瞬变电磁法在浅部地层分层划分中的应用

Application of transient electromagnetic method in stratification division of shallow strata

瞬变电磁法具有受地形影响小、异常响应强、形态简单、分辨能力强等优点,被广泛应用于含水地质体等探测。但不同的工作装置探测效果存在差异,通过对瞬变电磁法大定源回线装置和中心回线装置的探测效果对比试验,了解其装置特点和探测效果,为地质调查电磁法探测提供指导。试验探测表明:中心回线装置能够对浅部地层进行精细划分,但其探测深度受局限;大定源回线装置在地层精细划分探测方面效果较差,但其在深部地层探测方面却有独特的优势。在进行地质调查勘探时,可依据目标任务对工作装置进行组合,以达到最佳探测效果。

Transient electromagnetic method is widely used in detection of water bearing geological bodies because of its advantages such as small topographic influence,strong abnormal response,simple shape and strong resolution.However,the detection effect of different working devices was different.Through the comparative test of detection effect between the large fixed source loop device and the central loop device of TEM,it can be understood characteristics and detection effect of device,and to provide guidance for electromagnetic detection of geological survey.The test results showed that the central loop device can divide shallow stratum finely,but its detection depth was limited;the large fixed source loop device has poor effect in the fine division of stratum,but it has unique advantages in the deep stratum detection.In geological survey and exploration,the working devices can be combined according to target task to achieve the best exploration effect.