The principle of coupled action of surrounding rock and support is a basic theory to accurate reveal that the tunnel is effectively supported by support structure. The longitudinal deformation profile (LDP) of tunnel roof radial displacement of a practical project has been calculated based on spatial effects of the excavation face and E. Hoek empirical equation. Mechanical model that describes the coupled action of surrounding rock and support has been built, and then the mathematical model that describe the relation of the tunnel roof radial displacement and virtual support force in mechanical model is built. The coupled action between surrounding rock and support in their whole interaction process is analyzed by analyzing and studying of mathematical and mechanical model. For the principle of coupled action of surrounding rock and support at elastioplastic deformation stage, the latest understanding has been given. The supporting action effect of a practical project has been calculated and analyzed by the research results. In this paper，the interaction solution of complete action process of surrounding rock and support at elastioplastic deformation stage has been obtained, and the interaction of surrounding rock and support also can be on-line predicted or reproduced by the research results.

The main inducement to freeze-thaw damage of engineering rock mass is the frost heave and thawing shrinkage of moisture in rock, which is quite common in cold regions. The research on freezing rock can be mainly concluded to four parts, which are the physico-mechanical properties of freezing rock, phase transition process, the thermo-hydro-mechanical (THM) coupling at low temperature, the model of freeze-thaw damage and numerical simulation. During the last several decades, researchers have put efforts on freezing rock by theory analysis, numerical simulation, field test and laboratory experiments. Although remarkable achievements have been obtained, there is still long way to go in the field of freezing rock and plenty of researches have stayed in the stage of experiment. Research on frost damage of rock should base on microscale and take the water-ice phase transition as entry point. Furthermore the relationship between freeze-thaw action and crack propagation should be investigated, and extend to the influence of freeze-thaw action on the whole fracture network of rock mass.

The back analysis of pressuremeter test of sand is discussed. The measured data of pressuremeter test are used for inversive determination of the in situ state of the soil instead of the material parameters. The material parameters can be determined from the conventional laboratory tests. The characteristics of new hypoplastic model which is independent of soil state are used. The main contents include: establishment of the numerical model based on the finite element method for the back analysis, and determination of the material parameters for a specific sand using the related data from the literature; verification of the numerical model by simulating laboratory pressuremeter test; further numerical study carried out by changing the initial stress and relative density of soil, and establishment of relation between the measured pressuremeter, the stress and the relative density of sand based on the numerical results, which can be used for the back analysis.

The expansive soil in Luwangfen of Xinxiang in Henan is from the Tertiary marlite weathering, whose main clay mineral is kaolinite, and that owns weak expansive characteristic which is affected largely by the pore structure. In order to study the expansive characteristic of weak expansive soil in testing section, it studies of the expansion with loads, swelling stress and expansion-contraction cycle, and gets the different conclusions from other expansive soil before: (1) when the initial dry density is smaller and overlying loads are larger than expansive stress, the remolded weak expansive soil doesn’t occur expansion, but collapsible phenomenon after immersing water; when the compaction degree is more than 96%, even when the overlying loads are larger than expansive stress, the remolded weak expansive soil doesn’t occur collapsible phenomenon, and the swelling deformation tends to a constant value with the increasing of overlying loads; (2) The swelling stress of the weak expansive soil in testing section first increases then decreases with the increasing of initial water content, and occurs the expansive stress peak; (3) With the expansion-contraction recurring series increasing, the expansion-contraction characteristics of the weak expansive soil decrease rapidly, and the expansion-contraction deformation tends to be stabilized when the cycle progression reaches to 4th. The three expansive characteristics above show fully that the swelling characteristics of the weak expansive soil are related closely to the pore structure.

One of the necessary ways to control water pollution of Taihu Lake is to dredge its polluted sediments. Owing to our country’s current economic and technical limitations as well as the enormous quantity of contaminated dredged sediments, the underneath cohesive soil layers without any treatment are directly selected as impervious barrier of the Xuelang confined disposal facility (CDF). In order to prevent contaminants in dredged sediments from polluting surrounding environment and groundwater during dumping, a comprehensive experimental study for evaluating the ability of these soil layers to retard infiltration and transportation of main contaminants (total nitrogen, ammonia nitrogen, nitrite nitrogen, total phosphorus, chemical oxygen demand (COD)) in dredged sediments has been made using permeability test, static adsorption test, dynamic soil column test and so on. It is shown that the clay layers beneath the Xuelang CDF are capable to adsorb and retard the main contaminants greatly.

This paper investigates the deformation characteristics and damage mechanism of the lime-treated expansive soil. A series of mechanical property tests under uniaxial compression, one-dimensional consolidation, and triaxial compression are carried out for Jingmen expansive soil. The results show that the lime-treated soil remains fairly stable stiffness and shear strength even after saturated. Under uniaxial compression, whether unsaturated or saturated, the brittle failure occurs for the lime-treated expansive soil, whereas the untreated expansive soil has considerable plastic deformation capacity. On the other hand, under triaxial compression, the lime-treated samples present shear contraction and strain hardening before failure, with the shear dilatancy when the sample was about to failure and strain softening after failure. Moreover, it is observed that the confining pressure had an inhibitory effect on the brittle failure and the shear dilatancy, but even under the confining pressure is 200 kPa, the deformation of the sample is very small at the failure time, which demonstrates the brittle failure. Based on the mechanism analysis, the Duncan model is selected to describe the stress-strain-strength behaviour of the lime-treated expansive soil. The model parameters are calibrated from the aforementioned tests. The comparisons between the parallel tests and predicted results validate the selected model.

