含水层的一种普遍规律:渗透系数随深度衰减

A Common Regularity of Aquifers: The Decay in Hydraulic Conductivity with Depth

国内外多个含水层的研究都发现渗透系数具有随深度衰减的规律。给出了多孔介质和裂隙介质中渗透系数随深度衰减的一般模型及简化模型,并用该简化模型分析了多个含水层的渗透系数随深度衰减的规律。研究发现,随着渗透系数测试深度的增大,衰减系数明显变小;渗透系数测试深度相近的含水层,岩性对衰减系数有一定程度影响。渗透系数随深度衰减的规律应该在地下水科学的相关研究中引起重视。

It has been reported many times that hydraulic conductivity decays with depth in aquifers throughout the world. In this paper, general models characterizing the decay of hydraulic conductivity with depth are given for porous media and fractured media, respectively. It is found out that the general models can be simplified by the exponential decay model under certain conditions and the decay exponent is convenient for describing the decay rate of hydraulic conductivity. Using this simplified model, the regularity of decay in hydraulic conductivity with depth in several aquifers with different depths of hydraulic conductivity measurements and lithology from different places around the world is analyzed. For aquifers with different depths of hydraulic conductivity measurements, the decay exponent decreases with the measurement depth. The decay exponent of aquifers with measurement depth of several meters is on the order of magnitude of 10-1 m-1, while that of aquifers with measurement depth of thousands meters is on the order of magnitude of 10-3 m-1. For aquifers with similar measurement depths, lithogy also has influence on the decay exponent of hydraulic conductivity. Therefore, the regularity of decay in hydraulic conductivity with depth should not be neglected in analyzing groundwater problems.