A two-dimensional numerical model of coupled fluid flow and chemical dissolution processes in single fracture is presented in order to understand permeability changes of single rock fracture in the coupled fluid flow and mineral chemical dissolution processes. The numerical model is solved by using a COMSOL Multiphysics-based simulator, which is the first engineering tool that performs partial differential equation-based multiphysics modeling in an interactive environment. The model is validated through comparing our numerical results with the known experimental measurements in salt rock reported by the reference [1], which shows our model is credible. A rough fracture is generated numerically by using fractal theory and used in the simulation of coupled fluid flow and mineral chemical dissolution processes of a rough fracture in limestone. The simulated results indicate that: (1) The solute concentration plays an important role on the dissolution process; this causes that the dissolved thickness at inlet is bigger than that at outlet. (2) The permeability of fracture increases exponentially with time during the dissolution process.

The purposes with regard to all underground voids filled with tailings are categorized into three aspects such as improvement safety issues (i.e. ground control), increasing economics (i.e. enhancing ore recovery rate), and environmental requirements (i.e. reduction acid water drainage). The types of backfill technologies include slurry backfill, paste fill and rockfill. The first two types of the backfill are also called as hydro-backfill, and rockfill is called as dried-backfill; all of which are applied to Canadian mines. UCS (uniaxial compressive strength) and permeability are critical parameters for slurry backfill in minefill applications, which affect on the quality of underground minefill. On the one hand, cement needs to be added into the slurry backfill materials to improve the strength of the fill materials; the huge tonnages of which are used for minefill and cement takes up the large component of mine fill costs; on the other hand, the coarse solid recovery used for backfill materials is classified from underflow of hydrocyclones, meanwhile fine parts flow out through overflow of the hydrocyclones to the tailings pool; sometime the backfill tailings of the mines are deficit and sand needs to be bought, which is mixed up with the tailings to be filled into the voids of underground. It is the concernful research issues for mine industry how to reduce the amount of cement added into backfill materials and improve the solid recovery particularly fine parts from underflow of the hydrocyclones in order to save the backfill costs. The effects of flocculant-assistance on UCS of tailings for slurry backfill are investigated. The results of the experiments indicate that the strength of tailings could be improved largely by the flocculant-assistance; moreover, the maximum strengths of backfill with flocculant-assistance are achieved at the optimization value of flocculant dosage, whereas the over-dosage of flocculant could have an adverse effect.

The most important step of solving ultimate bearing capacity problem by using upper bound limit analysis is to form a suitable failure mechanism. The failure mechanism becomes complex when there is a void beneath the footing. By analyzing the mechanic properties and failure shape of strip footing above void, its failure mechanism was formed and the failure range was divided by various rigid and transition area. Upon upper bound method, the velocity field corresponding to failure mechanism was built, and the energy caused by external force and energy dissipation under limit state was deduced. Thus the object function of ultimate bearing capacity can be obtained and solved by mathematic optimization. Finally, the influence factors of ultimate bearing capacity, such as void roof thickness and size, were analyzed by using calculating example. The obtained results were also compared with the case which no void contains. It shows that ultimate bearing capacity is increased with the increase of void roof thickness and the range of failure mechanism is therefore diffusing from area beneath the footing to both sides of footing. And there also exists a critical void roof thickness beyond which, the influence of void can be neglect..

Comparative study of the model using geotechnical centrifuge for rail pile and anchor combined gravity retaining wall supporting soil slope are carried out respectively. The key roles of rail pile and anchor in the gravity-type retaining wall supporting soil slope are analyzed. The results show that the sliding deformation of soil slope supporting with gravity retaining wall is induced by heavy rainfall, threatening the stability of the slope. The rail pile which is nailed into foundation and retaining wall could reduced the wall offset greatly due to rainfall; but the local shallow slide at the top of the wall of the upper slope is inevitable. The anchor which is implanted in the upper slope and top of the wall can be inhibited the shallow slip on the slope. Without increasing weight, the ability of wall anti-overturning and shallow anti-slump are increased by the extension role of rail piles and anchoring role of the anchor the retaining wall under the premise of the next extension of the role of rail piles and retaining wall anchoring role of the anchor. The supporting effect of gravity retaining wall is improved from the slope of deep and shallow at the same time. Another the earth pressure of the retaining wall back is uniformed by using rail piles and anchor; the local stress concentration is avoided effectively.

The nonlinear analysis have been done for the load transfer mechanism of composite foundation of rigid pile with cap by assuming load-transfer function which is hyperbolic model. Based on the idea of literature[1], the controlled differential equations have been put forward for pile, soil under pile cap and soil between pile cap, including its vertical displacement, vertical stress, friction force and depth. The corresponding analytical formulas have also been derived by using the approximate solution of differential equation. Using directly the settlement of pile top as the known condition, the calculation results can image basically the work behavior rules of composite foundation of rigid pile with cap and provide the theory base for engineering design.

It is shown in both field and laboratory observations that the creep process of granular materials is accompanied by grain crushing. One-dimensional creep tests were conducted on sands. It is found in the tests that the amount of crushed grains increases with time at specified stresses; and the grain crushing rate is directly proportional to creep rate. Based on these findings, energy conversion in the process of grain crushing is analyzed; and the relationship between grain crushing rate and creep rate is obtained. It is concluded that the creep rate is directly proportional to grain crushing rate when granular materials are subject to creep at high stresses.

Loess seismic subsidence is a type of disaster when the earthquake occurred in a loess area. The characteristics of loess seismic subsidence with depth is studied by indoor dynamic triaxial test of 5 groups of original Malan loess Q3 samples in different depths. The results show that: (1) In terms of natural water contend, humidification or dehumidification, the depth of the loess seismic subsidence, with the increase dynamic stress, has a process of from smooth to rapid lowering, and then converging to the maximum depth of seismic subsidence. (2) Dynamic stress intervals are different corresponding to stages, interval in rapid lowering stage becoming narrow; the minimum dynamic stress shrinking with increase of water content; and the minimum dynamic stress can lower by 30% in term of 20% comparing to 5%. (3) The maximum depth of loess seismic subsidence is found and it is not affected by the dynamic stress and water content. Only the water content is able to reduce minimum dynamic stress when reaching maximum depth of the seismic subsidence and speeds up the development process. At last, the loess seismic subsidence curves of the depth converging to the maximum of depth of seismic subsidence with increasing of the dynamic stress; and in this experiment the maximum depth is 15.5 m.

