岩石摩擦滑动中声发射的多普勒效应 |
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引用本文: | 马文涛 马瑾. 岩石摩擦滑动中声发射的多普勒效应[J]. 地震地质, 1995, 17(4): 311-317 |
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作者姓名: | 马文涛 马瑾 |
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作者单位: | 国家地震局地质研究所 |
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基金项目: | Acoustic emission; Doppler measurement; Seismic phase; Rock frictional test |
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摘 要: | 在双剪摩擦滑动实验中可观测到声发射的多普勒效应。对于单个声发射事件,顺断裂扩展方向上的探头可记录到较短周期的初动波半周期,而在断裂扩展反方向上的探头记录则反之,在扩展过程中,声发射前续波由初始破裂引起的前激波、声源破裂扩展的扩展相和停止相组成,显示出声源破裂有一由静到动的加速过程。而在时间序列上,声发射事件存在着3个阶段:较强声发射事件发生初期,前激波时间超前较长,停止相不明显,声发射源的破裂速度较慢;第二阶段停止相突出,扩展速度加快,前激波到时超前量减小;最后,在原初始半周期处叠加了较大振幅的高频波
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关 键 词: | 声发射 多普勒测量 震相 岩石摩擦试验 |
THE DOPPLER EFFECTS OF AE WAVEFORM IN ROCK FRICTION |
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Abstract: | The waveform of AE(acoustic emission)events during rock friction has been studied.112large AE events through AE transducers attached along the faults have been recorded by a multi-channel digital recording system.The Doppler effects are evident by the waveforms of large AE events. For example,the firsthalf cycle of acoustic wave at AE transducers 1~3 is longer and at AE transducers 4~6 shorter.So it is shown that the displacement propagates in direction from AE transducer 1 to AE trans-ducer 3 with a dimension of 5.1 cm.The first phase(fore-excitation wave),source spreadingphase and stopping phase can be easily distinguished from the waveform of AE events.The ve-locity of fore-excitation wave and stopping phase is the same as P-wave. According to the break-ing phase recorded in different channels the breaking velocity of AE source increases from 0km/sto 2.62 km/s.It shows that the large AE events have an accelerating breaking process.The waveform of different events in a sequence of AE |
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