Based on a logistics processing warehouse of phase II and plant project reinforced by PHC pipe pile, the compaction effect of PHC pipe pile in dredger fill ground is analyzed. The changes of pore pressure around pipe and the displacement distribution characteristics of soil during pile-sinking are studied by piezometers and clinometers embedded in advance and with the aid of field test means. It is found that the excess pore water pressure decreases linearly with the increase of the distance to the pile and the area of effect is about 10 times of pile diameter. The maximum soil horizontal displacement occurs at a depth of 0.2-0.4 times of pile length, which is related to the subsoil properties and the depth of the soil. By simulating the field test results effectively with numerical simulation and then promoting the results, the law of the displacement of soil with depth and the radial distance during pile-sinking is got. The numerical simulation results show that the soil displacement field is greatly influenced by the friction feature of pipe-soil interface and the pile diameter.

Firstly, the concept of stress path is extended by proposing the three-dimensional stress path considering the rotation of principal stress axis. Then the deep analysis of the stress path during excavation is carried out by numerical method. It is shown that whether the horizontal or the vertical stress exhibits characters of unloading during excavation; and the magnitude of unloading of the inner part of foundation pit is larger than that of the outer part of foundation pit, which cause the changes of both stress and rotation of principal stress axis of the inner part of foundation pit are larger than that of the outer part of foundation pit. As the distance from the centre of foundation pit increasing, both the changes of stress and rotation of principal stress axis of the inner part of foundation pit decrease. The effects of excavation on the change of stress and the rotation of principal stress axis of the outer part of foundation pit decrease as the distance from the wall increasing. The main performance of the stress path of the inner part of foundation pit is that the mean compressive stress p and the generalized shear stress q decrease while the rotation angle of principal stress axis ? increases. And the main performance of the stress path of the outer part of foundation pit is that q and ? increase while p decreases. So on the basis of the main performance of the stress path, the typical stress paths of both inner and outer parts of foundation pit during excavation are obtained to guide the practice design analysis and indoor experiment of foundation pit engineering.

By using the image analysis software package PhotoInfor, which is based on the digital photogrammetry for deformation measurement technology, we analyze the generation, development and evolution process of displacement in sands during each load level of confined compression tests. The results can show that, the axisymmetric displacement fields of sands are similar like parabola, displacement’s equivalence lines are axisymmetric-distributed, and the largest increment of displacement always occurs at the bottom’s center of the up porous stone. With the monotonic loading, displacement increment mainly concentrates in the vicinity of localized deformation zones, with an obvious trend of continuous extention and transfixion. The displacement at the top and the middle position keeps linearly increasing with the overall compression deformation. However, the displacement of the testing point at the top is always larger than the middle one. Such phenomenon will be more obvious during the metaphase and the anaphase of the tests. Compared with the displacement fields of silty clay sample, the granular soil will represent a conspicuously different rule for the stress transferring route, deformation patterns and loading impact scope. The research can put forward a new concept to study the stress distribution rules under foundations, as well as to study the quantitative model of sands’ microstructure by macro experimental phenomenon.

An improved combined system with constant flow method and additional equipment to scour and quantify the air bubbles is introduced in detail. In order to make the measurement closer to the true value, we can correct the overflow of water by measuring the volume of the air bubbles. The curves of outflow with time are observed from one-step drying and wetting outflow experiment. The parameters which are evaluated using the HYDRUS-1D software are used to determine the drying and wetting soil-water characteristic curve (SWCC) and the hydraulic conductivity function. By comparing the measured data, it is shown that the method can fit the observed curves of outflow with time correctly so as to verity the reliability of the method. The difference of SWCCS between the estimated and measured is small. In addition, comparing with the traditional methods, the method proposed enables experiments to complete in a short period of time. Therefore, the method proposed for determining hydraulic parameters of unsaturated soils by one-step outflow test is feasible.

A new foundation type called pile-slab base is introduced for the 500kV transmission line tower according to the geological conditions of silt. Then the field mechanical tests of heap loading and uplifting are done for this new foundation after the pile integrity testing. At the same time, the pressure of the slab, the stress of steel bar meters and the displacement deformation of four corners of the slab and pile are monitored. The results show that the compressive and uplifting resistance performance is excellent and the foundation can function as a whole to resist deformation; the engineering demand also can be satisfied. Moreover, the field test is simulated by the ABAQUS software; the conclusions are verified further on the basis of consistence between numerical calculation results and test data; therefore, the numerical model can be applied to other mechanical simulation reliably.

Adopting the grading cyclic loading method in each bearing unit of dispersed pressure anchor cable, the changing law of internal force of each unit is studied by new geological mechanics model test. According to the test methods and the state of force of the dispersed pressure anchor cable, the elastic theoretical solution which is under the conditions of grading cyclic loading and based on the Mohr-Coulomb criterion is deduced. The test results show that, under the conditions of soft rock and silty soil, the strain and shear stress distribution of the former grouting body is relatively more concentrated, the influence between units is relatively minor during the loading process. And the elastic theoretical solution based on the Mohr-Coulomb criterion can describe the strain and shear stress distribution rule of grouting body better after grading cyclic loading. The research results have a good reference value for correctly analyzing reinforcing mechanism of the dispersed pressure anchor cable and engineering design.

