大应变作用下含水率对非饱和砂土动力特性影响的研究  

Experimental study on the effect of water content on the dynamic characteristics of unsaturated sandy soil under large-strain

作　　者：王海东[1,2] 陈曦[1] 李建文[1] 刘方成[3] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南大学建筑安全与节能教育部重点试验室,湖南长沙410082 [3]湖南工业大学土木工程学院,湖南株洲412008

出　　处：《地震工程与工程振动》2016年第1期193-199,共7页Earthquake Engineering and Engineering Dynamics

基　　金：新世纪优秀人才支持计划(NCET-13-0190);湖南省自然科学基金人才联合培养基金重点项目(13JJA001);中央高校基本科研业务费~~

摘　　要：本文利用WF循环单剪试验系统,完成大应变下,不同含水率和不同正应力下非饱和砂土的循环剪切试验,并分析了不同正应力条件下,含水率对非饱和砂土动力特性影响的规律。试验结果表明,剪应变γ≥2%,含水率对非饱和砂土动力特性的影响显著:(1)含水率对非饱和砂土滞回曲线的影响存在临界含水率,无论正应力大小,低于临界含水率时,滞回曲线相差不大,而高于临界含水率时,滞回曲线随含水率的增大迅速衰减;(2)峰值剪应力随含水率的变化存在相同的临界含水率,无论正应力大小,当含水率低于临界含水率时,峰值剪应力随含水率增大变化较小,而当含水率高于临界含水率时,峰值剪应力随含水率增大而减小,且正应力越大衰减得越明显;(3)阻尼比随含水率的变化也存在临界含水率。The tests of different water content of the unsaturated sandy soil under a series of shear strain and normal stress were completed with the cyclic simple shear test system WF. The effects of water content on the dynamic characteristics of the soil were analyzed. Results show that when the shear strain .y is greater than or equal to 2%, the effects are significant： First, the influences of water content on hysteresis loops exist critical water content. Whether normal stress is low or high, when water content is lower than it, the hysteresis loops change little with the variation of water content; when water content is higher than it, the hysteresis loops decrease rapidly with increas- ing water content. Secondly, there is an uniform critical water content in the relationship between peak shear stress and water content for different normal stress. When water content is lower than it, the peak shear stress has a little change. When water content is greater than it, the peak shear stress decreases with increasing water content especially under higher normal stress. Thirdly, damping ratio along with the change of water content also exist critical water content.

关 键 词：非饱和砂土 含水率 滞回曲线 阻尼比 滞回耗能 

分 类 号：TU43[建筑科学—岩土工程] P315.93[建筑科学—土工工程]