摘要
通过对杭州饱和软黏土进行应力控制的循环三轴试验,对循环荷载作用下各向异性固结软黏土的软化特性及残余应变发展规律进行了研究.试验结果表明,随着循环次数的增加和循环应力比的提高,软化指数逐渐减小;对于各向同性固结软黏土,软化指数与循环次数的对数表现为曲线关系,对于各向异性固结软黏土,两者表现为直线关系;对于各向同性固结土体,在循环初期,残余应变为负应变,随着循环次数的增加,负应变逐渐增大,当循环次数达到一定时,负应变开始逐渐向正应变发展;对于各向异性固结土体,随着循环次数的增加,残余应变均表现为正应变.在试验的基础上建立了各向异性固结软黏土循环残余应变-软化模型,该模型反映了软黏土循环软化特性及残余应变变化规律.结合该残余应变-软化模型对Iwan模型进行了修正,修正后的模型可以较好的描述各向异性固结软黏土的动应力应变关系.
The residual strain correlated to the degradation index of the anisotropic consolidated Hangzhou soft clay subjected to the uniform stress-controlled triaxial loading was investigated. The results show that the degradation index decreases with progressive cyclic number and increasing cyclic stress ratio. The degradation index changes linearly with the logarithm of cyclic number for the anisotropic consolidated clay; for the isotropic consolidated clay, the relationship between them is nonlinear. For an isotropic consolidated sample, the residual strain is accumulated in the direction of increasing negative strain at the beginning of cyclic loading. As cycling continues, the residual strain accumulating trend may reverse and the specimen begins to fail. Subsequently the residual strain may become positive. However for a specimen subjected to the initial shear stress, the residual strain is always posinve. Based on the test results, a residual strain-degradation model was also proposed for anisotropic consolidated clay. The model incorporates the cyclic degradation and the accumulation of residual strain. Based on the model. Iwan＇s series parallel model was modified to model the stress strain behavior of the anisotropic consolidation soft clay.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2008年第6期1058-1064,共7页
Journal of Zhejiang University：Engineering Science
基金
国家自然科学基金资助项目(50478081)
关键词
应变软化
循环荷载
残余应变
各向异性固结
strain-degradation
cyclic loading
residual strain： anisotropic consolidation
