非拘限含水层之水力传导系数模糊特性

Fuzzy property of hydraulic conductivity in unconfined aquifer

地下水流于非拘限含水层流动时,因含水层之非均质性,使得垂直平均之饱和水力传导系数随地下水水位高低而变化。本研究就屏东平原之水文变量及边界条件等已知资料,利用MODFLOW模式计算屏东平原之地下水水位与水力传导系数之相关性。并运用模糊理论之模糊集与归属函数,分析水力传导系数在指数函数变换下,其所具有之模糊归属函数分布特性。由分析可知,屏东平原各地下水位观测站井之水力传导系数随地下水位变化具模糊关系。因此,在进行现地地下水流数值模拟时,水力传导系数不能只假设为单一值。

While groundwater flows through an unconfined aquifer due to heterogeneity, the vertical average saturated hydraulic conductivity is a function of hydraulic head. In this study, the MODFLOW model was used to calculate the relation between hydraulic head and hydraulic conductivity in Pingtung Plain. The hydraulic conductivity was transformed with exponential function to examine the distribution properties of fuzzy function. The result shows that the variation of hydraulic conductivity with the changes of groundwater head in observation wells in Pingtung Plain is of fuzzy properties. This analysis indicated that the hydraulic conductivity could not be assumed as a constant value when groundwater flow was simulated with numerical model.