管道-裂隙岩溶含水介质非均质性的水文效应

Hydrologic Effects Caused by the Heterogeneity of Karstic Conduit-Fissure Medium

非均质性是含水介质的固有特性之一,对自然界的水文循环,地球浅层地质演变具有积极的贡献,因此是评价复杂地下水系统时所面临困难的最根本原因。通过SWMM模型对水文过程进行了室内模拟试验,研究了管道-裂隙岩溶含水介质非均质性对系统水文过程的影响。结果表明,管道尺寸、含水介质空隙度和地下水与地表水水量交换系数对系统出口处的水位和流量过程的影响均较小,但管道尺寸对地下水的最高水位有一定的控制作用;含水介质空隙度对地下水水位的增长和消落过程有一定影响;地下水与地表水水量交换系数则是对地下水水位的变化率和其能达到的最大值有着重要的影响。模拟结果证实,利用SWMM模型模拟管道-裂隙含水系统的水文过程是有效的。

The heterogeneity is one of the essential properties of karstic medium, which has significance on the natural hydrologic cycle and geologic evolution of shallow layer of earth. Therefore, the heterogeneity is the basic reason for the occurrence of difficulty in the evaluation of groundwater flow system. The SWMM model developed by EPA （U. S. Environmental Protection Agency）was used in this study to simulate the hydrologic process conducted in the laboratory, which investigated the effects of the heterogeneity of karstic conduit-fissure medium on the hydrological processes. The results indicated that the conduit size, the porosity of medium,and the exchange between groundwater and surface water have slight effects on the water level and discharge at the outlet of drainage area,but the conduit size plays an important role in controlling the highest groundwater level. Moreover, the porosity of medium can affect the increasing and decreasing processes of groundwater level, and the exchange coefficient between groundwater and surface water can affect significantly the variation rate of groundwater level and the highest value of groundwater level. The model results suggested that the SWMM model is applicable to simulate the hydrological processes of the karstic conduit-fissure system.