Firstly, influence of only horizontal or vertical earthquake loading on slope seismic safety factor is examined using stress integration along sliding surface and the dynamic FEM time-history analysis method. It is shown that under most conditions the vertical ground motion has the same significant effect on slope stability as the horizontal earthquake motion. Then, the effects of the time combination pattern of horizontal and vertical accelerograms on the dynamic safety factor are considered. It is concluded from the analysis results that the pattern with peak acceleration values meeting in time domain and the random time combination pattern may lead to over estimation of safety factors because of not giving the most significant superimposing effect for the vertical earthquake loading and the pattern with maximum action effects meeting in time domain is the severest pattern which allows for the minimum value of safety factor to be obtained. Due to the largely unknown behavior and random nature of earthquakes, the possibility for the pattern with maximum action effects meeting in time domain should be considered for slope under multiple-dimensional earthquake action to get the more conservative safety factor for the engineering design.

Based on Yin-Graham’s 1D elasto-viscoplastic model which can predict both primary and secondary consolidations, the long term settlements caused by triangle periodic loading during road service period are theoretically studied. The expressions of total settlement and post-construction settlement of road embankment on soft clay produced by the triangle periodic loading during its service period are achieved. The relationship between the long term settlement considering fluid-solid coupling and that without considering fluid-solid coupling under the triangle periodic loading is analyzed. It is proved that the soft clay has the behavior of which the ultimate settlement when periodicity trend to infinite is not affected by the fashion that stress increases with time under the triangle periodic loading. Based on the expression of the total settlement proposed in the paper and the physical parameters of clay for a definite engineering, the total settlement of road embankment during its service period is numerically calculated. The critical settlement of road embankment at the start of its service period can further be determined from the total settlement at the end of its service period. From the above results, a required settlement standard is provided for rationally determining the start time of road pavement in the construction of expressways.

According to the basic definition of porosity and mechanical equilibrium principle, and fully considering the primary deformation caused by the three aspects: the expansion of gas adsorption and shrinkage of desorption of coal seam , the expansion and shrinkage caused by the temperature effect, and the compression of the coal skeleton caused by the gas pressure of pore, a porosity dynamic evolution model of gas-filled coal under the compression condition (before expansion) and an effective stress equation expressed by adsorption thermodynamic parameters and gas pressure, are established According to the experimental data of porosity and triaxial stress test of gas-filled coal, the theoretical formula established above is verifed. The results show that the theoretical calculation results are consistent with the measured data and test conclusions. Fitting accuracy of theoretical model is good and the error is small. The research results have some guidance significance to the gas exploitation in coal seam and mining gas disaster prevention.

Based on the distribution and occurrence characteristics of underground shallow gas in Hangzhou area, and combined with the Hangzhou Metro project, a model test system was established; and influences of gas release and re-accumulation of the shallow gassy soil on stabilities of metro tunnel were studied by the physical model test. Results show that gas actions of shallow gassy soil may cause the tunnel crossing gas reservoirs to generate additional deformations and internal forces; disturbances on relative deformation and internal force of the shield lining segments are little; but influences on the global deformation of tunnel structures are significant; values of the additional deformation and internal force caused in gas re-accumulation are much less than those in the former process of gas release. For the metro tunnel in regions buried shallow gas, global stability of tunnel structure should be as the control emphasis; and the gas in strata should be released under control before construction so as to reduce the later adverse effects on metro engineering.

Comparative test study of anti-pulling property of X-shaped pile and circular section pile with constant section is carried out in the self-developed large-scale soil test model chamber. The distributions of axial forces, lateral frictions and displacement are analyzed. the lateral surface of The X-shaped pile is 31.5% greater than the circular section pile; but the distributions of lateral friction force along pile shaft are almost the same, which consist of two different zones, raising zone and decay zone. The friction force is fully exerted from 1.5 m to 3 m away the pile head, and the minimum value and peak value of X-shaped pile in the area are larger than circular section pile. Under the same settlements, the lateral friction force of X-shaped pile is greater than circular pile. The results show that the ability of X-shaped pile to resist uplift force is 16.7% higher than that of the circular pile.

Vacuum freeze drying method is utilized to prepare samples for SEM from one-dimensional consolidated clay, which is originally remolded and subsequently suffered the 5 grade pressures respectively. And then, simple and synthetical microstructure parameters of SEM photos obtained from horizontal, 45o inclined and vertical plane are studied to discover relation between macroscopical mechanics and micro structure. Study of simple parameters shows that grain area ratio and perimeter increase with consolidation pressure while other parameters have no constant tendency. Synthetical parameters come from two data analysis methods, namely principal component analysis and pedigree cluster analysis. It is shown that the first principal component approximately linearly increases with consolidation pressure. Samples can be exactly clustered into several families according to the pressure; and inner distance of a family nonlinearly increases with pressure. Synthetical parameter is distinctly superior to simple parameter in study of soil mechanics because the former can reflect the whole microstructure qualities; but the latter can’t.

Based on triaxial compression rheological experiments with water pressure coupled stress about the Jinping marble from the deep site in Jinping II diversion tunnel, the aging deformation characteristics，isochronous curve and aging failure mechanics are discussed in detail. The test results show that: (1) Water pressure can enhance the aging deformation capacity of the marble, and the steady-state creep rate under water pressure is greater than that when there is not water pressure. (2) Stress strength ratio of crack dilate instability can be used as creep instability threshold of brittle rock, and when stress strength ratio reached this threshold, the probability of rock instability increased sharply with time to develop. (3) Volume creep value is greater than the lateral or axial creep value, which indicates that there is a distinguishing dilate creep feature of brittle rock. (4) Isochronous curves of brittle rock at different time have obvious similarities, and accelerating creep ago, the curves are linear, but in the event of acceleration creep, the curves are significantly non-linear characteristics.

