By means of remedying stress on the slip surface and taking the whole sliding body as the loaded object, a global limit equilibrium analysis for the sliding body is proposed. Because all those relevant area integrals over the sliding body are transformed into the relevant boundary integrals through Green’s formula; meanwhile, no slices are necessary when implementing the proposed method. The proposed method enjoys excellent numerical properties and can be easily generalized to the three-dimensional situations in which all the six equilibrium conditions can be satisfied. This study demonstrates the application of the procedure to two- dimensional situations.

Using the coupled thermo-hydro-mechanical model for saturated-unsaturated porous media developed by the author and taking one set of real physical and mechanical parameters of buffer material, rockmass and canister (replaced by heater) as the basic computation condition, this paper conducts 2D FEM analyses for a hypothetical nuclear waste repository, in which high, middle and low permeability values were applied. Though investigating the change of magnitudes and directions of the flow velocities in the near field, it is realized that: under the condition that the other computation parameters are the same, the higher the permeability of the buffer, the faster the flow, and the time for the buffer to enter a saturated state is also shorter; after the buffer reaches the saturation state if the vitrified waste releases heat continuously, the action of the temperature gradient in the near field may exceed the action of the hydraulic gradient, so that the direction of the flow velocity reverses and the water transports from the inside to the outside; the flow velocity fields have an obvious difference according to different permeability values so that the diffusion of radioactive nuclide with underground water flow is also complex and changeable.

The motion and soil pressure of air dried sands are studied based on field observations and investigations. First, the driving and resisting forces for movement of dry sands, which is regarded as a continuous medium that can flow, are analysed thoroughly. Then the equations for velocity distribution along vertical direction of the dry sand flow and that for velocity of sand mass sliding along the subface and top surface are derived. Finally, a calculation model for the horizontal earth pressure of granular flowing class or sands on the retaining wall is derived in connection with practical retaining works, in which the dry sands are treated as a triangular body.

Based on dynamic relaxation of discrete element method (DEM), a control displacement solution for displacement integral is proposed to solve the problem caused by unreasonable time-step interval impacting on the stability of the result. The time-step interval is determined by pre-calculating the displacements of the discrete blocks. The proposed solution not only solves the problem of excessive overlap between blocks, but also improves the precision of displacement integral and calculating efficiency. The relevant program is developed with its flow chart, and a typical example is given in this paper.

The deformation of normal roadbed is mainly controlled by compaction of soils, but that of the permafrost roadbed in Qinghai-Tibet Railway is mainly influenced and controlled by cryogenic course. The results obtained from analysis of the course after construction of the railway and the data from in-situ engineering tests have pointed out that there exists an intimate relationship between the deformation of permafrost embankment in different phases and the soil’s cryogenic course. The results also show that if man can control the stabilizing time of the cryogenic course and the ground’s temperature field configuration of the filling roadbed, then the deformation of the roadbed can be reduced during the cryogenic course and the long-term operation course of the railway; thus ensuring the long-term stability of the roadbed project in permafrost regions effectively. This has been proved right in the engineering practice of the construction of Qinghai-Tibet Railway on permafrost soils.

The viscoelastic transient dynamic response of transversely isotropic fluid-saturated poro-elastic half-space for non-axisymmetrical dynamic load applied on surface is studied under rectangular coordinates. Based on Biot’s theory of porous media, the three dimension u-w type dynamic equations are drawn for transversely isotropic fluid-saturated porous media. Through rigorous theoretical deduction, the closed-form solutions for transversely isotropic fluid-saturated poro-viscoelastic media excited by non- axisymmetrical dynamic forces is derived by means of Laplace transform and double Fourier transform. The transient dynamic response of transversely isotropic fluid-saturated poro-viscoelastic half-space media is studied using initial and boundary conditions. The solution in time domain can be evaluated by the numerical Laplace transforms and Fourier inverse transforms. Comparisons with the existing closed-form solutions for rectangular foundation loaded steady vibration on an elastic half-space are made to confirm the accuracy of the present solutions. This study is reasonable for engineering practice and provides an effective method for transversely isotropic fluid-saturated poro-elastic media.

