在自主研制的孔隙介质热-水-应力耦合有限元程序中引入Taron等提出的颗粒聚集体的压力溶解模型,针对一个假设的实验室尺度且位于非饱和石英颗粒聚集岩体中的高放废物地质处置模型,拟定两种计算工况:(1)孔隙率和渗透系数是压力溶解的函数;(2)孔隙率和渗透系数均为常数,进行4a处置时段的数值模拟,考察了岩体中的温度、颗粒界面水膜及孔隙中的溶质浓度、迁移和沉淀质量、孔隙率及渗透系数、孔隙水压力、地下水流速和应力的变化、分布情况。研究结果表明:工况1计算终了时,压力溶解使得孔隙率和渗透系数分别下降到初始值的43%-54%、4.4%~9.1%。在核废料释热温度场的作用下,工况1、2中的负孔隙水压力分别为初始值的1.00~1.25倍、1.00~1.10倍,前者表现了压力溶解的明显影响;两种工况的岩体中的应力量值及分布基本相同。
The model of pressure solution for granular aggregates established by Taron et al is introduced into the FEM code for analysis of thermo-hydro-mechanical coupling in porous media developed by the first author. Aiming at a hypothetical model for nuclear waste disposal in an unsaturated quartz aggregate rock mass with a laboratory scale, two computational conditions are designed: (1) the porosity and the permeability of rock mass are functions of the pressure solution; (2) the porosity and the permeability are constants, then the corresponding numerical simulations for a disposal period of 4 years are carried out; and the states of temperatures, solute concentrations in the intergranular fluid film and at the pore space, removal and precipitation masses, porosities and permeabilities, pore pressures, flow velocities and stresses in the rock mass are investigated. The results show: at the end of the calculation in case 1, pressure solution makes the porosities and the permeabilities decrease to about 43%-54% and 4.4% -9.1% of their initial values; under the action of the release heat of nuclear waste, the negative pore pressures in case 1 and case 2 are about 1.0-1.25 and 1.0--1.1 times of the initial values respectively; so the former represents an obvious effect of pressure solution; the magnitttdes and distributions of stresses within the rock mass in the two calculation cases are much the same.