of rockburst using the theory of set pair analysis (SPA) based on data mining is discussed. A model for data mining in fuzzy difference coefficient using the concept of the approach degree is investigated during the procedure of SPA. The results from the application to practical example and comparisons with other methods are fairly good. And they also show that the improved method of SPA used to forecast intensity of rockburst is feasible and effective.

Based on nearly 100 test specimens from different locations, different depths and different degrees of weathering, under the conditions of different concrete strengths and different water contents, the direct shear.tests have been done. The relation among shearing strength of rock and concrete strength, weathering degree and water content have been studied. The test results show that the concrete strength affects the shearing strength of rock and concrete greatly. The contact shear strength is nearly equal to that of massive structure and sub-massive structure,and thear strength values reduce greatly to that of clastic structure and inter locked structure. The cracking location is not contact area of rock and concrete but partial contact plane and partial structural plane. With the water content increases, the cohesion force and inter-friction degree decreases. Laboratory shear test results only reflect the location of specimens. To gain the contact plane shearing strength, the cohesion force and inter-friction degree is looked as stochastic variables. Regionalized variable and variogram are introduced to represent the rock randomness and structure. Kriging equation is used to calculate weight values of test specimens. At last, the shearings strength of rock and concrete are obtained by statistical method.

Based on upper and lower bound theorems, according to the characters of discontinuous line of stress and velocity, the stress field and the corresponding velocity field were got by the numerical calculation to solve three kinds of boundary value problems. The weight of soil and the friction between soil and retaining wall were taken into account. The stress field satisfied with all velocity boundaries was found. The rigorous solution of earth pressure under discontinuous surface was solved. The computation results showed that the approach which solved the limit equilibrium problem is available.

The mechanical characteristics of unloading rock mass include nonlinearity, anisotropy and so on, and have many differences between assumptions and experiment results with the routine rock mass. The numerical simulation method is used to research the mechanical characteristics of unloading rock mass. The importance of researching the mechanical characteristics of unloading rock mass is described; the conditions of loading and unloading in numerical simulation are studied. Numerical simulation model is established by using ADINA. Analyzing the model and comparing with the experimental result, the law about mechanical characteristics of unloading rock mass is obtained.

Test results prove that the method, making use of artificial neural networks (ANN) for blasting fragment prediction, is completely feasible. The prediction precision of ANN is greatly improved by use of the data after normalizing sample data.

The joints that constitute the fractured rock masses normally change dramatically. After measuring the orientation of numerous joints in a given area, it is imperative to categorize the joints. Unfortunately, there is no widely accepted method to categorize joints at present. Joints are categorized into several clusters by using quick cluster analysis. The parameters of Fisher distribution model are estimated by maximum likelihood, and the model is finally verified by using Pearson test. The results demonstrate that the categorized clusters must be suitable, otherwise cluster centroids would change dramatically and the data around the centroids are not continuous, which leads to the failure of Pearson test. By using the proposed methods, it is effective to categorize the fissures in practice.

Currently, the indentation test is an effective method to characterize the mechanical properties of materials such as metals, polymers and ceramics. The objective of this work is to provide a comprehensive methodology for the characterization of geomaterials (rocks) by microindentation (indentation in microns). The study concerns the calibration of the device and its application to the characterization of rocks. Compared with the conventional axial compression test, Young’s modulus and compression resistance obtained by microindentation test are discussed. On the other hand, for the purpose of the microindentation test under confining pressure, the modified apparatus is presented. Through this type of microindentation, the dependence of sandstone on the confining pressure is shown.

The formula for the tensile strength of rocks under the Brazilian disc test is based on the plane analytic solution of elastic theory, which is obtained through the principle of maximal tensile stress..But the result is very different from the result of direct tensile test.According the data between direct tensile test and arc splitting test of ten kinds of rocks,the rule of 3-D stress because of central angle of arc loading area is analyzed; and adopting 3-D tensile strength principle to analyze the samples, it turns out that this principle is more suitable to Brazilian test.

The principles of distributed fiber optic temperature sensing technology are described briefty. From heat-transfer process of micro-body, a heat-transfer differential equation of porous medium with seepage and internal heat source is deduced. The monitoring equations of different monitoring methods are given. Based on persistent line heat-source, the basic principle of distributed fiber optic sensing technology for leakage monitoring is expounded.