With the adsorption, desorption and seepage of coalbed methane(CBM), coal mass deformation easily leads to coal-gas outburst in the process of production. Taking Tiandiwangpo Mine in Jincheng for example, the experiment of adsorption, desorption and seepage of coalbed methane(CBM) and deformation are simulated under complicated stresses condition. The relationships among pore pressure, desorption quantity and deformation are presented. The relationship expressions are studied. Some novel laws are obtained as follows. (1) At the beginning, desorption quantity increases rapidly over time; then it is stabilized latterly. (2) With the rising of pore pressure, the value of desorption quantity and deformation are increased; the desorption quantity and deformation are in parabolic curve relationship with pore pressure. (3) A minimal pore pressure exists; desorption time will increase with the increasing of pore pressure; the laws of desorption quantity and time will inconsistent when it is smaller than the minimal pore pressure. For the coal sample No.3, the minimal pore pressure is about 1.0 MPa. (4) Desorption quantity and coal mass deformation have a lot to do with loading methods; the result of loading methodⅡ is higher than loading methodⅠabout 13%-77%. The results provide a theoretical basis for security of coalbed methane(CBM) drainage and controlling of coal-gas outburst.

Aiming at analyzing the micro-local pattern and 12 topography parameters quantitatively, five kinds of rock under water-rock interaction of deep mine were tested using three-dimensional topography measurement instrument of Talysurf CLI 2000 type with high precision to achieve 0.5 μm. The test results conclude that the discreteness of rock surface height, the deviation degree of datum plane and the roughness are increased after water-rock interaction. The distribution probability of highness is more concentrated, which has changed from negative skewness to positive skewness and distributed more symmetrically than before. The arithmetic mean summit curvature of the surface(Ssc) has dropped regularly to about 0.62; while the highness difference of the rock surface is decreased and becomes more compatible. The process of hydration, hydrolysis and dissolution is simultaneous; but the effect of hydration is greater than hydrolysis and dissolution.

Based on the virtual work theory and the Winkler elastic foundation model, considering nonlinear deformation of sheet and net materials and composite foundation cushions as an overall net pad as well as taking the role of the level of resistance into account in the calculation, a formula for calculating the settlement of two-direction reinforced composite foundation was deduced. The deduced formula reflects the effects of load magnitude, the replacement ratio of composite foundation, rig ties of mattress and the surrounding soil, pile-soil stress ratio, etc. Besides, two groups model tests of composite foundation are designed and a large amount of data about the load-settlement, pile-soil stress ratio are obtained. Finally, through model tests and an engineering example, the reasonableness of the formula is verified. The results indicate that the horizontal resistance of reinforced mattress helps to reduce the residual settlement; and the effects of which should be treasured.

Using a dynamic hollow cylinder apparatus WF12440 as the test platform, this paper firstly studied the loess saturation by the back pressure method. The developments of pore water pressure, axial strain, deviatoric stress-axial strain curve during liquefaction are then investigated. Testing results indicate that the back pressure method can be successfully used for loess saturation; and the pore water pressure coefficient could achieve 0.95 and more. Under the condition of isotropic consolidation, pore water pressure increased slowly at the beginning; after several cycles the pore water pressure increased rapidly until it reached the effective consolidation pressure. The deviatoric stress-axial strain curve developed with the increase of cycles; and plastic strain increased step by step. When the axial strain was less than 2%, the pore water pressure increased slowly; afterwards, its increase ratio was much larger, and a strain of 3% could appear at the initial liquefaction process. Before liquefaction of the loess, the mean effective stress under negative deviatoric stress is larger than that under the positive deviatoric stress.

According to permeability test investigation of outburst-prone coal, permeability properties of outburst-prone coal specimens are analyzed systematically for different confining pressures, different gas pressures, and different stress-strain conditions. Quantitative and qualitative relations between outburst-prone coal permeability and confining pressure, gas pressure and stress-strain curve are established respectively. The controlling mechanism and changing law of outburst-prone coal permeability under variable loading conditions are discussed. The results show that the loading condition has an important impact on outburst-prone coal permeability, and the details are: (1) For fixed gas pressure condition, outburst-prone coal permeability decreases with increasing of confining pressure; and the decreasing rule obeys an exponential law. (2) For fixed confining pressure condition, the relation between permeability and gas pressure is showed a “V” curve approximately in shape affected by Klinkenberg effect, which happens in the gas pressure range of p < 1 MPa. (3) During the whole stress-strain process under triaxial compression, the change trends of outburst-prone coal permeability versus strain curve for different loading conditions are almost uniform, which are showed a “V” curve. At the stage of microfissure closing and elastic deformation, the coal specimen permeability decreases with the increasing of stress; after entering into the yield stage, the coal specimen permeability reaches the minimum and anti-exceeding is accomplished before reaching the peak strength. The permeability increases continuously until the end of test after reaching the peak strength. The outburst-prone coal permeability after anti-exceeding changes more mildly than before anti-exceeding.

Due to the effect of soil structure, the structure of natural sedimentary clays was meta-stable and would damage during the process of post-yield compression deformation. First, a one-dimensional disturbed state concept (DSC) compression model of structured soils was established based on the disturbed state concept to characterize the compression destructural behavior of natural soils under loading. Additional void ratio ?e was employed as a structured state parameter reflecting the influence of soil structure; and quantitativel analysis was conducted on the relationship between additional void ratio and consolidation pressure. Compression destructive index b was used to describe the rate of destructuring in the DSC model. Then, one-dimensional compression tests were conducted on the Taihu Lake swamped natural soft clay, silty clay and stiff clay, and the results of the tests were simulated and analyzed using the DSC model. A procedure was suggested to determine parameters in the model. The results show that the proposed DSC model can be implemented to describe the compression behavior of natural soils with various structures. The DSC model reflected the nonlinearity of compression curve, which contribute to the accurate calculation in the nonlinear consolidation and settlement of structural soils.

