Fully grouted rock bolts interact with surrounding rock in deeply buried circular tunnels under in-situ stress. In order to explore the mechanism of interaction，the action of a rock bolt is simplified as the distributed shear stress along the length of the bolt，and integral equations are established based on the deformation compatibility between the bolt and the surrounding rock. These integral equations are linear to the shear stress on the surface and are difficult to be solved analytically. In this paper，a numerical method is adopted，in which the anchor bolt is equally divided into n segments and the shear stress distribution in each segment is assumed linear. The shear stress at the node of each segment is regarded as the unknown quantity to be determined，and the linear equations of these unknowns can be obtained through the composite trapezoidal integration formula. The results will be precise as long as the value of n is large enough. The axial force acting in the bolt can also be calculated through the results of shear stresses. Then the effects of the length of the rock bolt，the arrangement angle and the parameter of surrounding rock are considered.

Adopting two cover systems including mathematical and physical covers，numerical manifold method can resolve the problems relating to cracks naturally. In order to apply the moving least square interpolation based numerical manifold method(MLS-NMM) in the dynamic crack propagation，a program which simulates the dynamic crack propagation by using MLS-NMM is developed. In the program，the Bathe implicit time integration scheme is utilized to improve the accuracy of time discretization，a new strategy for the inheritance of degrees of freedom is proposed to deal with the energy inconsistency in dynamic crack propagation，and the criterion of fracture mechanics is employed to predict the path of crack propagation. Through the solution of some typical problems of dynamic crack propagation，it is demonstrated that the proposed procedure simulates the dynamic crack propagation precisely.

In order to investigate the rate effect of rock material in the loading range of“static-quasi static-dynamic”and to overcome the shortcomings of the size effect in static loading and dynamic loading methods，on the basis of comprehensive analysis in eliminating the end effect in static test and achieving the force balance for dynamic test specimen，a cylindrical fine granite specimen with ?25 mm×50 mm was adopted. The compression tests were carried out in the range of static-quasi-static-dynamic by using the hydraulic servo tester INSTRON and SHPB(split Hopkinson pressure bar) device respectively. The variations of compressive strength，peak strain and tangent modulus with strain rate(loading rate) were obtained. The relationship between the strain rate and the loading rate was also investigated using the obtained experimental data，and the results show that there is a good linear relationship between them(taking logarithm respectively). In order to describe the rate effect of rock material from low to high loading rate(or strain rate)，a new model of dynamic increase factor(DIF) based on rate effect was proposed，and the applicability of the model to the compressive strength，tangent modulus and peak strain were investigated by using the strain rate and loading rate as the basic parameters respectively. The results show that the new model of DIF based on the loading rate effect can describe well the rate effect of compressive strength and tangent modulus.

Thermal cracking of rock induced by cryogenic liquid is widely observed in oil and gas exploitation，geothermal development and liquefied petroleum gas storage etc. To study the cryogenic fracturing，a theoretical solution of the temperature and stress distribution in a plate was derived with the thermo-elastic theory. The heat conduction characteristics and associated thermal stress evolution in the plate was theoretically studied with the derived theoretical formula. The effects of heat transfer coefficient on cooling rate and increasing rate of tensile stress were also analyzed. The results show that when the rock surface contacts with cold liquid，the temperature on the contact surface decreases rapidly at first，then slowly and finally the same as the environment temperature. The tensile stress rises sharply firstly and then decreases，and finally decreases to zero. In addition，the crack initiation，propagation process of cryogenic fracture in rock under thermal shock are numerically simulated. The effect of the heat convection coefficient on the evolution of temperature，stress distribution，the fracture mode and the number of fractures were analyzed. The numerical results indicate that increasing the heat convection coefficient not only raises the tensile stress on the contact surface between liquid and solid which results in rock easier to crack，but also raise the number of cracks which are helpful for enhancing the permeability of low permeability reservoirs.

