关键词: 砂性土, 离散元, 应力释放, 土拱效应, 侧压力系数

Abstract: The influence of unloading magnitude and porosity on stress release characteristics of sandy soil arching is analyzed by laboratory tests. Meso-study is also performed by PFC2D, the further study is focused on effect of particle friction property, stress and displacement field variation and stress release section division during arching. The results show: (1) The results of unloading magnitude effect by PFC2D agree well with laboratory tests; it's feasible to study stress release characteristics of sandy soil by PFC2D. (2) The vertical stress release in stress release section is larger than that in stress increase section, while horizontal stress release is not; the lateral pressure coefficient increases as getting closer to the unloading site in stress release section while the regularity is reversed in stress increase section. (3) The friction property of sandy soil reduces the influence of arching on stress release and lateral pressure coefficient. (4) The stress release factor increases as unloading magnitude or porosity increases; the lateral pressure coefficient increases in stress release section while decreases in stress increase section as unloading magnitude or porosity increases.

Key words: sandy soil, discrete elements, stress release, soil arching effect, lateral pressure coefficient