The interaction between footpad and soil is of great importance due to the strong impact produced during the brief period of the space lander touchdown which will affect the normal operation of the inner precision instrument. Based on the study of the landing process, the problem can be decomposed into two phases, vertical impact and horizontal sliding. A dynamic model of footpad and soil interaction is built through force balance and momentum theorem. Lots of vertical impact tests are conducted in the self-designed model test system. The soil density, impact velocity and impact mass are varied to investigate their influences on the penetration depth, the maximum axial force and acceleration of the footpad. It is concluded that the penetration depth and maximum axial force increase with impact energy increases, and tend to be stable. The denser soil is and the smaller impact mass is, the greater the maximum acceleration is. The test results are compared with dynamic model; it is proved that the dynamic model can reasonably reflect the dynamic characteristics of the lander during vertical impact.

The finite element method and stochastic response surface method are combined to analyze the reliability of seepage stability in Shuangjiangkou core-wall rockfill dam project. The seepage flow analysis of the core-wall rockfill dam and the reliability analysis can be conducted separately within the framework of reliability analysis based on the stochastic response surface method. The nodes with the larger hydraulic gradient are selected to establish seepage stability function using the finite element method and stochastic response surface method. The failure probabilities of seepage failure at each node are then calculated and the maximum failure probability is taken as the failure probability of the core-wall. The relationship between the hydraulic gradient of the nodes with maximum failure probability and the hydraulic conductivity of the core-wall and the alluvial deposits, the relationship between the hydraulic gradient of the nodes with maximum failure probability and the upper water level, and the effects of the hydraulic conductivity of core and the variation of upper water level on failure probability of seepage failure of the core-wall are analyzed. The results show that third order Hermite expansion is able to ensure good precision with acceptable time consumption. The seepage at maximum failure probability node in Shuangjiangkou core-wall dam is closely related to upper water level, but has a weak negative correlation with the hydraulic conductivity of the core-wall and is less significant with the hydraulic conductivity of alluvial deposits. On the other hand, as the coefficient of variation of the upper water level increasing, the failure probability increases drastically, but this effect is less significant with regard to the hydraulic conductivity of the core-wall. The results provide a further evidence for readily application of the stochastic response surface method to practical engineering.

The test results of three different coarse-grained soils are obtained with conventional triaxial cyclic loading test. Based on these results, some useful conclusions are drawn from the discussion and analysis of the phenomenon of volume-contraction in unloading of coarse-grained soils: The phenomenon of the volume-contraction in unloading of coarse-grained soil is more obvious with the increasing of stress level and with the decreasing of confining pressure. According to the test data, a relationship formula among volume contraction in unloading and stress level and confining pressure is obtained. Rebound modulus presents the curve of hump shape with the increasing of stress level and the maximum is obtained when stress level is 0.7. The ratio of average rebound modulus and initial elastic modulus with monotonic loading present decrease of a power function, this ratio of soil material whose mother rock is high hardness is larger and the ratio of soil material whose mother rock is soft is smaller. The general relationship between kur and nur which is obtained from rebound in unloading and k and n which is obtained from monotonic loading is that kur is approximately from 2.46 times to 4.60 times of k and nur is approximately from 0.540 times to 0.885 times of n respectively.

Based on the former experimental and theoretical researches on the reinforcement mechanisms of anchor bolt in jointed rock mass at home and abroad, and comprehensive considering of the tangential and axial deformability of anchor bolt, a deformation model of joint bolts under shear load is proposed. The deformation of joint bolts is divided into two parts: elastic deformation zone and crushing failure zone. A variable is introduced to express the length of crushing failure zone. Mechanism of interaction between bolts and rock mass is analyzed. Relationships between tangential load and tangential displacement, and axial load and axial displacement are deduced respectively. Through the analysis of yield failure model of bolt, a method to calculate the length of the crushing failure zone is proposed. Finally, a calculation example is presented to study the relationship between the length of crushing failure zone and the parameters, such as the bolt diameter, the rock mass strength, anchorage angle and so on. It is concluded that: (1) The shear resisting function of joint bolts is actually that the bolts arouse the compressive strength of rock mass to resist the shear load of the joint plane. In the hard rock with higher compressive strength, the crushing failure zone is limited near the joint plane and the influence area of bolt is small; while in soft rock with lower compressive strength, the length of crushing failure zone and shear deformation and the influence area of bolt is larger. (2) The yield failure mode of anchor bolt is related to rock properties and diameter of the bolt. Shear yield occurs in hard rock and bending yield occurs in soft rock. Bolt with little diameter usually go through shear yield and bolt with large diameter may go through bending yield. After yield failure, the plastic hinge appears. The length of the crushing failure zone on one side of the joint is 1-2 times of the bolt diameter, however, it no longer increases with the increasing of shear load. (3) The optimal anchor supporting angle of joint anchor bolt varies with rock properties. Hard rock has a smaller anchor supporting angle and the soft rock has a larger one.

The expressions of generalized shear stress and generalized shear strain are introduced. After analyzing the two expressions, mistakes in calculating the increment of generalized shear stress and generalized shear strain are pointed out, and then the right calculations are given. Based on this, two expressions of work increment that one is described by mean stress, volumetric strain increment, generalized shear stress and generalized shear strain increment and the other is described by three-dimensional stresses and three-dimensional strain increments are compared. The conclusion is that the two expressions are not always consistent except in some particular conditions. An example of the particular conditions is that loading in constant Lode angle and also the Lode angle of the three-dimensional stresses is equal to that of the three-dimensional strain increments. The same inconsistency still exists in applications of plastic work increment, while unfortunately the equation of Lode angle of the three-dimensional stresses and the three-dimensional strain increments is not always satisfied for practical geomaterials. So in the theory of geotechnical plasticity, for the condition of loading in constant Lode angle, the plastic work increment expressed by mean stress, plastic volumetric strain increment, generalized shear stress and generalized plastic shear strain increment is just a kind of approximation.

