关键词: 岩土力学, 孔隙气压, 热-水-气-应力耦合, 核废物, 地质处置, 有限元分析

Abstract:

In order to investigate the influence of pore gas pressure on the coupled thermo-fluid-mechanical processes in geological disposal of high-level radioactive nuclear waste, a 2D elastoplastic FEM code was developed by using the model of non-isothermal air flow and water flow in a deforming porous medium suggested by R. Leiws et al, in which an item of thermal water diffusion was added by the author. Against an assumed model of geological disposal of nuclear waste, the numerical simulations in which three kinds of original pore gas pressure in the buffer were applied, were carried out under the conditions of the same initial temperature, pore water pressure and in-situ stress. The distributions and changes of the principal stresses, saturations, fluid flow velocities, pore pressures and temperatures in near field of the disposal model were analyzed. The results show that the higher original pore gas pressure in the buffer gives a bigger effect on the stresses in rock.

Key words: rock and soil mechanics, pore gas pressure, thermo-fluid-mechanical coupling, radioactive nuclear waste, geological disposal, finite element analysis