等应力增量比路径下接触面应变软化模型

等应力增量比路径单剪试验条件下，部分土体与结构接触面表现出明显的应变软化和剪胀特性。基于广义位势理论，将土与结构的接触面问题看作应力空间上的二维问题，势函数取法向应力和切向应力，用塑性状态方程取代传统的屈服面，建立等应力增量比路径条件下的土与结构接触面应力-应变软化模型。采用指数函数，拟合单向压缩试验中法向应力与法向应变的关系，采用复合指数函数，拟合应力比与切向应变的关系，采用另一复合指数函数，拟合法向剪胀分量与切向应变的关系。通过对拟合函数进行微分，确定模型中待定系数的求解方法。结合试验结果对模型进行验证，模型拟合效果良好，具有一定的合理性。

Strain softening model of soil-structure interface under constant stress increment ratio stress paths

In simple shear test,under the constant stress increment ratio(CSIR) stress path,some soil-structure interfaces have the mechanical properties of strain softening and shear dilatation.Based on generalized potential theory,an elastoplastic model for soil-structure interface under the CSIR stress path is proposed.In the model,soil-structure interface problem is regard as a two-dimensional mathematical question in stress field;normal stress and tangential stress are taken as two potential functions respectively,and plastic state equations are used to replace the traditional yield surface.Relation curves of normal stress and normal strain in axial compression tests is described by an exponential function;and relation curves of stress ratio and tangential strain in simple shear test is simulated by a complex exponential function.Then,another complex exponential function is presented to express normal dilatancy and tangential strain relation curves.Furthermore,the model undetermined coefficient expressions are got by the differential of above fitting functions.Finally,the model prediction results have been compared with experimental data;and the results show that the model is reasonable and practical.