(1. State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan,Hubei 430072,China;2. Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering,Ministry of Education,
Wuhan University,Wuhan,Hubei 430072,China)
Abstract:High pressure packer test(HPPT) is an important field technique for estimating the permeability of rocks subjected to high seepage pressure. Up to now,no effective method has been proposed to estimate the permeability of rocks subjected to high seepage pressure and the estimation is still commonly performed based on the Darcy?s law as assumed in the constant head packer tests(CPTs). A formula for estimating the permeability of rocks through single borehole HPPTs was established based on Izbash?s empirical nonlinear equation between the apparent velocity and the hydraulic gradient. The P-Q curve obtained from HPPTs was divided into a linear,a nonlinear and a hydraulic fracturing stage correspondingly,where P is seepage pressure,and Q is seepage quantity. The proposed formula was validated against the in-situ measured data obtained in HPPTs performed to the surrounding rocks of the underground bifurcated pipe at Qiongzhong pumped storage power station. It was discovered that the permeability of rocks was not influenced by the flow pattern,and the estimated permeabilities in the linear and nonlinear stages basically had the same values. As the hydraulic fracturing occurred,however,the permeability increased drastically. The proposed formula provides an effective method for permeability estimation in rocks subjected to high seepage pressure.
孟如真1,2,胡少华1,2,陈益峰1,2,周创兵1,2. 高渗压条件下基于非达西流的裂隙岩体渗透特性研究[J]. 岩石力学与工程学报, 2014, 33(09): 1756-1764.
MENG Ruzhen1,2,HU Shaohua1,2,CHEN Yifeng1,2,ZHOU Chuangbing1,2. PERMEABILITY OF NON-DARCIAN FLOW IN FRACTURED ROCK MASS UNDER HIGH SEEPAGE PRESSURE. , 2014, 33(09): 1756-1764.
中华人民共和国行业标准编写组. SL31—2003水利水电工程钻孔压水试验规程[S]. 北京:水利电力出版社,2003.(The Professional Standards Compilation Group of People′s Republic of China. SL31—2003 Code of water pressure test in borehole for water recourses and hydropower engineering[S]. Beijing:Water Recourses and Electric Power Press,2003.(in Chinese))
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