The stability analysis and its protection in the excavation and unloading course of loess slope occupy an important position in the slope engineering. One centrifugal model test of non-reinforcement slope and two centrifugal model tests of soil nailing reinforcement slopes are performed on the centrifuge at Southwest Jiaotong University. The deformation characteristics, reinforcement effect of soil nailing and the stability in the excavation and unloading course of loess slopes are studied. Results of centrifuge model tests show that soil nailing can greatly increase the stability of loess slopes. Due to the anchoring effect of soil nailing, the range of deformation is wider, but magnitude is smaller, and the largest deformation is not in the surface, but in the anchor region of the nailed slope. Non-reinforcement loess slope has the potential failure surface of about 40cm below its crest. The models were substantially stable against failure and deformation due to soil nailing. The reinforcement with unequal length of soil nails is superior to that of equal length of soil nails for the resistance to slope failure. The research results provide references for excavation and reinforcement of loess slopes.

The relation between wave frequency and vibration frequency in Kelvin-Voigt viscoelastic medium was studied by applying the plural theory. The time- and spatial- attenuation of wave amplitude was studied in rock and rock mass with a series of parallel interfaces. The study indicated that the attenuation of stress wave amplitude was mainly decided by vibration frequency of stress wave. Stress wave energy was influenced by interface in rock mass with a series of parallel interfaces. And the time- and spatial- attenuation of stress wave amplitude is decided by distance and reflection coefficient of interface. The decrease of distance of interfaces and the increase of reflection coefficient resulted in increase of spatial-attenuation of rock mass and decrease of time-attenuation, while increase of viscosity coefficient led to the increase of spatial-attenuation and almost the same time-attenuation. This study result played an important role in detecting rock mass structure.

Consolidated drained and consolidated undrained triaxial creep tests of soft soil in Dongwan are carried out to have a comprehensive understanding of soil deformation mechanism. At the same time, scanning electron microscope test of the microstructure of undisturbed samples and samples after creep is done to analyze the soft soil creep properties and changes of micropre under different drainage conditions. The results show that different drainage conditions have a significant impact on the relationship between strain-time and strain-deviatoric stress of soil samples. Soil samples yield in undrained conditions showing significant creep deformation and do not yield in drained conditions very significantly because consolidation effect in the process of drained conditions weakens its nonlinear creep. Large pores decrease and small pores increase in soil samples after creep the shape of which is developed to be rounded and the orientation of which increase slightly. The changes of soil micropore in different drainage conditions can be taken as the internal reason of difference of soil creep. The gradual changing process of pore characteristics reveals micromechanism of soft soil creep deformation.

Because of the flexible interface and trapezoidal load, the failure modes and determination method of foundation under highway subgrade are different to the rigid foundation; so the study about bearing capacity of foundation under highway subgrade has valuable significance in theoretical research and practical engineering. Through centrifugal test of bearing capacity under different conditions such as flexible strip foundation, trapezoidal subgrade and flexible strip foundation of valley, bearing capacity of foundation under highway subgrade are studied; numerical simulation based on Mohr-Coulomb inside-tangent circle yield criterion are applied. Results show that it is difficult for subsoil under highway subgrade to come into being integer shear failure because of flexible foundation and rather high centrifugal acceleration; compared with rigid and flexible strip foundation, the central point under trapezoidal loading has greater displacement; the displacement of central point under flexible strip foundation are influenced by the valley terrain; ultimate bearing capacity is not obviously changed.

To study the mechanical characteristics of frozen silt of Qinghai-Tibet, the triaxial compression and the loading and unloading tests were performed at temperatures of -2 °C, -4 °C, and -6 °C under the confining pressures of 1.0-14.0 MPa. The stress-strain curve, strength and other mechanical characteristics of frozen silt were obtained. Results indicate that the stress–strain curves could be divided into three stages: the linear elastic stage, the plastic stage, and the strain-softening stage. When ? 3 <3.0 MPa, the strain-softening stage appeared and mitigated as the increase of confining pressure; when ? 3 increased to 14.0 MPa, the strain-softening stage would appear again. The strength and elastic modulus of frozen silt increased with increase of confining pressure; then decreased with further increase of confining pressures. The volume of frozen silt reduced with the increase of axial strain at first; then expanded with further increase of axial strain under low confining pressures; however, the volume only reduced under high confining pressures. The plastic volumetric strain dissipated energies increased to a peak value with increase of volume under low confining pressures, then decreased with decreasing in plastic volumetric strain for dilatation; but the plastic volumetric strain dissipated energies increased with increasing plastic volumetric strain all the time under high confining pressures. The plastic shear strain dissipated energies increased with increase of plastic shear strain; and the plastic shear strain has a good parabolic relationship with the dissipated energy.

The experimental tests for limestone specimens at 200 ℃ in uniaxial compression were carried out to study the mechanical effects of loading rates on limestone using the Rock Mechanics Servo-controlled Testing System MTS810, in which loading rate was treated as a variable. The mechanical properties of limestone such as the stress-strain curve, the variable characteristics of peak strength and the modulus of elasticity of limestone were studied under the loading rates ranging from 0.000 5 mm/s to 5.0 mm/s. The results show that (1) With the rise of the loading rates, the peak strength and elastic modulus of limestone increase sharply from 0.000 5 mm/s to 0. 005 mm/s at 200 ℃; bat show downward trend when the loading rates from 0.005 mm/s to 0. 5 mm/s; and show increase trend when loading rates over 0.5 mm/s. (2) The peak strain of limestone shows downward trend when the loading rates from 0.000 5 mm/s to 0.005 0mm/s; however, the peak strain increases slowly when the loading rates over 0.005 mm/s. The result can provide valuable references for the rock blasting effect and the rock engineering stability.

