According to the degrading and soil mechanical characteristics of municipal solid waste (MSW), a nonlinear constitutive model of total strain theory to describe the coupled effects of stress and degradation is established, on the basis of the stress-degradation model and isotropic compression characteristics and Duncan-Chang model. The mathematical expressions for volume and axial deformation of unit body changes with time in different stress states are given; and then methods for determining all parameters are also provided. Verification is implemented by simulating the stress-strain curves of MSW samples obtained from landfill and a few long term one dimensional compression tests in laboratory. The results indicate that the concept of the model is reasonable; the selection of parameters is relatively clear and the model is able to describe the constitutive relations of MSW with different degradation ages in a more comprehensive way, which can be used for analyzing the long term deformation of landfills.

By using the analytical Flamant and Melan solutions, the integral formulae derived from Mindlin’s equations, solutions in semi-infinite plane are derived to calculate displacements and compare with computed results from the finite element method. It is found that the calculated displacements are indeterminate in the line loading direction, where no absolute displacements but only relative displacements can be obtained. However, the calculated relative displacements increase with an increasing in the distance away from the reference point of displacement constraint; and they also increase with an increasing length of line load distribution normal to the half-plane, leading to non-convergence. This means the derived displacement solutions of pure half-plane problems are multivalued. Thus, it is necessary to analyze geotechnical problems using the half-space assumption.

Methane hydrate is recognized as one of the potential new resources to solve the current energy crisis. Soil assembly containing methane hydrate in the bottom of sea is called deep-sea methane hydrate-bearing soil (MHBS). The morphology of methane hydrate is different in MHBS, e.g. pore-filling and cementing. The cementing type has a great effect on the ensemble strength of MHBS, especially at a lower methane hydrate saturation. This constitutes the strong motivation of the paper. Methane hydrate as a cementing material forms among soil particles, and the bond thickness of methane hydrate changes in certain ranges. The relationship between methane hydrate saturation and inter-particle bond thickness is obtained through analyzing the SEM of MHBS. Based on the previous experimental findings, a novel inter-particle bonded model considering bond thickness has been proposed for investigating the effect of bond thickness of methane hydrate on the mechanical behavior of MHBS; and the calculation methods are elaborated to determine its relevant bond parameters.

A serious of centrifuge model tests of side-grouting uplift piles is performed to gain an insight into the mechanism of side-grouting and its effect. Mechanical properties of the contact surface, load-displacement curves and the development of skin friction resistance are discussed and compared with the in-situ test results. A further research shows that the development of side friction on uplift piles is a progressive procedure, with a leading increase of skin friction resistance at the upper part of the pile and followed by an increase of skin friction resistance at the lower part. Side-grouting leads to an increase in the ultimate skin friction resistance and a decrease in the relative pile-soil displacement at the ultimate state. Compared with the non-grouting pile, the side-grouting pile has a higher growing skin friction in the upper and lower part than that in the middle part. Both the centrifuge model and in-situ tests illustrate that the pile with side-grouting has significantly larger uplift stiffness and capacity than that without side-grouting.

Based on analyzing of the thermal effect generated by cavitation bubble breaking moment and sound field of cavitation noise, the theoretical formulas of coal permeability under the action of thermal effect are derived. The temperature and permeability tests are performed under different cavitation conditions (pump pressure and confining pressure). The results show that the coal temperature increases with the increasing pump pressure when confining pressure is constant; on the contrary, the coal temperature decreases with the increasing confining pressure of cavitation chamber when pump pressure is constant. When the thermal stress of coal is greater than the average effective stress, the micro deformation of coal appears under thermal expansion; and the tensile stress makes the increase in the width and number of cracks. Besides the increasing intrinsic energy of free gas causes the greatly reduces of molecular free path at the same time, due to coal matrix shrinkage effect, the coal methane desorption make the micro pore and crack structures expand, which affects the permeability. The index relationship between permeability and temperature is deduced, which is consistent with the regular pattern described by the theoretical formulas of permeability.

Over the last three decades, there has been a positive evolution in philosophy and practice from a wholly empirical approach to pavement design towards the use of a theoretical framework for design. However, this theoretical framework is mainly based on elasticity theory of soil and granular material behavior. A major limitation of this elastic analytical approach is that strength properties of pavement materials are not taken into account. Based on elastoplastic theory, shakedown analysis is able to provide maximum capacity of structures under cyclic loads; therefore it can be used as a theoretical basis for pavement design. This paper illustrates the shakedown theory and two classical shakedown theorems. Literature reviews summarize the origination and development of pavement shakedown studies, supported by experimental results. Residual stress distributions in pavements and two pavement shakedown solutions are discussed in detail and compared with limit analysis. A pavement design procedure using a lower bound shakedown solution is also presented; finally, the tendency of the pavement shakedown theory is predicted.