The problem of the total suction of unsaturated soils is an important branch in the studies of unsaturated soil mechanics. The theory of aqueous film is generally applied to petrochemical and soil sciences. On the basic points, this paper expands the aqueous film scope in the theory to the free water(gravity water) that results from the action of hydrate water, capillary effect and matrix suction. The corresponding disjoining pressure of aqueous films includes matrix suction and capillary action, accordingly; the total suction in unsaturated soils can be expressed as the disjoining pressure of aqueous films. The total suction of unsaturated soils is analyzed in the aspect of their characters using the aqueous film theory; the effect of the aqueous film on the total is then discussed. On this basis, the formula to calculate the total suction is deduced in the significance of the generalized unsaturated soil’s aqueous film theory; and finally, the relationship between the unsaturated soil’s total suction and the saturability when the soil has different sizes is given. The theoretical computation result is well accordant with the real situation, showing that the generalized aqueous theory is of significance to guiding the study of the total suction of unsaturated soils to a certain degree.

The swelling-shrinking mechanism of expansive soils was expounded; and the swelling force concept was analyzed. It was pointed out that the swelling force defined by nomenclature standard GB/T50279-98 is the maximum welling force or limiting swelling force. Then a new concept of physical swelling force was put forward, as its test method. It was the first time that the study was carried out about the variation regulation of physical swelling force changing with moistening degree. And it was performed that the trial research on the rules of swelling force with moistening degree, primary dry density, primary moisture content and so on, as well as the rule of swelling force with identical soil sample after various degree dehumidifying. Accordingly, some valuable conclusions were drawn, which made it more deeply to catch on the inotion of swelling force and more practically to be utilized.

The mechanism of passive piles to keep out the soil layers that move laterally is mainly the soil arching effect between piles; this effect is a phenomenon to transfer stresses from a yielding mass onto the adjacent stationary part of the soils. The geotechnial analysis software package named Plaxis tunnel 3D1.2 is used to study the mechanism and behavior of soil arching effects in passive piles due to surcharge loads using three dimensional finite element method. Limitations of two-dimensional finite element analysis used by former researchers for soil arching effect are discussed in brief. Taking into account of the effect of passive pile displacement, the geotechnical two-dimensional finite element software Plaxis 8.2 is used to study the behavior of soil arching effect. And the effects of different factors on soil arching effect and the ratio of loads on piles to that on soils are depicted, such as soil properties, piles spacing ratio, passive pile displacement, and the interface behaviors between pile and soils.

Soil and rock mixture is a kind of highly inhomogeneous and noncontinuous material which is different from soil and rock mass, being widely distributed over the Three Gorges Reservoir bank slopes. Considering that the water fluctuation of the reservoir would cause soil water content to change, the law, under which the shear strength parameters for soil and rock mixture vary in accordance with water content's varying, is studied. The relationship among c, ? and water content of the mixture with different macadam contents is established based on numerous tests. It could be a quantized basis for evaluating and enhancing the stability of the Three Gorges Reservoir bank slopes.

It is known from the analysis and research on 162 roof-falling accidences occurring in coal mining roadway supported by bolts that the deteriorative combination of roof strata is the major reason that accounts for percent 66 of the total accidences. RFPA2d system (the system of rock failure process analysis, developed by Northeastern University) is used to simulate the deteriorative process of different strata combination roof. The result suggest that the deterioration of strata combination is related to the change of soft interlayer positions, the thickness of hard strata, the ratio of height and span, and the thickness change of soft strata in the direct roof. The deteriorative rupture of strata combination results from the tensile failure, shear failure and their mutual action. Under the action of shear stress, the whole roof falls down; under the action of deadweight stresses, flexural failure of roof strata takes place; whereas under the mutual action of shear stress and tensile stress, the failure configuration of the laminated roof strata presents a form of roof-falling arch.

