Hardfill is a new type of architectural material for dam construction, with a wide application prospect. It is produced by adding low content cementitious material and water to rock-based material, and mixing them with simple device. Its mechanical performance lies between concrete and rockfill material. For further understanding and appreciating the mechanical behavior of hardfill material, a series of large-scale triaxial tests were performed on hardfill specimens at different ages. And strain-stress behavior of hardfill was investigated, showing that the failure strength of hardfill material follows the Mohr-Coulomb strength theory; with the age increasing, cohesion varies a lot while friction angle differs little. By subtracting stress-strain curves of rockfill, which represent the initial conditions of hardfill, from that of hardfill, the effect of cementation on stress-strain relationship was discussed. Based on the analysis of these results, an age-related constitutive model of hardfill was developed, which is a parallel model consisting of two components, rockfill component and cementation component. The rockfill component represents the conventional rockfill without any cementitious material, which reflects the influence of rockfill by playing a role of skeleton of this cement-rockfill mixture. The cementation component characterizes the impact of cementation. Moreover, comparison was made between simulated and experimental results, showing that the parallel model could reflect the mechanical characteristics of both rockfill-like nonlinearity and concrete-like age-relativity. In addition, a simplified method for determination of parameters was proposed.

A review of the creep behavior of soil and its constitutive models is performed. The contents of the review include the influences of time and stress on soil creep, the criterion for creep failure, the relation between creep potential and plastic potential, microscopic mechanism of soil creep, macroscopic and microscopic creep models. Based on the review, equivalent deformation processes for soil are proposed. The proper description of time effect in creep model is discussed. A method for accelerating creep test is proposed.

In order to determine the thickness of flat frozen soil wall with evident rheological properties, the triaxial creep properties of frozen soil are analyzed. Through theoretical analysis of rheological properties of frozen soil, the logarithmic creep equation of frozen clay is established under complex stress state. The triaxial creep tests for manual prepared frozen clay specimens are carried out by “cold box-triaxial pressure chamber” light test equipment system; so that the creep curves of frozen clay under complex stress state are obtained. According to the test results, the logarithmic creep equation parameters of frozen clay are obtained through regression analysis of logarithmical nonlinear creep equation. According to the rheological theory of frozen soil and the established creep equation, as well as the thickness formula of flat frozen soil wall, through adopting Visualc++ 6.0 and Matlab 6.0, the computer application software is exploited which can calculate thickness of frozen clay wall. With the software, the relationships between the thickness and the span, the pit exposure time, and the pit excavation depth are analyzed. The thickness of flat frozen soil wall possesses rapid growth trend with time extension in the short term and then gradually becomes stable. The thickness of flat frozen soil wall is affected lightly by the span; but it possesses gradual upward trend with the increasing of excavation depth of pit. The temperature affects the thickness of flat frozen soil wall significantly; the higher the temperature is, the larger the thickness is. Consequently, controlling the temperature is the key to the design of flat frozen soil wall. Thus, the results provide a basis for thickness determination of flat frozen soil wall with a large creep deformation.

Earthen architecture ruins is mostly found in the arid area, which suffers from strong wind erosion, freeze-thaw process. Influence of cyclic freezing-thawing on the durability of earthen architecture are researched. Cyclic freezing-thawing are conducted on the undisturbed and remolded specimens from Jiaohe cultural heritage, Xinjiang, China to understand the durability of earthen architecture to wind erosion and the strength attenuation. Test results show, under low original water content, the undisturbed and remolded specimens masses are increased during the beginning five freezing-thawing cycles. With the change of moisture content during the freezing and thawing process, undisturbed specimen weight expresses a decreasing tendency; and remolded specimens weight maintains a level of weight. With the increasing of freezing-thawing cycles, undisturbed specimens show a decrease in compressive strength and an increase in wind erosion quantity due to microstructure damage; that is, a weakening in durability. However, the remolded specimens exhibit an enhancement of microstructures at beginning cycles, characterized by an increase in strength and a decrease in wind erosion, that is, an improvement in durability. It is considered the healing effect of destroyed microstructure and the aging of chemical cohesive agents are responsible for the strengthening of remolded specimen at the earlier freezing-thawing cycles. At the further freezing-thawing cycles, the remolded specimens turn to exhibit a decreasing tendency on durability following the increasing damage of microstructure.

The field and laboratory tests are carried out to research the plugging effect of jacked prestressed concrete pipe pile under two different geological conditions. The test show that a higher plug would be caused by the longer pile with thinner wall jacked into stiffer soil. Open-ended pile is prone to a plugged mode when the hard soil is over the soft soil; while the plug is prone to sliding when the soft soil is over the hard soil. The general development of cone tip resistance of cone penetration test (CPT) is similar with that of annulus resistance; and the ratio of two is independent on incremental filling ratio and penetration depth. The ratios of annulus resistance to cone tip resistance, closely related to geological condition, are approximately 0.59 and 0.81 for muddy clay and silt respectively. The observed soil layers distribution in the soil column are similar to the subsurface condition, except for the convex interface for plug. Soil is evidently compressed during the penetration into pile, whereas reduced cohesion is measured probably due to the disturbance. The direct shear test results indicate evident time-effect on shear strength of plug column. The active plug length appears to be approximately 5-6 times pile diameter in silt, which is 70 percent of total plug length; whereas this value should be larger than 4 times pile diameter in muddy clay. The results are close to existing observations.

