基于伪随机信号的磁电法渗漏模型试验

Leakage model-based experimental study on magnetometric resistivity method combined with pseudo-random signal technology

磁电法是近些年在国内兴起的一种电磁勘探方法,该方法在探测地下渗流等长走向的良导地质体方面具有技术优势,但是其抗干扰能力差,易受外部噪声影响,一直未能推广。近年来,伪随机信号在物探领域开始广泛应用,该技术通过对冲激响应及阶跃响应进行卷积运算来达到降噪目的,可极大地提升抗干扰能力,因此,本文结合磁电法的勘探原理及伪随机辨识系统的辨识原理,提出将伪随机信号应用于磁电法中来提高其抗干扰能力,并通过渗漏模型试验来对其抗干扰情况进行分析,结合模拟计算结果验证其可行性。试验结果表明该方法降噪能力显著,可基本消除外部磁场干扰,在渗漏通道上方峰值处其相对误差小于3%,具有极强的抗干扰能力,为今后相关探测仪器的开发奠定了基础。

The magnetoelectric resistivity(MMR)method is a type of electromagnetic exploration method popular in China in recent years.It enjoys technical advantages in detecting long highly conductive geological bodies such as underground seepages.However,it is yet to be widely applied since it suffers poor anti-interference ability and is liable to be affected by external noises.In recent years,the pseudo-random signal technology has been widely used in the field of geophysical exploration.It allows noises to be reduced through the convolution operation of impulse and step responses,thus greatly improving the anti-interference ability.Based on the exploration principle of the magnetoelectric resistivity method and the principle of the pseudo-random identification system,this paper proposes the method of applying the pseudo-random signal technology to the magnetoelectric resistivity method to improve the anti-interference ability of the latter.Meanwhile,it analyzes the anti-interference effects through leakage model-based experiments,which have verified the feasibility of the proposed method.As indicated by the experimental results,the proposed method has remarkable noise reduction ability and can roughly eliminate the interference of external magnetic fields.Meanwhile,the relative errors at peaks above the leakage channel were less than 3%,indicating extremely strong anti-interference ability.This study lays a basis for the future development of related detection instruments.