Forward simulation and engineering application of transient electromagnetic detection of soil embankment leakage disease

Abstract

Leakage is a frequent disease in earthen dykes. Transient electromagnetic method is expected to achieve high efficiency detection in the low resistance area of deep seepage in dykes. The finite element method is used to simulate the diffusion process of the transient electromagnetic field inside the dam, reveal the response law of the transient electromagnetic measurement curve to the low resistance area of leakage, quantify the change of the magnetic induction intensity of the channel with and without leakage, and finally carry out field tests combined with practical projects. The result show that the transient electromagnetic field diffuses ellipsoid inside the dam, and the magnetic field distribution is relatively concentrated and the magnetic induction intensity increases greatly in the low-resistance area of leakage during a specific time period, which presents a local convex shape and obvious volume effect on the multi-channel map. In the process of response, the magnetic induction intensity decreases logarithmically, and the response of the leakage area in the embankment can be highlighted by using the relative deviation value. Through field test and comparison of core drilling, the transient electromagnetic method can effectively detect the low resistance zone of leakage, and the multi-channel map of relative deviation value and apparent resistivity map can directly show the distribution of low resistance zone inside the dam.

Keywords

dam leakage / transient electromagnetic method / multichannel map / numerical simulation / engineering application