岩土力学2017，Vol.38Issue(3)：678-684,7.DOI:10.16285/j.rsm.2017.03.009
干湿循环下膨胀土基质吸力测定及其对抗剪强度影响试验研究
Experimental study of matric suction measurement and its impact on shear strength under drying-wetting cycles for expansive soils
摘要
Abstract
This study measures the total stress shear strength indices of unsaturated expansive soils at different water contents under drying-wetting cycles by undrained shear tests using the conventional direct shear apparatus.Specifically,the total cohesion and the total internal friction angle are obtained to reflect the undrained shear strength of expansive soils.The matric suctions of soil samples in a fixed shear plane are measured using filter papers after shearing.A model of shear strength for the entire suction range of expansive soils is established based on the results of shear tests.The model is verified by experiment.The drying-wetting cycles significantly reduce the undrained shear strength of expansive soil.The total cohesion weakening is more significant than total internal friction angle reduction.The shear strength index of total stress shows a linear positive correlation with the logarithmic values of matric suction.The shear strength of soil increases nonlinearly with the increase of matric suction,and the increasing rate decreases gradually.The findings confirm that it is feasible to investigate the shear strength of unsaturated expansive soil using the conventional direct shear apparatus and filter paper method.关键词
膨胀土/干湿循环/基质吸力/抗剪强度Key words
expansive soil/drying-wetting cycles/matric suction/shear strength分类
建筑与水利引用本文复制引用
吴珺华,杨松..干湿循环下膨胀土基质吸力测定及其对抗剪强度影响试验研究[J].岩土力学,2017,38(3):678-684,7.基金项目
国家自然科学基金(No.51409182,No.41662021) （No.51409182,No.41662021）
南昌航空大学无损检测技术教育部重点实验室开放基金(No.ZD201529002) （No.ZD201529002）
江西省交通运输厅重点科技项目(No.2013C0006).This work was supported by the National Natural Science Foundation of China (51409182,41662021),the Open Fund of Key Laboratory of Nondestructive Testing of the Ministry of Education (ZD201529002) and the Key Technology Program of the Communications Department of Jiangxi Province (2013C0006). （No.2013C0006）
