摘要
基于SEAWAT-2000程序构建室内二维砂箱试验中咸水入侵数值模型,利用该模型分析了针对不同补给井井位、补给井流量、截渗墙位置及贯穿深度等多种情景下的咸淡水界面运移规律。二维砂箱实验模拟结果表明,当注水井位于盐水楔前锋附近,距咸水边界40 cm、砂箱顶部边界5 cm处时,注水井工程措施能达到最佳海水入侵驱退效果,回退系数达21.5%。当截渗墙布设于距咸水边界10 cm处,贯穿深度为35 cm时,截渗墙工程措施能达到最佳海水入侵驱退效果,回退系数达81.1%。在此基础上,结合实际场地条件,构建山东龙口地区滨海含水层中某典型二维剖面的海水入侵数值模型,探讨了不同截渗墙布设情景模式下海水入侵状况。模拟结果表明,当截渗墙布设于距海岸线600 m处,贯穿深度为18 m时,截渗墙工程措施达到最佳海水入侵驱退效果,回退系数达28.4%。研究结果揭示了补给井井位、补给井流量、截渗墙位置及贯穿深度等因素对咸淡水界面运移规律的影响,可为场地条件下滨海含水层海水入侵防治中的工程管理措施优化提供参考依据。
Seawater intrusion(SI)has become a global concern for groundwater environment.SI not only seriously threatens freshwater resources in coastal aquifers,but also undermines the balance of coastal ecosystem and further restricts the socioeconomic development.This paper simulates the SI process in a 2D synthetic aquifer constructed from sandbox experiment using the simulator SEAWAT-2000.The transport phenomenon of the brackish water interface is investigated by altering the location and injection rate of a recharge well and the layout of the physical barrier.The results show that when the recharge well is located near the toe of the salt water wedge of 40 cm from the coastline and 5 cm from the surface,the optimal performance of the recharge scheme is achieved with the repulsion rate up to 21.5%.When the physical barrier is located 10 cm from the coastline and the penetration depth is 35 cm,the toe of saltwater wedge is effectively driven to the coastline with the repulsion rate up to 81.8%.Moreover,we simulate the variable-density groundwater flow and transport in a typical twodimensional section of coastal aquifer in the Longkou District of Shandong Province.The SI model is established to evaluate the influences of different management schemes(i.e.,physical barrier and recharge well)on the prevention of seawater intrusion.The results show that when the physical barrier is located 600 m from the coastline and the penetration depth is 18 m,the toe of salt water wedge is effectively driven back to the coastline with the repulsion rate up to 28.4%.The results reveal the influence of hydraulic and physical barriers under different settings on the migration rule of the brackish water interface.The findings may provide insights into the optimization suggestions for coastal groundwater management under site conditions.
作者
吕盼盼
宋健
吴剑锋
吴吉春
LYU Panpan;SONG Jian;WU Jianfeng;WU Jichun(Key Laboratory of Surficial Geochemistry,Ministry of Education,School of Earth Sciences and Engineering,Nanjing University,Nanjing,Jiangsu 210023,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2021年第4期32-40,共9页
Hydrogeology & Engineering Geology
基金
国家重点研发计划“水资源高效开发利用”重点专项项目(2016YFC0402800)
国家自然科学基金项目(41772254)
中央高校基本科研业务费专项基金项目(14380105)。
关键词
海水入侵
数值模拟
SEAWAT
截渗墙
水力屏障
注水井
seawater intrusion
numerical simulation
SEAWAT-2000
flow barrier
physical barrier
recharge well
