地形起伏对高密度电法探测地下岩溶管道的影响试验研究

摘要

高密度电阻率法在岩溶区找水具有较好的效果,但岩溶区地形复杂,高密度电法受地形起伏影响较大.为了提高岩溶区高密度电法找水的勘探效果,掌握地形起伏对高密度电法影响的规律,本文采用高密度电阻率法微测系统,利用铜柱体模拟地下岩溶管道,研究地形起伏对高密度电法探测岩溶管道的影响.研究结果表明:高密度联合剖面法及高密度α2装置受谷地地形影响较大,容易在谷地中间产生虚假的低阻异常,矩形AMN和滚动MNB装置受地形影响较小;受谷地地形影响,高密度电法能勘探的有效异常体深度减小;同一电极距下,平地模型及谷地模型反演异常体顶部埋深均小于真实异常,横向宽度均大于真实异常,平地模型反演异常体的顶部埋深大于谷地模型反演异常体,横向宽度小于谷地模型反演异常体.%High-density resistivity method is effective in searching for water in karst areas.Due to complex topography condition in karst area,the high density resistivity method can be greatly influenced by the terrain fluctuation.In order to improve the prospecting its effect in water exploration,and mastering the regularity of the influence of the terrain fluctuation,this work uses a high-density micro-electrical measurement system and the copper cylinder model to simulate the karst pipe underground.It then studies the influence of terrain fluctuation on the high density resistivity method to detect the karst pipes.The results indicate that high density composite profile method and α2 device are greatly influenced by the valley topography.False low resistance anomaly can be easily appeared in the middle valley.Rectangular AMN and rolling MNB device are less affected by terrain.The exploration depth of high density resistivity method about the anomaly can be reduced by the valley topography.When the electrode spacing is fixed,the top depth of the inversion about the flat model and valley model is less than the true anomaly,but the transverse width is greater than the true anomaly.Otherwise,the top depth the inversion about the fiat model is greater than the valley model,the transverse width of the inversion about the flat model is less than the valley model.