It exists high liquid limit of laterite soil abundantly in southwest area of Hunan Province, which weathered from carbonate rocks due to the humid and rainy climate and geological conditions. The laterite soil possesses special features, such as high natural moisture, inherent large void ratio, strong structural features; so it is difficult to meet the normative requirements of compaction degree. In order to discuss the appropriate compaction technology and put forward an embankment compaction control recommendation for laterite soil, field tests are carried out which combined with many different conditions such as moisture, loose laying depth, rolling machines and so on. The results show that the compacted effect is better when using bumping vibration rolling, controlling the laterite soil filling with 25-30 cm loosing thickness and water content beyond the optimum moisture content 2%-5%. At the same time, the compacted soil will have more stable engineering characteristics.

Natural gas hydrate is one of the most important potential energy sources , at the same time which is the triggering factor of global climate change and geologic hazards. The phase equilibrium of hydrates bearing sediments (HBS) is a basic issue for resources evaluation ,exploitation and effection on environments. There is larger differece on association and dissociation of gas hydrate in pure water and sediments. By summarizing the research information both indoor and outdoor and based on the inverstigation needs of geotachnic engineering in the exploration and utilization of natural gas hydrates, the state of art on the effection of HBS formation mode, character of sediments, salinity of pore water and components of gases on the phase equilibrium of HBS, some techniques and methods for making samples, determination of composition content and the theoretical model is presented. Results show that formation mode, property of sediments, salinity of pore water and component of gases effect on phase equilibrium remarkably. There is poor precision in quantitative analysis or expensive costs in the numerous advanced methods and equips used in experiments and tests about HBS. The micro-theoretic models of phase equilibrium of HBS could model the phase equilibrium very well; however, complexity in expression and acquire hardly is the limitation of its application about geotechnical engineering problem in the exploitation of hydrate.

For the purpose of developing a new constitutive model, a lot of testing data are required. Consequently it is necessary to reform the old type triaxial apparatus to an automated one. After analyzing the old apparatus system, based on the principle of triaxial testing method, reformations are conducted on the controlling equipments for confining pressure and back pressure. Consequently, the reliability is improved and the operation is simplified. The automation of displacement and volume change measurements are carried out. Finally, the reliability is verified by a series of tests for Shanghai clay. The reformation works reuse the out-of-date apparatus and improve the research condition. The reformation method can be used for similar apparatus.

In order to analyze the stability of soaked subgrade filled with weathered phyllite, wetting deformation and resilient modulus of the subgrade are tested in field at Ankang eastern section of Shiyan-Tianshui expressway. Based on physico-mechanical property analysis of weathered phyllite, filling scheme of subgrade is put forward: for subgrade filled material with weathered phyllite California bearing ratio (CBR) >3%, the weathered phyllite is filled into the subgrade directly; for CBR<3%, the weathered phyllite is filled into the subgrade after improved with additive 3% cement. Through bearing plate field tests before and after immersion on the test road, the influence of soaking amount, soaking time on wetting deformation, rate of wetting deformation and resilient modulus of subgrade are analyzed. Combined with water content test of the test points in different depths, relationships between water content, seepage depth and wetting deformation are analyzed. The results indicate that soaking amount and soaking time are key factors that affect the seepage depth and water content; the wetting deformation of soaked common subgrade is more obvious than that of soaked improved subgrade. When both soaking amount and soaking time are equal, the resilient modulus attenuation of common subgrade is larger than that of improved subgrade.

The freeze-thaw history of soil is important to assess and predict frost heave. Different freezing modes will lead to redistributions of water and salt and variety of dry density. Choosing three freezing modes of unidirectional freezing, circular freeze-thaw with sinusoidal wave and circular freezing with negative temperature, experiments of red silty clay along the Qinghai-Tibet Railway are carried out in order to analyze variation of frost heave amount, redistribution condition of water and salt and change law of dry density. The results show that salt transfer is kept out of the freezing soil for ice self-purification during the unidirectional freezing; deformation amount of the soil experienced freezing and thawing is uncumulative. Salt convection with water is accompanied with salt diffusion during freezing and thawing. The existent compression deformation shows the intensified effect of freeze-thaw on soil structure.

To determine the side rock resistance of pile more accurately, the composing and the influence factor of it need to be researched. The mechanism of friction and adhesion between pile and rock is analyzed. It is pointed out that pile-rock interface strength is different from rock shearing resistance; the ultimate side rock resistance of pile is determined by the weak one between pile-rock interface strength and rock strength. Four groups of compression and uplift comparative tests for concrete short piles in medium weathered rock are accomplished. The value of ultimate side rock resistance and the resistance ratio of uplift test and compression test are obtained. Because the upper rock restriction to the rock connected with pile is weaker in uplift test than in compression test; the side rock resistance in uplift test decreases distinctly comparing with the result of compression test. ADINA software is used to analyze the test piles. By comparing the calculated value of ADINA program with the test value, the interface strength condition of pile and rock is analyzed. It is discovered that the ultimate side rock resistance of test pile is determined by the pile-rock interface strength; and the interface adherence force is the main part of interface strength.