Capillary barrier evapotranspiration covers have many advantages over conventional covers. But they are mainly used in arid or semi-arid areas in USA and Europe. Whether they can be used in humid areas remains to be determined. Using low plastic silty clay and gravelly sand as material, a soil column is constructed in outdoor environment in Hangzhou and vegetation is planted. Water content, percolation and surface runoff are measured. Peak rainfall season, sunny and hot season, typhoon period and winter season are experienced during the monitoring 15 months. Results show that volumetric water content of silty clay changes greatly under natural infiltration and evapotranspiration; the and small dry-wet cycles exist in gravelly sand. It is shown that evapotranspiration acts on the whole depth of the cover. There comes percolation when silty clay in the bottom becomes saturated and volumetric water content of gravelly sand approaches 4%. The cover becomes temporarily ineffective and will soon be effective again when water content decreases due to vapor movement. Rainfall, surface runoff and percolation are 1 782.6, 53.08, 19.64 mm respectively. Most rainfall are stored in soils and later returned to the atmosphere by evapotranspiration. The cover can prevent percolation effectively during the test period.

By direct shear test, strength behavior of rock mass containing discontinuous joints with different joint surface morphologies is researched. The extension process to the rock mass can be divided into 4 stages: before initial cracking stage, crack stable growth stage, unsteady growth stage and friction stage. According to the experimental phenomena and the shear deformation curve, initial cracking strength, critical strength, failure strength and residual strength are researched. With the same normal stress, the joint surface morphology is rougher, not only the failure strength is higher, but also the initial cracking strength, critical strength, and residual strength are higher. With different joint surface morphologies, the ratio of the initial cracking strength and failure strength is about 70%; the ratio of the critical strength and failure strength is about 90%; but the ratio of t initial cracking strength and failure strength is not stable, which is about 50%-90%. The experimental verification is provided to further study failure theory of rock mass containing discontinuous joints.

In order to investigate the volume change behaviour of compacted expansive soil, the one-dimensional swelling- compression tests are carried out for Jingmen weak expansive soil associated with six different compactnesses. Based on the results of one-dimensional nonloaded swelling tests, a time-swelling formula is presented which can fit the tested time-swelling curve satisfactorily with the physically meaningful parameters. Furthermore, the time-swelling curve can be characterized as three segments divided by a method presented. On the other hand, the results of the one-dimensional compression tests are used to investigate the interactive relationship between consolidation yield stress, compression index Cc, swelling index Cs, swell pressure and sample compactness, soil structure, swelling potential, void ratio in detail. The test results show that the volume change of compacted expansive soil is the consequence of the effects coupled moisture, external load, and swelling potential. And the volume change depends heavily on the hydro-mechanical path.

Dynamic penetration is one of wide applied in-situ test techniques. The rod length during operation could be as long as hundreds of meters, calling for length modification in practical applications. Two major methods are proposed in most present specifications for the modification of dynamic penetration rod length. These two methods are founded differently on Newton elastic collision theory and elastic rod waving theory, and derived totally different modified coefficients. How to apply rod length modifications to the results of dynamic penetration test has currently become major issues that limit their application. Indoor model tests are put forward for the modification issues, altogether with varies of heavy dynamic penetration model being conducted on sand and gravel soil with series of rod lengths (2.0, 8.9, 16.4, 23.4, 30.0, 36.0 m). The modification coefficient of heavy dynamic penetration rod length is obtained after the tests. It is analyzed and concluded that the modification to heavy dynamic penetration rod length followed the description of Newton elastic collision theory, and is independent of the material properties.

Permeability is an important property of sand soil. Factors that influence the permeability of sand include density, particle characteristics and properties of the fluid, among which the porosity and particle size are two important ones. However, previous investigations based on natural sand with mixed particles are not able to study the two factors independently. Therefore, constant head permeability tests are firstly carried out on sand soil with single particle size fractions to study the influence of grain size and porosity on the permeability, respectively. For sand soil with the same grain size fraction, the coefficient of permeability is found to increase linearly with the increase in porosity; for sand soil with the same porosity, the coefficient of permeability is found to increase linearly with the increase in porosity the square of average particle size. Based on this, the influence of gradation characteristics on the permeability of multi-particle-size sand soil is studied to extend the results from single particle size fraction to natural sand. The results show that the coefficient of permeability of multi-particle-size sand soil increased linearly with the increase the coefficient of curvature and coefficient of uniformity. The influences of different factors also differ from each other. The change in average particle size leads to change in order of magnitude of the coefficient of permeability. Finally, an empirical equation considering all the above factors is developed for engineering practice.

