Modeling and Simulation for Complex Faults of Large-Scale Underground Caverns Based on FLAC3D

Abstract

A new methodology called fault-implied composite element is used to simulate complex geological faults in large-scale underground caverns to solve the difficulty in modeling. In the process of modeling, the rock and soil mass is meshed first without considering the influence of geological faults, then faults are plotted according to their locations and occurrences in the space and implicitly comprised in solid elements. During simulation and computation, the composite elements comprising rock material and fault material are equally treated according to the influence degree of faults, which not only can make the numerical discretization of underground caverns simpler but also effectively reflect the effect of faults on the stability of the surrounding rock of underground caverns. The elements passed by faults are regarded as a transversely isotropic medium, so the anisotropic elastoplastic damage finite difference method is used to calculate the element stresses. A secondary development is carried out on free lossless audio codec (FLAC) 3-D software platform, and applied in the underground caverns with complex faults in a hydropower station. The calculation result shows that this method provides a very effective idea of modeling and analysis for complex faults.