Taking a tunnel engineering case as background, this paper makes multiple measurements during the construction process of tunnel’s portal section, including convergence deformations of surrounding rocks, stresses of bolts, stresses and deformations of primary and secondary liners, which give a great number of testing data. On this basis, numerical analysis is performed, the results provide reliable and scientific basis for both design and construction salty of the liners. Not only can all this work guide constructing technique of the tunnel under consideration but also accumulate valuable referential data for the projects of the same kind.

As an effective method of rock-soil reinforcement, the grouting technique has been widely used in civil engineering and well practiced; but the theoretical study is seldom concerned. In order to study the mechanism of soil reinforcement by pressure grouting, this paper, on the basis of brief analysis of the principle of sleeve-valve-grouting and grouting mechanism types, adopts a program of Particle Flow Code to simulate the effect of soil mass reinforcement under different grouting pressures in a single hole. With the increment of grouting pressures, the soil becomes denser; and with the increment of tensile stress in soil, the crack-induced grouting effect results, especially the special replacement ratio becomes great in soils surrounding the grouting hole. At the same time, the procedures of grouting slurry spreading, soil masses compacting and induced split grouting effect are also simulated. The results of simulation have also been verified by an in-situ grouting test. The technique of the sleeve-valve-pipe grouting has been theoretically proved to be a feasible method to reinforce soil masses.

To predict the run out distance and extent of the hazard area of rainfall-induced debris flows, we proposed a depth-averaged two-dimensional numerical model, in which the debris and water mixture is assumed to be a uniform continuous, incompressible, unsteady Newtonian turbulence fluid. As raster grid networks of digital elevation model in GIS can be used as the finite difference mesh, the continuity and momentum equations are solved numerically using the finite difference method. All the input data and output are processed in GIS. The model is applied to simulate the rainfall-induced real debris flow of July 20, 2003, in Minamata City of southern Kyushu, Japan. The simulation reproduces the propagation of the real debris flow; and the results are in good agreement with the field investigation. The two-dimensional numerical simulation using GIS can be used to estimate the potentially inundated areas, the potentially dangerous homes and roads for hazard and risk analysis.

Such unfavorable structural planes as weak interlayers play a decisive role to the stability of rocks surrounding underground openings in some cases and the safety of supporting structures. Using a FEM program FINAL of Austria that adopts a COJO element a perfect element to simulate the characters of weak interlayers, this paper has conducted systematic numerical tests to study the stability of a tunnel surrounded by rocks containing weak interlayers and the safety of supporting structures. In studying, the emphases are put on three situations where the interlayers are distributed at intervals of 0.2 spans, 0.5 spans and 1.0 spans respectively. Some quantificational results about the influence of weak interlayers with those three different spacing intervals are summarized, especially the influence on the deformation, stress of surrounding rocks as well as the inner force of shotcrete supporting structure. These results have referential and guiding significance to the site selection and layout, the majorization of supporting system and the construction of underground openings of the same kind.

80 % of silts abundantly contained in the Yellow River water rapidly deposit at the River estuary. From previous investigation, it was found that the topsoils on the tide flat of Yellow River delta have been in a nonuniform consolidation state. In order to reveal the mechanism of aforementioned phenomena, a series of experiments were conducted on the tide flat of Diaokou delta-lobe which lies in the north of Yellow River delta. The fluid sediments imitating the rapidly deposited seabed silts were made in situ, and the fluid sediments were promptly filled into a one-meter deep pit excavated at the tide flat. By field-testing methods, such as static cone penetration test, field vane shear test and pore water piezometer test, the variation of strength and pore water pressure are measured at real time. It is shown from the testing data that the consolidation speed of the rapidly deposited seabed silts measured by water piezometer in situ is much quicker than the speed calculated through the Terzaghi’s one-dimensional consolidation theory. It is also shown that after consolidation compression had completed, the strength of such silts increased unequally along the depth continuously. Thus the rapidly deposited silts present a nonuniform consolidation state and a quasi-overconsolidated state, which is similar to undisturbed soils of the Yellow River estuary. Analyses show that the formation of such quasi-overconsolidated state and nonuniformity changes of strength along depth are attributable to the coupling effects of wave and tide loading and that long-term effect of wave loading which can cause the accumulation of excess pore water pressure within certain depth is the fully convincing evidence to form the crust layer of tide flat topsoil at the Yellow River estuary.