Based on shaking table tests for scale model of pile foundation, which belongs to bridges at the unstable permafrost regions of high earth temperatures along the Qinghai-Tibet Railroad, on condition that the soil temperature around pile was below 0 ℃, it discovered that temperature increased at the spot of soil between piles and the interface of the piles and soil under seismic dynamic motions. Moreover, under the conditions of natural state and soil temperature increase, the characteristics of seismic response of pile foundation of the Qingshui River Bridge were analyzed by dynamic finite element analysis. It indicated that seismic response of the permafrost layer and pile foundation, under seismic motions, was obviously sensitive to the increase in temperature, while earth temperature above -1 ℃. Under artificial wave with exceedance probability of 2% in 50 years loading, the slippage and escape, between pile foundation and soil layer around, were enlarged due to relative displacement of pile foundation. Especially, on condition that temperature above -1 ℃, the slippage was so obvious that it influenced the stability of whole pile foundation.

Considering the depth attenuation effect of bedrock site, the artificial seismic waves with different spectra for large-scale underground cavern group are created by trigonometric series superposition. The time-history nonlinear dynamic response analysis method is used to simulate the seismic response to the large-scale underground cavern group of some hydropower station in Southwest China; and the displacement characteristics are studied in the case of different geostresses, peak accelerations and spectra. The results show that the relative displacements of underground cavern group increase with lateral stress coefficients and peak accelerations. Furthermore, waves with different stectra result in distinct displacement characteristics. The present work could be used as a primary guidance to the aseusnuc design for underground caverns.

The Qianjiangping landslide, located in China’s Three Gorges Reservoir（TGR）, occurred on 13th July 2003 , one month after the first impoundment to 135 m a.s.l. of TGR water level. This is the first reservoir triggered landslide in TGR. This huge landslide was a high speed dip rockslide with a volume of 15 million m3, a maximum sliding velocity of 16m/s. The maximum surge height was 24.5 m, and the sliding process was finished in less then 1 minute. The catastrophic landslide caused 10 people died, 14 people disappeared, destroyed 129 houses and 4 factories, and left 1 200 people homeless. After the landslide, the author continued research on the high speed slide mechanism in order to predict the same kind of landslide disaster in the TGR area and elsewhere in the world. On the research effort on the high speed slide mechanism seen in the Qianjiangping landslide based on geologic analysis and numerical computations, it is concluded that the Qianjiangping landslide had a typical geological structure needed to gestate a high speed landslide; the great decline in shear strength in the shear zone (from peak to residual) is the essential cause for the high initial sliding speed; and the potential energy of the high slope and the liquefaction of the shear zone accelerated the sliding.

Dynamic progressive process of layer separation, bending, sagging and fracturing of overburden strata induced by mining excavation is investigated based on numerical method and the improved Rock Failure Process Analysis code. The simulation result reproduces the formation of caving zone, fractured zone and bend zone. In addition the evolution of fracturing arch and the periodically common nature of strata movement are numerically obtained. It is shown that the overburden strata movement depends on the effect of broken expansion and the tension, shear failure of rock mass. Because the broken expansion of caving rock strata is employed, the fracturing arches do not expand vertically upward, but expand horizontally forward. The top of the arches keeps at the same level and the strata failure is of periodic law. The boundaries of caving zone, fractured zone and bend zone are obviously clear and the surface subsidence is more reasonable. Consequently the numerical results are more consistent with the measured data obtained in-situ.

Yele Dam is a rockfill dam with an asphaltic concrete core wall. The maximum dam height is 124.5 m; and the geological conditions of the foundation are quite complex with a high degree of seismic intensity. The dam area was shocked strongly at an epicentral distance of about 258 km. There are 9 accelerographs and some other monitoring instruments on the dam. And they obtained comparatively complete records of the earthquake and other monitoring data during Wenchuan Earthquake. The effects of Wenchuan Earthquake on Yele Dam were studied based on the earthquake records and the analysis of the deformation, stress and strain, as well as seepage and osmotic pressure. Based on these analysis there had no significant adverse effects on the dam, but it still had some disadvantage effects on the partial structure of the dam. It was concluded that there was no exceptional appearance and the dam remained in normal working state after the Ms8.0 earthquake.

The distribution and characteristics of liquefaction-induced damages during Wenchuan Ms8.0 Earthquake in China were summarized in detail according to the wide and detailed field investigation. The analytical results are as follows. (1) The liquefaction phenomena are evident, involving thousands of Hundreds thousands square meter of farmland. (2) The liquefied sites distribution and the liquefaction-induced damage distribution are correlated but not the same. Comparison of the liquefaction phenomena, the 3 liquefaction-induced damage areas in Deyang are the most serious; Dujiangyan, Mianyang and Jiangyou districts are the secondly serious; and other areas are relatively light. (3) In the liquefied sites, the poor houses without any consideration of seismic resistant design collapsed, even the houses/buildings with collar beams and constructional columns subsided or tilted. (4) The liquefaction phenomena are typically severe in schools, generating ground fissures and causing buildings tilting, subsiding and cracking. Three obvious characteristics of the liquefaction-induced damage are: (i.) The liquefaction aggravates the structural damage and no shock absorption phenomenon has been observed. (ii.) In the regions of seismic intensity of VI (PGA less than 0.05g), liquefaction phenomena and liquefaction-induced damage were observed and quite remarkable. (iii.) The liquefaction generated ground fissures are the significant cause of liquefaction-induced damage.