The separation of side resistance and toe resistance of PHC pipe piles during installation restricts the study of its penetration mechanism and bearing capacity. Full-scale tests are conducted on 5 opened PHC pipe piles jacked into stratified soils to monitor the variation of side resistance and toe resistance during installation base on quasi-distributed Fiber Bragg grating sensors. The results indicate that quasi-distributed optical fiber technology has strong operability and installation resistance separation is obtained well under bad construction condition. The variation of pile jacking force in stratified soils basically reflects the soil parameters difference, and the soil under pile toe has more influence on jacking force. The test piles jacking force, which pile toe locates on bearing layer, increases about 64.06% when jacks into the bearing layer, while the increment of toe resistance and side resistance are 97.41% and 17.92%, respectively; The pile jacking force variation is not significant which toe doesn’t locate on bearing layer. The variation of pile stress in field test is different from indoor experiments during installation, in which the mechanism of side resistance in upper is different with bottom; and the critical depth phenomenon of side resistance is not obvious because of bad construction condition and soil variation in depth.

A composite ground with partially penetrated granular columns is turned into a equivalent-double-layered ground on the basis of the general solution of the average degree of consolidation; and its simplifying analytical solution of 1D consolidation is worked out; furthermore, the simplifying formula of the average degree of consolidation is gained. Based on this solution, the present existing solutions and finite element method, these relevant programs are programmed. The consolidation process is investigated and the relevant results are prepared in graph forms which considering the influence of some factors including penetration ratio, permeability coefficient of a granular column, permeability coefficient of disturbed soil and impact factor of disturbed zone. The influence of various factors on the consolidation behavior of composite ground with partially penetrated granular columns is analyzed; and the comparative study of the average consolidation degrees by the three calculation methods is carried out; and then the applicability of the simplifying solution is discussed. The research results show that, the average consolidation degree of the simplifying solution under single-sided drainage or double-sided drainage conditions is between the ones of the existing solutions and the finite element method; and especially in the middle-latter of the consolidation process (≥50% degree of consolidation), the results of the simplifying solution meet the engineering precision requirements; and it is simple, and practical; and in the various influencing factors, both length and permeability coefficient of granular column have the most effects on the consolidation process.

The applicable conditions of dynamic Bouc-Wen model and influence of the model parameters on hysteretic loop, etc. are discussed. Based on the laws of thermodynamics, the incremental dissipation functional expressions of Bouc-Wen dynamic model are formulated. Then the energy dissipation mechanism of damming earth and rocks are analyzed under different levels of dynamic strain; and two threshold strains are found defined as the first threshold strain and the second threshold strain respectively. The corresponding modulus ratios are around 0.94 and between 0.50-0.80. The second threshold strain is equated with the traditional threshold strain using pore water pressure build-up or volume changes as standard. It is good for the further understanding of the dynamic response of soil.

The common character of schist is transversely isotropic due to the existence of regular bedding planes, which means that the failure mechanism and deformation characteristics of such rocks have the obvious difference with common rocks. In view of this point, uniaxial compressive test on samples of Wudang group schist, Tongsheng tunnel, Shiyan-Fangxian expressway, that with schistosity inclination of 0°, 45° and 90° respectively is carried out. The results show that: deformation parameters and failure mode of schist show obvious anisotropic characteristics. In the order of descending values of the modulus of elasticity, schistosity inclination of the samples are 90°, 0°, 45°respectively, in the order of descending values of the Poisson ratio, schistosity inclination of the samples are 45°, 0°, 90° respectively. The main failure mode is press off perpendicular to the spatial orientation of schistosity, shear and split off when schistosity inclination is 0°, 45°and 90° respectively according to schistosity inclination. Based on above, the mechanism of deformation and failure characteristics of schist is analyzed, via electron microscope scanning and FLAC3D numerical experiment, it is considered that, the main reason is the different relationships between spatial orientation of schistosity and axial force direction, which caused obvious differences of contribution that of schistosity surface to schist deformation.

Applying upper bound theorem and strength reduction method, a new approach for slope back analysis is proposed. This method is based on the location of slip surface, not the displacement and stress. The relationship between the location of critical slip surface and strength parameter is analyzed. When the geometry, unit weight, pore pressure of a homogeneous soil slope are given, and cohesion the critical slip surface was only related to expression with cohesion and friction angle . Thus, the slope strength parameter can be back analyzed through slip surface depth and the dimensionless parameter is introduced on that basis. The formulation of slope slip surface is obtained by upper bound theorem of limit analysis and strength reduction method. Calculation formula for critical slip surface is presented and the relationship between the slip surface depth at a certain position and the magnitude of is built. The existing slope engineering example is tested, and the effectiveness of this method is showed.

By using state-dependent yield function and dilatancy function, a state-dependent non-associated elasto-plasticity hardening model is proposed to simulate the undrained behaviors of saturated soils with different initial densities and confining pressures. According to the second-order work theory, the criteria for potential instability and static liquefaction of saturated soils are proposed. The proposed model and criteria were employed to predict a series of undrained triaxial tests on loose sands. The results showed that the static liquefaction occurs at the hardening stage before the plastic limit, the onset of static liquefaction accompanies with the peak of shear stress; and then the pore water pressure increases and the shear stress decreases with further loading. The stress-strain relationship of the municipal solid waste under undrained condition was also analyzed; the potential instability line was obtained and the onset of static liquefaction was predicted.

