弹塑性损伤蠕变模型的有限元数值实施

Finite Element Numerical Implementation of Elastoplastic Damage Creep Model

利用有限元软件ABAQUS为平台,采用隐式应力积分回映算法编制了UMAT子程序。对不同围压下的三轴压缩试验和蠕变试验进行有限元数值模拟,并与试验结果进行对比分析,结果表明所编写的本构模型数值模拟结果与试验结果非常接近,可以有效反映软岩的力学特性,丰富了ABAQUS的材料库。采用该模型对地下开挖进行数值计算,得到了岩体表面的位移关系和洞口顶部的下沉随时间的变化规律,结果表明该子程序是正确和可信的,可以为地下工程分析提供合理的建议。

Based on the implicit stress integration return mapping algorithm, the UMAT subroutine of the elastoplastic damage creep model is developed in FEM software of ABAQUS. Compared with experimental data, the numerical simulation of triaxial compression test and creep test is implemented in FEM respectively, it shows that the simulation results of the developed constitutive model is very close to the experimental results which proves that the UMAT can be used to accurately simulate the mechanical characteristics of the soft rock and overcome the deficiency of the model in ABAQUS. Using the constitutive model, the numerical analysis is applied to underground excavation, the displacement on the surface and the variation with time of the top of tunnel settlement are obtained. These results indicate that the developed UMAT is correct and reliable which can provide reasonable suggestions in underground engineering.