Experiment And Numerical Simulation On Anchoring Mechanism Of Pressure-type Anchor

With the rapid development of construction in foundation facilities, more and more problems of geotechnical problems need to be resolved. The prestressed anchor cable technology is the key technology to solve these problems. Pressure (diffusion) anchor cable have gotten extensive application in geotechnical engineering such as foundation treatment, slope reinforcement and tunnel reinforcement because of its good mechanical performance. However the current researches on this anchor technology mainly focus on macro-stress, less attention is paid to its micromechanical study. So the anchorage mechanism of pressure (diffusion) anchor cable is hard to analyze from the micro-level analysis.The indoor visual simulation test is carried out to study the anchorage mechanism of pressure-type anchor under the axial load at micro levels in this paper. Based on this, the mesoscale numerical simulation platform was established by discrete element numerical simulation software PFC2D. The mesoscopic mechanical parameters change rule of surrounding soils around pressure-type anchor and pressure diffusion anchor under under the action of the external load was simulated and analyzed to reveal the mesoscopic mechanics mechanism. The concrete research content is as follows: (1) Visualization model experiment on mechanical performance of pressure type anchorThe model of pressure-type anchor was designed and made to carry out the pull-out tests of pressure-type anchor under axial load. The mesoscopic structure evolution law of surrounding sand around the pressure type anchor was analyzed and studied by using digital photogrammetry and image correlation analysis. (2) Numerical simulation research on anchorage mechanism of pressure-type anchorBased on the theory of particle flow and PFC2D program, the model of pressure-type anchor was built to simulated stress condition of the cable under axial tension. The stress field and displacements of the model and mesoscopic physics and mechanics parameters such as particle porosity, coordination number, the amount of rotation to the particle contact force were researched to reveal the mesoscopic anchoring mechanism of pressure-type anchor. (3) Numerical simulation research on anchorage mechanism of pressure diffusion anchorConsidering the factors such as number of loading plates, distances between loading plates and diameter of loading plate, the model group of pressure diffusion anchor was built by using PFC2D program to simulate and analyze mechanical performance of pressure diffusion anchor. Then based on the analysis, the relatively parameters of pressure diffusion anchor were optimized.