Laboratory tests are made to study the mechanical properties of coal-serial mudstone under different temperatures by using the rock mechanics test system RMT－150B and high and low temperature environmental chamber GD－65/150. The effects of complete stress-strain curve, peak stress, peak strain, elastic modulus, deformation modulus and Poisson's ratios of mudstone at different temperatures are analyzed. The results show that, there are differences at different temperatures in mechanical properties of mudstone. As the temperature increases, peak stress and peak strain decrease in different amplitudes; peak stress decreases from 9.153 MPa in 25 ℃ to 8.271 MPa in 55 ℃, and a 9.6 percent decline; peak strain decreases from 11.002×10-3 in 25 ℃ to 8.249×10-3 in 55 ℃, and a 25.0 percent decline. Elastic modulus decreases gradually with the increasing temperature. Deformation modulus increases with the increasing temperature. Poisson's ratio decreases gradually with the increasing temperature; and the relation between various parameter variables and temperature is obtained. Research results provide a theoretical basis for the rock control in deep high temperature soft rock roadway.

189 ground motions from 3 551 recordings in the next generation attenuation (NGA) database are classified as pulse-like ground motions based on wavelet analysis; and all ground motions are rotated to orientations of the strongest observed pulse. Newmark method is used to calculate the permanent displacement of slopes induced by near-fault pulse-like ground motions; and the effects of velocity pulse-like characteristics on the slope permanent displacements are studied. The analyses indicate that the near-fault pulse-like ground motion has a significant effect on the damage of slopes, resulting in strong potential damage of permanent block and larger permanent displacement. It is shown that permanent displacement has a close relationship with the peak ground velocity; especially for the case of relatively large displacement. Two empirical predictive models for permanent displacements are developed by using the scalar intensity measure of peak ground velocity and vector intensity measures of peak ground velocity and peak ground acceleration. The scalar predictive model has small standard deviation when the permanent displacement is relatively large. The developed displacement predictive models can be used in probabilistic seismic hazard analysis for permanent displacement including the effects of near-fault pulse-like characteristics.

In order to investigate the influence of main parameters of pile and soil on the lateral vibration of pipe pile in saturated soil, the soil is divided into saturated soil around pile and inner pile saturated soil, and coupling dynamic model of the saturated soil-pipe pile is established by using the control equations of theory of porous medium. By considering the boundaries of saturated soil around pile and inner pile saturated soil, the lateral vibrations of saturated soil around pile and inner pile core saturated soil are solved with the uncoupling method of potential function. The horizontal vibration of pipe pile in saturated soil is also solved by considering the forces of saturated soil around pile and inner pile saturated soil acting on pipe pile, and the lateral dynamic impedance of the pipe pile at pile head is obtained; the influence of main parameters on the lateral vibration of pipe pile in saturated soil is also analyzed. The research results indicate that the influence of the inner and outer radii of pipe pile, shear modulus ratio, Poisson’ ratio of pile around saturated soil and pile core saturated soil on the lateral dynamic impedance of pipe pile in saturated soil is great; fluid-solid coefficient ratio has a certain influence on lateral dynamic impedance at low frequency; and the ratio of damping ratio has a certain influence on the damping factor of lateral dynamic impedance.

Analytical solutions to the complete action process of surrounding rock-support in elastoplastic stage have been provided. Supporting structures of anchor bolt, shotcrete and U-steel are commonly used in the practical projects. It is a critical theoretical issue to further study the three supporting structures on this basis. Based on the spatial effects of the excavation face, and according to the analytical solutions above-mentioned, the supporting structures respectively through project examples in which the surrounding rocks have diameters of 6 m, 5 m, 4 m, is studied. And the thesis mainly includes three the following parts: calculations of ultimate bearing capacity of the above three structures, calculation and analysis about the effect on controlling plastic deformation of surrounding rock based on the spatial effects of the excavation face, and analysis of the supporting effect on the Protodyakonov's surrounding rock pressure by the remaining supporting force. It is also studied U-steel constitutive relationship between load and displacement, proposes conception of the remaining force and analyses the mechanism of supporting structure restricting deformation of surrounding rock. Two conclusions are drawn as follows. (1) Compared with the in-situ stress(>10 MPa), the supporting forces (<1 MPa) provided by the three supporting structures are too low to control the elastoplastic deformation of the surrounding rock with diameters of 6 m, 5 m or more larger, but the supporting forces are effective for the surrounding rock with diameters of 4 m . (2)For the the surrounding rock with diameters of 6 m and 5 m or more larger, if the remaining supporting force can be reserved effectively, supporting structure can support Protodyakonov's pressure availably.

