摘要
土体的物理力学特性受到颗粒尺度及其级配的强烈影响,具有显著的颗粒尺度效应。文中采用天然黏土和商品石英砂,制备具有不同颗粒粒径和体分比的一系列三轴抗剪试样,通过不固结不排水和固结不排水三轴抗剪试验,测得了应力应变关系曲线以及剪应力屈服强度,基于试验结果对土体力学特性的颗粒尺度效应进行分析;同时,引入胞元土体模型,对土体力学特性颗粒尺度效应的物理机制进行解释。实验结果表明,随着土体中砂粒体分比增加和粒径的减小,土体的变形特性明显增强,其剪应力屈服强度也随之显著提高;砂粒的体分比对变形和强度颗粒尺度效应的影响比粒径的影响更为显著;胞元土体模型解释了实验结果的颗粒尺度效应的物理机制。
The physical and mechanical characteristics of soil are obviously affected by scale and grade of grains,exhibiting remarkable grain size effect. By using the natural clay and commercial quartz sand,a series of test samples with sand grains of different size and volume fraction are prepared, and curves of stress-strain and shear yield strength are obtained by unconsolidated-undrained and consolidated-undrained tri-axial shear tests. The analysis on the grain size effect of the soil mechanical characteristics is based on the test results, and the cell element model of soil is proposed to explain the physical mechanisms. The test results show that deformation properties and shear yield strength are improved remarkably with volume fraction increasing and particle size decreasing of sand in soil,and the volume fraction has a more obvious influence on grain size effect of deformation and strength characteristics than that of grain’s size. The cell element model of soil explains the physical mechanism of grain size effect of the tests results.
出处
《水利学报》
EI
CSCD
北大核心
2014年第6期742-748,755,共8页
Journal of Hydraulic Engineering
基金
亚热带建筑科学国家重点实验室自主研究课题资助(2012ZA04)
关键词
土体尺度效应
三轴抗剪试验
体分比
胞元土体模型
物理机制
size effect of soil
tri-axial shear test
volume fraction
cell element model of soil
physical mechanism
