弹塑性各向异性损伤模型的FLAC^(3D)开发与数值验证

Implementation and Numerical Verification of Elastoplastic-Anisotropic Damage Constitutive Model in FLAC^(3D)

探讨适用于硬岩的各向异性损伤模型在FLAC3D中的实现方法。首先,基于不可逆热力学框架下的弹塑性损伤本构基本理论,结合弹塑性力学塑性势与非关联塑性流动法则,导出了弹塑性各向异性损伤本构模型的增量形式及损伤演化速率的计算公式,在此基础上,采用复合M-C准则并考虑黏聚力随损伤的逐步弱化,详细给出了该损伤模型在FLAC3D中的实现流程并探讨了相关细节处理方法,编写了相应的DLL文件以供调用。进而,通过圆柱试样的压缩数值试验验证其正确性与合理性,结果表明该损伤模型能够较好地描述岩石材料的非线性力学行为;以一个概化的地下洞室分层开挖实例初步检验了模型的应用效果,计算所得洞周损伤较大部位与实际工程中直接或间接观测到的围岩损伤情况较为一致,由此表明以拉应变度量的损伤及其演化方程能够合理地反映硬岩的损伤本质。

The implementation of an anisotropic damage constitutive this paper. An incremental form of elastoplastic-anisotropic plastic mechanics theory and the elastoplastic-damage damage model in FLAC30 for hard rock is presented in constitutive equation is first deduced using the constitutive theory within the framework of thermodynamics of irreversible process. Meanwhile the concrete form of evolution rate of tence condition of damage damage tensor is determined by the consis- criterion. On the basis of these formulas, the detailed flowchart of numerical calculation by using the elastoplastic-anisotropic damage model and M-C yield criterion is established and some details about the numerical calculation are also discussed. A DLL（ Dynamic Link Library） file corresponding to the elastoplastic- anisotropic damage model is written to be called by the FLAC3D software. The uniaxial and triaxial compression nu- merical tests of cylinder sample are then conducted to test the validity of this user-defined model. The results show that this model is capable of describing the nonlinear behavior of hard rock. The validity of elastoplastic-anisotropic damage model in practice is further tested by applying it to a numerical simulation of staged excavation of a fictitious underground opening. in agreement with the Result show that the highly damaged zone around the opening determined by the simulation is actual observation in project area. The result also show that using the tensile strain tensor to measure damage and establish damage criterion grasps the nature of hard rock damage.