Sludge is an important process of sewage treatment plant. Unsuitable disposal of sludge may induce secondary pollution. With the enhancement of the consciousness and intensity of environmental protection, many geoenvironmental engineers at home and abroad focus on the studying the disposal and utilization technologies of sludge. Based on the summarization of published literatures, the paper discusses the disposal and utilization technologies of sludge are discussed. The commonly using methods of sludge treatment are summarized, including common landfill, sludge incineration, agriculture utilization, solidification and stabilization, and bioremediation. The advantages and disadvantages of various methods are analyzed and evaluated

Using the large triaxial apparatus, the wetting character of coayse-grained material for Shuangjiangkou dam is studied under different confining pressures and different wet stress levels; and its the shearing strength after wet distortion. Is analyzed The shearing strength indices approximately equal under different wet stress levels; its c value is between in air-dried condition, and saturated condition, approaches the valu in saturated condition; but the ? has the same rule, its value slightly below the consolidated air exhaust shear test, value and approaches in value in saturated condition.

Testing studies of transition zone material of sandstone for Shuangjiangkou high embankment dam are performed with large-scale triaxial apparatus. Through test of constant ?3 stress path on transition zone materials with different sample sizes and different maximum sizes of grain, the influences of D, dmax on stress-strain-strength characteristics are analyzed to study the scale effect that exists in laboratory tests. The results indicate that the failure principal stress, internal friction angle and initial tangent elastic modulus increase as the sample size decreases for a kind of sample with same grading. And the increasing trend of failure principal stress and internal friction angle is obvious under low confining pressure, while the increasing range decreases with the raising of confining pressure. For the same size sample, the failure principal stress and internal friction angle increase with the increasing of maximum sizes of grain and the increasing trend is also significant under low confining pressure.

Through preparing different water contents dredged material (DM), the influences of water content on the cement solidification effect of DM are studied. Test results show that the unconfined compressive strength of cement solidified DM decreases with increasing initial water content in power relation. With the increase of initial water content, the plasticity of cement solidified DM increases, failure strain increases and cohesion decreases. With the increase of initial water content, the quantity of cement hydration products per unit volume decreases, the whole strength is low. In practical engineering, it is better to reduce the initial water content for more economical benefit.

Lots of sludge solidifying materials are used for sludge treatment, but the role of every material is not clear. The orthogonal test is carried out to optimize materials and reveal the influences of Portland solidification materials, alkali solidification materials and clay mineral materials. Test results show that the Portland solidification material and alkali solidification material play a major role in solidified sludge. Basic materials provide early strength for solidified sludge Portland solidification material provides the latter part strength. The clay mineral materials can construct skeleton to form monolithic body.

when environment is deteriorating continuely, and the fitting soils soil for engineering are short and become more expensive. Technique for converting soft sludge to fitting engineering soil with content strength is very important and urgent. By mixing an extent lime to sludge dredged from riverway,and then, carrying on vacuum preloading added calcium lignosulfonate, serials of quality have been improved, including coefficient of permeability, unconfined compression strength and settlement deformation etc., at one time, the relationships of dosages of calcium lignosulfonate and stable drainage-water volume and stable settlement and unconfined compression strength and void ratio would be studied and analyzed. The test results show that the strength is growing more quickly, hole volume of soil is being squeezed to a smaller, and subsequent settlement is becoming more little under lower water content situation after vacuum preloading. The soil will be consolidated to satisfy the standard qualification of fill. At last, through economical analysis, it is shown that this way could be accepted.

Wetting-drying cycle in expansive soil is studied by experiments, and the expansive soil is borrowed from construction site of widening alteration of Jiangsu No. 222 provincial road. The experiments include direct shear test and unconfined compressive strength test. Through analyzing the experimental data, the change law of expansive soil with the strength of wetting-drying cycle is found out. The experiments can supply the reliable data for practical engineering.

Nowadays, harmonious coexistence between human and environment is important to social sustainable development. Various questions between human and environment are brought for the municipal solid waste increases sharply. The sanitary landfill method is considered as the most extensive and completed method which has got more and more concerns and been studied. The construction of sanitary landfill is closely related with a great deal of respects in the field of environmental geotechnology. On the basis of current materials which introduce the domestic and international relevant development situations, in accordance with the characteristics of Xi’an city, the following aspects: landfill site and type, solid waste engineering property index, seepage prevention treatment, settlement computation and slope stability are discussed. The corresponding suggestion and expected directions are also given.

