关键词: 压力溶解, 颗粒聚集岩体, 弹塑性模型, 热-水-应力耦合, 有限元分析

Abstract: This paper introduces the model of pressure solution for granular aggregates established by Taron et al. into the finite element code for analysis of thermo-hydro-mechanical (T-H-M) coupling in porous media developed by the first author. Using the Mohr-Coulomb yield criterion, a hypothetical disposal model for nuclear waste located in a saturated quartz aggregate rock mass with a laboratory scale is simulated. Two computation cases, the elastic analysis and the elastoplastic analysis are designed. Then the corresponding numerical simulation for a disposal period of 4 years is carried out. The states of temperatures, solute concentrations in the intergranular fluid film and at the pore space, migration and precipitation masses, porosities and permeabilities, pore pressures, flow velocities and stresses and plastic zones in the rock mass are investigated. It is shown that, because of the stress adjustment and the increased molecular diffusivity in the elastoplastic analysis, there are obvious changes of solution, migration and precipitation of aggregate medium in the plastic zones, and the seepage field (including pressures and flow velocities of pore water) and the stress field are markedly influenced. But the differences of solution, migration and precipitation of aggregate medium in the elastic zones for two cases are not significant.

Key words: pressure solution, aggregate rock, elastoplastic model, thermo-hydro-mechanical coupling, finite element analysis