Multiple deep cracks appeared at the top arch of galleries in Dagangshan high arch dam before the impoundment. Cracking characteristic around the access gallery at E.L. 979 m，foundation gallery at E.L. 940 m and drainage gallery at E.L. 937 m before and after the impoundment was analyzed using the installed microseismic monitoring system in the high arch dam. The process of crack inducement was reproduced and the real cause of cracking in galleries was studied. The results show that the microseismic activities in galleries are significantly coherent to the water level. Before the impoundment，the microseismicity of the gallery top arch of dam heel area was strong which exceeds its cracking limit，thus inducing gallery cracks in the cross sections of river. After the impoundment，with the rising of water level，the gallery cracks in the area of arch dam heel tends to be stable while galleries in arch dam toe area tend to crack. The trend of the cracking which transferrs from the dam heel area to the dam toe aera during the impoundment process was revealed. It is recommended to keep a close eye on the damage conditions of concrete in arch dam toe area during the impoundment period.

The strength of clay-bearing siltstone is strongly susceptible to the moisture and the moisture-induced decay of strength endangers seriously the safety of engineering constructions. The results of experiments on the full process saturation and dehydration of argillaceous siltstones were presented. During the dehydration stage，the sizes of rock samples and their P-wave velocities were monitored. The mechanical properties of the samples，especially the compressive and tensile strengths，were discussed at designated degrees of saturation. The results indicate that the shrinkage of rock samples has clearly four stages during the dehydration and that the maximum rate of size reduction lies in the range of degree of saturation 55%–40%. The P-wave velocities of rock samples decrease firstly and increase subsequently，and reach the minimum at the degree of saturation of 65% . With the increasing of the degree of saturation，both the strength and elastic moduli of rock samples drop. Over 60% of the strength loss(68.2% of compressive strength loss and 62.6% of tensile strength loss) occurs in the low saturation interval(below 40%). The tensile strength is more susceptible to the softening effect of water than the compressive strength. The microscopic mechanisms of the softening effect of pore water on argillaceous siltstone may be divided into two categories：one is the load-dependent mechanisms including the change of pore water pressure，flow of pore water，lubricating effect of bound water film and the Rhebinder effect；the other is the load-independent mechanisms including clay mineral hydration and dissolution of soluble minerals. Finally，the dominant mechanism of rock softening under different saturations is discussed.

Determining the thickness and number of fractured zones in surrounding rock is important for excavation and supporting of cave at deep underground. A new approach to analyze the zonal disintegration of surrounding rock was put forward according to the periodical characteristic of tension-compression stress along the bolt length. A mechanical model of interaction between the full-size grouted bolt and surrounding rock was established based on deformation compatibility. The neutral point on the bolt and the formulas of maximum axial force were deduced. The range of plastic area in every zone in the surrounding rock was analyzed. The mechanical criterion about the tensile rupture of the surrounding rock on elastic-plastic interface after stress redistribution was proposed based on the Griffith?s strength theory. Then，the number of fractured zones in the surrounding rock was determined. The results show that the stress of the surrounding rock is redistributed after excavation. Under the condition of the maximum circumferential stress，radial tensile rupture happens on the elastic-plastic interface of surrounding rock when the tensile stress is greater than its ultimate tensile strength and the multiple fractured zones and non-fractured zones occur alternately. The displacement rate of rock within the fractured zone is different from that of non-fractured zone along the radial direction，leading to multiple neutral points along the bolt length. The thickness of the fracture zones in surrounding rock based on the back analysis of the radius of each neutral point shows a decreasing trend on the whole until the rupture of the surrounding rock stops. Finally，the above results were confirmed in a real engineering project.

The traditional fractal dimension describing the characteristics of discontinuity orientation is influenced by both the joint number and the characteristics of discontinuity orientations. The definition of representative fractal dimension is proposed to overcome the limitations of traditional methods. Monte Carlo method is introduced to generate the discontinuity samples that conform to the Fisher distribution and to represent different dispersion levels. The analysis of the fractal dimension with changing sample size reveals that there is a“three-level”trend generally，i.e.，the fractal dimension increasing fast at first，then slowly and finally reaching almost stable. The joint number at the increasing rate of fractal dimension slowing down for the first time is defined as the optimal joint number，and the corresponding fractal dimension is defined as the representative fractal dimension. The clustering method is introduced to group the joint data in a mining slope project. Comparison between the clustering results of representative fractal method and traditional validity index indicates that the fractal dimension does not require a pre-defined distribution form for joint sample and can describe the characteristics of discontinuity orientation better.

