岩体高压压水试验的渗透系数取值方法探讨

Study on the determination of permeability coefficient of fractured rock mass under high pressure test condition

在高压压水试验条件下岩体渗透系数的取值是工程渗流分析关键参数之一。通过对高压压水试验孔周围岩体中的水流形态分析,推导出利用压水孔压力、流量以及附近渗压孔的水压力计算岩体渗透系数的公式。利用某工程高压压水试验资料,应用本文推荐的渗透系数计算公式和现行压水试验规程中推荐的公式等进行计算对比研究。研究成果表明当高压压水条件下岩体中水流仍满足层流假定时,本文推荐的公式可以用于岩体高压渗透系数的估计。

Permeability coefficient of fractured rock mass under high pore pressure is one of the key parameters for seepage analysis.In this paper,a formula of permeability coefficient of fractured rock mass is derived through an analysis on the time variations of water flow in rock mass around the pressure borehole,based on the measured data of high pressure permeability test such as borehole discharge and pore pressure of the rock mass near the borehole.Calculations of permeability coefficient with the proposed formula under the test conditions of a practical project are compared with that of the pressure test standard.This study indicates that the proposed formula gives a good estimation of the permeability coefficient in the laminar flow case.