一种基于边界面的饱和软黏土弹塑性动本构模型  

An elastoplastic dynamic constitutive model for saturated soft clay based on bounding surface theory

作　　者：冯双喜 雷华阳[1,2,3] FENG Shuang-xi;LEI Hua-yang(Department of Civil Engineering,Tianjin University,Tianjin 300354,China;Key Laboratory of Coast Civil Structure Safety ofMinistry of Education,Tianjin University,Tianjin 300354,China;Key Laboratory of Comprehensive Simulation of EngineeringEarthquake and Urban-Rural Seismic Resilience,CEA,Tianjin 300354,China)

机构地区：[1]天津大学建筑工程学院土木工程系,天津300354 [2]天津大学滨海土木工程结构与安全教育部重点实验室,天津300354 [3]中国地震局地震工程综合模拟与城乡抗震韧性重点实验室,天津300354

出　　处：《岩土工程学报》2021年第5期901-908,I0005,I0006,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家重点研发计划项目(2017YFC0805407);国家自然科学基金项目(51890911,52078334)。

摘　　要：弹塑性动本构模型对循环荷载作用下路堤和地基基础的设计具有重要意义,构建兼顾实用性和通用性的动本构模型是目前岩土工程设计面临的主要问题。在临界状态和边界面理论框架下建立了综合表征饱和软黏土循环退化、非线性、滞回和变形累积特性的弹塑性动本构模型。在p’-q空间中,将参数n,ξ引入剑桥边界面方程,提出了反映水滴形和类椭圆形的广义剑桥边界面方程,统一了边界面形状。结合三角形相似原理建立了加载面和屈服面之间映射关系,形成了考虑循环退化模量场。通过常规的室内试验,确定了模型中9个参数。开展了等向循环加载和不等向循环加载的动三轴试验和数值模拟,分析了饱和软黏土应力-应变关系和应力路径,研究结果证明了试验结果与模型预测结果基本一致,模型可合理分析饱和软黏土的循环退化、非线性、应变累积和滞回特性。The elastoplastic dynamic constitutive model plays an important role in the design of embankment or foundation under cyclic loading.The main challenge in the design of geotechnical engineering is to establish a dynamic constitutive model which is practical and universal.Based on the critical state theory,an elasto-plastic constitutive model is established to characterize the cyclic degradation,hysteresis and deformation accumulation of saturated soft clay under cyclic loading.In the p’-q space,parameters n andξare introduced into the Cam-clay model,and the Cambridge bounding surface equations,which can reflect the shape of water drop and similar ellipse,are proposed.Based on the triangle similarity principle,the mapping relationship between the loading surface and the yield surface is established,and the cyclic degradation modulus field is formed.Nine parameters in the model are determined by the routine laboratory tests.To verify the correctness of the model,the dynamic triaxial tests and numerical simulations are carried out under the isotropic cyclic loading and the anisotropic cyclic loading.The stress-strain relationship and stress paths of the saturated soft clay are analyzed.The research results demonstrate that the test results are basically consistent with the predicted ones by the model,and the proposed model can correctly analyze the cyclic degradation,nonlinearity,strain accumulation and hysteresis characteristics of saturated soft clay.

关 键 词：饱和软黏土 动本构模型 边界面理论 广义剑桥边界面方程 循环退化 

分 类 号：TU43[建筑科学—岩土工程]