基质吸力变化引起的体积应变研究  

LABORATORY TEST STUDY ON VOLUMETRIC STRAIN DUE TO A SIMPLE CHANGE OF SUCTION

作　　者：戚国庆[1] 黄润秋[2] 

机构地区：[1]中国电建集团贵阳勘测设计研究院有限公司,贵阳550081 [2]地质灾害防治与地质环境保护国家重点实验室(成都理工大学),成都610059

出　　处：《工程地质学报》2015年第3期491-497,共7页Journal of Engineering Geology

基　　金：贵州省科学技术基金[黔科合J字(2010)2022]项目资助

摘　　要：与降雨有关的边坡表层变形位移,其根源是基质吸力降低引起的非饱和土体积应变。利用某滑坡体的原状样及其重塑样,分别在100k Pa、200k Pa围压作用下,采用单纯增加基质吸力的应力路径,对基质吸力引起的体积应变,进行试验测试。结果显示:(1)试样的体应变,随基质吸力的增大,单调增大,服从对数函数关系;(2)围压由100k Pa增加到200k Pa的试样体积模量,随基质吸力的增大,单调增大,服从幂函数关系;(3)与基质吸力有关的体积变化系数,随基质吸力的增大,单调减小,服从幂函数关系;并且当基质吸力大于200k Pa以后,随基质吸力增大,体积变化系数接近于常数,约为0.0059左右。在此基础上,本文针对这种由单纯基质吸力变化引起的非饱和土体积应变规律及机理,进行了探讨。The slope surface deformation and displacement are related to the precipitation. The root cause is volumetric strain caused by suction decreasing in unsaturated soils. By simply increasing the suction stress path,under net confining pressure of 100 k Pa or 200 k Pa,the test of volumetric strain due to suction is done on undisturbed landslide samples and its remolded sample. The results show:( 1) The volumetric strain of the specimen monotonically increases with suction increasing,which obeys logarithm function relation;( 2) Bulk modulus during net confining pressure from 100 k Pa to 200 k Pa,monotonically increases with suction increasing,which obeys the power function relationship;( 3) Coefficient of volume change associated with the suction monotonically decreases with suction increasing,which obeys the power function relationship. When the suction is greater than 200 k Pa,with the suction increases,the volume change of coefficients is close to a constant of about 0. 0059. Based on these results,the pattern and mechanics of volumetric strain caused by a simple suction change are discussed in this paper.

关 键 词：基质吸力-体积应变关系 非饱和土 体积模量 体积变化系数 

分 类 号：TU41[建筑科学—岩土工程]