Significant residual stress may be formed along a jacked pile during installation. Field tests are conducted on a 26 m pile jacked into sandy soil, involving observations on the variations in residual stress in a 212 d test period after pile construction. The test scheme includes a cyclic loading test, installation of three adjacent piles, a reloading test and a relatively long-term rest. The results show that the residual stress of pile is further accumulated in the cyclic loading tests as the number of loading cycles and the level of cyclic loading increase. The magnitude of residual stress, however, is reduced by the tensile effect of jacking the adjacent piles. Such effect is found to be the maximum when the penetrating pile tip approaches the observed depth. The residual stress of pile tends to decay to a stable value for a relatively long period. The influence of time on the residual stress of pile is mainly related to the creep behavior of sandy soil that weakens the soil arching effect around pile and reduces the contact pressure at the tip of pile.

In order to study the mechanical property of cement-soil, the plane strain tests and consolidated drained triaxial (CD) tests are carried out. Characteristics and strength properties of stress-strain curve of cement-soil are discussed. The results show that the stress-strain curve has softening behavior; the softening degree is related to confining pressure and it is obvious under the condition of plane strain state; the strength failure envelopes of both CD test and plane strain test are linear and the Mohr-Coulomb criterion can be applied here; the residual strengths of both CD test and plane strain test increase linearly along with the increase of confining pressure. Moreover, the residual strength of plane strain test is greater than that of CD test; the ratio of residual strength to peak strength increases with the increase of confining pressure and the increasing rate slows down. Under the condition of plane strain, the failure strength is 1.4 to 1.6 times of the CD test result. According to the microstructure and conservation of energy principle, the softening causes of cement-soil are analyzed. The gel material such as cement hydrate is the major factor. The softening characteristic is intensified because of the effect of intermediate principal stress.

Creep deformation regularity of municipal solid waste(MSW) is researched by indoor creep tests. Taking 2 series of sampels of MSW with initial void ratios from 2 to 4 and organic matter content from 15% to 75% respectively, compression- degradation tests are carried out. The findings indicate that slope of stress-strain-time curve decreases with the increasing of initial void ratio and organic matter content; and the material compression modulus decreases gradually. An exponential model is proposed to fit the stress-strain-time curve and obtaining good fitting effect. Parameters of this model are easy to get and can reflect the compressibility and its mechanism. The tangent compression modulus of MSW is obtained by the exponential model derivation and it shows exponential attenuation with the increasing of initial void ratio and organic matter content. The initial compression modulus attenuates rapidly when the initial void ratios are 2-3. That is to say, the influence of initial void ratio on deformation of MSW is larger.

The filter paper method is one of indirect methods for measuring soil suction. The accuracy of the measurement is highly dependent on the suction calibration for the testing filter paper. The basic principle of the filter paper method is introduced and its relevant studies are reviewed. A kind of domestic filter paper, named “Double-circle No.203”, is selected for the total suction calibration test with the sodium chloride solution method; and the result of the calibration test is well fitted by a bilinear regression curve. The suction calibration curves of the domestic filter paper with a brand name of “Double-circle No.203” are compared with those of a typical abroad filter paper of “Whatman’s No.42”. It is found that the matric suction calibration curves of the two filter papers are nearly the same, while the break-point water content of the total suction calibration curve of the “Double-circle No.203” filter paper is higher than that of the “Whatman’s No.42” filter paper.

The generalization of constitutive model has great significance in describing the three-dimensional mechanical behaviors of soil. The Mises criterion cannot reflect the effect of Lode’s angle on deformation and strength of material and the g(θ) method cannot reflect the effect of stress level on those on the π plane. To overcome these problems, an approach named transformed stress method considering the effect of Lode’s angle is proposed without adding any extra parameter and can be simply applied to numerical analysis. Combining the constitutive model proposed by authors with the transformed stress method based on SMP(spatially mobilized plane), three-dimension of overconsolidated unsaturated soil is realized; continuous transition from shear yield to shear failure is achieved. Many characteristics including hardening, softening and dilatancy of overconsolidated unsaturated soil with different Lode’s angles are described and compared with test data.

According to experiments on granite under uniaxial compression at high temperatures (normal to 850 ℃) and after high temperatures (normal to 1 200 ℃) cooling and reloading, the mechanical properties of granite have been researched. The variations of uniaxial compressive strength, elastic modulus, longitudinal wave velocity, cut-slip strain with temperature are analyzed; then the effects of thermo-mechanical coupling are studied. Some results are achieved: (1) The peak strength and elastic modulus decrease continuously at high temperature. (2) Reloading after high temperature, the strength changes little from 25 ℃ to 600 ℃, then decreases suddenly at about 800 ℃. (3) The longitudinal wave velocity decreases gradually as temperature rises. (4) The cut-slip strain is small, and varies little below 800 ℃, then increases rapidly and the granite presents distinct plastic behavior over 800 ℃. (5) Based on the proposed concept of thermo-mechanical coupled factor, one-dimensional nonlinear thermo-mechanical coupled damage constitutive equation is established; and model curves are in agreement with experimental curves.