An explicit three-dimensional discontinuous deformation analysis(3D DDA) method based on the central difference scheme is proposed to improve the computational efficiency of the traditional 3D DDA method in solving large-scale discontinuous problems. With the explicit 3D DDA method，it is not only easier and faster to obtain the solutions，but also more convenient to achieve the efficient parallel computing. Based on the first entrance and shortest exit principle，formulae are derived to estimate the positions of entrance points during the entrance process regarding two basic entrance mode and the entrance information is determined. These contact treatment measures ensure the computational accuracy and the tempo-spatial coherence of the contact constraints. Numerical examples demonstrate that the explicit 3D DDA has sufficient computational accuracy and higher computational efficiency. The explicit 3D DDA is promising for the discontinuous numerical analysis in large scale rock engineering after achieving parallel computing.

The tunnel-type anchorage is the primary anchorage type for suspension bridges. The anchor plug and the surrounding rock form a complex force system. The bearing mechanism and the complete mechanical damage behaviors of tunnel-type anchorages are still not very clear. An elastic-brittle plastic damage constitutive model for rocks is developed in finite element software ABAQUS. The damage model considering both the tensile and shear failure mechanisms can better simulate the rock deformation and failure process，and expand the application areas of the original model embedded in ABAQUS. The numerical analyses are conducted to reveal the mechanical damage behaviors of tunnel-type anchorages buried at different depths. The results show that the deforming of tunnel anchorages exhibits a significant progressive failure behavior. The change of failure modes influenced by buried depth is related to the confining pressure，and the increasing of confining stresses improves the ductility or plasticity of rocks. For the shallow buried tunnel-type anchorages with low confining stresses，the mechanical system is a little bit of brittle，so a horn-shaped failure surface and a composite mechanical mechanism of tensile and shear failure are found. For the deep buried cases with high confining stresses，the mechanical system has high ductility，the shear failure occurs at the interface between the anchor plug and surrounding rocks，and the limit bearing capacity has an evident increasing compared with the shallow buried cases. The investigated horn-shaped failure surfaces in this study are very different from the failure surfaces traditionally used in practical engineering，which may affect directly the establishment of calculation model of bearing capacity. Hence，the extra attentions should be paid to the actual failure form in the design of tunnel anchorages.

In order to investigate the influence of cyclic wetting and drying on the dynamic tensile strength of rock，a series dynamic Brazilian disc tests on red-sandstone were carried out through split Hopkinson pressure bar (SHPB) apparatus with a diameter of 50 mm. The laboratory test results indicate that cyclic wetting and drying have a strong deterioration effect on the static and dynamic tensile strength and that the static and dynamic tensile strength both decrease with the increasing of the number of cycles. Under the different conditions of loading rate，all specimens(the times of wet-dry cycles as the variable) have a critical loading rate . When the loading rate is below ，the dynamic tensile strength increases with the increasing of loading rate. While the dynamic tensile strength remains unchanged when the loading rate is above . When the loading rates are the same，the dynamic tensile strengths decrease with the increasing of the number of wet-dry cycles，and the decreasing rate appears quickly initially and slowly later. There is an obvious fractal feature of red-sandstone fragment after different wet-dry cycles，ranging from 2.46 to 2.81 of the fractal dimension，The relationship between the fractal dimension and loading rate is logarithmic. An empirical equation considering the combined effect of the wet-dry cycles and loading rate is established to calculate the dynamic tensile strength of red-sandstone.

Collision between rock blocks and the slope is the key to accuratly predicting the falling trajectory of rock. To investigate the effect of velocity and size on the normal coefficient of restitution(NCOR) and to reveal the possible damage and fragmentation phenomenon，a device implementing the normal collision of marble spheres is developed. The results show that three types of damage pattern of marble sphere exist(no macro crack type，macro crack type and fragmentation type). Moreover，a new mechanism of energy dissipation(the propagation of macro cracks) causing a significant decrease of NCOR is found. The measured NCOR of marble spheres decreases with the increasing velocity and decreasing diameter，and the effect of velocity on NCOR is also related to the size of marble sphere. The proposed averaged rate of contact stress has a good correlation with the NCOR and is able to fully describe the velocity effect and size effect of NCOR. Finally，the viscoelastic contact theory is used to describe the NCOR and it proves that the decreasing of NCOR with the decreasing of diameter is reasonable.