The static drill rooted nodular pile is a new type of composite pile foundation which consists of precast nodular pile and the cemented soil along the pile shaft. This kind of composite pile has a good bearing capacity, and the mud pollution will largely be reduced in its construction process. A group of experiments were conducted to provide a comparison between this composite pile and the bored pile. The axial force of the nodular pile was measured by the strain gauges attached on the pile shaft to analyze the distribution of the axial force and the skin friction along the shaft; and then a three-dimensional model was built by using the ABAQUS finite element program to investigate the load transfer mechanism of this composite pile in detail. The results of the field tests and ABAQUS simulation showed that: the bearing capacity of the static drill rooted nodular pile is better than that of the bored pile in soft soil area. The settlement of the composite pile is controlled by the precast pile, and the deformation of the precast pile and the cemented soil can be considered as deformation compatibility. The nodes on the nodular pile play an important role during the load transfer process; and the skin friction of the static drill rooted nodular pile is about 1.05-1.10 times of the skin friction of the bored pile in the same soil layer.

Exploiting protective layer is one of the most effective measures for control of coal and gas outburst; and the key problem is to locate the protection scope exactly. Aimed at the problem of locating the protection scope for the exploiting of steeply clined upper-protective layer, based on the theory of gas leak flow and the coupling effect between deformation of coal & rock and gas seepage, the methane gas seepage field equation and coal & rock deformation field equation are established; and then the mathematical models of gas leak flow coupled solid and gas of steeply clined upper-protective layer are also established. Taking a coal mine in Nantong mining area for engineering example, by using multi-physical field coupling system for numerical calculation of the model, the law of gas pressure distribution in protected layer is gained after protective layer was mined. Furthermore, the pressure-relief scope of protective layer mining is also obtained. It is shown that the protection scopes of numerical simulation are basically closed to the results of practical test. Therefore, this study results can provide theoretical guidance for locating protection scope and are of great significance for practical matters.

From the viewpoint of probability theory, combined with the deterministic vector sum method, the stability evaluation methods are studied for the bank sections of gravity dam under random seismic loads. Firstly, deterministic stability evaluation is made through the history curve of safety factors, which is obtained by dynamic vector sum method, under a certain seismic load. Secondly, the probability density function(PDF) of the minimum value of dynamic stability safety factors and the dynamic reliability are got through the Gram-Charlier series fitting method and the weighted maximum entropy method under random seismic loads. Thirdly, comprehensive evaluation is made by both deterministic results and probabilistic ones during the whole design period. The example results show that the deterministic and probabilistic methods can complement each other to make a comprehensive seismic stability evaluation for the bank sections of the gravity dam during the whole design period.

Compressed air energy storage is a kind of technology to storage energy and generate electricity using compressed air as the medium. Underground structure for compressed air energy storage(CAES) is a decisive factor to choose the location of compressed air energy storage plant, in which artificially-excavated hard rock cavern is more worth researching for little restricted to geology and wide adaptability. To select a scheme of underground cavern for compressed air energy storage, the stability of CAES cavern under high inner pressure is studied by FEM. Plastic zone and tangential strain of CAES cavern with typical buried depth (200, 300, 500 m), various layouts(tunnels and jars) and dimensions, are calculated by finite element software Abaqus. By analyzing the stress and deformation characteristics of surrounding rock after excavation and inflation, suitable cavern form is achieved. When surrounding rock class is Ⅱ and inner pressure is 10 MPa, caverns buried in depth of 300 m are of good stability. Buried in the depth of 300 m, the maximum tangential strain of 6 m-diameter round cavern and jar cavern are 7.55 and 5.54 respectively, which lays a foundation for research on elongation and durability of sealing material in different temperatures.

As known to all, the fact that the stability of underground rock is mainly controlled by joint; and the stochastic distribution of geometric and mechanical parameters of joint causes high degree of uncertainty; a reliability analysis method about stability of rock blocks considering uncertainty in geometric parameters and mechanical parameters of joint combined with key block theory is presented; and a proper, combined evaluation model for failure probability is developed. The main objective of this research is to develop a probabilistic approach that can be implemented to assess the probabilistic occurrence and probability of failure of wedges within excavations. This approach is based on the use of stochastic fracture networks FracSim3D to simulate the fracture network and key block theory to identify the wedges and calculate the factor of safety. A programming code based on Fortran 95 has been implemented to perform the main probabilistic wedge occurrence and wedge failure analysis. To evaluate the feasibility of this new probabilistic approach, the procedure is applied to a practical example, a cooper mine in Adelaide, Australia, with considering the uncertainty of dip angle, dip direction, cohesion and friction angle. Finally, the analysis method of conditional probability is proposed to find the failure probability of wedge in plane failure. The calculation results show that the occurrence probability of wedge in plane failure is 11.0%, and the probability of failure is 3.85%, which is greater than the general engineering acceptable risk level. Results of the probabilistic method indicate that the method can be used as a basis model to evaluate the reliability of wedge.

