砂土各向异性与非共轴特性的本构模拟  

Constitutive modeling of anisotropic and non-coaxial behaviors of sand

作　　者：陈洲泉 黄茂松[1,2] 

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土与地下工程教育部重点实验室,上海200092

出　　处：《岩土工程学报》2018年第2期243-251,共9页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(11372228);国家重点基础研究发展计划(“973”计划)课题(2012CB719803)

摘　　要：在考虑组构各向异性的砂土状态相关本构模型的基础上,引入了修正的非共轴流动法则建立了相应的非共轴本构模型。对于逆向加载的塑性问题,比如纯环剪加载,将通过引入边界面的概念进行处理。同时根据广义应力状态下的剪胀方程推导的塑性势面,建立了π平面内的非关联共轴流动方向。另外,将非共轴流动方向定义为同当前应力状态主方向正交的方向,并同共轴流动方向一样与塑性加载因子相关联。对Toyoura砂的空心圆柱两种加载模式的剪切试验,即固定主应力轴方向的单调加载和纯环剪切,进行了模拟,结果表明本模型能较好地描述砂土力学行为中的各向异性和非共轴特性。A non-coaxial constitutive model is proposed from the elasto-plastic constitutive model based on the state-dependent critical state model considering the fabric anisotropy of sand. The bounding surface plasticity is introduced to deal with the reversal loading condition, such as pure rotation shear tests. And a potential surface is derived from the multiaxial formulation of the dilatancy equation, indicating the non-associated coaxial flow direction in the π plane. In addition, the non-coaxial flow direction is redefined as the orthogonal direction of the current principal stress and is affected by plastic loading index just as the coaxial flow direction. Two types of loading modes of hollow cylindrical shear tests oan Toyoura sand are simulated by the model, namely tests with fixed principal stress axes and those with rotation of the principal stress axes. In comparison with the experimental data, the simulated results can reflect the characteristics of anisotropic plasticity and the variation of the non-coaxial phenomenon reasonably.

关 键 词：砂土 临界状态 状态相关组构各向异性 非共轴流动法则 弹塑性理论 

分 类 号：TU441[建筑科学—岩土工程]