超固结土的蛋形弹塑性本构模型  

Egg-shaped elasto-plastic constitutive modeling for over-consolidated clay

作　　者：蒋佳琪 徐日庆[1,2] 裘志坚 詹晓波[4] 汪悦 成广谋 JIANG Jia-qi;XU Ri-qing;QIU Zhi-jian;ZHAN Xiao-bo;WANG Yue;CHENG Guang-mou(Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China;Engineering Research Center of Urban Underground Space Development of Zhejiang Province,Hangzhou 310058,China;Hangzhou Metro Group Co.Ltd,Hangzhou 310020,China;Zhongtian Construction Group Co.Ltd,Hangzhou 310008,China)

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江省城市地下空间开发工程技术研究中心,浙江杭州310058 [3]杭州市地铁集团有限责任公司,浙江杭州310020 [4]中天建设集团有限公司,浙江杭州310008

出　　处：《浙江大学学报（工学版）》2021年第8期1444-1452,共9页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(41672264);浙江省重点研发计划资助项目(2019C03103).

摘　　要：为了描述超固结软土在不同应力条件下的强度变形特征,以蛋形函数为基本框架,建立并发展适用于超固结土体的弹塑性本构模型.通过对一系列超固结土应力路径三轴压缩试验结果的分析,探讨土体在超固结状态下塑性应变的发展规律(剪胀/剪缩).在先前提出的旋转塑性势面流动法则基础上对其进行发展与改进,引入峰值应力比,构建剪胀状态下归一化塑性势面旋转角与应力状态参数之间的近似线性关系,以满足超固结土的塑性变形特性.结合基于等效硬化参量的广义塑性功硬化原理构建超固结软土的蛋形弹塑性本构模型.将三轴压缩试验数据与数值预测结果进行对比以验证模型有效性,结果表明该模型可以有效反映超固结软土在不同加载条件下的应力应变特性,比如软化与剪胀.An elasto-plastic constitutive model suitable for over-consolidated clay was established within the framework of egg-shaped function,to describe the strength and deformation characteristics of over-consolidated soft clay under different stress conditions.Firstly,the development of plastic strain(dilatancy or contraction)for clay under over-consolidation state was analyzed according to the test results from a series of stress path triaxial compression test.Meanwhile,the previously proposed rotational plastic potential flow rule was developed to meet the plastic deformation characteristics of over-consolidated soils by introducing the peak stress ratio and constructing approximate linear dependence between the normalized plastic potential rotational angle and the stress state parameter under dilatancy.Then the egg-shaped elasto-plastic constitutive model for over-consolidated clay was be well established by introducing a generalized plastic work hardening principle in which the equivalent hardening parameter was employed.Finally,the validity of this model was demonstrated by comparison between test data and model prediction of triaxial compression test.Results show that the proposed model can effectively reflect the stress-strain characteristics of over-consolidated clay under different loading conditions,such as softening and dilatancy.

关 键 词：超固结软土 应变软化 剪胀 蛋形本构模型 旋转塑性势面 广义硬化原理 

分 类 号：TU43[建筑科学—岩土工程]