摘要
岩石渐进破坏伴随着裂纹的开展发育,岩石的渗透性演化与裂纹的开展规律有着密切的联系。运用三轴渗流伺服装置对凝灰岩进行了不同围压和渗压下的渗流-应力耦合试验,分析了岩石在渐裂过程中不同裂纹开展阶段渗透率的演化规律。结果表明:在裂纹的稳定扩展阶段,渗透率的变化不明显,起裂强度对应的渗透率可用于确定最小渗透率;进入裂纹非稳定扩展阶段后,渗透率出现明显增大,增大过程可以分为两个阶段,裂纹环向应变能较好地反映渗透率增大的两个阶段,其拐点可用于确定起始渗透率的位置;在峰后软化阶段,渗透率出现下降并进入残余稳定阶段,裂纹环向应变率可以反映渗透率的下降阶段,并可用于确定峰值渗透率的位置。
Rock progressive failure is usually accompanied by development of cracks. The propagation behaviour of rock cracks is closely related to the evolution of rock permeability. In order to investigate the permeability properties of rock during progressive failure, a series of hydro-mechanical triaxial coupling tests is carried out on tuff specimens under different confining pressures and seepage pressures using triaxial servo-controlled seepage equipment. Based on the experimental results, the following conclusions are drawn. At the stable crack growth stage, the permeability keeps low and stable and the permeability corresponding to crack initiation strength can be used to determine the minimum value of permeability. At the crack unsteady growth stage, the permeability increases significantly and the increase of permeability can be divided into two stages, which can be reflected by crack circumferential strain. The inflection point of crack circumferential strain curve is used to identify the initial permeability. At the softening stage after failure, the permeability decreases and enters into a residual stable stage, which can be reflected by crack circumferential strain rate. The circumferential strain rate can be used to determine the position of the peak of permeability.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2016年第10期2761-2768,2779,共9页
Rock and Soil Mechanics
基金
国家重点基础研究发展计划(973)项目(No.2011CB013504)
国家自然科学基金项目(No.11672343
No.51479193)
中央高校基本科研业务费专项资金资助(No.2016B20214
No.2016B08014)~~
关键词
岩石渐进破裂
裂纹扩展
起裂强度
损伤强度
渗透率演化
progressive failure of rocks
crack propagation
crack initiation strength
damage strength
permeability evolution
