Applied Mechanics and Materials Vols. 170-173

Abstract: Based on pit excavation of Shenzhen Airport Rail transport hub project, combined with anchorage stress characteristics, difficulties was studied and numerical calculation for the envelope structure was undertaken. The successful application of design provides new ideas, improved design methods for super soft soil foundation engineering, which can greatly promote the application and development of anchor block in soft foundation excavation.

Abstract: By using ANSYS, 3D high-temperature stope models based on the in-situ experiment of reinforcement with fully grouted cable bolts in the test stope hangingwall of Dongxiang Copper Mine are established and analyzed. Results show that both displacements of ground surface and stope hangingwall are in their allowable scopes. The surrounding rock rising displacement caused by heated rock expansion can partly or fully offset the subsidence displacement caused by gravity. Hangingwall rising displacement occurs if stope temperature is equal to or greater than 100°C. Mining is safe if stope temperature is equal to or less than 500°C. The stope hangingwall anchoring parameters can meet the requirements of surrounding rock stability in the process of extraction.

Abstract: Indoor model experiments were made to study loads on single pile under the wave-current flow. Take three different velocities of the current and three different diameters of piles in the experiments to get the variations of loads. Drag and lift forces were measured by a two-component balance. Analysis on experiment results shows that, both drag force and lift force increase with the increase of the pile diameter and the current velocity. The drag coefficient Cd increases with the increase of Kc number until Kc researches 12, when Kc is more than 12, Cd decreases with the increase of Kc; while the inertia force coefficient Cm decreases with the increase of Kc, when Kc is more than 12, C_m changes little. And the lift coefficient shows no correlation with the Kc number.

Abstract: In order to research the mechanical properties of the backfill cream-body under engineering conditions in the coal mine, the uniaxial compression test of backfill cream-body with different ages abtained from the filling locale of Daizhuang coal mine is conducted with MTS815.03 rock test system. The characteristics of backfill cream-body in the limited space and a certain environment are studied. Research shows that, the strength of backfill cream-body is high, but coagulability is bad and the discreteness of mechanical properties is different; Uniaxial compressive strength is 2.3 ~ 13.17 MPa and the average is 5.436 MPa; The elastic modulus is very low ,which is only 53.66 ~ 2614.35 MPa and the average is 645.14 MPa. The deformation is bigger when absorbing load; Poisson's ratio is low, which is only 0.0001 ~ 0.2112 and the average is 0.0265, which indicates that the backfill cream-body doesn't need the space of transverse deformation when bearing compression deformation; The mechanical parameters of backfill cream-body with different ages are fitted and regressed. Test results is important to control surface mining subsidence effectively, liberate the coal resources under buildings, railways and waterbodies and protect the ecological environment.

Abstract: A mathematical model is presented to describe the scattering of a fast compressional plane wave (fast P-wave) incident at an arbitrary angle on isotropic cylinder embedded in a fluid-saturated porous medium. The expressions of components of solid and filtration displacement, pore fluid pressure and stress tensor in porous medium are obtained by potential function using the Biot’s theory and that of isotropic cylinder are also given. We investigate the properties of the form function of a backscatted fast P-wave for cement and steel cylinder system. It shows the influence of incident angle on form function for steel is more obvious than that for cement cylinder and form function curves are very different between steel and cement cylinder.

Abstract: Floor heave is a kind of deformation form that rock and soil mass of roadway floor enter a plastic flow state under surrounding stress. Installing anti-slide piles is an effective method to control floor heave. Considering the stress conditions and the characteristic of slip line fields in geometry size when floor heave emerges, some parameters used to design anti-slide piles are proposed to control floor heave, which will provide theoretical basis for further designs of roadway support.

Abstract: A group of deformation and stability calculation equations on the low strength pile (LSP) composite foundation is deduced from the LSP composite foundation deformation model. The stress-strain compatibility equations are yielded, in which the interactions among the pile, soils and cushions are considered. At the same time, the pile-soil stress ratio and the equal-settlement-surface (ESS) analytical solution are also yielded. Furthermore, the pile and its surrounding soil stress distribution regulation, compression deformation, the up- pricking-deformation of the cushion and the under-pricking-deformation of the subsoil are all obtained. Through the summary of the composite foundation subsoil settlement and the soil among piles compression deformation, the whole settlement of the composite foundation is deduced. In the above equations, the pile stability and flexibility are analyzed using elastic foundation beam theory. The methods put forward here can be a significant reference for the future research and design of the LSP composite foundation.

Abstract: On the basis of the limit equilibrium method and the physical significance of Coulomb’s yield criteria, extremum conditions of yield functions is established, which will be the fundamental equations for the limit analysis of soil mass. Once the stress equation along a sliding surface is available, the normal stress on the sliding surface can be obtained, a new limit analysis method, generalized limit equilibrium method (GLEM), can be established. With the generalized limit equilibrium method, an analysis method to solve the problem of slope stability can be obtained without introducing any other assumptions or simplified conditions but the sliding surface. With this algorithm, any discretionally possible sliding surface can be trial calculated and the least value of the calculated results of different sliding surfaces is taken as the safety factor. As long as a selected sliding surface is close to the true sliding surface, the derived safety factor will be approximate to the genuine solution to a problem of slope stability.

Abstract: The test on was rammed soil-cement pile composite foundation was done,On the basis of the test. Numerical simulation was analyzed to rammed soil-cement piles.The conclusions were draw from the main frequency,level acceleration, vertical acceleration and influence factors.Theory basis was provided for the study on rammed soil-cement pile composite foundation in the future

Abstract: Underground water level rise because of irrigation has induced a lot of loess landslides in South Jingyang Plateau located in Shanxi Province, PR China. This paper presents a detailed initiation analysis of the landslides through field investigations, a series of GDS triaxial tests composed of isotropically and anisotropically consolidated undrained (ICU/ACU) compression tests and constant-shear-drained (CQD) triaxial tests for undisturbed saturated loess and numerical modeling. The tests show that the contractive failure will cause excess pore water pressure that cannot be dissipated instantly, and will result in the decrease of the shearing resistance. Shear deformation during failure moves the soil toward the critical state rapidly and make the loess completely in liquefactive condition. Therefore, the slope is prone to rapid and long run-out flow slide after failure under the action of gravity because of its high water content.