Based on seepage characteristics of core dams, seepage analysis model and dam slope permeability stability analysis model are established. And more, according to compression characteristics of soft ground under dam, the model of seepage analysis related to current stress state is also put forward. For different water level operating modes, the models are applied to calculation of typical earth dam section on soft foundation of a hydro-project. The effect of seepage prevention of core wall and the influence on seepage stability of soft clay layer are analyzed in detail.

On the basis of in-situ survey and landslide controlling design, a contact FEM program using contact elements is designed in the light of the characteristic of the interaction between piles and soils. Then, the anti-sliding effectiveness of prestressed cable piles is evaluated according to the calculation results of such factors as force-bearing distribution, pile shaft bending moment, displacement and prestress etc. Finally, an optimum prestress value for prestressed anti-sliding cable piles is suggested, which is of significance for guiding engineering design to a certain degree.

The stress-path of the soilmass surrounding the periphery of a foundation pit project during excavation is simulated using a true triaxial unit; and two kinds of unloading tests are conducted under drainage and undrainage conditions respectively. It can be known from the comparison between the testing results that there is a remarkable difference in the stress-strain relationship of the soilmass provided the drainage conditions are different, which shows that the drainage, condition has an effect to a certain degree on the soilmass’s deformability. Further studies are conducted on the relationship between generalized shear stress and generalized shear strain under drainage conditions during unloading, the results showing the nonlinear relationship of those strain and stress. Finally, the equation to calculated the soil’s unloading shear modulus is deduced when the intermediate principal stress coefficient is defined in the real stress-strain path of the soils.

Rainfall and its infiltration into a soil-rock-mixture slope is one of the most important factors affecting slope stability. The problem of soil-rock-mixture slope instability caused by rainfall has been paid close attention by people all the time, but the study on this problem not enough systemic and thorough. In order to improve our understanding of the fundamental mechanism of rainfall infiltration induced landslides in soil-rock-mixture landslide and to clarify some of important characteristic of slope performance, artificial rainfall simulation tests and field synthetic monitored method were carried out on a typical soil-rock-mixture slope in Guizhou province near Shangrui Freeway. The monitored results demonstrate that the deformed zone of soil-rock-mixture landslides caused by rainfall infiltration lies within the top 0~4 m soil layer, where the deformation value of slope surface is the biggest, which gradually reducing from dome to the deep part of slope. The average percentage of infiltration during the first 2 hours is 86 %, it reduces gradually with time later because of the increase of the surface runoff. The average percentage of infiltration drop to a relatively stable value (50 %) 6 hours later. Rainfall infiltration leads pore-water pressure to increase, which may result in a reduction of shear strength due to a decrease in effective stress and wetting-induced softening. The double effects of rainfall infiltration are the main reasons of rainfall infiltration induced landslides in soil-rock-mixture slope.

By soil samples soaking, the performance of a medium expansive soil embankment covered by lime-treated soil subjected to weather influence is simulated; the variant mechanical and deformation behaviors in soaking and non-soaking statuses are investigated through field direct shear tests, plate loading tests and swelling ratio tests. Based on the above test results, an analytic model of embankment subjected to weather influence is established; then the pavement deformation due to subsoil performance changes under soaking swelling and traffic loading conditions is calculated. According to the comparison between computed differential settlement and deformation allowance, the probability of pavement structure damage is evaluated, which is of referential significance to the design of medium expansive soil embankment.

3D-FEM is applied to simulate the construction of parallel shield tunnels, and the laws of displacement, deformation and internal force of the old tunnel are analyzed along with the dynamic driving of the new one. In analyzing the interaction between shield machine and lining structure is taken into consideration in the model, as well as the transverse isotropy of lining structure. The results show that in the existent tunnel longitudinal nonuniform settlement and lateral displacement appear around the shield machine, and traverse torsion occurs behind the shield machine. The construction of new tunnel will apply the “lateral loading” effects to the old one, decrease the moment and increase the axial force in the traverse section, and make the internal force state of left and right sides to be not symmetrical any more. The longitudinal force-bearing state of the existent tunnel experiences a process of first compression followed by tension, and the most unfavorable stress state appears in its side far away from the new one. The thrust force, grouting pressure, and stratum loss, which should be controlled strictly, have great effects on the old tunnel; and the counterforce of thrust has a minor effect comparatively. This work offers references for the construction of similar engineering.

