考虑裂隙的连通率、间距、孔隙基质和裂隙材料在表征单元(REV)中的体积分数,并假定双重孔隙-裂隙介质的等效内摩擦角保持常数,而等效黏聚力是固有黏聚力、等效塑性应变、基质吸力、溶质浓度及温度的函数,提出了一种在热-水-应力-迁移耦合条件下确定表征单元内任一平面上等效的黏聚力及内摩擦角的方法。针对一个假定的位于非饱和双重孔隙-裂隙岩体中的高放废物地质处置模型进行了数值模拟及分析。结果表明,基质吸力对于等效黏聚力的增强作用大于等效塑性应变和溶质浓度的减弱作用,使得等效黏聚力得到了提高,故减少了围岩中的塑性区;由此岩体应力、孔(裂)隙水压力及流速、孔(裂)隙溶质浓度的分布及量值也发生相应的改变。
Considering connectivity rate and spacing of fractures, volume fractions of pore matrix and fractured material in a representative element volume(REV), a method for determining the equivalent cohesion and internal friction angle is proposed under the condition of thermo-hydro-mechanical-migratory coupling. While the equivalent internal friction angle of the medium is assumed to be a constant, the equivalent cohesion will be a function of inherent cohesion, equivalent plastic strain, suction, solute concentration and temperature. A hypothetical disposal model for nuclear waste located in unsaturated dual-pore-fracture rock mass is analyzed and simulated with the proposed method. The results show that the enhancement for the equivalent cohesion by suction is larger than the weakening effect by equivalent plastic strain and solute concentration. The plastic zones in the surrounding rock mass reduce with the increasing of equivalent cohesion. Thus the distributions and values of rock mass stress, pressure and flow velocity of pore water and fracture water, solute concentration in pore and fracture also change correspondingly.