关键词: 应力腐蚀, 压力溶解, 饱和度修正, 双重介质, 热-水-应力(T-H-M)耦合, 有限元分析

Abstract: For the models of stress corrosion and pressure solution used in the 2D finite element method(FEM) code of thermo-hydro-mechanical coupling analysis for dual-porosity medium developed by the authors, a correction factor for water saturation is introduced. Aiming at a hypothetical model for geological disposal of nuclear waste located at a water-bearing stratum, three computation conditions with different initial fracture saturations were designed(Sw20=1.0、0.8、0.2), then the corresponding two-dimensional numerical simulation for the coupled thermo-hydro-mechanical processes were carried out; and the states of temperatures, rates and magnitudes of aperture closure, pore and fracture pressures, flow velocities and stresses in the rock mass were investigated. The results show：With the change of initial fracture saturation from high value to low value, the closure rates caused by stress corrosion and pressure solution vary from fast to slow, and the times of fracture aperture tending to its residual value and contact-area ratio of asperity tending to its nominal area from their initial values also increase, as well as the drop in stress intensity factors slows down; the changes and distributions of fracture and pore pressures in near-field as well as the states of flow vectors have obvious distinctions; the magnitudes and distributions of stresses within the rock mass in three calculation cases make little difference.

Key words: stress corrosion, pressure solution, saturation correction, dual-porosity medium, thermo-hydro-mechanical coupling, finite element analysis