Based on the thermo-elasticity and McNamee-Gibson displacement function，a displacement function method，to study the development of thermal stress and thermal deformation in layered pavement structure，is presented. Starting with the governing equations of plane strain problem of thermo-elasticity，a relationship between the generalized strain and stress is established by using the displacement function and Laplace-Fourier transform. Combining with the contact and boundary conditions，strict solutions of the thermal-induced stress and deformation of the layered system are derived. The results show that the proposed method is capable of producing accurate solution to the thermal-induced deformation problems of layered pavement structures. Due to the time effect of heat conduction，the heat loading affects mainly the surface and base layers at the initial stage，and then the influenced region develops gradually towards the inner layers with the time going. The vertical thermal-induced expansion diminishes with the depth and the greatest expansion takes place at the surface layer，leading to the stress concentration and accordingly possible pavement cracking. It is therefore recommended that the bonding conditions between the surface and base layers should be strengthened to ensure the structural integrity of pavement structures.

The design method is crucial to meet the requirement of safety and economy of the support system of foundation pit. On the basis of the soil strength design method according to plastic deformation and the engineering experience，the deformation mechanism of the foundation pit system was modified，and an improved MSD method was proposed. This method is suitable for the analysis of excavating process of deep foundation pit with internal bracing. In the energy conservation equation，the influence of the compressive deformation energy in the internal support，the bending deformation energy in the retaining wall above the excavation surface and the buried depth of the excavation surface of the foundation pit are considered. The curve form of the variable wave peak is proposed to be cosine function. The improved method has been successfully applied in engineering practice. In comparing with the original MSD method and the vertical elastic foundation beam method，the improved MSD method agreed better with the measured values.

Considering the influence of the building load on the additional stress of the soil，the building load is changed into the covered soil with a certain thickness according to the effective gravity of the soil. In terms of the Mindlin solution of elastic mechanics，the analytical solution to the additional stress of the surrounding soil is given，which is caused by the front thrust of the cutter head as well as the frictional force between the shield and the soil under the load construction of the upper structure. Simultaneously，the analytical solution to the additional stress of the surrounding soil resulting from the friction force between the cutter and the soil is derived. Combined with specific calculation cases，the distribution of the additional stress of soil caused by the front thrust，shield shell friction and cutter friction force is analyzed，and the influence on the surrounding environment is also taken into account. Moreover，the effects of different superstructure loads on the additional stress and distribution law of the soil are analyzed，in which the additional stress is original from the front thrust of the cutter head and the friction force of the shield. The result shows that both the positive thrust and cutter friction between shields have an important impact on the additional stress of surrounding soil in the shield construction with superstructure loads. As the main influencing factors，they have certain degrees of diffusion，and in which the additional stress component along the propelled direction is more obvious. However，the friction force of the cutter disk has little influence on the additional stress of the surrounding soil but has a certain degree of fluctuation，and the additional stress has approximately an antisymmetric distribution on axis. Especially，the fluctuation of additional stress caused by the friction between the cutting tool and the soil body is particularly significant. Different building loads have obvious impacts on the amplitude and law of additional stress  and  which caused by shield friction，and the effect of   is most significant. The above research is of fundamental significance to guide the design and construction of the shield tunnel.

In this paper，the dynamic characteristics of defective large diameter piles cast-in-place in saturated soil are investigated. Firstly，the frictional forces of the soil acting on the pile shaft according to the Biot?s theory of porous elastic medium considering the construction disturbance are obtained by using the complex stiffness transfer method. Then，the dynamic impedance and velocity response of the pile top are obtained considering the transverse inertia effect and combining the boundary conditions. Afterwards，the reliability of the obtained solution is verified by fitting the existing solution to the measured curve. Finally，a parametric study is conducted to give insight to the sensitivity of dynamic characteristics in low-strain integrity testing on defective piles.

