高密度电法在勉县城市浅层地下水调查评价中的应用

Application of High-density Electrical Method in Investigation and Evaluation of Urban Shallow Groundwater in Mian County

勉县位于汉江流域上游,是国家南水北调工程汉江流域的重要水源涵养区,同时也是引汉济渭工程的直接水源地。该文利用高密度电法在勉县城区开展浅层地下水调查评价工作,结果表明:勉县城区浅层地下水主要赋存于连续稳定、孔隙度大、储水空间充足的含砾石中粗砂层中;第四系潜水含水层埋深从山前至汉江逐渐变浅,富水性逐渐增强;第四系潜水含水层厚度较为稳定,在40~60m之间;勉县地区地表地层中卵砾石层持水性差,为透水层,一般不含水或弱含水,含砾石砂层为储水层,黏土、粉质黏土为隔水层。

The Mian County is located in the upper reaches of the Hanjiang River Basin.It is an important water conservation area in the Project of South-to-North Water Transfer.At the same time,it is also the direct water source of the Han Wei River Diversion Project.In this paper,the investigation and evaluation of shallow groundwater in Mian County urban area is carried out by using high-density electrical method.The results show that the shallow groundwater in Mian County urban area mainly exists in the medium coarse sand layer containing gravel with continuous stability,large porosity and sufficient water storage space;The burial depth of the Quaternary phreatic aquifer gradually becomes shallower from the front of the mountain to the Hanjiang River,and the water yield gradually increases;The thickness of Quaternary phreatic aquifer is relatively stable,between 40~60m;The pebble gravel layer in the surface stratum of Mian County has poor water holding capacity.It is a permeable layer,generally free of water or weak water.The gravel sand layer is a water storage layer,and the clay and silty clay is an impermeable layer.