Micro seismic phenomenon is an important information before fracturing of rock mass; studies of micro seismic characteristics of the fracturing process of rock mass are of important significance for prediction of fracturing and destabilizing of rock mass and guaranteeing the safety of mine production. The coal mine underground micro seismic monitoring system which is made by Shandong University of Science and Technology is used to monitor the behavior of overburden strata of mining face. The close relationship between evolvement of micro seismic and fracturing of the overburden strata is proved by location of the monitored micro seismic events. The fracturing of rock mass can be precisely predicted according to the change law of finite difference of frequency, energy and distance of micro seismic events. This is of important instructing significance for prediction of rupture and instability of the rock mass underground coal mine by micro seismic monitor technology.

The method to prepare lightweight soil specimens is discussed. The results from the studies on the relationship among density, unconfined compressive strength and compositions of lightweight soil specimens have shown that the density is mainly influenced by the addition amount of EPS grains but the unconfined compressive strength is mainly influenced by the addition amount of both cement and EPS grains. On the above basis, the mixture proportion equations applicable to engineering uses are given.

For stability analysis of underground oil/gas storages in laminated salt rocks, it is of paramount importance how to select the appropriate constitutive model for the characteristics of laminated salt rocks. In consideration of the laminative geological structural character of most salt mines in China, a new user-defined FLAC3D interface program is developed using the Visual C++ flat on the basis of 3-D expanded Cosserat medium constitutive model that takes the mesotropic bending effect into account in the sense of macro average; and in the meantime, a dynamic link library(DLL) is compiled in connection with the main calculation methods of FLAC3D software. A simple tunnel example shows that the calculating results using the present model are reliable. Furthermore, the new model can describe the progressive damage failure of compound element composited by two layers with different mechanical characters, and can also reduce greatly the number of element meshes through introducing some statistic parameters such as volume percent. The present model embedded in FLAC3D is expected to lay a foundation for stability analysis of the underground openings in layered rocks.

Shear strength parameters are important factors to evaluate the stability and economical efficiency of a geotechnical project. The most effective and mainly used method to estimate the shear strength parameters is linear regression. When this method is applied to calculate the shear strength parameters of core clay in Xiaolangdi dam with 320 triaxial tests, the results have shown that the standard deviation and coefficient of variation decrease when the number of sample increases. The theory analysis also revealed this trend. So the conventional linear regression method cannot reflect the real variation character of shear strength parameters. A modified weighting linear regression method whose results are stable and do not vary with the sample size, is developed based on the probability theory. The modified method is applied to calculate the shear strength parameters of core clay of Xiaolangdi dam; and the results are compared with the outcome obtained from the moment method, which verifies the validity and practicability of the new method.

Soil anchors are commonly used as foundation systems for structures requiring uplift or lateral resistances, such as transmission towers, sheet pile walls and foundations of floating offshore platforms. This paper applies displacement finite element analysis to estimate the ultimate pullout capacity of pre-embedded inclined strip anchors in normally consolidated (NC) clay. Results are presented in the familiar form of break-out factors, which are based on various soil strength profiles, anchor embedment ratios and pullout inclined angles. The influences of the soil self weight, soil strength gradient and anchor base type on the pullout capacity are discussed. The continuous pullout analysis, in which Remeshing and Interpolation Technique with Small Strain model (RITSS) is applied, shows that the ratio of the vertical stress to the soil shear strength plays an important role in the separation underneath the plate when vented base is assumed.

