地下水开采诱发海水入侵特征试验研究

Experimental Study of Seawater Intrusion Induced by Groundwater Exploitation

为明晰滨海地区地下水开采诱发的海水入侵过程及特征,利用高密度电阻率成像技术为主要数据获取方法的物理砂箱试验,从四维时移电阻率图像角度分析了地下水开采诱发海水入侵特征。结果表明,在获取的电阻率图像中,海水入侵区呈明显的低阻楔形体,对应的咸淡水分界面电阻率值为25Ω·m,该等值面的动态变化反映了海水入侵过程和特征;地下水开采诱发的海水入侵优先作用于入侵楔形体中下部并引起局部海水升锥现象,持续开采底部出现海水回退,并逐渐向含水层浅部发展,最终在入侵侧抽水井附近形成一近似垂向分界面。

In order to further clarify the process and characteristics of seawater intrusion induced by groundwater exploitation in coastal areas,sand box test by high-density resistivity imaging technology as the main data acquisition method was analyzed to seawater intrusion induced by groundwater exploitation from the perspective of four-dimensional timeshifted resistivity image.The results show that the seawater intrusion area appears as obvious low resistance wedge in the obtained resistivity image,the corresponding resistivity values recorded water interface is 25Ω·m.The dynamic changing of the isosurface reflected the seawater intrusion process and characteristics.The seawater intrusion induced by groundwater exploitation has priority on the middle and lower part of the aquifer,which leaded to the cone-rising phenomenon in the middle of the seawater wedge and the regression phenomenon at the bottom of the aquifer,then gradually develops to the shallow part of the aquifer,and finally forms an approximate vertical boundary surface near the pumping well at the invasion side.