基于应变软化与剪胀性特征的粉砂土双硬化弹塑性本构模型  

A double hardening constitutive model for fine sands based on both the dilatancy feature and strain softening

作　　者：张宏博[1] 黄茂松[2] 宋修广[1] 

机构地区：[1]山东大学土建与水利学院,山东济南250061 [2]同济大学土木工程学院地下建筑与工程系,上海200092

出　　处：《山东大学学报（工学版）》2008年第6期55-60,共6页Journal of Shandong University（Engineering Science）

基　　金：国家自然科学基金资助项目(10272083);山东省自然基金资助项目(Y2007F35)

摘　　要：针对上海粉细砂不存在惟一临界状态线的特点,对传统的砂土本构模型进行了改进,提出了一个能合理描述剪胀性和应变软化特性的粉细砂弹塑性本构模型.该模型采用双屈服面形式,可同时反映剪切变形及压缩变形机理.模型对传统修正剑桥模型中的剪胀性公式进行了改进,考虑了状态转换应力比与初始有效围压的相关性.为了描述应变软化特性,提出了一个利用残余状态应力比和峰值应力比的应变软化公式,可较为合理地反映粉细砂的应变软化特性.通过对上海粉细砂的多组试验结果模拟,验证了本文模型的合理性和有效性.Aiming at the characteristic of Shanghai fine sands for which a unique critical state line does not exist,the traditional models for sands were modified and a constitutive model for fine sands was developed which can describe both dilatancy feature and strain softening reasonably.The two yielding surfaces can individually reflect shear deformation and compression deformation.The traditional dilatancy equation of Cam-clay model was modified and the relativity between the phase transformation stress ratio and initial effective pressure was considered.In order to describe the characteristic of strain softening,a strain softening equation using the stress ratio at steady state and peak state was formulated,which can preferably reflect strain softening of fine sands.The model was verified by several test results of Shanghai fine sands.The good predictions show the rationality and validity of the proposed model.

关 键 词：粉细砂 剪胀性 应变软化 双硬化 本构模型 

分 类 号：TU441[建筑科学—岩土工程]