层状介质中异质体变化散射波特征分析

Analysis of heteromer change scattering wave characteristics in layered media

在层状介质中,波在层交界面会产生一次以上多次反射,当浅部存在洞穴,瑞利波发生散射,浅部入射波场由瑞利波主导,其散射能量较强,分层介质中形成多模态瑞利波,不同模态瑞利波的位移随深度分布不同。鉴于此,基于散射波理论,采用数值模拟计算层状介质半无限体中瑞利波的产生及传播特征进行研究,建立层状介质含异质体(软、硬质体)半无限体模型,对层状介质中异质体散射波场的特征进行对比及时域和频域的分析,探究软、硬质体波场差异,提高探测地下异质体结果的精度。

In the layered medium,the wave will produce more than one and multiple reflections at the layered interface,when there is a cave in the shallow part,the Rayleigh wave scatters,the shallow incident wave field is dominated by the Rayleigh wave,its scattering energy is strong,and a multimodal Rayleigh wave is formed in the layered medium,and the displacement of different modal Rayleigh waves is distributed differently with depth.In view of this,based on the scattered wave theory,numerical simulation is used to calculate the generation and propagation characteristics of Rayleigh waves in the semi-infinite body of the layered medium for research,a semi-infinite model of heterosomes(soft and hard bodies)in layered media is established,and the characteristics of the scattering wave field of heterosomes in layered media are compared and analyzed in the time domain and frequency domain,explore the difference between soft and hard body wavefields,so as to improve the accuracy of detecting underground heteroms.