Through model tests under direct shear condition, the shear deformation of rock containing coplanar close joints with the same continuity and different undulating angles are studied under different normal stresses. Direct shear tests show that before peak shear strength, the shear stress-displacement curve of intermittent joint has linear and nonlinear segments; the rock bridge produces some degree of weakening under normal and shear loads; and shows macroscopic shear stress softening when accumulated to some degree. The four stages of crack development and characteristics of shear stress-deformation curve are described in detail; and an empirical constitutive model is suggested which can fit the whole process of shear stress-shear deformation curve. Piecewise function is used to describe curve characteristic. Data analyses show that the model can fit the shear stress-shear deformation trends and has a high fitting accuracy which verifies the correctness of this new model; finally, its inadequacy is also given briefly.

In order to obtain the performance of assembly foundations composed by the concrete footing slab and steel angle column, which are used for the transmission line engineering in Taklimakan desert, the four in-site full-scale of two sizes tests on the bearing capacity of assembly foundations combined uplift with horizontal loadings are carried out. The curves of load-displacement both of footing slab and foundation top plane, and the soil pressure on the footing slab are all obtained. For the foundation top plane, combined the uplift with horizontal loadings, the curve of uplift loading-displacement develops slowly; and the curve of horizontal loading-displacement increases linearly. The anti-overturning bearing capacity of assembly foundation is weak because of light dead weight of the steel support frame and the loose property of aeolian sand. The assembly foundation composed by concrete footing slab and steel angle column has a good property of coordinated performance. Influence of horizontal loading on bearing capacity of assembly foundation is obvious. According to the test data of ultimate uplift bearing capacity, the average frictional resistance of aeolian sand is 2.6 kPa, which is calculated by mechanical model of prismatic fracture plane.

According to model tests of pure sand foundation, horizontal reinforcement foundation and horizontal-vertical (H-V) reinforcements foundation, the influences of single layer H-V reinforced depth and number of H-V reinforced layers on foundations are studied. Through comparing the horizontal reinforcement foundations and combining the sliding surface of H-V reinforced soil, the reinforcement mechanism is analyzed. The test results show that the reinforced effect of H-V reinforcements is better than that of horizontal reinforcement at the same experiment condition; the bearing capacity decreases with the increase of the single layer H-V reinforced depth; effect of reinforcement on foundation bearing capacity is not obvious when the reinforced depth exceeding a certain range. For multilayer H-V reinforced foundation, bearing capacity increases and settlement decreases with the increase of number of reinforced layers.

The soil bed formation is a complex process which involves sedimentation and dead-weight consolidation. However, there isn’t a simple and feasible method for measuring the water content, density, grain size, pore water pressure and total stress during its physical model test now. An improved laboratory testing method has been carried out. Compared with the available testing methods, the surface settlement, water content (density) distribution, dissipation profiles of excess pore water pressure, and grain size distribution variation of deposition at different depths and times in the process can be obtained by using the improved method. The experimental results show that the measured data are reasonable; and error of consistency test is small; and the improved laboratory testing method is feasible

In accordance with bearing water pressure and cracking, using test system made up by self-made concrete sample mould, self-made controlled cracking device, self-made controlled water pressure device, and crack width measuring instrument, experiments for permeability of cracked concrete are carried out under the conditions of different water pressures, concentrations of chloride ion, crack widths and soaking times. The experiment results show that chloride ion content of concrete increases significantly with the increasing of water pressure when the other experimental conditions are same; and the migration laws are different; and crack width threshold which is independent of water pressure controls the migration of chloride ion. This method can provide a reference for similar study.

Based on the theory of elasticity, the analytic solution of temperature stress of shaft wall of coal mine is deduced. It is shown that when the temperature of inwall is higher than that of ectotheca of shaft wall, the temperature stresses and get maximal values at inwall and minimal values at ectotheca. Temperature stress will become larger with increases of elastic modulus E, Poisson’s ratio , coefficient of dilatation and depth of shaft wall z separately; while temperature stress will decrease with increase of temperature difference . It is also shown that the place of inwall of shaft wall will be broken earlier than ectotheca, which is validated by reality. In the factors which induced the failure of shaft wall, the weigh of temperature stress is larger than that of shaft wall dead weight. Therefore, temperature stress plays an important role in the failure of shaft wall.

Layered soil such as landfill and cracked soils are often found in engineering. Its coupled infiltration and deformation during rainfall is significant for development of unsaturated soil mechanics. Based on fluid mass conservation, Darcy’s law, and the constitutive model proposed by Lloret et al., coupled governing equations for seepage and deformation in unsaturated soils are obtained. The unsaturated coefficient of permeability is expressed using Gardner’s model and the water retention characteristics are expressed using Boltzman’s model. The analytic solution to the coupled equation is developed by Laplace transformation. The analytic solution and parameter analysis results show that the effect of coupling between unsaturated seepage and deformation is related with time. The modulus related to suction changes F has a marked effect on the pore water pressure. The larger the F ratio values for two-layer soils are, the more slowly the suction dissipates. The results indicate that a large F for the top-layer soil can effectively reduce the coupling effect. Volumetric moisture content changes in two-layer soils play a limited role in the suction distribution.

