非线性法向变形节理对岩体电磁辐射传播的影响研究

STUDY OF EFFECT OF NONLINEAR NORMAL DEFORMATION JOINT ON ELECTROMAGNETIC EMISSION(EME) INTENSITY INDUCED BY STRESS WAVE

为了明确非线性节理对岩体电磁辐射传播过程中强度的影响,从压电效应机制出发,给出含石英等压电介质岩体在应力波作用下所产生的电磁波与入射应力波之间的关系。并依据两者之间的关系及应力波在非线性节理面的透反射解,获得应力波作用下岩体电磁辐射强度变化与节理参数之间的关系表达式。同时,研究节理的变形和入射波频率对电磁辐射强度的影响。结果表明,在震源中心,电磁辐射强度最大,随传播距离发生衰减。电磁辐射强度随节理变形增大而增大;并且随着传播距离的增大,高频电磁信号衰减比低频信号衰减要快得多。

In order to study the effect of the nonlinear joint on intensity of the electromagnetic emission（EME） during propagation process, the relationship between induced EME and incident stress wave was presented based on piezoelectric effect mechanism. According to the obtained relationship and the resolution of transmitted and reflected coefficients when the normal incident P-wave propagated to the nonlinear normal deformation joint, the relational expression between the intensity variation of EME and parameters of joint was obtained. And the effects of parameters such as joint deformation and incident frequency of wave on the intensity variation of EME were investigated. It is shown that the intensity of the EME induced by stress wave was the highest in the explosion-center and attenuated with the propagation distance; the intensity of the EME increased with the joint deformation; the higher frequency EME attenuated faster than the lower frequency signals.