地下水人工回灌气相堵塞特征的试验研究

地下水人工回灌可以高效地利用雨季丰沛的水量来缓解地下水过量开采造成的海水入侵、泉水断流等环境水文地质问题，但回灌堵塞一直是制约人工回灌效率的关键问题。针对雨洪水回灌携带的大量气泡问题，设计室内砂柱试验模拟装置，利用曝气水进行人工回灌，定时记录试验过程中测压管读数及出流流量，利用达西定律计算各层渗透系数，研究气相堵塞的发展过程和规律。结果表明:回灌过程中由于气相堵塞导致含水层渗透系数随时间呈指数衰减，气相堵塞主要发生在介质浅表层（0~30 cm），且随时间有向下发展的趋势，堵塞速率随深度的增加逐渐减小，在回灌过程中适时停灌进行排气有利于减小气相堵塞对回灌效率的影响。

Experimental studies on gas-clogging characteristics during groundwater artificial recharge

Groundwater artificial recharge has been widely used to effectively utilize abundant rainfall in rainy seasons for managing a number of environmental problems such as seawater intrusion and depletion of spring flow caused by groundwater overexploitation. However, physical clogging (including suspended solid clogging and gas clogging) is an important factor that may negatively affects efficiency of groundwater artificial recharge. To tackle the problem of gas-clogging (i. e., a large amount of bubbles contained in artificial recharge water), an indoor device for conducting column experiments is designed. A column is filled with sand of multiple layers, and the hydraulic conductivity of each sand layer is estimated based on the Darcy's law to investigate the processes and mechanisms of gas-clogging development. The laboratory results show that, due to gas clogging, hydraulic conductivity is not a constant but a temporal function of exponential decay. The results also show that gas clogging mainly occurs in the upper layer(0-30 cm)of the sand column, and that the clogging rate decreases gradually with depth. The results suggest that, to reduce the negative effects of gas clogging on efficiency of groundwater artificial recharge, it is necessary to occasionally pause recharge and to conduct degassing during the recharging processes.