AMT静态效应和对导电薄层分辨能力的正演模拟

FORWARD MODELING FOR THE STATIC EFFECT OF AMT AND THE RESOLUTION OF CONDUCTIVE FOLIA

静态效应是AMT法在山区找水中不可回避的问题,第四系地下水勘查中人们有时更多关注隔水层黏土层的空间分布。针对这两个问题,利用二维有限单元数值模拟方法来讨论静态效应对TE、TM极化方式视电阻率曲线的影响以及对导电薄层的垂向分辨能力。研究表明:TM模式视电阻率受静态影响严重,TE模式视电阻率对深部地质体的反映优于TM模式;TM极化模式放大了横向上不同电性体的电性差别,在山区找水中对断层反映敏感;AMT对导电薄层的垂向分辨力与围岩的电阻率比值有关,加密点距,并不能提高垂向分辨率。

The static effect of the AMT method is an unavoidable problem in groundwater survey in mountainous areas. Nevertheless, people have often paid too much attention to the special distribution of clay layers in Quaternary groundwater survey. Focused on the above two problems, the authors applied 2D finite cell numerical modeling to simulating the influence of the static effect on the TE, TM polarized apparent resistivity curves and the vertical resolution of conductive folia.