Based on the analytical solution of stresses and deformations for composite foundations with equal strain assumption, the expressions for stress ratio, settlement ratio, radial displacement and lateral pressure coefficient are obtained. The variations with the ratio of compression modulus and the ratio of area replacement are illustrated and compared with the Priebe’s method. The influences of assumptions in Priebe’s method on computational results are also analyzed in detail. The analytical results show that the assumption of ignoring volumetric strain of pile should induce obvious errors in Priebe’s method; and the composite influences of assumptions of radial displacement computation and lateral pressure coefficients are relatively small as a result of counteracting of each influence

Compared with the conventional multiple scattering theories for vibration isolation of Aviles, an improved expansion method of wave functions using more complete Fourier-Bessel function series has been adopted. With the help of boundary conditions and Graf’s addition theorem, the analytical solutions for transmission coefficient of several elastic cylinders, which are randomly located in homogeneous unbounded soil, have been gained under the incidence of horizontal shear wave (SH wave). Then, all the cylinders are distributed in two parallel lines, which makes the problem turn into the vibration isolation using double row of elastic piles. The dimensionless displacement (the ratio of the displacement of soil in total wave field to the displacement only in SH wave incidence field) and transmission coefficient (the average value of dimensionless displacements across the barrier) are introduced to research isolation of barrier. The effect of this vibration isolation system and other properties of the system are investigated with the variation of the distance h between two rows and the shear modulus ratio . Specially, the problem will reduce normal vibration isolation of single row discontinuous barrier if h=0

Aiming at the disadvantages of the modeling method which is based on approximately parallel sections, a 3D geological modeling method based on the way of dividing the spatial cells is proposed by utilizing intersected section data. Based on self-governing thought, the method divides the complex overall regional modeling into a single lattice modeling. Finally, the whole model is got by splicing all lattices of sub models together using opposite steps

Geological information acquisition, geophysical prediction and data interpretation are three major links of tunnel geological prediction. In this article the methods of geological logging were firstly discussed, including tunnel risk classification, geological sketching on tunnel face, then the geological plane map was plotted and the three-dimensional geological model was built. The location of the defective geological karst-fractured groundwater in adjacent tunnel could be calculated from the geological model Based on this situation the key issues of instruments were discussed in detail, and developed the tunnel geological prediction automatic selection system, which could help the operators choose proper methods for zones with different rock characters, structure development characters and underground hydrological features, and make suggestion for special geological zones. At last the criterions on data analysis of staple prediction methods of typical adverse geological bodies were given, which had a certain reference to tunnel advanced geological prediction.

Deformation of ground surface above old mine goaf is a complex nonlinear process, which has complex, sudden, and long-term features. The foundation stability and residual deformation must be evaluated before building life or service facilities above old mine goaf. A new method is put forward for stability analysis and evaluation of buildings above goaf by multiscale decomposition using empirical mode decomposition(EMD) method. Trough case study, detail signals of dynamic deformation of buildings above old mine goaf are obtained using multiscale empirical mode decomposition method. Decomposition scales are analyzed so as to evaluate the deformation characteristics reflected by original data and research the deformation mechanism effectively. Precision prediction for deformation is obtained by multiscale prediction model which is better than traditional method. This prediction model can provide a theoretical basis for stability evaluation of buildings above old mine goaf.

The diffusion wave and incident wave stress fields of simple harmonic wave propagation in viscoelastic media with Kelvin model are presented. The propagating wave is divided into two parts of diffusion wave and incident wave. The diffusion wave and incident wave stress fields in elastic media are deduced firstly. Then the diffusion wave and incident wave stress fields in viscoelastic media with Kelvin model are presented combining elastic wave theory and viscoelastic theory. And the deduced stress fields can be expressed with the displacement and velocity expressions of diffusion wave and incident wave. The results are propitious for application of wave theory to viscoelastic media

An improved anti-overturning safety factor calculation method of the cement-soil retaining wall in layered soil is presented. Based on the improved method, the influence of different soil structures on the anti-overturning safety factor is analyzed. When the soft soil is over the hard soil the anti-overturning safety factor increases with increasing of the width and the embedded depth of the wall respectively. Similarly the anti-overturning safety factor also increases with increasing of the width of the wall but has less change with increasing of the embedded depth of the wall when the hard soil is over the soft soil. The reason for that is the anti-overturning safety of the cement-soil retaining wall relies mainly on the passive earth pressure; that is to say, the anti-overturning safety factor is influenced by the lower soil’s strength mainly. If treating the layered soil parameters according to the thickness weighted as the homogeneous soil, the anti-overturning safety factor is smaller which inclines to conservative when the soft soil is over the hard soil. Unlike that the anti-overturning safety factor is bigger which has the security risk when the hard soil is over the soft soil. Compared with the conventional calculation method, the improved method presents a more reasonable and safe result.

In order to improve the design and calculation of single piles under combined vertical and lateral loads when the pile deformation is comparatively great, considering the P-? effect (with the meaning of vertical load can magnify the deformation induced by lateral load) caused by vertical load and yield of soil, dead weight of the pile, and skin friction of the pile side, assuming that the coefficient of subgrade reaction increases linearly with depth, the power series solutions of the deformation and internal force for the pile shaft under ground surface are obtained. Combining the pre-existing power series solutions for the pile shaft above ground, the relevant computer program is developed by Fortran language. The calculation results indicate that the displacements at the pile head and the ground surface, and the maximum bending moment increase when the vertical and lateral loads, and the pile length above ground increase; and decrease when the yield displacement of soil increases. The vertical load may cause the instability problem for the pile. The boundary condition at the pile head plays an important role in pile responses. The computed and the model test results are in good agreement, meaning that the obtained solutions and program are dependable.

