粘土数值建模方法与Duncan模型的对比研究

以塑性体应变与塑性剪应变之间的相互作用原理为指导,对粘土本构关系的数值建模方法进行了研究。采用包含应力路径函数的两个本构泛函作为模型基本框架,可以反映出应力路径相关性。应力应变增量关系的表达式包含两个偏导数的交叉项,用于反映塑性体应变与塑性剪应变的相互作用。利用三轴试验结果建立了粘土的弹塑性本构模型,该模型能够反映出土的三大基本力学特性:压硬性、剪胀性和应力路径相关性。通过可视化,分别给出在整个应力场中剪切和体积的三维变形曲面。此外,从模型的理论基础、基本框架和预测结果等方面与Duncan模型进行对比,显示出数值建模方法优于传统方法。

Contrastive Study on the Method of Numerical Modeling and Duncan Model for Clay

Based on the principle of interaction between plastic volumetric strain and plastic generalized shear strain,the method of numerical modeling for constitutive relations of clay is studied.The two constitutive functionals including the function of stress path were used as the basic framework of constitutive model,which are able to reflect the dependence of stress path.The two cross terms of partial differential appear in the expression of stressstrain incremental relation,which are used to reflect the interaction between plastic volumetric strain and plastic generalized shear strain.The elastio-plastic constitutive model for clay is constructed by using the triaxial test results.The three basic characteristics of deformation for soils,pressure sensitivity,dilatancy and dependence of stress path are sufficiently described by the model.Through visualization,the three-dimensional surfaces of shear and volume strain in the whole stress field are respectively given.In addition,contrastive study on the method of numerical modeling and Duncan model is made on the aspects of rationale,basic framework and prediction results et al,which shows that the numerical modeling method is superior to the traditional one.