热-水-应力耦合影响的有限元分析

为了考虑应力拉压和压力（化学）溶解对裂隙开度的综合影响，对所建立的双重孔隙-裂隙介质热-水-应力耦合模型中裂隙开度的计算模型作了改进。通过一个假定的高放废物地质处置库算例，就岩体裂隙开度变化的3种工况，分析了岩体中的温度、孔（裂）隙水压力、地下水流速和主应力的变化、分布情况。结果显示：3种工况的计算域中温度场基本相同；孔（裂）隙水渗流场形态相似，但其量值有一定差别；工况1的裂隙开度在应力和压力（化学）溶解的共同作用下闭合量最大，负孔（裂）隙水压力增值最高；核废物的释热效应明显地改变了岩体自重应力场的水平分量，但对其垂直分量影响较小。

Finite element analysis of influence of pressure solution of fracture aperture on T-H-M coupling in dual-porosity medium

In order to consider the composite impact of mechanical dilation/compaction and pressure solution on fracture aperture, the coupled thermo-hydro-mechanical model for dual-porosity medium established by the first author was improved. Taking a hypothetical nuclear waste repository as a calculation example, three coupled THM cases in which fracture aperture changes with different patterns were simulated numerically by FEM. The variations and distributions of temperatures, pore (fracture) pressures, flow velocities of underground water and normal stresses in the rock mass were investigated. The results show: the temperature fields of three cases are near the same; the forms of seepage fields of three cases are similar; but their quantity values have some differences; the closure degree of fracture apertures under the combined action of stress and pressure solution in case 1 is the maxmium one; so the negative pore pressures in this case are the highest; the liberated heat from vitrified waste changes obviously the horizontal component of gravity stress field of rock mass, but exerts smaller effect on the vertical component.