摘要
通过室内模型试验研究了卸荷尺度及孔隙率对砂性土成拱应力释放特性的影响,并应用离散元分析软件PFC2D进一步对颗粒摩擦性质影响、成拱后应力场以及位移场变化规律和应力释放分区进行了细观研究。研究发现:(1)数值模拟对卸荷尺度影响因素的研究结果与室内试验一致,应用PFC2D研究砂性土应力释放特性是可行的。(2)应力释放区内竖向应力释放大于应力加载区,而水平应力释放小于应力加载区;侧压力系数在应力释放区内距离卸荷位置越近增量越大,而在应力加载区距离卸荷位置越近增量越小。(3)砂性土摩擦性质会减小土体成拱对应力释放以及侧压力系数变化的影响。(4)应力释放随着卸荷尺度及孔隙率的增大而增大;对于侧压力系数,在应力释放区内随着卸荷尺度或孔隙率的增大而增大,而在应力加载区随着卸荷尺度或孔隙率的增大而减小。
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.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2013年第2期395-403,共9页
Rock and Soil Mechanics
基金
国家自然科学基金资助项目(No.50878151)
关键词
砂性土
离散元
应力释放
土拱效应
侧压力系数
sandy soil
discrete elements
stress release
soil arching effect
lateral pressure coefficient
