Using prestressed anchor cables is one of the most common approaches for reinforcing slopes. By establishing a calculation model for a high and steep slope, the changes of displacement of slope foot and increment of force on the cables under different prestresses were calculated. Furthermore, the influence of prestress on the changes of displacement of slope foot and force on the cables was analysed. By analysing the changes in force on cables in different parts of the slope, the reinforcement mechanism of a prestressed anchor cable on the slope was attained. The result showed that the reinforcement effect of prestressed anchor cable on the slope was mainly attributed to it effectively restricting the displacement of sliding mass in the slope, while the effect of cables in the lower part of the slope was more significant than that of those in the upper part of the slope. Therefore, to reduce the number of cables, decrease the construction difficulty of cables and save money, it is feasible to remove cables in the range of the upper-third of the slope. Afterwards, by improving the cable prestress in the range of the lower-third and reducing the cable prestress in the middle, the safety factor of the slope can satisfy design requirements, thus reinforcing the slope.

The dynamic strength and accumulated plastic strain are two important parameters for evaluating the dynamic response of soil. As a special clay, the remolded red clay is often used as the high speed railway subgrade filling, but studies on its dynamic characteristics are few. For a thorough analysis of the suitability of the remolded red clay as the subgrade filling, a series of long-term cyclic load triaxial test under different load histories are carried out. Considering the influence of compactness, confining pressure, consolidation ratio, vibration frequency and dynamic load to the remolded red clay dynamic property, the tests obtain the development curves of the dynamic strength and accumulated plastic strain under different test conditions. Then, through curve fitting method, two different hyperbolic models respectively for the dynamic strength and accumulated plastic strain are built, which can match the test datum well. By applying the dynamic strength model, the critical dynamic strength of the remolded red clay are gained. Meanwhile, for providing basic datum and reference for relevant projects, all key parameters for the dynamic strength and accumulated plastic strain of the remolded red clay are given in the paper

In terms of Biot's dynamic theory, the method of complex function is used to solve the problem of the dynamic response of circular-arc channel in a liquid-filled solid half-space under harmonic plane compressional waves. The equations of the Biot wave motion are decoupled to Helmholtz equations by introducing potential functions and the general solution is obtained. Utilizing the general solution of the potential functions, expressions for the displacements, stresses and pore pressures within the liquid-filled solid and surface channel can be obtained for certain boundary conditions. Here, a circular arc with large radius are used to simulate the straight boundary of the liquid-filled solid half-space. With different parameter conditions, Numerical results are showed and some laws are given and discussed.

It is a very complex problem of pile foundation stability evaluation in karst area, which has been gotten more and more attention in the engineering field. There are many factors that affect the mechanical properties of the pile foundation, including the size, quantity and spacing of the karst. In this paper, numerical simulation is carried out, the results show with the cave number increases, pile axial force increases overall. The larger the size of the cave or the smaller the spacing of the cave, the greater the additional axial force of the pile under the same depth. The cave size has the greatest influence on the additional axial force of pile, and the cave spacing has minimum influence.

Based on Biot's dynamic theory and the complex variable function, a new method is used to solve the dynamic response of a pipeline in half-space porous medium to incident harmonic plane body waves. Here, a circular arc with large radius is applied to simulate the half-plane boundary. By using the theory of Helmholtz, The equations of the steady-state Biot wave motion are decoupled to Helmholtz equations by introducing in the potential functions. The general solution of Helmholtz equations is given by means of the complex series expansion technology. Utilizing the general solution of the potential functions, the expressions of the displacements, stresses and pore pressures of porous medium and those of the displacements and stresses at the pipeline can be obtained with certain boundary conditions of this problem. Then the variations of the coefficients of dynamic stress concentration and the pore water pressures concentration at boundaries of the pipeline structure are discussed with different parameter conditions. The results of the given numerical example indicate that the thickness and the shear module of the pipeline have great influence on the dynamic stress and strain of the pipeline. The proposed methodology in this paper may provide a new method for the analysis and design of underground pipelines accounting for transverse forces.

In terms of Biot's dynamic theory, the multi-polar coordinate and complex function are used to put forward an approximate analysis method for scattering and dynamic stress concentration of harmonic plane SV-waves around a circular unlined pipeline in half space of saturated soil. Here, a circular cavity with large radius is used to replace the straight boundary of the half space of saturated soil . By using the theory of Helmholtz, the general solutions of the Biot's wave functions are given, and a system of infinite linear algebraic equations for the problem studied in this paper are generated by means of the complex series expansion technology and the boundary conditions of the solid matrix and the fluid. This research also presents the variation of the coefficient of dynamic stress concentration at boundaries of the unlined pipeline with different parameter conditions. The results of the given examples indicate that the method used in this paper is useful and efficient to the scattering and dynamic stress concentration of harmonic plane SV-wave around the Unlined Pipeline in a Half-space of Saturated Soil.