The method for determining the geological strength index (GSI) with the surface condition and structure of rock mass mainly depends on their qualitative descriptions. There is much more subjectivity because the value is hard to get through the qualitative description. So, the quantitative indices are firstly used to determine GSI, such as process surface condition rate (SCR), joint condition coefficient (Jc), surface rate (SR) and quantitative block volume (Vb). SCR and Jc are used to reflect the surface condition. SR and Vb are used to reflect the structure of rock mass. In order to reflect the uncertainty of the quantitative indices, interval values are used to express them. Then the method for determining the interval values of GSI can be presented through the study of the determination of quantitative index values. Secondly, the interval combination method is presented to calculate the rock mass shear strength parameters according to the Hoek-Brown strength criterion. And the method for determining rock mass shear strength parameters based on interval theory and GSI is suggested. Finally, the method is used to determine the shear strength parameters of a hydropower station water intake tunnel in Hunan province. Compared with the existing analysis method, the results show that the method is reasonable and feasible. It provides a new approach to determine the shear strength parameters of rock mass, when the test data are less

Based on the movement law of the potential sliding body sliding in the inclined plane by dead weight effect, the assumption that the direction of the anti-sliding force is perpendicular to the intersecting line of the sliding surface and the horizontal plane are proposed. Citing a concept of played factor of inter-slice shear strength, a three-dimensional limit equilibrium method for calculating slope stability are proposed using force equilibrium of each pillar and moment equilibrium of the whole slope body in three directions. Through case study, when all the shear forces among columns are neglected, the safety factor is similar to the result of two-dimensional Spencer method. If considering part of the shear forces among columns, the safety factor is similar to the result of the reference [5]. If considering all the forces among the columns including the contribution of transverse shear force on the slope stability, the safety factor is the highest; this assumption can reflect actual conditions of slope better and the results are closer to reality.

Based on the special characteristic of multi-resolution of wavelet function, Daubechies wavelet has strong superiority in solving some engineering problems such as high stress gradient, strong nonlinearity and some other singular problems in engineering. But because of the limited computation scope of connection coefficient, Daubechies wavelet finite element method has only been used in the computation of bar, beam, and beam on elastic foundations with a constant foundation coefficient. In the computation of pile foundations based on ‘m’ theory, the foundation coefficient is assumed as linear function. So the foundation coefficient of load in deflection curve differential equation is a linear variable. But the computation methods or results of relative connection coefficient have not been proposed in any documents up till now. Thus Daubechies wavelet method cannot be employed to conduct the computation of pile foundations based on ‘m’ theory. Aiming at the feature of computation model of pile foundations, a new type of connection coefficient is put forward based on ‘m’ theory. Thus Daubechies wavelet is applied to the computation of pile for the first time. Typical models of pile foundations are computed using the new type of connection coefficient mentioned above. The calculation result verifies the correctness of the educed new type of wavelet connection coefficient; and it is shown that pile foundations can be calculated with high accuracy by using wavelet finite element method.

Using monitoring data to analyze and evaluate internal force of supporting structure is an important problem in dynamic design and construction of tunnel, which has great significance for construction safety. According to the characteristics of shotcrete layer in initial support and the theory of circular beam on elastic foundation, based on touch stresses between shotcrete layer and surrounding rock, the analytical solution of internal force is deduced. The stress concentration position is obtained, which is convenient to make relative safety countermeasures in the following construction. The analysis of tunnel project excavated by bench method shows that the analytical expression of solving internal force based on touch stresses is a new and effective way, so as to provide a more reliable basis for the safety assessment of tunnel structures.

Reinforced mixing pile is a typical composite material pile; theoretical analysis of core pile axial stress and cement soil pile-core pile interface shear stress of reinforced mixing pile are carried out based on composite material mechanics and Mindlin displacement solution. Regularities of distribution of core pile axial stress and interface shear stress are deduced; theoretical results are compared with field test results. The comparison results show that theoretical analysis results are accordant with field test results and they can be verified each other. Theoretical study has significant value for analysis of performance mechanism of reinforced mixing pile.

Horizontal slices method is adopted to deduce active earth pressure formulas of cohesive soil under seismic condition; and analytical solutions of resultant force of active earth pressure and its application position, distribution of earth pressure and critical rupture angle are obtained. The influential factors of horizontal and vertical seismic accelerations, dip angle of wall back, cohesion and internal friction angle of filler, cohesion and external friction angle between filler and wall back and uniform distributed overloading are considered and analyzed. Results show that active earth pressure formula under seismic condition is the same as that obtained by Rankine theory, Coulomb theory or Mononobe-Okabe theory. The distribution of active earth pressure along wall back is nonlinear. Horizontal seismic acceleration increases active earth pressure while vertical seismic acceleration makes active earth pressure decrease.

