摩擦型岩土材料土拱效应微观机制颗粒流模拟分析

Analysis of microcosmic mechanism of soil arching in frictional geotechnical material by particle flow simulating

利用离散单元计算软件模拟太沙基活动门试验,从散粒体和微观角度研究在摩擦型岩土材料中产生土拱效应时颗粒位移、荷载传递的特点,并进一步研究了颗粒粒径、土体孔隙率、颗粒摩擦系数、活动门宽度以及活动门位移对土拱效应的影响。结果表明:由于土拱的作用,从拱脚往上一定范围内会将拱顶上方的竖向荷载转化成水平荷载并向两侧传递,同时伴随着两侧土体的侧向挤出。伴随活动门的下移,土拱效应在不断调整,增大颗粒粒径、减小孔隙率、增大颗粒摩擦系数、减小活动门宽度,不但可加强土拱效应,而且还能减小土拱效应的影响范围。

By simulating the ＂trapdoor＂ test of Terzaghi using discrete element program, the characteristics of displacement of particles and load transfer are studied from granular and microcosmic viewpoint when soil arching existing in frictional geotechnical material; moreover, the influences of particle diameter, porosity, particle frictional coefficient, width of trapdoor and trapdoor displacement on soil arching are also studied. The results indicate that due to the effect of soil arching, the vertical loading above soil arching is transformed to horizontal loading within a certain range above the arch foot; then the horizontal loading will transfer to both sides of soil, which leads to horizontal displacement of soil. When the trapdoor moves downward, the effect of soil arching evolves continuously; and enlarging the particle diameter and frictional coefficient, decreasing porosity and trapdoor width will not only enhance the effect of soil arching but also narrow the influence range of soil arching.