基于高压压水试验的裂隙岩体非线性渗流参数解析模型  

An analytical model for nonlinear flow parameters of fractured rock masses based on high pressure packer tests

作　　者：刘明明[1,2] 胡少华[3] 陈益峰[1,2] 周创兵[1,2] 

机构地区：[1]武汉大学水资源与水电工程科学国家重点实验室,湖北武汉430072 [2]武汉大学水工岩石力学教育部重点实验室,湖北武汉430072 [3]武汉理工大学资源与环境工程学院,湖北武汉430070

出　　处：《水利学报》2016年第6期752-762,共11页Journal of Hydraulic Engineering

基　　金：国家自然科学基金项目(51222903;51179136;51579188);国家重点基础研究发展计划(973)项目(2011CB013503)

摘　　要：高渗压条件下裂隙岩体的渗透特性是高压引水隧洞近场渗流场分析与工程防渗设计的重要参数,一般通过现场钻孔高压压水试验获得。针对钻孔高压压水试验流量-压力曲线的非线性特征,建立了基于Forchheimer方程的裂隙岩体非线性渗流参数(渗透系数k和非线性系数b)解析模型。该解析模型中的渗透系数解析表达式与现行钻孔压水试验规程推荐公式一致,不仅形式简洁,而且物理意义明确,是现行规程推荐公式在非线性流条件下的拓展,可作为高压压水试验条件下钻孔压水试验规程修订的重要依据。对海南省琼中抽水蓄能电站高压岔管区钻孔高压压水试验成果的分析表明:Forchheimer方程很好地表征了高压压水试验过程中流量-压力曲线的非线性特征,本文提出的解析模型为高渗压条件下裂隙岩体非线性渗流参数的合理取值提供了有效的方法和手段,克服了现行钻孔压水试验规程对高渗压条件下裂隙岩体渗透性难以正确表征的局限和由此带来的工程防渗设计风险。The permeability of fractured rocks is an important hydraulic property for seepage analysis anddesign of seepage control system in the surrounding rocks around an underground tunnel subjected to highwater pressure. High pressure pack test（HPPT） is an effective technique for characterizing the permeabilityin the fractured rocks under high water pressure. Based on the nonlinear characteristics of the P-Q curves,a Forchheimer’s law-based analytical model was established to estimate the nonlinear flow parameters ofthe tested rocks（hydraulic conductivity k and nonlinear parameter b）. Given that the expression of k is con-sistent with the Hvorslev equation recommended in the currently-applied codes of borehole water pressuretests,the proposed model is hence an extension of the recommended formula from Darcy’s to non-Darcy’sflow condition. With its simple form and clear physical meaning,the proposed model could be treated asan important basis for revision of the codes of borehole water pressure tests under high injection pressures.The proposed model was validated against the in-situ measurement data obtained in the HPPTs conductedin the surrounding rocks of a branched tunnel section at a pumped storage power station located in Qiong-zhong County,Hainan Province. It is demonstrated that the nonlinear characteristics of the P-Q curves ob-tained in the HPPTs could be well interpreted by Forchheimer’s law,and the proposed analytical modelprovides an effective approach for reasonably evaluating the nonlinear flow parameters of fractured rock mass-es and reducing the risks in the design of a tunnel system under high water pressure condition.

关 键 词：裂隙岩体 渗透特性 高压压水试验 解析模型 非线性流 水力劈裂 

分 类 号：TV139.14[水利工程—水力学及河流动力学]