气液二相非饱和岩体热–水–应力耦合模型及二维有限元分析

Modeling and 2D FEM analysis for coupled thermo-hydro-mechanical processes in vapor-liquid two-phase unsaturated rockmass

针对高放射性核废料地质处置中水及水蒸汽二相共存的非饱和孔隙岩体,根据相关的理论,推导了应力平衡方程、流体连续性方程及能量守恒方程,使用Galerkin方法将各控制方程分别在空间域和时间域进行离散,初步开发出了相应的分析热–水–应力耦合弹塑性问题的二维有限元程序。通过一个核废料处置概念库的计算认识到:高放废物地质处置后的几十年内,缓冲层中的温度及液相饱和度均上升,同时该区域内要出现明显的应力、孔隙水压力、温度、液相饱和度和气相饱和度的集中现象。

According to the related theory, the momentum equilibrium equation, the continuity equation for water, the energy balance equation and the elastoplastic matrix for the vapor-liquid two-phase unsaturated porous rockmass in geological disposal of the high level radioactive nuclear waste were established. By using the Galerldn method all the governing equations were discretized in the space domain and in the time domain respectively, then a two-dimensional FEM code for analysis of coupled thermo-hydro-mechanical elastoplastic processes was developed tentatively. Through the numerical computation for a conceptual nuclear waste repository it was shown that after geological disposal of the high level nuclear waste the temperature and the liquid phase saturation in the buffer zone would raise, and in the same zone obvious concentration phenomena of stresses, pore pressures, temperature, liquid phase saturation and vapor phase saturation would occur in scores of years.