破碎花岗岩非达西渗流的试验研究  

Experimental Research on the Non-Darcy Flow in Cataclastic Granite

作　　者：贺香兰 周佳庆[1,2] 魏凯[1,2] 王敏[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,武汉430072 [2]武汉大学水工岩石力学教育部重点实验室,武汉430072

出　　处：《中国农村水利水电》2017年第9期150-155,共6页China Rural Water and Hydropower

基　　金：国家自然科学基金项目(51579188;51409198)

摘　　要：为研究破碎岩体的渗流特性和非达西流的判别准则,利用Triaxial Cell三轴试验系统将3组饱和完整花岗岩进行破碎,获取破碎岩体,开展不同围压条件下高水力梯度的渗流试验。试验结果表明,采用Forchheimer方程拟合水力梯度▽P与渗流流量Q的实测数据点,相关系数趋近于1,渗流表现出显著的非线性;随着围压的增大,Forchheimer方程拟合系数A与B呈上升趋势,即岩样渗透性降低,渗流非线性增强,并且破碎花岗岩的非达西系数β随着固有渗透率k的减小近似呈幂函数关系增大。利用该幂函数关系式提出一类能直观判定达西流和非达西流的指标参数——水力梯度比Φ_P和流量比Φ_Q,指标参数的选择和临界值的确定取决于不同工程的目标需求。In order to explore water flow in cataclastic rock and the criterion for non-Darcy flow, three intact granite samples were broken by the means of triaxial compression test, and then water flow tests were conducted in a triaxial cell under different confining stresses. The experiment results show that Forchheimer Equation adequately describes the relation between pressure gradient （VP） and flow rate （Q）, because all the correlation coefficients come close to 1. In other words, significant nonlinearity can be obtained in the water flow in cataclastic granite. Moreover, for a granite sample, Forchheimer Equation coefficients A and B gradually increase with an increase in confining stress, which means rock＇s permeability becomes lower and non-Darcy effect in seepage becomes stronger. More specifically, the non-Darey coefficient （β） approximately increases as a power function of decreasing intrinsic permeability （k） of cataclastic granite. Based on the power function, an intuitive criterion is proposed for distinguishing between Darcy flow and non-Darcy flow, which relies on the pressure gradient ratio （ Фp ） or flow rate ratio （ ФQ ）. How to choose a proper parameter from ФP and ФQ and then how to determine corresponding critical values depend upon the goal-oriented requirements for different projects.

关 键 词：破碎花岗岩 非达西流 Forchheimer方程 

分 类 号：TV131[水利工程—水力学及河流动力学]