Experimental characterization and micromechanical modeling of damage-induced permeability variation in Beishan granite
Experimental characterization and micromechanical modeling of damage-induced permeability variation in Beishan granite
复制标题
北山花岗岩损伤引起的渗透率变化的实验表征和微观力学模拟
DOI：
10.1016/j.ijrmms.2014.07.002
复制
发表时间：
2014-10-01
影响因子：
7.2
通讯作者：
Jing, Lanru
中科院分区：
文献类型：
--
作者：
Chen, Yifeng;Hu, Shaohua;Jing, Lanru
对甘肃北山地区450-550 m深的花岗岩岩心进行了三轴压缩试验和渗透率测定。北山花岗岩的渗透率随应力-应变的变化规律为：微裂纹闭合区渗透率明显降低，弹性区渗透率保持不变，裂纹扩展区渗透率显著增加。随着偏应力的增加，渗透率增加两个数量级以上，直至试样破坏;但在给定的偏应力下，渗透率随围压的增加而显著降低。通过将微观结构变化的机理与渗透率变化联系起来，提出了一个经验上限渗透率模型，该模型能很好地模拟实验结果。结合现场地质特征和数值模拟，讨论了实验结果对我国高放废物处置的启示。(C)2014爱思唯尔有限公司版权所有。
Triaxial compression tests with measurements of permeability were performed on core granite samples taken at 450-550 m depth from the Beishan area in Gansu Province, a potential site for China's high-level radioactive waste (HLW) disposal. Corresponding to the distinct features in the stress-strain behaviors, the permeability of the Beishan granite was found to evolve with a clear permeability decrease in the initial microcrack closure region, a constant permeability value in the elastic region and a dramatic permeability increase in the crack growth region. The permeability increases by up to and over two orders of magnitude as deviatoric stress increases up to sample failure; but at a given deviatoric stress, the permeability reduces remarkably with the increase of confining pressure. An empirical upper bound permeability model was presented by relating the mechanisms involved in the microstructure alteration to the permeability change, and the experimental results were well simulated by the proposed model. Combined with field geological characterization and numerical simulation, the implications of the experimental results for China's HLW disposal were discussed. (C) 2014 Elsevier Ltd. All rights reserved.