The drainage hole is usually indispensable to seepage control for hydraulic engineering, which influences greatly the safety and stability of structures. Thus optimization design of drainage holes is very important and it is necessary to simulate drainage holes correctly in convenience. Various schemes of drainage holes should be studied for optimization design, which contains multiple factors, while the preprocessing work of seepage analysis is troublesome and time consuming because of the existance of drainage holes. The orthogonal design method is adopted to reduce the times of seepage analysis for fewer schemes of drainage holes. The composite element method(CEM) is adopted for the convenience of preprocess, by which the drainage holes needn’t be meshed out and optimization design needs only one set mesh for different schemes of drainage holes. The optimization design of drainage holes based on orthogonal experiments and CEM contains the following steps: determination of testing indexes, factors and levels; selection of drainage hole designs by the corresponding orthogonal table; seepage analysis by CEM; range analysis and selection of the optimized scheme. The optimized design of drainage holes can be obtained by the method, which is valuable for engineering application. The feasibility and effectiveness of the method are verified by practical project cases.

In millisecond blast engineering, the key to achieving initiative control of vibration damages by means of wave interference is to ascertain reasonable delay time interval. The designed or selected time of delay is always different from the practical time of delay due to the delay errors of ordinary detonators; and it influences the effect and successful implementation. It is significant to identify practical time of delay in millisecond blasting engineering. The authors have made use of time-energy density analysis based on wavelet transform and time-frequency domain transform techniques, and obtained the reasonable delay time interval by separating every sub-signal from measured millisecond blast vibration signal and comparing the superposition effect of sub-signal in different delay time intervals. The results show that the reasonable delay time interval is not generally a single value, but multi-time-intervals. The method proposed shows a high theoretical and practical value; and it lays a theoretical and technical foundation for the study of controlling and forecasting blast vibrational damages.

So far there has been no a ripen criterion to judge the stability of a rockmass that can be accepted unanimously. That is, no a clear system has not been formed yet that covers a series of basic problems, such as definition and quantitative judgment of stability or theory and method and criterion to analyze rockmass stability. At present, the commonly used method it to judge the stability of rocks surrounding a project according to plastic zones. However, this method is just used mainly for determining the failure scope of surrounding rocks. It is too dangerous if the method is used to determine the minimum rock cover thickness above a submarine tunnel, because ordinary submarine tunnels are mostly excavated in hard rocks, producing small plastic zones. Therefore, it is necessary to establish a method to determine the minimum rock cover thickness of a submarine tunnel. The mumerical analysis method FLAC3D applicable to simulalating large deformations of rocks and soils is adopted in this paper to establish a criterion according to the deformation or deformation rate criterion of surrounding rocks that be used for determining the minimum rock cover thickness of a submarine tunnel. This criterion has been successfully used in Xiangshan harbor’s submarine tunnel, and the estimated minimum rock cover thickness is coincident with that from traditional engineering analogy method, which shows the rightness and avidity of the method proposed in the paper.

In the light of parts of tension-shear yield area inside a rock slope, Hoek-Brown criterion is more suitable for the stability analysis of the rock slope than Mohr-Coulomb criterion because Hoek-Brown criterion can be used to analyze both tension-shear yield and compression-shear yield of the rock slope. Parabola Drucker-Prager criterion based on Hoek-Brown criterion is deduced to get rid of the difficulty which Hoek-Brown criterion is hard to use in numerical analysis. In order to use strength reduction FEM based on parabola Drucker-Prager criterion for the stability analysis of a rock slope, the rationality of reducing material parameters of parabola Drucker-Prager criterion is proved. With these research results, the paper analyses the stability of the slope on the right bank of Cihaxia Hydropower Station under natural and atomization conditions due to spillway discharging. The result indicates that the slope is stable under natural condition, but unstable on atomization condition. Therefore, the engineering measures are necessarily taken to enhance stability of the slope against instability under the atomization condition due to spillway discharging.