Based on Biot’s theory and considering the property of moving loads, the boundary integral equations in the frequency domain-wave number for semi-infinite saturated soil is obtained by using the integral transform methods. The Cauchy type singularity of the 2.5D boundary integral equation is discussed and the effectiveness of passive vibration isolation using the open trench on the saturated soil is analyzed. Comparing the result with an existing one shows a good agreement. Numerical results show that, the present 2.5D boundary element method (BEM) is not only adaptable to solve the dynamic responses of moving loads with complicated boundary conditions, but also the computation time can be decreased greatly. For moving loads with high velocity, a considerable oscillation reduction of the pore pressure and the vertical displacement can be achieved by using open trench. The open trench barrier has no effect on the horizontal displacement for moving loads with lower velocity, even has the amplificatory effect on the vibration. Moreover, with the increasing of the distance between the vibration source and the open trench, the isolation effect of the surface wave propagation may be improved.

In order to explore the seepage stability of slurry cake formed in the cutoff wall hole of coarse-grained soil, the impermeable characteristics of slurry cake are tested by the self-made slurry seepage apparatus. After the slurry cake wall is formed by the slurry seepage through sand samples with some particles gradation under some pressure difference, the seepage experiments of water passing through the frontal face of slurry cake or through the reversal face of slurry cake are carried out under some pressure difference. Through the analysis of test results, the following knowledge are obtained. The cutoff effect of slurry cake bearing with large gradient is significant. There are different seepage characteristics of slurry cakes formed under different pressure differences. The greater the pressure difference when the slurry cake are formed, the more compact the slurry cake is, the stronger the ability is to resist infiltration and damage, the smaller the permeability of the slurry cake is. The impermeability of water passing through reversal face of slurry cake under some pressure difference is smaller than through frontal face of slurry cake under same pressure difference. With the sustaining time of hydraulic action increasing, the structure of slurry cake will change and its seepage velocity also increases. Under the large hydraulic gradient action the slurry cake damage may occur under certain osmotic pressure difference. The critical hydraulic gradient is closely associated with the loading pressure difference of slurry cake formation. The larger the pressure difference is, the larger the critical hydraulic gradient is. On the contrary, the smaller the critical hydraulic gradient is. The above-mentioned knowledge has theoretical and practical importance that the design method and construction technology of cutoff wall in large depth covering layer is improved by investigating the impermeable characteristics of slurry cake.

Based on the simplified model for estimating the clogging time which was made by Rowe and Fleming, the assumptions and derivations are developed reasonably due to the time-space distribution of clogging in drainage layers; and a simplified model is obtained which can reflect the development of clogging and the variation of hydraulic conductivity of the drainage layers. Using the cell analysis of water balance, a method for calculating maximum liquid depth in drainage layers which is based on the maximum liquid depth clogging model is proposed. Comparing with the steady and transient results, it is shown that no clogging results are in accordance with the transient results, which all tend to the steady results. And the clogging must be considered when clogging is serious which may affect the liquid depth markedly. Parameter analysis shows that the greater previously (the smaller later) the hydraulic conductivity, the longer the drainage distance, the faster the infiltration rate, the higher the concentration, the more serious the impact of clogging on liquid depth. At the same time design suggestions are proposed for improving the drainage system.

Hardening and softening properties of the materials is described by introducing plastic internal variables to hardening function in most softening constitutive models of rock, without considering the damage effects of micro-crack growth and different performances of initial yield strength f0 and yield limit fu between the uniaxial tensile and compressive loadings. Plastic yield criterion is used simultaneously with the damage criteria to simulate the physical behavior of rock-like materials based on D-P criterion, and elastoplastio damage constitutive model with its numerical algorithm is also proposed. Borja’s hardening/softening strain function is employed as the plastic yield function, indicating the plastic internal variables and stress states are two important factors to the hardening function. Volume expansion caused by micro-crack growth is responsible for rock damage evolution D, which can be characterized by proposed function of volumetric strain. The code of elastoplastic damage constitutive model of rock is implemented using return mapping implicit integration algorithm. The proposed model is used to uniaxial tensile and compressive tests and the results agree well with the characteristics of rock-like materials and experimental curves.

The Xiqing Road Tunnel of Tianjin West Railway Station Hub crosses over the existing tunnel boxes of the operating Tianjin Metro Line 1. The bottom plate of the Xiqing Road Tunnel is just 0.3 m away from the upper plate of the existing tunnel boxes, so the deformation of existing metro tunnel due to construction should be controlled strictly. The design bring forward some pertinence construction plans and measures, including ground improvement, excavation in sections and back pressure of heaped load timely. Base on the analysis of monitoring data during the construction and excavation of anti-floating piles and triaxial cement mixing pile of Xiqing Road Tunnel adjacent to the existing metro tunnel, and the corresponding deformation rules and characteristics in the different stages are summarized. The measured results show that the construction of bored piles adjacent to the existing metro tunnel could lead to the tunnel settlement, while the excavation could cause the heave of the tunnel. Due to excavation in sections, Back pressure of heaped load as well as the observational method, the vertical deformation of existing tunnel caused by excavation and the different deformation between the two adjacent boxes can be controlled effectively.

