地下水人工回灌过程中多孔介质悬浮物堵塞实验

地下水人工回灌技术的发展与推广常因其回灌过程中物理、化学及生物作用产生的入渗介质堵塞现象而受到严重制约。针对堵塞现象中最常见且最主要的悬浮物堵塞问题，采用室内模拟实验方法，通过将悬浊水连续注入均质的石英砂柱中，来刻画多孔介质中悬浮物堵塞的现象及发生的过程，并分析其发展规律，同时量化计算了堵塞速率。实验结果表明：回灌15 h左右表层介质渗透系数开始降低,即堵塞在表层开始发生，并随时间增加不断向深部发展;连续回灌100 h后表层渗透系数趋于稳定，进入介质内部悬浮物的量减少，内部堵塞发展也趋于稳定，此时堵塞主要在入渗深度10 cm左右的范围内。计算不同堵塞层的堵塞速率λ:表层0～1 cm的λ最大，为0.038 3 h^-1，λ随入渗深度增加而减小。对于介质整体的渗透性而言，其降低明显滞后于表层介质，但随时间发展主要受堵塞层的控制。

The Porous Media Clogging Due to Suspended Solid During the Artificial Recharge of Groundwater

Techonology and development about the groundwater artificial recharge have been limited by clogging due to physical, chemical or biological reactions during recharge. Laboratory column was used to describe the clogging process by injecting water with suspended particles into virgin quartz sand. The results indicated that clogging occurred at the beginning of the reduction of the hydraulic conductivity(K) in the upper layer, and extended deeper to about 10 cm until about 100 h when K of the upper layer became steady. The calculated clogging rates(λ) of different layers decreased with depth, the largest value of which is 0.038 3 h^-1 in the upper 1 cm. Moreover, the overall hydraulic conductivity began to fall later than the surface layer, and increasingly affected by the clogging layer within the time.