降雨对裂隙型岩溶含水系统演化影响的数值模拟研究

Numerical simulation of precipitation impact on fractured karst system evolution

本文在构建有降雨入渗及河流补给的裂隙型岩溶含水系统的概念模型基础上,采用有限差分数值方法,利用裂隙渗流立方定律及Dreybort(1996)经过实验总结出的碳酸钙溶蚀经验公式,定量地计算了裂隙型岩溶含水系统经过10 000年溶蚀的演化形态及岩溶泉的变化。模拟发现,岩溶含水系统的溶蚀主要发生在降雨入渗面处、河流补给处和岩溶泉的出露点附近。随着溶蚀的进行,岩溶含水系统的潜水位不断下降部分岩溶泉被疏干,通过计算岩溶泉汇流管道的隙宽变化,发现岩溶含水系统会出现明显的差异性溶蚀。在模拟过程中调节降雨量的大小发现降雨入渗对有河流补给的岩溶含水系统的演化影响并不显著。

The 10,000 years evolution of fractured karst system,which has precipitation infiltration and river recharge, is calculated using finite difference method, cubic law and Dreybort＇s （1996） empirical formula af- ter building on the conceptual model of fractured karst system The result shows that the dissolution of karst aquifer system mainly occurs in the point of precipitation infiltration, recharge rivers and karst springs. With the dissolution of the karst aquifer system, the water tables were declining and some of the karst springs were dry. We found that the number of precipitation infiltration does not significantly affect the evolution of fractured karst system which has river recharge.