Natural soil is usually nonhomogeneity and anisotropy. However, the calculation methods of stability against upheaval which are commonly used are applicable to isotropic and homogeneous soils. Considering the failure criterion of nonhomogeneous nonlinear anisotropic rocks and the primary anisotropy of soil, assuming Prandtl failure mode, analysis of stability against upheaval is given using the model of foundation pit bearing capacity. According to capacity calculated by the slip line method and using finite difference method combined with boundary conditions, the related calculation program is compiled； then stability coefficient against upheaval is defined. The results show that the larger the anisotropy ratio of soil strength is, the smaller the safety factor is. And with the increasing of internal frictional angle and the retaining wall insertion ratio, the safety factor will be enhanced significantly.

Rock mass in the excavation disturbed zone (EDZ) would be disturbed under the process of mining, and the mechanical properties and strength parameters will be deteriorated in EDZ. The main problem is how to make sure the deterioration laws of the mechanical properties. Taking the object of test stopes on induced caving roof which is based on the continuous mining method in the No.92 ore of the Tongkeng mine, based on the unloading rock mass mechanics theory, the calculation procedure is established to simulate and analyse the rock mass mechanical parameters under excavation unloading. Combined with FEM, the equivalent model of rock mass unloading is built; and the 6 steps of continuous unloading calculations are carried out. The deterioration laws of the mechanical properties of the roof rock mass unloading are obtained in underground continuous mining. The relation functions between unloading rock mass mechanical parameters and the unloading percentage are fitted by polynomial fitting method. The results show that, after the 6th step unloading, the calculation is non-convergence. It indicates that the roof has totally been destroyed and fallen. As to the rock mechanical parameters, it shows a gradual weakening trend, including the internal friction angle, cohesion and the modulus of elasticity. These values gradually decrease to 55%, 50% and 50% of the initial value. For Poisson's ratio, it gradually increase to 1.15 times of the initial value. It is demonstrated that the rock mass mechanical parameters are deteriorated under mining unloading. The dynamic analysis theoretical basis of mining mechanical response is provided by the relation functions of unloading rock mass mechanical parameters and the unloading percentage.

For the silty fine sands of 3 to 5 m thickness justly formed by dredging at the material yard of a bulk cargo wharf, based on the instrumented monitoring results of a testing area improved by vibro-compaction without additional backfill materials and trace inspection in the project, the change of excess pore water pressure and range of validity of vibroflotation is analyzed. The strengths are compared before and after vibroflotation. The design parameters, construction techniques and quality control method of vibro-compaction are proposed for the large-scale practice. In the first inspection, the problem of local poor compaction inside the vibroflotation column is found; the resulting reasons are analyzed and resolving measures are put forward. The final inspection results of large-scale practice indicate that the proposed parameters are feasible; the quality of improving ground satisfies the design requirements. The testing and application of this project indicates that vibro-compaction method without additional backfill materials for silty fine sands can be used for large-scale practice after the scientific testing methods quality tracking and solving measures of defects carried out.

Due to long service time of the gob-side entry retaining and large deformation of surrounding rock, it is very important to calculate reasonably the width of roadside backfill. Based on activity rules of overlying strata of the gob-side entry retaining, The paper establishes a mechanical model of key blocks and immediate roof and analyses the interaction mechanism between key blocks and surrounding rock around the gob-side entry retaining, derives calculating formula of the gob-side supporting resistance, and introduces stability coefficients K1, K2 of key blocks and sensitive coefficients of influencing factors. If K1>1, extrusion instability will emerge; If K2>1, sliding instability will emerge. By taking No. 512（5） working face in Xieyi coal mine in, Huainan as project background. The paper determines reasonable width of roadside backfill, calculates stability coefficients of key blocks, and obtains sensitive coefficients of influencing factors on the stability of key blocks. The case study shows that the mining height has great influence on the stability of key blocks, so applying the technique of the gob-side entry retaining to working face with large mining height is of significant difficulty.

The process of shield tunneling at Chengdu Metro Line 1 in sandy cobble ground is simulated in meso-scale and marco-scale by laboratory experiment and using particle flow code in 2D (PFC2D) and finite element software of Plaxis 3D, respectively. The settlement character and failure mechanism driving by earth pressure balance shield (EPBS) in sandy cobble ground are revealed. Based on the comparison of the estimated values from meso and macro simulation results with the in-situ soil settlements and construction parameters, the surface settlement trough and subsidence patterns are approached. The influence of the chamber pressure at the tunnel face and the grouting pressure at the tail gap on the ground surface subsidence are analyzed; and the suitable values for the chamber pressure at the tunnel face and the grouting pressure at the tail gap are suggested. Compared to the grouting pressure, chamber pressure has relatively smaller effect on both the shape of the curve and the maximum surface settlement based on the analysis results. However, much attention should be paid to the chamber pressure, which may have greatly influence on the stability of the tunnel face and result in abruptly collapse in sandy cobble ground due to the effect of arching.

