基于时移电阻率法的平谷局部地区地下水时空特征研究

Spatio-temporal distribution of groundwater in the local area of Pinggu,Beijing derived using the time-lapse resistivity method

平谷平原区是北京市重要的地下水水源地之一。为了解地下水的时空分布特征且不破坏地层,在平谷区北杨家桥村开展了非侵入式的时移电阻率法温纳装置和偶极—偶极装置互换观测。剖面观测数据和其归一化数据的最小二乘法反演结果表明:研究区潜水含水层和承压含水层近似呈水平层状分布,潜水含水层从北侧补给,流向由北向南;整个观测期内潜水含水层水位下降且向下方承压含水层发生越流。在2021年4月24日至9月12日期间包气带含水量增加,承压含水层水量相对稳定,无明显变化。研究成果为该区域后续第四系和地下水研究工作打下基础,为该地区地下水的开发、管理和使用提供了重要参考,也为研究地下水动态过程提供了新思路。

The plain area in Pinggu is a major groundwater source for Beijing.To ascertain the spatio-temporal distribution of groundwa-ter in the study area without damaging the strata,this study,using the non-intrusive time-lapse resistivity method,conducted the recipro-cal measurements with Wenner and dipole-dipole arrays in Beiyangjiaqiao Village,Pinggu District.The least-squares inversion results of the profile observation data and normalized data show that:(1)the phreatic and confined aquifers in the study area are approximately horizontally stratified,with the phreatic aquifer being recharged from the north and flowing from north to south;(2)during the entire ob-servation period,the phreatic aquifer showed a drop in water level and leakage into the confined aquifer below;(3)the water content in the aeration zone increased from April 24,2021 to September 12,2021.In contrast,the water content in the confined aquifer remained relatively stable in this period,without experiencing significant changes.The results of this study lay the foundation for the subsequent research on Quaternary strata and groundwater in the study area.Moreover,they can be used as an important reference for the develop-ment,management,and utilization of groundwater in the study area and provide a new philosophy for research on the dynamic process of groundwater.