基于修正Mohr-Coulomb准则的弹塑性本构模型及其数值实施

An elastoplastic constitutive model based on modified Mohr-Coulomb criterion and its numerical implementation

针对Mohr-Coulomb准则高估岩土体抗拉性能的局限性,建立考虑最大拉应力准则的修正Mohr-Coulomb模型;系统地论述隐式本构积分算法的主要内容,推导相应的一致性刚度矩阵。以ABAQUS软件为平台,采用向后欧拉隐式应力积分算法编制了UMAT本构程序,对单轴拉伸试验和三轴压缩试验进行数值模拟,对比分析ABAQUS自带模型和自编模型的优劣,结果表明编写的修正Mohr-Coulomb模型能够有效地反映岩土介质的抗拉性能,弥补了ABAQUS自带模型的不足。

Due to the conventional Mohr-Coulomb criterion used for geotechnical materials with its limitation for overestimation of tensile performance, a modified Mohr-Coulomb model is established considering maximal tensile stress criterion. The main contents of the implicit constitutive integration algorithm are discussed systematically; and the consistent stiffness matrix is deduced. Based on the implicit Euler stress integration algorithm, the UMAT subroutine of the modified Mohr-Coulomb model is developed in ABAQUS. With the new developed model, the numerical simulation of uniaxial tensile test and triaxial compression test is implemented respectively. The study shows that the developed modified Mohr-Coulomb UMAT subroutine could effectively depict the tensile performance of geotechnical materials and fill up the deficiency of the Mohr-Coulomb model in ABAQUS.