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DEVELOPMENT OF LONG-TERM ROCK MONITORING SYSTEM AND ITS APPLICATION TEST

岩石长期监测系统研制及应用试验

基本信息

批准号：
06555311
负责人：
YAMATOMI Jiro
金额：
$ 5.57万
依托单位：
THE UNIVERSITY OF TOKYO
依托单位国家：
日本
项目类别：
Grant-in-Aid for Developmental Scientific Research (B)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

项目摘要

Development of a long-term rock monitoring system and its application test is the purpose of the present research project. The employed method for rock monitoring is to detect AE signals emitted around micro-scaled fracturing, which can be used to predict a large-scaled instability inrock mass.First, we have made a couple of AE sensors incorporating operational amplifiers and highpass filters ; they were designed to be installed in drilled holes in rock mass and their performances were also examined in the laboratory.Three kinds of rocks were uniaxially compressed and elongated to induce microscopic fractures in order to check whether our handmade AE sensors can detect any AE signals and identify any characteristics of AE wavetrains and spectra. It was found, there were two types of AE signals. One of them has a predominant frequency around 100 kHz and the other one has low frequency components around 50 kHz. We could not find clear correlation between AE characteristics and failure modes/rock types, however. From the tensile experiments on same kinds of rocks, one of distinctive features of AE signals is found to be high frequency components superimposed on low frequency ones. However, it was impossible to identify whether these signals are inherent in extension tests. Moreover, source location tests were also conducted in the laboratory to examine the applicability of the monitoring system in in-situ.Finally, we have had in-situ measurements of propagation velocity of AE and attenuation constant in the Tochibora Mine of Kamioka Mining & Smelting Co.Ltd., in Gifu prefecture. Wecould obtain successful results about field measurements and confirm the reliability of the developed AE monitoring systems ; however, it was unfortunate that none of naturally induced AE were picked-up during the site examination. We hope that the present research may contribute to further investigation and development of long-term rock monitoring.

本课题的目的是研制一套长期的岩体监测系统并进行应用试验。岩石监测的方法是检测微尺度破裂周围发射的声发射信号，它可以用来预测大尺度的岩体失稳。在实验室中对三种岩石进行了单轴压缩试验，为了检查我们的手工AE传感器是否可以检测到任何AE信号并识别AE波列和光谱的任何特征，我们将拉伸以诱导微观断裂。发现声发射信号有两种类型。其中一个具有约100 kHz的主导频率，另一个具有约50 kHz的低频分量。然而，我们无法找到AE特征与破坏模式/岩石类型之间的明确相关性。通过对同类岩石的拉伸实验，发现声发射信号的一个显著特征是低频成分与高频成分的叠加。然而，无法确定这些信号是否是扩展测试中固有的。此外，还在实验室进行了声源定位试验，以检验该监测系统在现场的适用性。最后，我们在神冈矿业冶炼有限公司的Tochibora矿进行了AE传播速度和衰减常数的现场测量，在岐阜县。我们可以获得成功的现场测量结果，并确认开发的AE监测系统的可靠性，但不幸的是，没有自然诱发的AE在现场检查。我们希望本研究能有助于岩石长期监测的进一步研究和发展。