Quantitative assessment of vulnerability for hazard bearing body is a difficult problem in landslide risk assessment. Taking impulse of landslide impact as disaster-causing strength index and taking whole shear force of building as disaster-resisting performance index, the quantitative assessment model for vulnerability of typical hazard bearing body is deduced. On this basis, considering the influence of randomness of movement parameter on vulnerability, the risk curve and maximum risk index are put forward so as to reflect the influence of uncertainty in process of landslide hazard. Influence of geometrical parameters of slope, space location and disaster-resisting performance of hazard bearing body on vulnerability are analyzed based on the model. Using risk index for case study and comparing with the existing methods, the quantitative assessment model can reflect the relationship between damage degree of hazard bearing body with each influential factor in two-dimension condition. The model provides a new way for quantitative assessment of vulnerability

In order to study the impact of groundwater on slope with planar failure surface, three common forms of water pressure distribution are generalized; and the rationality of assumption for water pressure is described. According to the limit equilibrium theory, using Matlab to program, and through two examples with or without tension fissures, combined the methods of quantitative and qualitative analysis, sensitivities of the factors such as water depth, failure surface angle in sliding surface, slope height, slope crest angle, horizontal angle of tension fissure are analyzed. Dynamic law of influence of the factors on slope safety factor is discussed under different water pressure distributions. The results show that the critical angle of planar sliding slope could be calculated by program according to limit equilibrium theory; and the variation of critical angle is obtained considering groundwater; 10% of empirical value is the floating range. Influence of factors on slope safety factor is enhanced as the rising of groundwater table. The influence of slope height is significant; but the influences of slope crest angle, horizontal angle of tension fissure, and distance from crest to tension fissure are not obvious.

In order to understand the influence of seepage under high pressure condition on stress and deformation of fractured rock mass, fully coupling model based on porous media mechanics is employed to study the variations of pore pressure and displacement of measuring point in rock mass during the experiment period, combined with measured data of pore pressure and displacement obtained in high pressure permeability test at Heimifeng pumped storage power station. The hydro-mechanical coupling model is validated by the comparison of calculated results of pore pressure and displacements with measured data. It also indicates that rock mass stress increases sharply under the effect of water pressure in water injected borehole and pore pressure in rock mass. During the experiment, it occurs larger displacement in rock mass due to the seepage. After stopping injection of water, the deformation remains due to the existence of pore water pressure and hydraulic gradient in rock mass. The part of deformation is not the plastic residual deformation of rock mass after the unloading of water injected borehole. Hydro-mechanical coupling effect of rock mass under high water pressure condition is obvious. The evaluated results of rock mass stability with the consideration of hydro-mechanical coupling effect have more significance for engineering design.

By analyzing hydrogeological conditions of Panxi coal, temperature field and seepage field distributions of fractured rock mass are described based on the fluid-heat coupled model. Combined with boundary condition and parameters, the numerical simulation and analysis are carried out by using numerical software. The results of numerical simulation show that the heat transfer resulted from fracture flow has major impact on the temperature field distribution of fractured rock mass. The fault zone and ground water flow's existence change the original temperature field distribution of the rock mass. In the initial period, the vector of temperature gradient flows along the transfusion direction to the both sides. Because the permeability coefficient of rock in the both sides is lower than the fault zone place; the right isothermal line and the temperature gradient vector direction gradually move to the transfusion direction. At the same time, temperature field distribution of the both sides is changed. By the reduction of permeability coefficient, the change of permeability coefficient has impact on the temperature field distribution of fractured rock mass. The permeability coefficient is larger, the thermal migration is larger, the influence on temperature field distribution is also larger.

Based on the modern testing technologies and actual measuring data of coalbed methane (CBM) well, using physical and numerical simulation methods, the dynamic variation effect of coal reservoirs permeability during gas recovery has been discussed. The results indicate that permeability has larger difference, which may reach 1-2 order of magnitude; the two opposite regularities of dynamic variation of coal reservoirs permeability are presented between experimental simulation and numerical simulation; that is to say, numerical simulation permeability decreases with the decrease of fluid pressure; while experimental simulation permeability increases with the decrease of fluid pressure. Dynamic characteristics of permeability for two methods seem contradictory; but in fact interrelated. Coal reservoir permeability will be improved gradually during gas recovery. According to comparative analysis, the causes of differences between two methods are revealed. During the whole process, dynamic permeability index should be used to adjust and optimize the work system continuously.

Aiming at the practical situation about engineering geological conditions and productivity requirements of Xinshan ore block of Kafang mine, the optimization schemes of 3 feasible mining sequences are proposed based on the reconstructed mining environment idea. By using finite element analysis software MIDAS/GTS, a three dimensional finite element model of complex ore body is built. The mechanical time-varying effects of the 3 schemes are simulated and analyzed by numerical simulation. The results show that the stress and displacement of stope gradually increase and significant stress concentration appears as the advance of mining steps. In the 3 schemes, the maximum compressive stress is up to 27 MPa in the stope surrounding rock; to the roof, the maximum compressive stress is no more than 15 MPa and the maximum tensile stress of the roof reaches 1.2 MPa; for the subsidence displacements of roof, the maximum values of the 3 schemes are 82.9 mm, 84.4 mm and 84.5 mm separately. A wide range tensile stress area appears with mining in roof; the maximum proportions of the tensile stress area occupying the roof area are 22%, 22.3% and 23.5% separately. However, the time-varying laws of the tensile stress area show remarkable feature of imbalance and mutability. According to the process response laws of the stope structure under mining, the evaluating indices of the tensile stress damage area and the subsidence displacements of the roof are chosen. The optimal scheme is proposed and it is the scheme 1

