【摘要】 介绍了声电效应的物理基础和利用声电效应进行隧道地震波场物理模拟的可行性研究.基于制作的人工冻砂半空间隧道物理模型和虚拟仪器技术的同一观测平台的声声观测方法与声电观测方法,采用不同的观测排列分别采集了声声直达信号、声声反射信号、声电直达信号、声电反射信号.应用时域分析和频域分析技术对所采集信号进行处理,分离出来自反射界面的纵横波直达声信号、纵横波反射声信号和纵横波直达声电转换信号、纵横波声电转换反射信号.研究结果表明,相对于声声信号,声电信号采集受固有频率限制小,频谱明显拓宽,时间波列大为缩短,信号分辨率提高,有效的克服了窄带声传感器对隧道地震波场信号采集的影响.此外,由于声电观测中的采用电极接受,电极直径一般为2～3mm,尺度远远小于声传感器,极大改善了声声观测中由于大尺度换能器带来的模型尺度、耦合性能等诸多方面的困难,增强了隧道地震波场物理模型观测精度.更多还原

【Abstract】 This paper introduces the mechanism of seismoelectric effect and its feasibility for stnding of tunnel seismic modelling.Using both acoustic-acoustic and acoustic-electric methods based on the same platform built by the virtual instrument technology,we have measured the direct arrival of acoustic-acoustic signals,the reflective acoustic-acoustic signals,the direct arrival acoustic-electric signals,the reflective acoustic-electric signals from a half-space tunnel model made with artificial frozen sand.Then,the data were processing and analyzed by using time-domain analysis and spectral analysis methods,and the separation of direct arrivals of P-wave and S-wave,reflective arrivals of P-waves and S-waves signals of the tunnel seismic model were achieved.The results show that the acoustic-electric conversions signals is widely broadened,comparing with the spectrum of acoustic-acoustic signal.This is due to the receive electrode has limitation.As a consequence,the latter wave trains are much shorter,which greatly improves the signal resolution.Moreover,as the size of the receive electrode can be made in very tiny scale,usually its’ diameter being about 2-3mm which is much smaller that of a acoustic transducer,the problems of model size and coupling et.at.,caused by large size of acoustic transducer with acoustic-acoustic measurement can be effectively solved,so that the observation accuracy of the seismic modelling are enhanced.更多还原