The detection of water-bearing structures is the key problem needed to be resolved. Apparent percent frequency effect as one parameter of frequency domain induced polarization (IP) is sensitive to water. And frequency domain IP is introduced to water-bearing structure advanced detection in tunnel. Frequency domain IP on advanced detection about theoretical forward, physical simulation and interpretative method is researched systematically. Firstly, the problem of numerical forward on advanced detection of frequency domain IP is solved by using finite element method. The response pattern of apparent percent frequency effect to typical water-bearing structures is found by forward modeling systematically. The maximum of apparent percent frequency effect curve has important characteristics, for which water-bearing structures exist ahead of tunnel face. Secondly, the method of joint judging the location of water-bearing structures using two maximum of apparent percent frequency effect curves is put forward, basing on large number conclusions of numerical forward. At last, the physical model test and engineering application show that water-bearing structure location of advanced detection of frequency domain IP is almost in agreement with actual situation. Frequency domain IP is efficient in detecting water-bearing structures. And it provides a feasible approach to solve the problem of advanced detection of water-bearing structures

Using explicit finite element method and artificial transmitting boundary, the seismic response analysis of a 2D canyon model is performed under three incident SV seismic waves respectively with the assumptions of vertical incidence and oblique incidence at the angle of 30 degrees. The canyon surface ground motions have been compared and the distribution characteristics of ground motions are summarized. It indicates that canyon topography has significant influence on the distribution of ground motions. The peak ground accelerations (PGA) vary greatly from the bottom of the slope to the upper corners. Ground acceleration at high frequency band beyond 1 Hz has been more greatly amplified. And the canyon ground surface has been characterized by relative displacements (RD). It is also found that the incidence angle shows significant influences on the ground motions. Under oblique incident SV waves, the discrete degree of the PGA and RD observed at the canyon surface are much larger than that under vertical incident SV waves.

Based on salinity field observations and qualitative analysis results at salinization belt of the typical earthen ruins in the research area, the paper summarizes the characteristics of earthen ruins with saline soil and generates a brief concept of aeolian erosion ullage effect. And then, on the basis of wind tunnel simulation experiment and microstructure analysis results of reconstituted samples going through dry-wet circulation after being mixed with different content of common salts Na2SO4 and NaCl, it reveals that the saline process of those salts have significant impact on anti-erosion ability of the site, and a good correlation existing between microstructure characteristics parameters of pore and wind erosion rate of the samples under saline process is also proved by statistical analysis method. Finally, with a combination of the qualitative analysis and the experimental results, depletion mechanism of the effect of aeolian erosion ullage at the salinization belt of earthen ruins is preliminarily discussed from a microcosmic standpoint.

The mechanical properties of frozen soil depend on not only the single factor, such as water content, temperature, strain rate, salt content, confining pressure etc., but also on the possible interaction between the mentioned factors. In order to make sure of the dependence relationship of frozen soil strength and modulus with these factors, the significant and interaction of influencing factors of frozen soil mechanical properties is studied according to the experimental data and statistics theory. The study shows that the mentioned factors have obvious influence on the mechanical properties of frozen soils; however the factor of temperature is the most important one. Furthermore, the interactions on strength, which originating between temperature, water content and strain rate, are found to be obvious enough and can’t be neglected. Therefore, it is not rational that only some separate factors are taken into account as studying the mechanical properties. The most appropriate method is to study it in overall factors and with the interaction taken into consideration.

Based on the blasting similarity theory, a mechanical model of consequential rock slope with weak intercalation is established. The design idea and method of the blasting model lamination test and shear test are introduced. Using the clay of one limestone quarry as weak intercalation, the lamination property and stability of the bedding rock slope with weak intercalation are studied through the similarity model test. The test results show that the weak intercalation after blasting is divided into four regions: blasting cavity region, tightness region, affected region and undisturbed region. The blasting cavity region, tightness region, affected region constitute the lamination region. The anti-slide safety coefficient is the greatest before blasting, the second after blasting and the smallest in the course of blasting. The lamination range directly affects the anti-slide safety coefficient of the model. The thickness of weak intercalation has a great impact on the lamination range and the anti-slide safety coefficient of the model.

Based on successful reinforcement projects of the sliding zone of the ancient debris landslide with applying deep high pressure grouting method, and combined with various detection measures and elastoplastic finite element analysis, the mechanism of deep high pressure grouting to reinforce sliding zone, physico-mechanical parameters of the soil in sliding zone before and after grouting, the remnant sliding force and safety factors of the landslide have been studied. Electron microscopy experiments show that, The filling replacement rate of cement slurry to rock and soil in sliding zone is 5%～10%. The soil tests results indicate that the soil cohesion increase from 20.20 kPa to 39.54 kPa and its internal friction angle from 16° to 21.30°. The sound wave CT scanning experiments show that the sound wave velocity of the soil in the sliding zone increases about 31%. The finite element analysis show that pressure grouting could make the unstable landslide go into the basic stable state and the remnant sliding force reduces a lot. These can provide optimization basis for retaining structure design. Tests and calculation results show that high pressure grouting method for enhancing the rock and soil in sliding zone is feasibility. The mechanical performance of the rock and soil in sliding zone has been significantly improved and the safety of the slope has been enhanced.

Borehole radar is a well geophysical method for obtaining the high-resolution information of deep underground environment. According to the common point unfavorable geo-bodies in borehole radar exploration, such as cavities, karst caves and buried objects, etc., the forward simulation of response of the tool to point unfavorable geo-bodies of different surrounding rock and filling condition is investigated with finite difference time domain (FDTD) method. The influence of surrounding rock and filling condition on response characteristics of borehole radar is analyzed. The results indicate that the relative value of dielectric constant of surrounding rock and filling substance affects the contrast of radar reflection profile, and when the relative value of dielectric constant increasing, it is easier to ascertain the subsurface media distribution. While high-conductivity surrounding rock can attenuate most of radar signal, it is almost impossible to detect the cavities with single borehole reflection method. According to the different borehole radar cross-sectiorn and its response characteristics, the filling condition in the cavities can be qualitatively distinguished.

