含杂质盐岩加载过程渗透特性及细观特征研究
Study on Penetration Characteristics and Mesoscopic Features of Impurity Salt Rock During Loading Process
作者：曾寅(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065;四川大学 水利水电学院, 四川 成都 610065)；刘建锋(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065;四川大学 水利水电学院, 四川 成都 610065)；徐慧宁(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065;四川大学 水利水电学院, 四川 成都 610065)；裴建良(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065;四川大学 水利水电学院, 四川 成都 610065)；徐杨梦迪(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065;四川大学 水利水电学院, 四川 成都 610065)；李志成(四川大学 水力学与山区河流开发保护国家重点实验室, 四川 成都 610065;四川大学 水利水电学院, 四川 成都 610065)
Author：ZENG Yin(State Key Lab. of Hydraulic and Mountain River Eng., Sichuan Univ., Chengdu 610065, China;College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China)；LIU Jianfeng(State Key Lab. of Hydraulic and Mountain River Eng., Sichuan Univ., Chengdu 610065, China;College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China)；XU Huining(State Key Lab. of Hydraulic and Mountain River Eng., Sichuan Univ., Chengdu 610065, China;College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China)；PEI Jianliang(State Key Lab. of Hydraulic and Mountain River Eng., Sichuan Univ., Chengdu 610065, China;College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China)；XU Yangmengdi(State Key Lab. of Hydraulic and Mountain River Eng., Sichuan Univ., Chengdu 610065, China;College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China)；LI Zhicheng(State Key Lab. of Hydraulic and Mountain River Eng., Sichuan Univ., Chengdu 610065, China;College of Water Resource & Hydropower, Sichuan Univ., Chengdu 610065, China)
收稿日期：2018-02-28 年卷（期）页码：2019,51(3):85-91
期刊名称：工程科学与技术
Journal Name：Advanced Engineering Sciences
关键字：杂质含量;盐岩;渗透率;体积应变;CT扫描;孔隙率
Key words：impurity content;salt rock;permeability;volumetric strain;CT scan;porosity
基金项目：四川省青年科技基金项目（2017JQ0003）；国家自然科学基金项目（51874202）
中文摘要
利用THMC岩石试验系统与工业CT，对不同杂质含量盐岩进行加载全过程气体渗透测试及加载前与破坏后的细观扫描，探讨了围压与杂质含量对含杂质盐岩加载过程渗透特性的影响。研究表明：杂质盐岩在5 MPa围压时的渗透率整体呈增大-平缓变化特征，但高杂质下的平缓期明显滞后杂质含量低的盐岩；在10 MPa围压时的渗透率具有下降过渡点，整体表现为增大-降低-上升至平缓的变化特征；围压对加载破坏过程中的渗透性具有显著影响，含杂质盐岩在10 MPa围压下破坏过程的渗透性，均比5 MPa围压状态下低约2～3个数量级。杂质含量低于45%时，杂质含量越高，破坏过程中渗透率越低；杂质含量超过45%时，破坏过程中的渗透率较高，量值与纯盐岩相当。杂质盐岩加载前的孔隙率约为1%，渗透破坏后增大了约10倍，加载破坏后高杂质盐岩与纯盐岩的孔隙率接近，杂质含量低的盐岩的孔隙率相对较低。研究获得了不同围压和杂质含量影响下渗透性差异的裂纹分布细观特征。低围压下的杂质含量低的盐岩呈单剪切面破坏特征，纯盐岩和高杂质盐岩呈共轭双剪切面破坏特征。导致破坏过程的渗透性较高；高围压下呈横向大变形特征，其破坏特征为裂纹方向与σ1方向一致的密集型微裂纹，破坏后的渗透性较低。
英文摘要
Using the THMC rock test system and industrial CT, the gas permeability test of the whole process of loading of salt rock with different impurity content and the pre-load and post-failure mesoscopic scanning were carried out. The influence of confining pressure and impurity content on the permeability characteristics of contaminated rock salt during loading was discussed. The results showed that the permeability of contaminated salt rock at 5 MPa confining pressure showed an overall increasing-pacing variation. However, the high-impurity looming phase obviously lags behind the low-content salt rock. The permeability at 10 MPa confining pressure had a declining transition point and the overall performance was increasing-decreasing-rising to flattening characteristics. The confining pressure had a significant effect on the permeability during the loading destruction process. The permeability of contaminated salt rock under a confining pressure of 10 MPa was about 2~3 orders of magnitude lower than that under 5 MPa confining pressure. When the impurity content was less than 45%, the higher the impurity content, the lower the permeability during the destruction process. When the impurity content exceeded 45%, the permeability during the destruction process was high, and the amount was equivalent to pure salt rock. The porosity of the impurity salt rock before loading was about 1%, and increased about 10 times after the infiltration damage. The porosity of the high-impured salt rock and the pure salt rock was close to that after the loading and destruction, however the porosity of low salt rock was relatively low. The microscopic characteristics of crack distribution under different confining pressure and impurity content under different influences were obtained. The low-concentration impurity content of low-salt rock was characterized by a single shear surface failure, and pure salt rock and high impurity salt rock showed the destruction characteristics of the conjugate double shear surface, resulting in high permeability of the destruction process. The high confining pressure was characterized by large horizontal deformation, and the failure characteristics were dense micro-crack with the direction of the crack in the same direction asσ1, and the permeability after failure was low.
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