The prediction of residual deformation and analysis of damage mechanism of breakwater are complicated problems in seaport engineering during earthquake. The nonlinear constitutive model of a multiple shear mechanism type in strain space is used in the study; and the effect of rotation of principal stress axis direction has been considered. The effective stress analysis of breakwater is given by considering both fine content of clay and equivalent SPT N-value; and some conclusions are achieved that the greater residual deformation of breakwater is induced by softened soil due to higher pore water pressure of soil. Then, the index of extent of liquefaction is applied to scale residual deformation of the breakwater; and the prediction relation of function is achieved between residual deformation and extent of liquefaction. The prediction values are close to investigation and numerical analysis values; it is shown that the function of prediction is credible. Some reference is provided by this prediction method of residual deformation by extent of liquefaction for similar breakwaters.

In order to explore drainage effect of desilting soil on the Yellow River dike，three drainage measures including horizontal blind ditches, geotechnical mesh drainage cushions，and horizontal and vertical infiltration PVC drainage pipes, are tested in the Dongming section of the Yellow River embankment in Shandong province. Relationships between groundwater level and time are obtained through measuring groundwater levels of observation point in the deposition zone. The test results show that drainage measures can speed up the soil consolidation of the Yellow River dike by desilting; but effects of drainage are related to drainage measures. The difference of drainage effects of the earthwork mesh drainage cushions and blind ditches are not obvious; and it is related to thickness of soil layer. The drainage effect is very good when setting up a drainage layout such as blind ditch drainages or earthwork mesh drainage cushions with about every 3 m thickness dike by desilting, but drainage effect is bad if desilting soil thickness increases. With the thickness increment, the collapse of transverse dikes can not be prevented by the two types of drainage methods. Horizontal and vertical seepage drainage pipe program has the best effect of these methods，especially for the establishment of the vertical PVC pipes; and the collapse of transverse dikes can be effectively prevented. The test results provide reference for design and construction for speeding up drainage rate of the Yellow River dikes.

For overlapped tunnels construction, excavating the second tunnel is an unloading process for first tunnel. So the lining of first tunnel will deform toward second tunnel; but this is temporary. Based on Laojie ~ Shaibulu shield tunnel of Shenzhen metro line 3, 3D FEM and centrifuge model test are used to study the longitudinal displacements of first tunnel induced by second tunnel construction directly above. The results indicate that the differential displacements of first tunnel induced by second tunnel construction mainly occurs in the range between 3.5D (3.5 times the diameter of the new tunnel) in front of and 3D behind the excavation face. According to this, the countermeasures have been taken into account, mainly including temporary ballast and temporary support. In the range of (0-1)D, (1-2)D, (2-3)D adding temporary ballast of 20 t/3 m, 20 t/6 m, 20 t/9 m respectively to first tunnel; and setting temporary support in first tunnel in the range between 4D in front of and 4D behind the excavation face will well reduce the differential displacements of lower tunnel induced by upper tunnel excavation.

The lateral earth pressure of retaining wall mainly depends on the displacement of the wall. The calculation method of earth pressure coefficient under any lateral displacement is obtained based on the asymptotic state formula of sand, which describes the different stress-strain relationships of soil under different constraint conditions of deformation, considering the relationship between principal stresses in the plane strain state and the dilatancy behavior of sand. The parameters in the formulations can be determined through simple tests. Compared with model test results, the reasonableness of the proposed method is verified.

The integrality of rock mass is assessed based on the geometrical character and cementing status of structural plane, in which the structural plane statistic method and cementing status recognition method are used together. The geometrical character of structural plane is assessed according to volumetric joint count, and the geometrical integrity index of rock mass (Ig) is introduced to represent it. The cementing status of structural plane is classified into five grades based on joint opening and cemented fills. The qualitative character of each grade is given; and the cementing status coefficient of structural plane (Ip) is introduced to represent it. Then the integrality index of rock mass (Irm) is defined as Irm=Ig×Ip. The integrality of rock mass is classified into five grades: integrated, moderate integrated, cracked, moderate cracked, and highly cracked. The qualitative character and Irm of each grade are given. Taken a highway tunnel for example, the integrality of surrounding rock mass of tunnel is assessed by the sound wave test method, the volumetric joint count method and the method suggested in this article respectively; then the assessment results are compared as well. It is found that Irm obtained with the method suggested in this article coincides with Kv gained by sound wave test method, while the results of volumetric joint count method are commonly higher than the sound wave test method.

Based on the limit equilibrium method, a rounded analysis for rock slope have been undertaken, in which several influencing factors such as water pressure, surcharge, seismic loading and anchoring force have been taken into account. The safety factor expressions for rock slope stability subjected to the condition of many factors have been deduced. Parametric analysis has shown that depth of water in tension crack, groundwater seepage force, blocked outflow suture, seismic loading, surcharge have a disadvantage effect on the rock slope stability against sliding; but anchorage effect of anchor blots has a beneficial effect on the rock slope stability against sliding. Parametric analysis has also shown that depth of water in tension crack, blocked outflow suture, horizontal seismic loading have a disadvantage effect on the rock slope stability against overturning; but surcharge, anchorage effect of anchor blots and vertical seismic loading have a advantageous effect on the rock slope stability against overturning. Finally, the project proposals have been put forward according to the engineering practice.

By analyzing the effect of groundwater water on rock bedded slope, it is found that the stresses of groundwater mainly act as fissured water pressure and drag force on structural plane. And through the analysis of the dominant joint plane controlling the stability in sliding failure, this paper holds that the fissured hydrostatic tension on this plane, the pressure on sliding surface and the drag force are all decided by water filling at the back edge of the fissure. In this paper, also on the assumption that typical rock slope samples are simplified, making use of the simplified hydraulic model of slopes, two numerical expressions are presented. One is about the slope stability and the other is about the critical height of water filling in cracks which decides the slope stability. Based on the analysis and calculation of actual slopes, the proposed formula is proved to be reasonable. It is also concluded that the decrease in slope stability under the influence of groundwater is mainly related to hydrostatic pressure instead of its penetration.

