基于亚塑性模型的砂土直剪试验研究

Numerical simulation of sand direct simple shear test based on hypoplastic model

介绍具有独特建模思想的Gudehus-Bauer亚塑性模型理论,该模型以非线性张量为基础,自动隐含弹塑性理论中的屈服面、塑性势、流动法则、硬化定律等概念和假设。基于Gudehus-Bauer亚塑性理论,对直剪试验进行合理假设,建立砂土直剪试验的数值模型,并对不同初始孔隙比下砂土的直剪试验进行数值模拟,验证了该模型的适用性。通过直剪试验的数值模拟研究发现,Gudehus-Bauer亚塑性数值模型不仅能分析不同孔隙比砂土的非弹性、非线性及剪胀(剪缩)等力学特性,而且能很好地反映砂土在循环受力状态下的应力应变演化规律。

The Gudehus-Bauer hypoplastic constitutive theory is introduced in detail.This model is based on nonlinear tensorial functions and has automatically implied some basic concepts and factitious assumptions such as yield function,plastic potential,flow rule,hardening law.Based on Gudehus-Bauer hypoplastic model,a hypoplastic model of direct simple shear test is presented by making reasonable assumptions for shear test.The rationality of the model is verified by simulation of direct simple shear test of sand in the different original void ratios.Besides,the numerical simulation of direct simple shear test was illustrated and the results show that the model not only can grasp the main mechanical properties of the different void ratio of sand,e.g.unelasticity,nonlinearity,dilatancy(shrinkage)and so on,and can simulate the mechanical characteristics of sandy soil under cyclic stress.