人工抽水对滨海潜水含水层咸淡水分布的影响

Influences of groundwater pumping on unconfined coastal aquifers

为了研究人工抽水对滨海潜水含水层的影响,采用二维渗流槽试验模拟非完整井抽水对咸淡水界面的影响。抽水导致咸水升锥的形成和海水入侵,结合图像处理技术,用海水楔长度和面积随时间的平均变化率定量表征海水入侵的速率。结果表明,在海水楔平衡后,咸水升锥位于抽水井靠近向海边界一侧。抽水量为34.8mL/min时,咸水楔的顶端与井底处在同一水平面上,最终抽水井出水中海水的含量基本恒定。在此基础上进行抽水恢复试验表明,停止抽水后海水楔可基本恢复至抽水前的状态。无论是在抽水还是停止抽水后,相对于总体变化趋势,海水楔长度的变化均滞后于海水楔面积的变化。

The two-dimensional seepage tests are performed to investigate the influence of groundwater pumping on the unconfined coastal aquifers in which a partially penetrating well was located above the saltwater wedge. The pumping groundwater leads to the saltwater up-coning and the seawater intrusion. Based on the image analysis processing, the average varying rate of the length and the area of the saltwater wedges with the time is used. The results indicate that the saltwater up-coning is located on the side of the seaward boundary when the equilibrium state is reached. The top of the saltwater up-coning and the bottom of the well are almost on the same horizontal plane when the pumping rate is 34.8mL/min and the steady- state saltwater content of pumped water is essentially constant. The saltwater wedge can return to the state before pumping after the pumping is stopped. The change of the saltwater wedge＇ s length lags behind the change of the saltwater wedge＇ s area concerning the overall trends.