Taking Fangdoushan tunnel for example, the 3D finite element model is built; and the stability of tunnel supporting structure is simulated and analyzed. The horizontal stresses, vertical stresses and displacement, anchor bar axial forces and the failure fields of the section which distance to the hole is about 10 m are analyzed; and the characteristic points of the section on the supporting structure is studied too. The results show that the stresses and displacements increase when the distance between the section and heading face are less than 30 m; after that, the stresses and displacements is convergent; and the increments are small. All of these show that the supporting structure is stable. The numerical simulation results of primary support stress and axial force of anchor bar are compared with the monitored results, from which it can be known that they are consistent basically.

Based on complete measurement information, it has important practical value for guiding back analysis practice in geotechnical engineering to study the identifiability and optimal measured arrangement of elastic back analysis of parameters. Via planar elastic function of complex variable technique and general elastic theory, the analytic formulas of displacement and stress are derived; and based on the displacement and disturbed stress solutions for the plane elasticity problems, this paper studies the identifiability and optimal measured arrangement of back analysis of elastic parameters by use of differentiability condition of parameters and most sensitive principle of optimal measured arrangement, and uses a simple example to validate the conclusion. The study shows, based on the complete measured information to carry out elastic back-analysis, the five parameters P, Q, M, E and ? can be identified uniquely under condition that the measured arrangement is appropriate and the parameters satisfy the restrictive conditions. The identifiability of inversion parameters is influenced by the shape complexity of tunnel; and with the shape complexity of tunnel increasing, the restrictive conditions of the parameters are decreased; the requirement for the measured arrangement is also reduced. To avoid the substantial fluctuation of inversion results arisen from a small error of measurement data in engineering practice, the combination of measured points (lines) which has the largest sensitivity coefficient value of each inversion parameter should be chosen as the optimal measured arrangement based on the most sensitive principle.

Vibrations of a plate on viscoelastic foundation under moving rectangular loads with variable speeds are investigated; and the general solution of dynamic deflection of the plate is derived using the double Fourier transform. By employing fast Fourier transform (FFT), a rigid pavement is chosen to obtain the numerical results; and the calculation results are consistent with ones of classical solution. The effects of initial moving velocity and acceleration on the dynamic deflection are discussed. The results indicate that the initial velocity and acceleration of the rectangular load have influence on the dynamic response. The dynamic deflection of plate at critical velocity decreases significantly with the increase of the initial moving velocity and acceleration. The maximum dynamic deflection appears when the moving load velocity reaches the critical velocity of plate.

At present, in engineering application, there are something to improve and extended in unloading rock mass mechanics theory. First, unloading has effect on horizontal displacement of slope before and after anchor is applied; second, overbreak and anchor lag have effect on horizontal displacement of rock in the concrete engineering. Third, the connectivity rate of structural plane has effect on displacement of unloading rock; fourth, unloading rock has horizontal displacement response under earthquake action. Fifth, different connectivity rates have effect on horizontal displacement under earthquake action. So, based on unloading rock mass the theory, it carries out the research of Dagangshan dam abutment slope developing horizontal displacement. Adopting construction. It carries out the research of Dagangshan dam abutment slope. Pointed out that rebound deformation and compression deformation after the rock excavation unloading will be greater than does not take into account when calculating the deformation of the rock deterioration. Statistics of profiles of the horizontal displacement the characteristics with the development of the earthquake acceleration at different elevations, the proposed horizontal displacement with changes in earthquake acceleration was nonlinear region the focus of aseismic and reinforcement for the earthquake region it is. Indicated that the two types of program under unloading condition engender the smaller impact to the slope horizontal displacement, multi-stage overbreak, anchoring measures is lagging behind the scene of the feasibility of the construction process to provide a basis. The research shows that increase of connectivity rate will cause that plastic zone of unloading fissure XL9-15,XL316-1 increase obviously, but within fissures extension the increase of plastic zone is obviously not the key point reflected in the changes in slope, and the excavation work could cause the apparent smaller displacement of the status of the sudden collapse.

Based on the upper bound limit analysis theorem and the shear strength reduction technique, the equation for expressing the critical limit-equilibrium state was employed to define the safety factor and its corresponding critical failure mechanism for a given layered soft-rock slope by means of the kinematical approach of limit analysis theory. The definition of safety factor was adopted in the present method so that the results from the limit analysis can be applied to engineering practices directly. The case study and comparative analysis show that the solutions presented agree well with available predictions; and the validity of the analysis method could be illuminated. From the numerical results, it is also shown that the safety factor and the instability failure range of layered soft-rock slope are controlled by slope angle, bulk density, slope height, seismic effect coefficients and strata inclination; and when the strata inclination within a certain range, the instability probability of layered soft-rock slope reaches its maximum.

Based on Rankine's earth pressure theory, assuming the internal friction angle of backfill and the displacement are in nonlinear, a calculation model for calculating the passive and active earth pressure acted on the retaining wall is put forward. This model is continuous with displacement variation and can consider the friction of interface between soil and wall. By contrasting the calculated results and the model test results of sands, it is shown that they can agree with each other very well. So it is reasonable to use the calculation model to calculate the active or passive earth pressure. In addition, according to the calculation model, the paper deduces a new kind of effective calculation method to estimate static earth pressure coefficient.

Owing to involving to unsaturated soil mechanics, numerical simulation for deformation of unsaturated road-embankment under rainfall infiltration is still a difficult point. The present strength reduction finite element methods usually only reduce strength parameters, which result in the deformation fields of road-embankments are different from the practical ones. This paper holds that under rainfall infiltration, not only the strength parameters of road-embankment soils will reduce, but also the deformation parameters will also change with the changing of soils stress levels and strength parameters. Using the developed FLAC program by authors, the numerical simulation for a high road-embankment deformation under different rainfall infiltration depths are conducted; and the results of numerical calculation are compared with those of the laboratory model tests. Then the influence law of rainfall infiltration depths on the road-embankment slope stability and sliding arc changing characteristics are analyzed by strength reduction finite element methods and limit equilibrium method (Bishop method).

