利用声波速度估算岩体不同深度的平均渗透系数

摘要

The depth-decaying hydraulic conductivity is a widely observed phenomenon and has a great control on groundwatcr flow. However, due to the limitations of testing method and the high cost, it is always difficult to establish the relationship between hydraulic conductivity and depth. Sonic velocity has been widely applied to obtain mechanical properties of rock masses. Due to its high resolution, it is practical to establish the relationship between sonic velocity and depth. In this paper, a granite rock mass is used as an example to analyze the relationship between mean p-wavc sonic velocity and mean hydraulic conductivity at different depths. A power law model and a negative exponential model are employed to fit their relation. This study indicates that the sonic velocity is a useful method to obtain the depth-decaying hydraulic conductivity.%含水层渗透系数具有随岩体深度衰减的特点,对渗流具有重要影响.但受试验方法及试验费用的限制,很难获取渗透系数与岩体深度的定量关系.声波速度测井通常用于间接获取岩石力学参数,且分辨率高,便于统计得到声波速度与深度的关系.以某花岗岩体为例,分析了不同深度纵波速度均值和渗透系数均值的相关性,建立了表征其相互关系的幂次率模型和负指数模型.研究表明,声波速度为获取不同深度的平均渗透系数提供了一种可靠方法.