The erosion process of cemented soil blocks by H2SO4 solution with different concentrations is simulated through tests in lab. The relationship of the electrical resistivity with various parameters and unconfined compression strength is studied using the resistivity method. The result has shown that after eroded by H2SO4 solution, the electrical resistivity and compression strength of cemented soil are decreasing, whereas the formation factor and the density of cemented soil are increasing with the increment of H2SO4 solution concentration; the compression strength of cemented soil blocks is in proportion to electrical resistivity. By taking into account the erosion factor, a electrical resistivity equation related to H2SO4 concentration and porosity is proposed using the corrected Archie’s law. After analyzing the results of unconfined compression strength test and observing the photos of sample surface erosion, a method is proposed to evaluate the erosion degree of cemented soil eroded by H2SO4 solution through the electrical resistivity.

The Qianjiangping landslide, occurred soon after the TGP Reservoir had retained water for the first time, belongs to a large scale landslide. Based on the survey and exploration of the Qianjiangping landslide and its adjacent influenced slope, this paper reveals the components, textures and boundary conditions of the landslide, analyzes the factors causing slide, and sets up the landslide’s geological model and the mechanical model. From the analysis it is indicated that the Qianjiangping landslide was a palingenetic rock landslide trigged by the cooperation of the reservoir water and rainfall; but the reservoir water is a key factor.

Optimal construction scheme of high concrete face rockfill dam(CFRD) is studied taking into account creep deformation of rockfill. The results show that creep characteristic of rockfill influence on deformation of dam bedding node under different construction schemes. The zone by zone character of various materials of a rockfill dam decides objectively the necessary existence of an optimal scheme for the construction of filling ascension works. The maximum normal displacement of the facial slab is small in the filling. Scheme where the rock-filling body ascends uniformly and its distribution along the slab slope is also rather uniform, which is favourable to the harmony between the deformations of slab and pad layer beneath it. From the view of the majorized filling scheme, it is suggested that the rolling and compacting construction procedure producing uniform ascension of filling shall be used for high rockfill dams.

Under the condition of considering unexcavated coal seams as an elastic ground base, this paper deduces the equation of rock beam’s deflection line using the symbolic operation software—Maple 9.5. Then it deduces the equilibrium equation for the rock beam-coal pillar system when the system deforms in a quasi-static way, which is the equilibrium equation of fold catastrophe model. The discrimination of stability by using total potential energy function of fold catastrophe shows that, the system of rock beam and coal pillar is in an unstable equilibrium state in premonitory phase of rockburst, and critical condition of rockburst in coal pillar is Cook’s stiffness criterion. The criterion can be expressed dynamically that, the required energy input rate of the environment approaches to zero while the deformation of coal pillar increases. The releasing amount of earthquake energy is calculated; and it is clarified that the mechanism of rockburst in coal pillar is that the elastic energy released by rock beam exceeds the energy dissipated by the deformation of coal pillar with softening characteristics after peak value. The obtained findings is described by the geometric form in which the curves of energy input rate, rate of change of rock beam’s elastic energy and dissipated energy of coal pillar are given. Calculations show that, the stiffness coefficient of unexcavated coal bed has faint influence on the rock beam’s equivalent stiffness. The excavation of working surface and the increment of exhausted area lessen rock beam’s equivalent stiffness remarkably.

Along with the acceleration of the city modernization course, it is demanded to increase means of transportation construction. It is very important and its prompt development for the metro to city traffic because of the special condition of city. The influence of metro construction on neighboring buildings is becoming the emphasis and the difficulty in metro engineering. So it must adopt credible measures according to the subsidence and tilt control criterion of buildings in the course of metro construction to supervise effectively metro construction and to strictly control ground settlement and to ensure the security of buildings. This paper aims at the influence of metro construction on various buildings, putting forward the procedure, means and contents of construction and management, and the normal protection measures of buildings. It can instruct the construction of similar engineering and ensure the engineering to go on wheels.

Based on mechanism of pile-soil interaction, the elastic differential equation of negative skin friction in homogeneous ground is established. An iterative procedure on the basis of finite differential method to calculate displacement of a pile body is proposed. The computing results indicate that the procedure given in this paper is of good convergence and well coincident with reality. The neutral point appears below the pile body according to its definition, showing the agreement with the previous conclusions. The results also show that PCC pile has a small settlement compared with the solid pile of equal cross section area.

