高应力下花岗岩耦合节理在剪切过程中渗透率演化特性  

Permeability evolution of coupling granite joint during shearing under high-stress condition

作　　者：张强[1,2] 李小春 胡少斌[3] 牛智勇 汪芳[4] 范坤 邵光强[5] ZHANG Qiang;LI Xiao-chun;HU Shao-bin;NIU Zhi-yong;WANG Fang;FAN Kun;SHAO Guang-qiang(State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;University of Chinese Academy of Sciences,Beijing 100049,China;College of Civil and Transportation,Hohai University,Nanjing,Jiangsu 210098,China;Research Institute of Petroleum Exploration and Development,Beijing 100083,China;Tarim Oil Field Company,CNPC,Korla,Xinjiang 841000,China)

机构地区：[1]中国科学院武汉岩土力学研究所岩土力学与工程国家重点实验室,湖北武汉430071 [2]中国科学院大学,北京100049 [3]河海大学土木与交通学院,江苏南京210098 [4]中国石油勘探开发研究院,北京100083 [5]中国石油塔里木油田公司,新疆库尔勒841000

出　　处：《岩土力学》2018年第10期3641-3650,共10页Rock and Soil Mechanics

基　　金：国家重点研发计划项目(No.2016YFB0600805);中国清洁发展机制基金赠款项目(No.2014069)~~

摘　　要：节理滑移时其渗透率的演化特性是岩体水力特性重要的科学问题之一。为了深入了解花岗岩节理在高应力条件下剪切滑移时渗透率的变化规律,对花岗岩耦合节理剪切时的渗透率进行了试验研究。为了解决剪切时高压孔隙流体的密封问题及节理渗透率测量问题,设计了一种适用于高压孔隙流体作用下的剪切渗流试验系统。通过剪切渗流试验获得了渗透率随剪切位移的变化规律,以及剪切应力和法向变形与剪切位移的关系。试验结果表明:高应力条件下剪切峰后节理发生明显的剪胀,但其渗透率呈降低趋势;节理剪切过程中节理的剪胀、压缩和凸起的剪断磨损机制共同影响渗透率的变化;高应力一方面限制了节理的剪胀特性,另一方面也增强了凸起的剪断磨损机制,因此,节理剪切时节理渗透性被显著降低。Permeability evolution of the joint is a key scientific problem for the hydraulic characteristic of rock mass. To further understand the permeability variation of coupling granite joint during shearing under high normal stress, the permeability of coupling granite joint was measured during shearing. To solve the sealing problem of high-pressure pore fluid during shear and the measurement of joint permeability, we designed a shear flow testing system for high-pressure porous fluid. Shear flow tests were conducted to obtain the variation of permeability with shear displacement, and the relationship between shear stress/normal deformation and shear displacement. Experimental results show that the joint permeability tends to decrease after shear stress peak under high-stress conditions, though dilatancy occurs during shearing. During the shearing process, the damage mechanism of dilation, compression and asperities contribute to the change of permeability. Under high-stress conditions, the dilatancy characteristics of joints are limited, but the shearing mechanism of asperities is enhanced. The joint permeability under joint shear is thus reduced.

关 键 词：裂隙 剪切滑移 高应力 渗透性 压力脉冲法 

分 类 号：TU432[建筑科学—岩土工程]