Response analysis and application of the TEM using small-fixed loops

Analyzing transient electromagnetic responses of typical geological anomalous bodies is crucial to improving the accuracy of interpretation. Because the self and mutual induction effects are difficult to calculate, the transient electromagnetic method (TEM) using small-fixed loops is challenging to obtain ideal induced electromotive force through numerical simulation. The existing related research lacks model tests; we have established five model tests were used to investigate the transient electromagnetic response using small-fixed loops to typical geological anomalous bodies based on the common construction accidents. Compared and analyzed the transient electromagnetic inversion results of the central loop and the small-fixed loops before and after correction. The results show that both the central loop TEM and the TEM using small-fixed loops observation data could well reflected the geological anomalous bodies. Compared with the central loop results, the corrected TEM using small-fixed loops has a more accurate response to anomalous bodies and can better delineate its spatial distribution and shape characteristics. The research results effectively guide the practical engineering application and obtain good detection results. Theory and practice show that compared with the traditional central loop transient electromagnetic detection, the TEM using small-fixed loops has higher exploration efficiency and detection accuracy of typical geological anomalous bodies.