膨胀土完全软化强度指标试验研究  

Experimental study on fully softened shear strength of expansive soil

作　　者：张坤勇[1,2] 徐娜[2] 陈恕 ENAMULLAH Baba Kalan 谢宇飞 ZHANG Kun-yong;XU Na;CHEN Shu;ENAMULLAH Baba Kalan;XIE Yu-fei(Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering,Hohai University,Nanjing 210024,China;Geotechnical Engineering Institute,Hohai University,Nanjing 210024,China;Water Resources Bureau of Shenzhen Municipality,Shenzhen 518000,China;School of Municipal and Environmental Engineering,Henan University of Urban Construction,Pingdingshan 467036,China)

机构地区：[1]河海大学岩土力学与堤坝工程教育部重点实验室,江苏南京210024 [2]河海大学岩土工程科学研究所,江苏南京210024 [3]深圳市水务局,广东深圳518000 [4]河南城建学院市政与环境工程学院,河南平顶山467036

出　　处：《岩土工程学报》2020年第11期1988-1995,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(51578214)。

摘　　要：以引江济淮试验段工程项目为依托,开展膨胀土完全软化强度试验,分析了膨胀土完全软化强度指标在不同含水率、剪切速率下的变化规律,并在此基础上与膨胀土干湿循环强度指标展开对比分析。完全软化状态下,膨胀土黏聚力接近0,完全软化强度主要由内摩擦角决定;内摩擦角受含水率影响不大且几乎不受剪切速率影响;黏聚力普遍较小,符合完全软化状态黏聚力接近0的定义。分别采用干湿循环后强度指标和完全软化强度指标,对简单膨胀土边坡开展了干湿循环后浅层稳定性分析。结果表明,和干湿循环试验相比,完全软化试验工作量小,试验周期短,能反映膨胀土边坡浅层滑塌的破坏机理,可用以对膨胀土边坡受干湿循环作用后的浅层稳定性分析。The fully softened strength tests are carried out on the expansive soil samples from the Yangtze-Huaihe River Water Transfer Project.The fully softened strength indexes under different moisture contents and shear rates are discussed and analyzed.On this basis,they are compared with the shear strength indexes from the wetting-drying cycle direct shear tests on expansive soil.The results show that in the fully softened state,the cohesive force of expansive soil is close to zero,and the fully softened strength is mainly determined by the inernal friction angle.The inernal friction angle is little affected by the moisture content and shear rate.The strength indexes obtained from wetting-dring cycle tests and fully softened tests are applied to the safety analysis of simple expansive soil slope respectively.Compared with the wetting-drying cycle direct shear tests,the fully softened strenght tests need less lab work and shorter test peroid.The fully softened strength indexes can also reflect the failure mechanism of the shallow failure of expansive soil slopes after wetting-drying cycles in practice.It is recommended to apply the fully softened strength indexes in the analysis of the shallow stability of expansive soil slopes after wetting-drying cycles.

关 键 词：膨胀土 完全软化强度 干湿循环 浅层滑动 

分 类 号：TU443[建筑科学—岩土工程]