Large-diameter rock-socketed piles are used to support the pier with the height of 195 m at Hezhang bridge, to acquire its bearing behaviors, distributed fiber optic sensing technology is implemented to monitor the continous distributed strains of the large-diameter rock-socketed piles. At first, indoor model tests are performed to verify that the fiber optic technology is available to monitor the compressive strain when the pile is loaded. And then, the design and in-situ installation of fiber optic sensors is carried out on the basis of Hezhang bridge; and the testing data during construction are collected as well. Through the data treatment and analysis, the bearing behaviors and load transfer mechanism of the large-diameter rock-socketed piles are researched. Comparing with the actual settlement of the support engineering, fiber optic sensing technology is further testified to be feasible. The research results have reference value for pile theory and the application of fiber optic sensing technology to similar projects.

Excavation of the pit will cause the rebound, the deeper the excavation is, the greater the rebound will be; the large amount of rebound will cause a variety of engineering problems. Existing rebound calculation methods require specialized rebound experiment or a particular stress path experiment to determine the unloading modulus. The application of modulus obtained from conventional laboratory tests and commonly used Mindlin solution and Boussinesq solution combined in a simple and practical way to get the rebound is studied in this paper. Four calculation methods for different combinations between the stress calculation of the Mindlin solution and Boussinesq solution and the deformation calculation of e- model and Duncan-Chang model, are obtained; and then the amount of rebound is calculated by the application of the layerwise summation method; and the accuracies of four methods are explored respectively. A more practical method for the application of engineering excavation rebound calculation is obtained. Compared with the measured values, the Mindlin solution and e- model are recommended respectively to calculate the stress and modulus; and then a calculated rebound which is very accurate to the measured values can be obtained with the application of the layerwise summation method.

Based on the geological conditions, underground mining situations, as well as the status of cracks and ground surface deformation of Chengchao Iron Mine, a cantilever beam mechanical model is proposed. The bottom-up tubular collapse in the deep rock mass causes the horizontal tectonic stress release which favors the bending fracture deformation and destruction of the NWW-trending joints. This model can explain the formation of four zones in the deep rock mass: rupture zone, the transition zone of rupture to deformation, the deformation zone and the undisturbed zone. In such a mode, it inevitably leads to different deformation areas on the ground surface related to the different zones in the deep rock mass. So the mine surface is divided into four related areas: cumulative deformation area, crack-producing area, crack-extending area, and crack-closing area. As mining progresses, four zones of the deep rock mass will gradually extend downward, while four areas of the ground surface deformation will gradually expand outward.

For the purpose of trying to find a reasonable criterion for stability analysis of three-dimensional slope based on strength reduction method, the displacement mutation criterion and the connectivity criterion of plastic zone are analyzed based on Zhenzhuba slope by FLAC3D; and then the results are compared with the ANSYS and two-dimensional limit equilibrium’s ones. It is shown that, in the stability analysis of three-dimensional slope using strength reduction, mutations are easily identified in the curve between the increments of total displacement and reduction factors and reasonable feature points should be selected on the top of the slope for the displacement mutation criterion. Meanwhile, a modified criterion is put forward due to the shortcomings of the connectivity of plastic zone criterion. It is that the mutations, which are on the curve between the increments of penetration rate of the plastic zone and reduction factors, are used to judge the instability state of three-dimensional slope. So the reasonable choice of three-dimensional slope’s instability criterion should be as follows. If the slip band is known clearly, the increments of penetration rate of the plastic zone criterion is suggested; if not, the displacement increment mutation criterion is suggested.

The nature of pile-rock interface has important influence on the pile-rock joint mechanical properties. A large number of engineering shows that the pile-rock interface has obvious shear rheological phenomenon. On the basis of displacement compatibility theory, the hyperbolic transfer function iterative calculation method is introduced, and an iterative method, which takes the rheological property of pile side rock into account to analyze the pile rock joint stress reaction, is established. The comparison of the iterative results and the site model pile test results shows that the hyperbolic transfer function iterative method can describe pile-rock joint mechanical properties accurately. Considering the pile rock interface shear rheology, the axial force throughout the pile grows gradually over time until it is stabilized. Pile axial forces are larger than that without considering the rheology. The iterative calculation results and the measured results are in a good agreement, which have certain reference value to the research of pile-rock joint mechanical properties.

For the purpose of legitimately determining each major factor weight and objectively analyzing debris flow susceptibility, a model for analyzing debris flow susceptibility is established based on minimum entropy analysis and uncertainty measurement theory. Nine major factors of 26 typical debris flows along Jinsha River are selected. By utilizing the minimum entropy analysis, the contribution rate to debris flow system and weight of each major factor are obtained. And then, the multi-index comprehensive evaluation measure vector of each debris flow catchment is determined based on the uncertainty measurement theory. The final susceptibility degree is acquired by credible degree recognition criteria. By comparing the debris-flow susceptibility results with reference[11], we find that only seven debris flow catchments are different. Comparing the susceptibility results with field observations, 22 of 26 debris flow catchments agrees very well with real status of debris flow; and the susceptibilities of four debris flow catchments are conservative. Thus, the proposed model is shown to be quite effective in predicting debris flow susceptibility, which can be applied to actual engineering; and the analyzing results can provide rational suggestion for debris flow prevention.

