中南大学学报（自然科学版）2018，Vol.49Issue(6)：1481-1490,10.DOI:10.11817/j.issn.1672-7207.2018.06.022
冻融循环下粉质黏土不排水剪切性状的试验研究
Experimental study on undrained strength characteristics of silty clay after freeze-thaw cycling
摘要
Abstract
In order to study the freeze-thaw cycling effect on stress-strain relationship, pore water pressure-strain relationship, effective stress path, critical state line and shear strength index of soil, freeze-thaw cycling tests and consolidation-undrained triaxial shear tests were conducted on compacted silty clay from Qinghai—Tibet Plateau. The results show that stress-strain curves of samples before and after freeze-thaw cycling are strain hardening type and strain softening type, respectively. The undrained shear strength decreases continuously with each additional freeze-thaw cycle. The pore water pressure keeps increasing with the increase of both number of freeze-thaw cycles and confining pressure, and so is the pore water pressure coefficient in shear failure. The effective stress path inp'-q plane also develops towards the lower left, and in low confining pressure it will transfer from monotonously increasing type to "S" type at the same time. Both the characteristics of pore water pressure and effective stress path reflect that the degree of consolidation decreases with freeze-thaw cycling. The positions of critical state lines inp'-q plane are lowered, and the critical state stress ratio keeps decreasing by freeze-thaw cycling. Compared with the total stress strength index, the effective stress strength index can reflect the comprehensive effect of freeze-thaw cycling and confining pressure on soil mechanical properties more accurately. The variation regularity of cohesion and internal friction angle versus number of freeze-thaw cycles can both be fitted and further predicted by the Logistic model.关键词
粉质黏土/冻融循环/孔隙水压力/有效应力路径/临界状态线/不排水抗剪强度指标Key words
silty clay/freeze-thaw cycling/pore water pressure/effective stress path/critical state line/undrained shear strength index分类
建筑与水利引用本文复制引用
胡田飞,刘建坤,王青志,房建宏..冻融循环下粉质黏土不排水剪切性状的试验研究[J].中南大学学报（自然科学版）,2018,49(6):1481-1490,10.基金项目
交通运输部应用基础研究计划(重点平台)项目(2014319363200) （重点平台）
国家自然科学基金资助项目(51378057,41371081) (Project(2014319363200) supported by the Applied Basic Research Plan (Key Platform) by Ministry of Transport of the People's Republic of China （51378057,41371081）
Projects(51378057, 41371081) supported by the National Natural Science Foundation of China) （51378057, 41371081）
