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采用二维颗粒流程序PFC2D建立格栅加筋砂土的格栅拉拔试验数值分析模型,分析了格栅拉拔过程中位移场、接触力、孔隙率、配位数等参数的变化规律.根据剪切带厚度将试样划分成四个区域,通过开发细观组构统计程序记录格栅拉拔过程中各区域砂土细观组构演化,探讨砂土颗粒的接触法向、接触力分量的各向异性演化规律及其与试样宏观抗剪强度之间的关系.研究结果表明:拉拔试验过程中,剪切带内平均法向接触力增大,切向接触力减小.剪切带内砂土抗剪强度受控于法向接触力及其各向异性的变化,拉拔过程中,砂土颗粒间法向接触力各向异性主方向的变化与大主应力的方向相一致.
The two-dimensional particle flow program PFC2D was used to establish the numerical analysis model of the grid pull-out test of the grid-reinforced sand. The variation law of the displacement field, contact force, porosity, coordination number and other parameters during the grid drawing process was analyzed. According to the thickness of shear zone, the sample is divided into four regions. Meso-structure evolution of sand in each region during the drawing of the grid is recorded through the development of mesostructure statistical program. The contact normal and contact force of sand particles are discussed. The anisotropic evolution of the component and its relationship with the macroscopic shear strength of the specimen.The results show that the average normal contact force in the shear zone increases and the tangential contact force decreases during the drawing test. The shear strength of sand in shear zone is controlled by the change of the normal contact force and its anisotropy. During the drawing process, the change of the main direction of the principal contact force anisotropy and the change of the direction of the principal stress Consistent.