The complex geological conditions and rock mechanics environmental changes in the dam area directly affect the abutment stability of rock against sliding and the safety of arch dam. In Southwest China, the dam area of Wudongde ultra-high arch dam has extremely complex engineering geological conditions. After the dam is unloaded, the nature geological conditions become the main factors to affect the abutment stability, such as formation lithology, fault structures, karst system, skewback discontinuous fissures. Based on the geological exploration data, two-dimensional geological sections and engineering data of the feasibility study stage, the object-oriented technology, and a variety of collaboration software are used to establish a geometric model of the natural geological conditions and engineering objects. Finally, a three-dimensional fine finite element model which is suitable for the analysis of the abutment stability is built under the conditions of inversion analysis of ground stress, the dam load, exaction and so on. The three-dimensional fine finite element model simulates the complex structure of engineering largely, which provides a good foundation for the comprehensive analysis of the stability of high arch dam abutment rock. The results show that stress level of both the near-surface ground stress zone on both sides of the valley and deep ground stress zone of riverbed is close to the actual measured value. After the excavation of dam abutment is completed, the maximum displacement reaches 12.9 mm near the right bank of 800 m elevation of spandrel groove. There are some differences in the 9 sliding blocks under the different loading combination conditions; and the stability of the left abutment is stronger than that of the right on the whole. Under the combinations of seismic loads, all safety factors of the wedges will reduce largely; but there is still some margin of safety.

The model of pressure solution for granular aggregates established by Taron et al is introduced into the FEM code for analysis of thermo-hydro-mechanical coupling in porous media developed by the first author. Aiming at a hypothetical model for nuclear waste disposal in an unsaturated quartz aggregate rock mass with a laboratory scale, two computational conditions are designed: (1) the porosity and the permeability of rock mass are functions of the pressure solution; (2) the porosity and the permeability are constants, then the corresponding numerical simulations for a disposal period of 4 years are carried out; and the states of temperatures, solute concentrations in the intergranular fluid film and at the pore space, removal and precipitation masses, porosities and permeabilities, pore pressures, flow velocities and stresses in the rock mass are investigated. The results show: at the end of the calculation in case 1, pressure solution makes the porosities and the permeabilities decrease to about 43%－54% and 4.4%－9.1% of their initial values; under the action of the release heat of nuclear waste, the negative pore pressures in case 1 and case 2 are about 1.0－1.25 and 1.0－1.1 times of the initial values respectively; so the former represents an obvious effect of pressure solution; the magnitudes and distributions of stresses within the rock mass in the two calculation cases are much the same.

A phenomenon is found that the pore water pressure in the soil specimen inclines to delay during the single-drainage consolidation test by using the oedometer which can measure the pore water pressure at the bottom of specimen. In order to analyze its cause, a one-dimensional dynamic consolidation equation in which the vertical strain is set as its dependent variable is presented to take into account of the dynamic effect due to instantaneous loading, and the numerical analysis is performed by using the finite difference method. A new parameter CD composed of the modulus of compressibility, coefficient of permeability, density and thickness of specimen is introduced to characterize the dynamic effect; and then its influence on the pore water pressure in the process of consolidation is investigated. The numerical results indicate that the dynamic effect due to loading is a cause of delay of pore water pressure in the specimen, and the phenomenon is easier to appear for the soil specimen with greater modulus of compressibility or coefficient of permeability. In addition, the dynamic effect has a certain influence on the consolidation degree in the early period of consolidation. Finally, the consolidation cases are discussed that the dynamic effect can be negligible.

Aiming at problems that rock is opaque and damage can not be observed easily, the method of coupling smoothed particle hydrodynamics (SPH) method with finite element method are used to investigate the mechanism and damage evolution of abrasive water jet impaction on rock which is based on J-H-C damage constitutive model. According to numerical results, the damage forms of abrasive water jet impaction on rock are staged along cross direction and long direction. The depths of abrasive water jet penetration are in relation to the shape and density of abrasive. The shape of damage caused by impaction in rock is staged. The distance from surface impacted by abrasive water jet is shorter, the damage gradient ascent violently and vice versa.

By modeling the uncertain geotechnical parameters as spatially random fields instead of traditional random variables, a local average method of two-dimensional triangular elements is proposed based on the local average theory of random field. The analytical calculation and numerical calculation for the covariance matrix of triangular elements of the local average random field is provided by the transformation of area coordinates and the Gauss numerical integration. An illustrative example is presented to demonstrate the analysis process and the validity of the proposed method; and the advantage of the proposed method is proven by comparing these results with the results derived when the random fields of geotechnical parameters are divided based on arbitrary quadrilateral elements method. The results show that the local average method of triangular elements can perfectly combine with the finite element method of triangular elements; and the corresponding relation is clearer; and the program is simpler. For the mean of the random field mesh, the calculation results are the same based on the proposed method and the arbitrary quadrilateral elements method. For the variance of the random field mesh, the calculation results are smaller based on arbitrary quadrilateral elements method. Therefore, the local average method of triangular elements is more scientific and reasonable.

