核废料处置概念库开挖及封闭后近场热-水-应力耦合数值分析

Numerical analysis of thermo-hydro-mechanical coupling in excavation and after closure for near field of conceptual nuclear waste repository

考虑了缓冲层中温度梯度水分扩散、水蒸汽扩散对水连续性及能量守恒的影响,进一步完善了饱和-非饱和介质中热-水-应力耦合现象的控制方程。应用缓冲材料的实验资料,对核废料处置概念库开挖及封闭后近场的热-水-应力耦合过程进行了数值模拟,以考察围岩中的位移、塑性区、主应力、孔隙水压力和温度的分布及变化。认为开挖是引起洞室围岩中的变形及应力重新分布的主要原因,但坑道封闭后的热-水-应力耦合过程对变形及应力状态也产生了明显的影响。

considering especially the influence of the thermal water diffusivity and the isothermal vapor diffusivity on the continuity of water and the energy balance, the author improved further the established control equations for analyzing coupled thermo-hydro- mechanical phenomena in saturated-unsaturated porous media. Using the experiment data of the buffer material and the 2D FEM code developed by the author, a numerical simulation for the coupled thermo-hydro-mechanical processes in near field of a conceptual nuclear waste repository in excavation and after closure is carded out; and the distributions and the changes of the displacements, plastic zones, principal stresses, pore pressures and temperatures in the surrounding rockmass are investigated. The computation results show that the excavation is the main reason for the displacements and redistributions of stress in surrounding rockmass of a cavern; and the coupled thermo-hydro-mechanical processes after the cavern closure also produce obvious influence on the displacements and stress states in the rockmass.