The composite foundations are getting more and more application to construction engineering. However, the research on their seismic behavior under dynamic loading, especially under seismic loading, is quite limited. Now, the seismic response analysis in the time domain is performed with ADINA program, considering the interactions among foundation, footing and superstructure. The influence of earth surface peak acceleration, displacement and pile moment, shearing force under different pile body moduli, the influence of peak moment and accumulated plastic curvature of superstructure under different bedding cushion characters (different moduli, different depths), are analyzed. Based on these analyses, some conclusions which may be useful for seismic design of this type composite foundation are drawn.

For the problem of wetting collapsible loess foundation in railway and highway and dam engineering, the in situ experiment of collapsible loess foundation, dealt with a new comprehensive treatment technology named IDITI method which includes impedance, drainage, interdiction, truncation and infiltration, was carried out under wetting and loading. The results show the settlement of loess foundation dealt with IDITI method is small under wetting and loading and the water content keep invariable after surface founder. The IDITI method is with the anti-seepage and draining double effects. The foundering loess foundation dealt with IDITI method was simulated by numerical method, so as to repeal the water content distribution of stratum. The calculating result also shows the increase of water content is small in treatment foundation. So the IDITI method is feasible.

Deep foundation pit is affected by several factors, and becomes the key problem in geotechnical engineering. The deformation must be controlled rigorously according to the actual situation surrounding environment and building safety grade. After analyzing the measured data of deformation, the prediction of deformation of supporting structure is made, and the safety of deep foundation pit is guranteed. To insure the construction quality of the deep foundation pit, deformation observation of the supporting structure is carried out in many deep pit in order to predict the development of deformation accurately during construction. A radial basis function (RBF) neural network learning algorithm based on immune recognition principle is studied. In the algorithm, the input data are regarded as antigens, and antibodies are regarded as the compression mapping of antigenas, i.e. the hidden layer centers. The weights of the output layer are determined by adopting the least square method, which can improve convergence speed and precision of the RBF neural network. A new time series prediction method based on artificial immune RBF neural network is also presented, and its application is discussed. The simulation experiment indicates that this method is effective in time series prediction.

Discontinuous Galerkin method(DGM) used node displacement approximations as trial functions, and weakened the continuity of first order and n-th order differential in the internal element boundary, reduced the difficulty to construct the shape functions, so this method is especially fit for solving the problem of higher order differential equation. Based on the principle of DGM, the integral weak form of the forth order differential control equation of elastic foundation beam is established. Numerical calculation and convergence analysis are carried out by the computer program. The results of calculation show that it is efficient for DGM to solve the elastic foundation beam problems.

The Dalongtan Reservoir Project is located in Jingxi County of Guangxi Autonomous Region; of which the masonry dam, is 249 meters long; it was completed and impounded in 1963. The dam foundation occurred a large number of water leakage; a number of vortex of leakage appeared; water flows under the dam into lower reaches. When emptying the reservoir, it is found that some karst collapses in the reservoir bottom. The past used conventional methods can only understand a single exploration drilling vertical direction of the geological conditions, not conducive to identify foundation for the development of horizontal and cave with broken spatial distribution. CT-between electromagnetic detection with drilling technology integration, it can make up for this deficiency. CT-between electromagnetic detection Dalongtan Reservoir dam foundation in the exploration of karst results show that this approach is feasible and effective.

In order to analyze the influence of ground shear modulus on train-induced dynamic stresses, the contact force between reaction of foundation surface and dynamic stresses induced by train are computed for different moduli at two speeds based on the solution of stress responce induced by moving load. It is found that the contact force decreases with shear modulus increasing for both speeds. But the variation of dynamic stress with shear modulus is different at different speeds.

Tunneling has certain influences on adjacent pile foundations, even on safety and stability of overall building. The large finite element analytical software ABAQUS is employed to simulate and analyze the influence on the working performance of adjacent pile foundation induced by tunneling based on an engineering example. Firstly the reaction and the change laws of single pile induced by the changes of horizontal distance between adjacent pile foundation and vertical axial line and the change of pile length are analyzed. Then, the responses of pile group induced by adjacent tunneling are studied, and some comparisons between pile group and single pile are made. Finally, some conclusions are drawn to offer the references to related engineering.