Energy produced by explosion in soil can be used to improve soft foundation. The shape of crater and variation of soil properties are different under different conditions of charge masses and buried depths. Numerical simulation technology of explosive fluid dynamics based on Euler formulation is adopted to analyze explosion problem in soil. The result shows that the final shape of crater is consistent with the obtained field results; and nonlinear relation between crater diameter and charge mass and buried depth is obtained. The pressure wave has the similar feature of shock wave at the near field; and then as the wave propagating from the charge centre, it changes to the stress wave style with reduced amplitude. With increase of buried depth, the compaction effect is more distinct; but the compaction effect produced by explosion in shallow layer of soil is quite limited.

Aiming at granular system composed of polyhedral granules, based on discrete element method, the neighbor list is established for each particle. The ray crossing method is applied to the collision detection of polyhedral granules stored in the neighbor list. By these steps, the simulation method for the dynamics of granular system is proposed, which effectively realizes the numerical simulation of the dynamics of granular system. The simulation method has significant theoretical value, which can be used to simulate dynamic process of packing and collision of granular system in numerous engineering fields.

Drift-pile-beam-arch (Drift-PBA) method has become a major construction method in Beijing metro engineering, which can reduce soil deformation and effect on adjacent structures effectively. Based on the Huangzhuang station project of Beijing metro line No. 10 and the field monitoring data of surface and pipeline settlement, a three-dimensional finite element model of station structure, soil and pipeline is established. The influence of metro station built by drift-PBA method on ground movement is examined; and the response of adjacent rigid-joint pipelines is systematically researched from the aspects of settlement, deformation and pipe-soil interaction. The results show that the ground settlement induced by the two key stages composed of construction of pilot tunnel and center arch region accounts for more than 90 percentage of the total settlement. The settlement and deformation of rigid-joint pipelines, and differential settlement between pipe and soil are closely related to spatial relationship between station and adjacent pipes, and mainly induced by the excavation of soil below the pipelines. The whole body of the rigid-joint pipe bears deformation in common; and the pipeline sustains bending and axial deformation caused by ground movement; therefore, it is suggested that the pipeline strain should be used as deformation criterion

Blasting pressure relief technology can be applied to reduce the stress concentration of coal-rock mass and avoid the rockburst disasters effectively in coal mine. Taking the working face 23 130 of Yuejin coal mine for example, the effect of blasting pressure relief is simulated by using the fast Lagrangian analysis of continua in 3 dimensions (FLAC3D). Stress distribution of surrounding rock and diversion law under different conditions are studied; and effect of pressure relief on mining site is tested by electromagnetic radiation (EMR) monitoring technology. The result shows that stress peak value decreases and transfer distance increases with the increasing of explosive charge. Stress peak value decreases with the increasing of coal seam thickness, but transfer distance is nearly unchanged. Stress peak value decreases with the increasing of mining depth, but transfer distance decreases. The result of pressure relief is efficient with the decreasing of EMR signals in blasting region. Combining the numerical simulation method and electromagnetic radiation technology, the result provides a basis for selecting reasonable blasting parameters in working face and reducing rockburst risk effectively

Discontinuous deformation analysis (DDA) is an efficient algorithm for calculating block system deformation and displacement. Citing Newmark integration in the structural dynamic differential equation and considering inertia force and damping force computation, DDA source code is improved so as to optimize adaptive step size. The convergence rates of linear acceleration method, constant acceleration method and average acceleration method in Newmark integration are investigated by comparative analysis; the principle of adding or deleting non-balance force is introduced; and a scheme is given to control the error range. Using the improved DDA method to simulate a coal and gas outburst during a coal seam excavating, the results have a good match with the investigation data. The improved DDA method with adaptive step size can provide a new way to deal with the dynamic calculation for block system.

Combining seepage finite element calculation and slope stability analysis of strength reduction finite element method, slope stability of earth-rockfill dam is analyzed. When considering the effect of seepage, the seepage field of the dam is calculated by finite element method at first; and then the position of the spill point and the saturation line at steady seepage are calculated through iteration; the seepage forces are calculated according to the hydraulic gradient. Seepage forces, dead weight, buoyancy and seismic force are loaded on the dam; the critical instability state and safety factor of the dam are calculated using temperature-driven parameter reduction finite element method. The analysis results show that the method is reasonable and efficient for slope stability analysis of earth-rockfill dam

Artificial freezing method is widely used in construction of cross passage for shield tunnel, while due to lack of measurement data, no clear rule for determining frost-heave force is given for tunnel design. Based on the Shanghai Yangtze River Tunnel project, a careful in-situ monitoring is carried out by utilizing a new type earth pressure gauge. Firstly, the main characteristics of PAD type earth pressure gauge and the installation method are introduced. Secondly, the automatic data collection system and the layout of measuring points are described. Aforementioned efforts successfully protect all 5 gauges, and valid data are obtained. The data show that the maximum measured frost-heave force is much smaller than the prediction. It is due to the countermeasure of pressure release hole, which reduced the frost-heave pressure on segment.