Unsaturated hydraulic conductivity is a primary soil parameter required when performing seepage analyses for unsaturated soil. The measurement of unsaturated hydraulic conductivity is normally time-consuming and limited in a narrow range. Wetting front advancing method is newly developed for a rapid measurement of unsaturated hydraulic conductivity. It is capable to measure the hydraulic conductivity function in one week and over a wide suction and permeability range. In this paper, the accuracy of this method is investigated through numerical test. The results demonstrate that the soil hydraulic conductivity curve (SHCC) calculated by wetting front advancing method can agree with the “real” SHCC perfectly, i.e. the input PF. The instantaneous profile method is also used to calculate SHCC in the numerical test. The results indicate that the difference between the result data and the input SHCC increase with the increase of monitoring section space. A monitoring section space of 20 mm can result in a SHCC, which still worse than the data from the wetting front advancing method.

At present, the deformation analysis in the large-scale landslide physical model tests is mainly carried out with point based measurements which are generally more accurate and precise than area based techniques, especially when control targets are used. However, point based measurements provide only information of a few selected monitoring points and not on the whole surface of the model. 3D laser scanning technology captures the integrated, comprehensive, consecutive and associated panoramic coordinate data with a high degree of precision and resolution in extreme speed. It also describes factually the frame and configuration of the object. 3D laser scanning technology has been successfully applied to displacement monitoring and deformation measurement in the large-scale landslide physical model tests. In order to assess the effectiveness of the measurement methods applied to measure displacement in the laser scanning and evaluate their performances, a validation simulation experiment has been carried out. The error evaluation model of the point positional accuracy is derived. The point density in laser scanning is analyzed theoretically; and a practical test stabilized with model piles has been carried out to better understand the mechanics of such type of landslides. The displacement and deformation obtained by cloud to cloud comparison method, the barycenter method and scan data collection at two different epochs are reasoned to describe synthetically the deformation evolution process of the model here. Researches show that: the error evaluation model and point density model provide a theoretical basis for the evaluation of measurement achievement and the optimal designs for the measurement scheme. The cloud to cloud comparison method and scanning data collection techniques are area based measurements, while barycenter method and the benchmark method are point based. With point based measurement small deformations can be detected in only a few selected positions due to the largely manual measurement process. The area based methods give a good approximation of the displacement amplitudes and provide the whole deformation of the slope surface. The application of the 3D laser scanning technology to the landslide model test has the advantage of combining both the point based and area based methods. It provides the whole deformation while maintaining the high precision for the selected positions.

The stress measurement of deep soft rock mass is very hard; and the existing testing technique is not available. Thus, a 3D compressive sensor is particularly invented to measure the geostress of soft rock mass; the corresponding method of calculation is introduced; the calibration test, interference test and laboratory model experiment for the sensor are also performed. The calibration test data show that the static properties, such as linearity, repeatability, etc., are well. As the load increases gradually, the measuring error of sensor is diminishing, until zero, and then increasing, but less than 10% as a whole; so a conclusion is obtained that the stress within a reasonable range can be perceived accurately. The interference test shows that the mutual disturbance of three perception surfaces is negligible. The laboratory model experiment data show that, when forcing repeatedly, the value detected by the sensor approach to the load application more and more, almost equal finally, and further summing-up is gained that the 3D compressive sensor basically meet engineering practice requirements. In addition, the optimization design of the sensor is discussed preliminarily.

In order to study the efficient and reasonable dynamic moduli testing technology of subgrade, based on analysis of the portable seismic property analyzer(PSPA) for its working principle and testing characteristics, the testing principle of PSPA is described; and the calculation formula of dynamic moduli is deduced according to the elastodynamics and spectral analysis of surface wave theory (SASW). Combined with the actual working conditions of subgrade field testing, the testing procedures and the main technical points of PSPA are put forward, and the distance between two detectors or detector with emission source of PSPA are both recommended according the different depths testing for subgrade. Combined with the project, a large number of on-site comparing tests on subgrade are made to obtain the dynamic moduli of PSPA, dynamic moduli of PFWD, resilient moduli of bearing plate, penetration ratios of dynamic cone penetrometer (DCP); and compactnesses of sand cone method in order by point to point, the correlation between dynamic moduli of PSPA and other indexes are established. The results show that all the absolute values of correlation coefficient are more than 0.80 to indicate the good correlativity existing between the testing results with PSPA and other testing methods, it means that using PSPA for rapid testing dynamic moduli of subgrade is reasonable and feasible, it can apply to the quality control in construction procedure of subgrade and provide reliable parameters and basis for pavement design.