The full-face tunnel boring machine (TBM) has been widely used in projects nowadays; it is significant to understand the key technology of rock breaking by TBM disc cutters. In order to study the rock breaking mechanism and consider the effect of disc cutter rings’ cross-section shape, rock strength and joint orientation, we build a series of two-dimensional numerical models of rock broken by disc cutlers using UDEC method and simulate the process of rock fragmentation by TBM disc cutters. The case study and comparative analysis show that rock breaking mechanism is a composition of shear failure and tensile failure; tensile failure is the main reason for crack initiation and propagation. From the numerical results, it is also shown that wider flat cutters and blunter wedge cutters are good at breaking rock; and flat cutters is better than wedge cutters to break hard rocks, while they are same in soft rocks; and disc cutter is good at breaking the jointed rocks which have a joint angle between thirty degrees and sixty degrees; wedge cutter is better than flat cutter to penetrate jointed rocks due to its splitting effect.

To ensure the safety and normal usage of geotechnical engineering, it’s necessary to analyze the creep of rock mass. The “time step-initial strain” method is commonly used to compute the creep of rocks. Numerical manifold method (NMM) is a recently developed numerical method which is used to simulate the deformation of jointed rock mass but has not been used to analyze the creep of rocks. A "time step-initial strain" computing module has been added to the NMM code. The result of simulating the deformation of generalized Kelvin model shows that the new program can reflect the trend of viscoelastic creep of rocks and could be used to simulate the creep strain of jointed rock mass; so the adapted NMM now can compute both linear elastic and viscoelastic deformation of rock mass. It reflects rocks’ deformation trend more comprehensively, and extends the usage scope of NMM in geotechnical engineering.

The numerical simulation of the excavation shows that, for each basic deformation modes of the retaining wall, for example the forward rotation, reverse rotation and deflection, distribution of the ground surface settlement outside pit shows obvious regularity, which can be fitted by the exponential curve with a unified format, then the empirical formulas are got. Arbitrary deformation mode of the retaining wall can be fitted using the three basic deformation modes above, and the maximum displacement value for each basic deformation mode can be obtained. Using the empirical formulas above, the corresponding ground surface settlement for each basic deformation mode can be calculated. Then superimpose the settlement and obtain the distribution curve of ground surface settlement.

Based on three-dimensional numerical simulations of composite foundation both on the condition of ordinary use and ground subsidence, changes of settlement, skin friction distribution and axial force of pile in composite foundation after ground subsidence induced by groundwater level lowering are analyzed. It is shown that, settlement of reinforced pile and foundation increases, and neutral point in pile moves down gradually, axial forces in reinforced pile increase gradually along with ground subsidence increasing. In reinforced piles of composite foundation, neutral point in centre pile is the lowest, neutral point in border pile is the second, neutral point in corner pile is the highest. Along with ground subsidence increasing, the differences of neutral point position in centre pile, border pile and corner pile decrease gradually, the length impacted by negative skin friction of upper part pile over neutral point lengthens gradually, value of negative skin friction increases gradually.

Drilling data is one of main sources for building 3D strata model. Usually the stratigraphic interfaces are constructed by interpolation based on drilling data. Processing drilling data accurately is the basic premise of building realistic 3D strata model. Because the option of the interpolation data of the stratigraphic interfaces is not unique mathematically, the complex topological relationships of the strata usually result in the condition that the building 3D strata model is not realistic. In order to gain unique and realistic interpolation data, a stratigraphic column, which records the chronological order of the strata and their topological relationships, is defined in accordance with geological history. The topological relationships of the strata are generalized into two classes: either ‘onlap’ or ‘erosion’. According to the stratigraphic column, the unique interpolation data of the stratigraphic interfaces can be determined and then be used to build realistic 3D strata model. Python is used to implement the algorithm of the preprocessing of drill data. The examples prove that the project can validly forecast realistic strata.

Installation of a preformed pile gives rise to residual stress locked in the pile. Such stress is difficult to be measured in-situ, hence little focus has been paid on its significant effect. Alternatively, a simulation approach is put forward in this study by incorporating the principle of energy conservation. The proposed model adopts assumptions that the load transfer behavior along the pile-soil interface is ideally elastoplastic and the distribution of residual friction resembles a folded line. By looking through the physical process of pile penetration and rebound, the energy equilibrium equation during pile installation is established on a primary consideration of the elastic deformation energy of pile. Parametric studies show that the ratio of pile length to pile diameter and the interface shear friction are two key issues affecting pile residual stress. The rationality of this model is assessed against the measured post-installation residual stress of a full-scale pile.

Based on basic theory of unloading rock mass mechanics, a simulation method of unloading which the change intervals of plastic volumetric strain increment are corresponding to mechanical parameters of rock masses in different unloading zones is put forward by using three-dimensional finite difference software. Changes of the maximum volumetric strain increment and damage area of surrounding rock at different lateral pressure coefficients combination conditions are simulated. The results of numerical simulation show that, the external surface of area of plastic volumetric strain increment near the hole wall is approximately like an vertical oval at lower lateral pressure coefficient. With the lateral pressure coefficient increasing, the external surface of area of plastic volumetric strain increment becomes more rounded, and finally to a horizontal oval. The greater the lateral pressure coefficient, the unloading effect of surrounding rock is more significant and plastic volumetric strain increment of surrounding rock near the hole wall is greater, so the damage area of surrounding rock is correspondingly greater. The results provide foundation for the stability analysis of deep tunnel and supporting design of the cracked surrounding rock.

