基于应力响应包络的土体典型本构模型比较  

Comparison among some typical constitutive models for soils based on stress response envelopes

作　　者：黄文雄[1] 沈建[2] 

机构地区：[1]河海大学力学与材料学院,江苏南京210098 [2]河海大学土木与交通学院,江苏南京210098

出　　处：《岩土工程学报》2012年第3期508-515,共8页Chinese Journal of Geotechnical Engineering

基　　金：国家重点基础研究发展计划项目(2007CB714103);国家自然科学基金项目(11172088/A020304)

摘　　要：应力响应包络是本构模型切线刚度的一种几何表达,也是研究本构模型定性特征的有效工具。针对亚弹性、弹塑性及亚塑性等3种类型的土体本构模型,分别以邓肯模型、剑桥模型和Gudehus-Bauer模型为例,讨论了相应的应力响应包络形态,并比较了3类模型各自的特点。并且,通过分析不同模型的应力响应包络及其在主应力空间中的变化规律,说明了亚弹性模型用于模拟土体的加、卸载存在着本质缺陷;弹塑性模型在屈服面附近的中性变载和卸载响应存在一定的问题;亚塑性模型描述的土体切线模量随应变增量方向连续变化的特征比较合理,但简单亚塑性模型难以准确模拟土体不排水剪切应力路径。The stress response envelope,a kind of geometric representation for tangential stiffness of constitutive models,is an efficient approach for qualitative studies on characteristic features of the constitutive models.With regard to the typical constitutive models for soils falling in the categories of hypoelasticity,elastoplasticity and hypoplasticity,the Duncan model,the Cam-clay model and the Gudehus-Bauer model are taken as examples for this study.Stress response envelopes are presented with a discussion of the general features of the corresponding constitutive models.Comparisons are made for the characteristics of the models of three types.It is shown that the essential defects exist in the hypoelastic model for modeling soil loading and unloading.For the elastoplastic model,the model response to a change of loading direction at stress points near or on the failure surface is unrealistic.For the hypoplastic model,while the main feature of continuous dependence of the tangential stiffness on the direction of strain increment is expected,difficulty exists in simple formulation for capturing stress paths of soil tests in undrained conditions.

关 键 词：本构模型 应力响应包络 亚弹性 弹塑性 亚塑性 

分 类 号：TU43[建筑科学—岩土工程]