工程地质学报2018，Vol.26Issue(6)：1433-1438,6.DOI:10.13544/j.cnki.jeg.2017-348
高水压力作用下裂隙岩体渗透性的变化研究
EQUATIONS FOR PERMEABILITY VARIATION OF FRACTURED ROCK MASS UNDER HIGH WATER PRESSURE
摘要
Abstract
Hydraulic conductivity is an important parameter to describe the permeability characterization of fractured rock mass. It is often determined using the water pressure tests of borehole in hydraulic and hydro-power engineering. When the water pressure is very low, the permeability variation of rock mass is not obvious owing to its integrity and strength. But under high water pressure, its permeability would change obviously. The main reasons are that fractured apertures can be increased, some close fractures may be re-opened, and the small and unconnected fractures are penetrated between each other under the action of high water pressure. Changes of permeability would lead to some difficulties for seepage analysis, because hydraulic conductivity is often considered to be constant. The calculated hydraulic head and flux have great errors if the variation of permeability coefficient hasn't been considered. On the condition of high water pressure, the relationship between hydraulic conductivity of fractured rock mass and water pressure is deduced according to the Non-Darcy flow equation in this paper. Three equations for calculating hydraulic conductivity are provided here. The first equation is applied to the condition for low water pressure. The results of field water pressure test show that when the hydraulic fracturing of rock mass occurs, hydraulic conductivity increases obviously. It can be calculated through the variation of water flux and waterpressure. In this paper, variation characteristics of permeability coefficient before and after hydraulic fracturing are verified using the results of high pressure water test from pumped storage power stations. Field test results are used to calculate hydraulic conductivity of rock mass. A comparison is conducted for measured and calculated hydraulic conductivity values to validate the rationality of deduced equation. The errors between measured and calculated values are less than 15 percent and the average error is about 10 percent, which show the calculated hydraulic conductivity is basically in agreement with measured value. Expressions of hydraulic conductivity provide selection criteria of seepage analysis for hydraulic and hydro-power engineering or large deep tunnel project.关键词
高压压水试验/裂隙岩体/水力劈裂/渗透系数Key words
High water pressure test/Fractured rock mass/Hydraulic fracturing/Hydraulic conductivity分类
建筑与水利引用本文复制引用
黄勇,周麟桐,周志芳..高水压力作用下裂隙岩体渗透性的变化研究[J].工程地质学报,2018,26(6):1433-1438,6.基金项目
国家自然科学基金(41572209) （41572209）
江苏省青蓝工程项目(2016B16073)资助. （2016B16073）