By using the discrete means of the block element method, the 3D slope is partitioned into a proper number of block elements conjoined with the structural planes. It assumes block elements are rigid, stresses only existed in structural planes. Base on the lower bound limit theorem, and regarding the stresses of structural plane as unknown variables, the statically admissible stress fields that satisfy the equilibrium, boundary conditions and yield criterions are constructed. A linearization yield criterion is used for avoiding nonlinear mathematical programming. Finally, the lower bound limit analysis model of linear and nonlinear mathematical programming for 3D slope stability is established; four examples are used and the results agreed well with those from the rigid limit equilibrium and upper bound method.

Evaluation of surrounding rock stability is a complex system problem of uncertainty. Based on the projection pursuit (PP), the particle swarm optimization (PSO) and the logistic curve function (LCF), a new model for evaluation of surrounding rock stability is developed, which is referred as projection pursuit based on particle swarm optimization (PSO-PP). The model, on the one hand, uses PSO to optimize the projection index function and the parameters of LCF so as to ensure the accuracy of the parameters used in the model; on the other hand, the nonlinear relationship between projection values and experiential grades is established according to LCF. The test result of the model indicates there is a very good precision. In this study, the evaluation result obtained by applying the model developed here to an underground project is well consistent with the real situation. It is shown that the model here is feasible and effective in evaluating surrounding rock stability.

The deformation stability of three-dimensional slope is analyzed based on Hoek-Brown criterion. Rock slope at a surface mine is chosen as the analysis object. Three-dimensional numerical analysis model is established by fast Lagrangian explicit-finite-difference code of continua (FLAC3D); and some monitoring points are located in the slope. In order to obtain the accurate values of displacements for these monitoring points, an internal routine (FISH) is developed to calculate the interpolation displacements. The static and dynamic displacements after slope excavation are analyzed, which reveals the slope macroscopic deformations in different zones and gives guidance for engineering practices. Finally, the strength reduction method in the Hoek-Brown criterion is applied to calculating the safety factor of slope after excavation. In the analysis, the non-convergence of calculation is chosen to describe the failure of slope. The calculation further extents the application of strength reduction method of Hoek-Brown criterion in three-dimensional slope stability analysis.

In the system of uniaxial loading with servo control, the experiment of uniaxial loading on the samples of prefabricated cement mortar with multiple fissures was made, aiming to explore the influencing rules of strength of fracture failure which belong to the rock-like material with different angles and densities of distribution of the fissures. Basing on the arrangement and analysis of the experimental data, a strain-softening model is established by using the software-FLAC3D; and then the numerical analysis of the strain-softening model carried out. The experimental data and the results of numerical calculation show that: When the density distributions of fissures are the same, the angle of the fissures plays an obvious part in the strength of fracture failure of the samples. And when the angle of the fissures is about 25°, it has the minimum value of strength. When the angles of the fissures are the same, the strength of fracture failure of the samples has a relationship with the density distribution of fissures. When the angle has a small value, the effects of density distribution of fissures are obvious. And with the increasing of the inclination angle of the fissures, the effects are increasingly weak. This conclusion provides a basis for predicting the changing rules of strength of the wall rock with multi-fissures in the underground projects.

Present design method based on the elastic theory and experience is unreasonable while used to evaluate the safety of pavement structure. Shakedown theory can provide theoretical basis for bearing capacity analysis of pavements under complex loading. Based on the lower bound theorem of shakedown, a method for shakedown analysis of pavements has been presented. By applying the shakedown analysis of pavement, influence of load distribution, structural configuration, material properties of pavements on shakedown bearing limit are obtained. The analytical results show that the proposed method is valid for analyzing the pavement structure. Therefore, shakedown theorem can provide a useful tool for analysis and design of pavements.

The successfully monitoring and early warning for highway slope in operation period are not common though the highway landslide is the common disaster. The main reason is that the highway slope has the characteristics including spot distribution along road, long interval, small scale, large quantity and lack of statistics, which cause the high monitoring costs and difficult early warning. In this paper, the wire pulling displacement meter with the precise of 1 mm is used to monitor the surface displacements of landslide, and the GPRS net of China Telecom is applied to transform the monitoring data; the whole system has high automation and low cost. Meantime, the FEM software PLAXIS is used to conduct the strength reduction analysis and plastic analysis. Based on the calculation results with different parameters, the relationship between the slope safety factor and surface displacement is established in lack of the strength parameters, permeability and soil water characteristic curve; and the corresponding early warning measures are proposed according to the change of surface displacement. This method has been applied to a highway landslide in Hunan province.

Based on the principle for tensiometer to measure the unsaturated soil matric suction, a new matric measurment device was made. With continuously reviewing and improvment for the measurement result , the unsaturated soil matrix suction measurement device with more simple, convenient, fast and reliable advantages was achieved in the experiment. With this device, the matric suctions of silty soils with different water contends, different compactness or cyclic wetting-drying were measured; and the soil-water characteristic curves of silty soils with different compactnesses were obtained. Through the Boltzmann model in Origin sofeware to fit with the experiment curve, it’s show that the influence for the water content to the matric suction was improved greatly by the high compactness, and cyclic wetting-drying influence the matric suction and shear strength of the silty soils greatly.

The slopes of mountainous highways are of such characteristics as dotted distribution, relatively large number but small scale, and easily affected by human activity and environment variation. According to these characteristics, an individual slope monitoring device system is established in this essay. The system mainly aims at displacement and rainfall monitoring, and is developed based on the GPRS technology. By integrating the trigger displacement meter, grid pluviometer, data acquisition and transmission unit, and solar power supply device, the system is proved to be economical, energy-saving and highly efficient. Based on Microsoft Visual C++ network technology and SQL Server 2005 data base，the software system of remote monitoring and forecasting for geological disasters is developed, which realizes the real-time remote receiving and visual management of monitoring data. Due to the variety of slope deformation and failure modes, the system also integrates several time forecast models to establish the slope deformation prediction model database. The monitoring and forecasting system has been successfully applied to Chang-Ji highway, and provided a guarantee for the highway safety in extremely bad weather.