Through FEM calculations, this paper discusses the influence of foundation rigidity and pile shafts on the bearing capacity of the composite ground of saturated loess and mucky soil with deep mixing cement piles under a flexible foundation. The results indicate that reducing foundation rigidity is beneficial to the bearing capacity of the soil between the piles, and that the degree of influence of pile shafts on the bearing capacity of saturated loess is larger than that of mucky soil. Finally, on the basis of the formula to calculate the bearing capacity of compound grounds reinforced with deep jet cement piles under a rigid foundation, two coefficients-foundation rigidity coefficient and soil bearing capacity coefficient are proposed according to the in-situ testing results and FEM calculation results; mean while, the value ranges of those new affecting coefficients are suggested. The formula proposed in this paper have been successfully applied in real projects.

According to the decomposition of principal stress into hydrostatic stress and deviatoric one as well as to the correlation between them in Mohr’s circles and deformations, the paper deduces the mathematical expression of modified Mohr-Coulomb’s theory. This expression solves many shortcomings of Coulomb’s theory and Mohr’s theory theoretically and particularly, it describes the influence of intermediate principal stress on shear strength. At the same time, a four-parametric criterion is established. The computing results using this four-parametric criterion are quite agreement with those obtained from tests on concrete specimens of different kinds.

Using 8-nodes isoparametric element based on Mindlin plate theory and Newmark method, the dynamic responses of both thin and thick elastic plates resting on Winkler foundation subjected to moving load are analyzed. The results of thin plates are compared with the available results obtained by finite strip method. The effects of velocity, foundation modulus, and system damping ratio are studied. Results indicate that the system has an inherent resonant velocity. The foundation modulus is the key factor determining the resonant velocity. The deflection shapes of thin plates are significantly different from those of thick plates. Results also show the efficiency and accuracy of the presented method. Some of these findings can be applied to practical engineering.

In allusion to the problems of the low gas-penetration and low ratio of gas drainage during draining gas and prevention outburst, it is designed the high-pressure water jet installation of cutting coal which is installed in the draining bore, and tested the nozzle and the ejector in scene. The result showed that the effect of the coal cut by high-pressure water jet is the best when the angle of water jet is +100, the diameter of nozzle is 1.5mm, the cutting speed is 0.2m/min and the pressure of the pump is 30MPa; it is showed that the draining ratio is raised about 18.8% and the draining time is shorten over 90% when the coal is cut by the high-pressure water jet, too. Therefore, the technology is very important to the draining gas and preventing outburst.

According to the fact of the undrained shear strength decreasing during field vane test, applying the cylindrical expansion theory, it is assumed that saturated soft clay satisfies Tresca yield criterion, and then the disturbance degree function is given on the basis of the sensibility of saturated soft clay, and the function D is logarithm function of the plastic radius. Considering the undrained shear strength su is the function of the disturbance degree, the elastoplastic solution of the cylindrical expansion is gained.

Since large scale construction of underground railways was carried out in Tianjin, more and more deep foundation pits have been to be excavated in soft soils. In the period of excavation activities, it is very important to give a suitable control criterion to ensure the pit stability. To find out the recommended criterion value, some comprehensive measurements have been made in some typical pit engineering during the construction of No.1 Line. The observed data of earth pressure, retaining structure displacement, ground surface settlement and water pressure have been picked up and analyzed. A finite element method has been adopted to simulate the procedure of pit construction. By comparing the calculation results with the observed data, the calculation model has been optimized; and calculation parameters have been determined. The established approach has been applied to simulate the failure procedure of deep foundation pit. The main influence factors including the displacement of retaining structures, the length of retaining structures and the force in braces, have been analyzed. The ratio of retaining structure displacement and maximum ground surface settlement over pit depth are recommended as the control criterion of pit stability during construction.

Through summary and evaluation of the experimental investigation on small strain of soil, the paper points out that recent stress history has an important influence on threshold and variation of stiffness within the range of small strain; and it is worth while to further study. Meanwhile, it is also shown that the experimental investigation on small strain could have an active effect on Chinese engineering practice.