A modified three-dimensional plastic limit analysis method is proposed for lateral bearing capacity of the large-diameter pipe pile in the inhomogeneous and anisotropic soft ground. The bearing capacity is also numerically analyzed utilizing the FEM software ABAQUS, in which the soil is assumed to obey the Hill’s yield criterion. Both the failure mechanism assumed and the plastic limit analysis predictions are validated by numerical computations based on FEM. Through a parametric study, it is shown that the effect of soil strength anisotropy on the bearing capacity of the structure in inhomogeneous soil is smaller than that in homogeneous soft ground.

Through analyzing of the unconfined compressive strength and electrical resistivity of the cement-soil core samples from a test site of T-shaped bidirectional cement-soil deep mixing columns, some conclusions are drawn as follows. The quality of the cement-soil deep mixing column body is closely related to its construction technology. Under a certain kind of construction technology, the cement mixing ratio and cement-soil mixing homogeneity are two important factors effecting the column body quality. The vertical electrical resistivity of a core sample at any given depth is higher than its horizontal electrical resistivity. There exists a good linear relationship between the unconfined compressive strength and electrical resistivity; so the strength of the core samples can be evaluated from their electrical resistivity. The standard deviation of horizontal electrical resistivity can be used to analyze the cement mixing ratio and cement-soil mixing homogeneity. Therefore, the quantitative analysis of the column body through electrical resistivity and related index of cement-soil under the condition of large-scale column construction is an economic, nondestructive, simple and scientific detection method.

A research based on the static load test is studied, and according to the Q-S curve the ultimate bearing capacity of single pile is confirmed. The relationship between the ultimate bearing capacity of single pile and the final pressure of static pile is disscussed with mathematical statistics method; and a related estimation method between them is proposed. It can provide certain basis for the further promotion and the application of static pressure pipe pile technology .

3# ore cluster is striped mining turn into underground due to exploiting requirement; and the parameters of rock mass mechanics are determined by way of rock structure investigation, sampling, indoor rock mechanics experiment and engineering analogy its aim to reclaiming resource mostly and guaranteeing 3# ore cluster overlying rural road safety operation; then unloading simulation with 3D finite elements is applied based on three exploiting scheme methods; the simulation results are as fellows: the settlement height of road ground surface is increased nonlinearly with increasing height of exploitation; and the more exploiting height, the more settlement height; the height of settlement is 7cm, 20 cm, 50 cm and 135 cm when exploitation horizon is 1288, 1300, 1310 and 1320 correspondingly. The stabilization of rock mass would be damaged when exploiting horizon is more than 1300. The settlement height is less than 15 cm by commercial test while exploiting horizon in 1300, which could be guaranteed safety of road operation. The method of applying with synthesis analysis of rock mass mechanics parameters and unloading simulation to analyze rock mass stabilization is effective and feasible by commercial test.

The design philosophy，calculational methods of bearing capacity and settlement of multi-element composite pile foundation with long and short piles are discussed. Meanwhile, taking foundation treatment engineering of compounding with lime-sand pile and CFG pile for example, the design, construction technique and treating effect on it are described. Engineering practice shows that, the composite pile foundation with long and short piles has multifarious compounding form, which do not restrict types of piles, which can actualize single-element or multi-element compounding, and so it can make full use of the potentials of soil and long and short piles. Long and short piles foundation demands fewer long piles, but it can effectively improve foundation bearing capacity; and it can control the average settlement and differential settlement; effectively, therefore, it will be very immensity foreground of engineering practice.

A new method which can reduce the of derivation workload is developed to obtain the transfer matrix for nonaxisymmetric Biot consolidation of multilayered soils. Based on the nonaxisymmetric Biot consolidation equations in the cylindrical coordinate system, introducing intermediate variables, together with the technique of the Fourier expansions with respect to coordinate ?, and taking Laplace-Hankel transform with respect to time t and coordinates r, two sets of ordinary differential equations of 6 order and 2 order for Biot consolidation are obtained; then the transfer matrix for the nonaxisymmetric Biot consolidation of a single layer soil is acquired by taking Laplace transform and its inverse with respect to coordinates z. The solution of multilayered soils in the Laplace-Hankel transform domain is obtained by using the transfer matrix method combined with the continuity conditions of adjacent layers and boundary conditions. The solution in physical domain can be obtained by inverting the Laplace-Hankel transforms. Numerical calculations and analysis are carried out. The method has a high speed of computation and is convenient for engineering application.