This paper presents an improved three-dimensional anisotropic elasto-viscoplastic constitutive model which is based on overstress theory of Perzyna and critical state theory. In this model a rotational hardening law of Wheeler is also adopted to account for initial anisotropy and changes in anisotropy due to stress. The viscoplastic strain will not occur when the stress state is located within the static yield surface. A power-type scaling function is adopted for the viscoplastic strain-rate. The constitutive model is programmed in ABAQUS software by writing UMAT subroutine, which is integrated with Return Mapping Algorithm. Anisotropically consolidated undrained (CU) triaxial creep test for Sackville clay is simulated by proposed model and the suitable integration time step is determined. Then other CU triaxial creep tests and CU triaxial constant strain rate tests are simulated. By switching the anisotropic features off, the proposed model is degraded to the isotropic model. The simulation results show (1) The CU triaxial creep tests with rotational hardening law is more accurate than isotropic model in the high level of the shear stress; (2) The CU triaxial constant strain rate tests rationally reflect that the undrained strength of soil increase with loading rate.

CO2 geological storage is one of effective measures for reducing emissions of greenhouse gases, and now CO2 disposal in deep saline aquifers becomes a feasible and most promising technology for CO2 storage. The previous studies show that the Songliao Basin is one of potential and promising storage sites. Based on the preliminary study of geological formation of the Songliao Basin, the first member of the Yaojia formation, the second and third members of the Qingshankou formation in the Sanzhao Depression are selected as the suitable aquifers for CO2 injection. Then a generalized two-dimensional model is set up to characterize the injection of CO2 into the Yaojia and Qingshankou formation, and to investigate the migration of CO2 in the aquifers. The results of model show that CO2 would migrate upwards and spread laterally over time after injection; and the phenomenon of convective mixing could occur obviously later, which could enhance the dissolution of CO2 process. The residual gas saturation and the ratio of horizontal to vertical permeability have the greatest effects on the results of model. Besides, the interbedded shale layers in the reservoir can enhance the dissolution of CO2. It’s suggested that the reservoirs with low-permeability intercalation could be allowed when the injectivity and storage capacity are guaranteed.

Elastic model for jointed rock masses supported by shotcrete lining and anchor bolt is established by composite element technique. In this model, general finite element mesh can be generated without considering the existence of joint, anchor bolt and shotcrete lining; then composite element information can be formed according to the relevant information of them. The localized nonlinear deformation and interactive relationship of anchor bolt and shotcrete lining on joint can be mainly considered in the model. Then numerical example is given to verify the rationality of the model. This composite element algorithm includes the advantages of equivalent simulation and discrete simulation and will be of good application prospects.

Sloped weak ground under the load of the embankment easily triggers major engineering accidents such as large lateral deformation and slump. It is the core design principles of embankment on sloped weak ground that application of reinforced by concrete anti-slide pile at the corner of embankment can effectively limit lateral deformation of the foundation. This paper studies the influence of the pile design parameters such as pile spacing, pile length, elastic modulus, cross-section dimension and the position of piles on its internal forces and deformation by using 3D fast Lagrangian analysis of continua, comparing with the results of indoor geotechnical centrifugal model tests, and building precise numerical analysis model of embankment on sloped weak ground reinforced by anti-slide piles. Research results show that, using anti-slide piles at the downhill toe of embankment could significantly restrict the lateral deformation of sloped weak ground. It will comprehensively consider the factors such as force, economy, construction etc. in order to confirm the reasonable pile spacing; anti-slide piles must penetrate potential slip surface, but with the increase of the length of pile, the reinforcement effect does not significantly increase; with the increase of elastic modulus, cross- section dimension of pile, the reinforcement effect is improved in some extent; anti-slide pile is suitable to set at the middle of bypass downhill slope of the embankment

Based on the ABAQUS finite element code, the soil dynamic nonlinear constitutive model of Ramberg- Osgood has been modified. Based on the appropriate assumptions, the procedure and the algorithm for evaluation of the model’s parameters R and ? are derived. Loading and unloading rules of the hysteresis correspond to the revised Masing criterion. Three-dimensional nonlinear ground seismic analysis has been performed, the influence of seismic waves with different input peak value on soil stress-strain relationship has been analyzed, and the results have been compared with that of the one-dimensional soil dynamic analysis on Shaking code. The results show that the horizontal displacement and relative displacement obtained by the nonlinear analysis are greater than that obtained by equivalent linearization method, which indicates that the selection of constitutive model will affect the obtained results of ground seismic response; thus it is necessary to select the appropriate model in engineering application and make reasonable judgments for the final result.

With the comprehensive study of the existed data of hydropower engineering, and considering their distributed characteristics, a method of 3D geologic body modeling based on grid partition is proposed. Due to the difference of ground surface data and geologic data, two different partition algorithms are proposed accordingly, namely, contour partition based algorithm of ground surface data and partition algorithm of geologic data based on the distributed feature of drill data; and edge matching method is used to solve of fracture caused by partition. After establishing the model of 3D geologic body, considering the feature of grid partition, a quick excavation algorithm based on grid partition is presented; and the advantage of grid partition based geologic model over the traditional geologic model is also analyzed. Finally, to test the correctness and feasibility of grid partition based on geologic modeling, an empirical study of a hydropower project is conducted.