基于FLAC^(3D)的改进Burgers蠕变损伤模型的二次开发研究

Second development of improved Burgers creep damage constitutive model of rock based on FLAC^(3D)

岩石的流变变形对于岩质边坡和地下结构产生重要影响,其时效特性越来越引起人们的关注。然而通用分析软件所提供的岩石流变本构模型均有其特定的使用范围,往往不能满足工程数值分析的需要。考虑到岩体中参数劣化造成的影响,采用了一个变参数的改进Burgers蠕变损伤模型,该模型认为岩体的蠕变参数是随时间因子逐渐弱化的,这弥补了FLAC3D自身流变模型的不足,并利用FLAC3D(Version2.1)提供的二次开发程序接口,分析了蠕变损伤模型二次开发程序运行的基本原理,给出了该模型具体的程序框图和代码编写中应该注意的关键问题。介绍了该模型的几种退化形式,通过算例分别验证了该模型黏弹性、塑性和损伤的力学性质,分析了损伤参数对蠕变曲线的影响,并由此介绍了验证流变模型二次开发程序正确性的一般步骤。由于采用了面向对象的编程技术,FLAC3D二次开发接口简单实用,研究思路可为其他流变本构模型的二次开发提供参考。

Time-dependent deformation behavior of rock has a significant impact on the stability of rock slopes or underground constructions,and more and more attention is paid to the rheology of rock. However,most rock rheological constitutive models supplied by FEM software have specific usage,and the requirement of engineering numerical analysis can not be satisfied. In this paper,the deterioration effect of the rock parameters is considered and an improved Burgers creep damage constitutive model with variable parameters is established. In this model,the creep parameters of the rock deteriorate with time gradually that makes up the defect of rheology models in FLAC3D. Based on the second development program interface of FLAC3D Version 2.1 software,the basic principle of the second development program for the creep damage is analyzed. The program flow diagram on the special execution of this rheological model and several case techniques that should be taken into account in the process of code compiling are given. Several degradation modes of this model are introduced; and visco-elasticity,plasticity and damage mechanical characters are got through a numerical example. The influence of damage parameters on creep curve is analyzed; and the approach to verify the right and credibility of the second development program compiling is proposed. The second development environment is more friendly and effective with the support of object-oriented approach. Therefore,proposed design mode can bring forward references for the second development of other rheological models.