Using the composite stiffness principle and double parameters method, and choosing suitable parameters, ground displacement, angle and maximum bending moment of laterally loaded pile with four kinds of section types such as reinforced concrete pipe pile, reinforced concrete circular pile, reinforced concrete rectangular pile and steel tube confined concrete pile in different engineering geological conditions are calculated. Crack width of reinforced concrete pile and strength of steel tube confined concrete pile are checked; analysis and comparison of bearing capacities of long piles with different kinds of section types under same laterally loads in different engineering geological conditions are also made. These results can be used for optimum design of reasonable section type of laterally loaded piles of large building structures. The comprehensive evaluation shows that the reinforced concrete pipe pile is better for sand soil and clay soil; steel tube confined concrete pile is better for weathered rock.

The Qiantang River has high water level because of the tidewater. It is difficult question for foundation pit how to guarantee slope safety and construction convenience on the condition of high water level. The dewafering design and monitoring methods of building foundation pit nearby the Qiantang River are carried out according to the engineering case. The effects of foundation pit dewafering. The results show the foundation pit dewafering is effective by means of deep well for the soil layers of large permeability coefficient. When the water level of the Qiantang River is high, it is necessary to lower the high water lever by use of cut-off well.

Based on the service ambient with sulflate condition, the evolution of strength unconfining, elastic modulus and stress-strain curve of corresponding samples under various conditions are investigated by experimental simulation method; the deterioration of mechanical properties of soil cement is also studied. Results show that the parameters of different rations of cement to soil and different water contents and ambient condition have great influence on strength and elastic modulus of soil cement. The mechanical behaviors such as compressive strength and elastic modulus of soil cement can be degraded by underground water with sulfate due to complicated physicochemical reaction between soil cement and water and sulfate ion in ambient. And the bad effects of sulfate ion in ambient on mechanical behaviors of soil cement is prominent within 90 d ages.

Experimental study and theoretical analysis indicate that effective length of flexible piles exists. Considering the resistance of rigid foundation to the relative displacement between piles and soils, assuming the frictional resistance distributed as triangle form, and based on the pile-soil compatible deformation, the effective length of piles is deduced. And the settlement of flexible piles composite foundation is divided into three sections to be calculated. Comparing the method introduced in this paper with several other methods, it is proved that the method is effective and feasible.

For the bearing capacity problems of man-made crust (MMC) with solidified dredged sediment over dredged wastes dump sites, the effects of the MMC unconfined compressive strength, MMC thickness and sediment undrained shear strength to the ultimate bearing capacity of the MMC over dredged wastes dump sites were studied with model test. Test results show that the ultimate bearing capacity increases exponentially with the increase of MMC unconfined compressive strength, and increases linearly with the increase of MMC thickness.

Treatment of defect pile is a difficult issue in engineering construction. Taking Dandu Bridge project as an example, in which the concrete strength of pile foundation does not meet the design requirements, and on the basis of engineering specification and empirical values of pile-soil parameters, the treatments of defect pile are proposed. The comparison between the vertical and the horizontal bearing capacities of the defect pile before and after the treatment is analyzed thoroughly; and the analysis can be used as references.

As a new type support structure, anti-slide micropile has some distinctive advantages. It has been widely used in geotechnical engineering practice. The development of the anti-slide micropiles, including the engineering application, experimental and design calculation are described. According to the research on application development, some problems and suggestions are proposed.

Tailings pond is a place where is used for depositing tailings of the metal and nonmetal mine after the selecting process. It is one of the high potential energy and human-caused mud-rock flows. It will bring huge harms to the district peripheral environment and downstream inhabitant's life and property when tailings pond’s paroxysmal accidents happen. In view of the quantity of small and medium-sized tailings pond, the lower safety management level, furthermore, diversified and uncertain causes during accidents, the paper has made hierarchical structure model according to the influence factors of tailings pond safety operation. Using Delphi method to construct correlation factor’s judgment matrix, the combination of qualitative and quantitative analytic hierarchy process (AHP) is applied; and finally can be obtained in the weight of coefficient and arrayed in order. The analysis shows that the biggest influence factor is the expel-flood system. the second is the embankment system, manage or maintenance, back-water and transportation system. Therefore the related unit may depend on the sequences of the facility to have constituted respectively guard measure, which could supply guiding sense and reference value so as to eliminate each kind of accident hidden dangers and enhance the management level and ensure the tailings pond safety operation.