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A study on piezoelectric effect of Rock

岩石压电效应的研究

基本信息

批准号：
09450383
负责人：
OKUBO Seisuke
金额：
$ 4.22万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Electromagnetic (EM) signal emitted from compressed and/or fractured rocks has been studied for many years. Some kinds of rocks contain many piezoelectric materials, for example, quartz. Therefore some researchers consider the piezoelectric effect as the dominant cause of the EM signals.An experiment was carried out in which EM signal was emitted from a block of granite which contains a lot of quartz. The block of granite was manually impacted with a hammer ; a shockless hammer or a standard steel hammer. As a result of the experiment, it was found that EM signal was emitted on hammering. The first phase of the. observed EM signal was similar to strain measured by strain gauge affixed on the steel hammer. EM signal was also observed simultaneously by the electric robes on the surface of the block. Each electric robe was located at position separated by a distance from the hammered point. No time lag or delay was observed in this case. The primary/peak value of the observed voltage was inversely proportional to the distance from the hammered point. The same results were observed in all directions through the experiments. The later part of the EM signal was similar to the elastic wave observed with an acoustic emission (AE) sensor. The elastic wave signal observed with the AE sensor was delayed in proportion to the distance from the hammered point. It can be concluded that the EM signal is relatively large and potentially used for civil or mining purposes.

多年来，人们一直在研究受压岩石和/或破裂岩石发出的电磁信号。有些种类的岩石含有许多压电材料，例如石英。因此，一些研究人员认为压电效应是产生电磁信号的主要原因。对一块含有大量石英的花岗岩块发射电磁信号进行了实验。这块花岗岩是用锤子、无震动锤子或标准的钢锤手动撞击的。实验结果表明，锤击过程中产生了电磁信号。第一阶段。观测到的电磁信号与安装在钢锤上的应变片测得的应变相似。同时，块表面的电袍也观察到了电磁信号。每件电袍都放置在与锤击点相隔一段距离的位置。在这种情况下，没有观察到时间延迟或延迟。观测电压的初级/峰值与距锤击点的距离成反比。通过实验在各个方向上都观察到了相同的结果。电磁信号的后半部分类似于用声发射(AE)传感器观测到的弹性波。用声发射传感器观测到的弹性波信号与距锤击点的距离成比例地延迟。可以得出结论，电磁信号相对较大，可能用于民用或采矿目的。