太行山贫水区含水层结构物性特征研究

Study on geophysical characteristics of aquifer structures in Taihang Mountain water-shortage area

选取太行山地区几个贫水县市作为典型研究区,采用激电测深法、超高密度电阻率法等物探方法进行地下水勘查工作,针对石家庄西邻太行山沿线变质岩、页岩、灰岩及第四系沉积区等地质条件,总结了不同岩性地层的含水层结构的物探特征。在对已知“靶区”的电法勘查工作总结后发现:①在基岩区,电阻率曲线的斜率在完整的基岩中基本呈近45°延伸,在遇含水的破碎带时曲线会出现变缓顿挫的“台阶”状;②在黏性土所占比重较大的地区,由于黏土的低阻特性与地下水体较为接近,仅仅依靠电阻率值和电阻率曲线形态难以对水量进行判断,还需要考虑所在测点位于冲积扇的方位,同时要结合地下水体的极化特性对极化率数据加以研究和利用。实践证明,运用以上的研究成果取得了很好的勘查结果,保证了钻探工作的成功率,既解决了老百姓的用水难题,又节省了钻探成本。

Several counties and cities of water-shortage area in Taihang Mountain area were selected as the typical research areas.In the study,the groundwater survey was carried out by geophysical methods such as electric bathymetric method and ultra-high density resistivity method.Based on the geological conditions such as the lithologic characteristics of metamorphic rocks,shale,limestone and Quaternary sedimentary areas along the Taihang Mountains in the west of Shijiazhuang,the geophysical characteristics of aquifer structures composed of different lithologic strata were summarized.The results of the study showed that:First,in the bedrock area,the slope of the resistivity curve basically extends by nearly 45°in the intact rock;it shows“stepped”shape of slope in the case of a water-bearing fracture zone.Second,in the areas with large proportion of viscous soil,because the low resistance characteristics of clay are relatively similar to those of underground water bodies,it is difficult to judge the amount of water by relying solely on the resistivity value and the resistivity curve form,it is necessary to consider the location of the measurement point in the alluvial fan,and make a deep research and utilization of polarization rate with the combination of the polarization characteristics of underground water bodies.Practice has proved that with the application of above research results,we have achieved good exploration results and ensured the success rate of drilling work,which not only solved the problem of water use by the people,but also saved the drilling cost.