Comparative studies on the accuracy and convergence of implicit and explicit integration schemes of a constitutive model for unsaturated expansive clays are conducted. The differences and interactions between mechanical and water retention behaviours of macrostructure and microstructure are considered in the model. The model is rather complex due to the adoption of bounding surface theory，multi-plastic mechanism，multiple hardening parameters，coupling hardening law，etc. Based on the Euler forward method，an explicit integration scheme combining an automatic sub-stepping scheme with a method to determine the number of active plastic mechanisms is proposed. Comparisons on the accuracy and convergence of the explicit integration scheme and existing implicit integration scheme are carried out according to the calculated results with different strain increment size on control-strain tests，which provides a basis for selecting the stress integration scheme of complex models.

The methods in establishing the existing anisotropic constitutive models are reviewed systematically. It is pointed out that the description of the fabric direction should be attributed to the coordinate transformation of fabric and stress. For anisotropic materials，the total stress needs to be allocated according to the actual bearing area of each component，because the effective bearing areas of soil skeleton in different directions are different. Therefore，by introducing the transformation matrix，the equivalent stress tensor is proposed to describe the anisotropy of granular materials，the true stress inside the material and the relationship between the fabric direction and the stress direction. Therefore，the material anisotropy in macro-scale can be regarded as the result of the application of anisotropic stress on an equivalent isotropic material in micro-scale. The equivalent stress tensor is used to describe the anisotropic stress and the existing isotropic model is used to describe the mechanical property of the equivalent isotropic material. A general method of transforming the existing isotropic failure criterion and constitutive model into anisotropic ones，named“Equivalent Stress Method”，is put forward from the perspective of stress. Finally，the SMP criterion is transformed into anisotropic one as an example. The comparison with the existing experimental results proves the rationality and validity of the anisotropic transformation.

The safety of shield tunnel construction requires the proper estimation of surrounding soil deformation. The random field theory together with the finite difference analysis and Monte Carlo simulation are used to carry out the stochastic analysis on the surrounding soil deformation induced by twin tunneling in multi-layer soils considering the spatial variability of soils. The effects of scales of fluctuation(SOF) of Young?s modulus in both vertical and horizontal directions and coefficients of variation(COV) of Young?s modulus on the surrounding soil deformation are investigated and discussed in detail. Results show that the effects of COV of Young?s modulus on the deformation are more important than SOF. The effects of the anisotropy coefficient on the maximum deformation are limited when increases to 32. Additionally，the pattern of the surface subsidence curve depends highly on the distribution of the modulus above the tunnel. According to the results，the equivalent characteristic modulus is proposed for tunnel design in the typical weathered granite stratum in Xiamen.

The synthesis mechanism and physical-mechanical properties of hydraulic limes prepared from loess- doll were researched in this paper. The compositions of loess-dolls before and after calcination were investigated by means of X-ray fluorescence spectrometer and X-ray diffract meter. The physical-mechanical properties of mortar specimens were studied by using a deformation field inspection system with white light DSCM (Digital Speckle Correlation Method). The microscopic morphology of the specimens at different ages was characterized by scanning electron microscopy. The results show that the main ingredients of loess-dolls are CaO，2CaO•SiO2 and 2CaO•Al2O3•SiO2 after calcination of 8 hours at 900 ℃，which are similar to that of European hydraulic lime NHL5. The contents of CaCO3 and 1.5CaO•SiO2•xH2O(C-S-H) increase gradually during the curing process，but the content of Ca(OH)2 decreases gradually，and the content of 2CaO•Al2O3•SiO2 remains constant. At the early age of 1 to 5 days，the shrinkage rate increases linearly with the age. At the middle age of 6 to 17 days，the shrinkage rate increases slowly with the age. At the later age of 18 to 28 days，the shrinkage rate remains constant. The tensile and compressive strengths of hydraulic limes increase with the age，and the mechanical strengths of the samples meet the standard of NHL5. The area of deformation zone increases with the tensile stress at early stage of loading, the localization band occurs as the adjacent deformation zones merge，and the macro-cracks form and cause the sample to fail. A network structure is formed by the connection of C-S-H and CaCO3 in samples with the increasing of age，which enhances the mechanical strengths of samples.