Prediction of underground water channel in southwest karst area based on depression cone curve equation

Abstract

[Objective] In order to investigate the potential existence of karst water channels within the depression cone area, and to provide solutions for addressing collapse risks in karst regions and groundwater flow issues near inadequate waterproof or intermittent curtains, [Methods] taking the Panlong lead-zinc mine area in Guangxi as a case study, the theoretical value(difference)of the water level at the observation point is calculated using the descending funnel curve. By comparing and analyzing the differences between the theoretical and measured(difference) values, along with on-site drilling and collapse data, a prediction of the underground water channels in the karst region will be made. [Results] The result prove that the proposed method can accurately predict the karst water channel. [Conclusion] In a karst aquifer that forms a stable depression cone, when the measured water level of a borehole is lower than the theoretical value(h_Measure<h_Theory), or when the measured difference exceeds the theoretical difference(Δh_Measure>Δh_Theory), it indicates the presence of a karst water channel at the borehole. The concept of the landing funnel is introduced, suggesting that the relative aquifuge within the influence range of the funnel alters the horizontal distance of the measurement points outside the aquifuge. The adjusted distance should be represented as l+r. The diffraction characteristics of the cone of depression can indicate the presence of runoff channels within the adjacent aquifuge.</h

Keywords

southwest karst areas / Dupuit presupposition / falling funnel / water conducting channel / diffraction characteristic / influencing factors