基于超声波平测的巷(隧)道岩爆破裂演化试验研究

Experimental Study on Fracture Evolution of Roadways(Tunnels) Rockburst Based on the Ultrasonic Plane Testing Method

针对岩爆试验及监测研究的不足,基于超声波平测法声波监测,利用真三轴加卸载试验系统开展了直墙拱形巷(隧)道在单面约束情况下的双轴压缩岩爆试验,分析和探讨了岩爆破裂演化与平测波形规律。结果表明,随着垂直载荷的增加,巷(隧)道围岩两帮呈现出起伏、粗糙破裂面和片剥体,整体试样产生沿加载方向发展演化的裂纹;实现了全程的超声波平测法声波监测,经过波形对比分析,可以较好的反映围岩表面附近和内部的破裂演化进程,波形开始畸变可做为围岩岩爆破裂演化的前兆;通过监测分析平测法声波波幅,可以掌握围岩内部的全程发展变化情况,实现对围岩能量聚集、耗散与释放过程的识别;对于巷(隧)道围岩层裂、离层及完整围岩岩爆等可应用超声波平测法进行声波检测与监测。

Aiming at the deficiencies in rockburst test and monitoring study, using the true three axis loading and unloading test system, the biaxial compression rockburst test was carried out under the one side constraint on straight-wall-toparch roadways （tunnels） based on the ultrasonic plane testing method. And the rockburst fracture evolution and wave pattern was discussed. The results were concluded as follows. Firstly, with the increase of vertical load, two sides of the surrounding rock presented rough and undulant failure surface, as well as thin strip body. The whole sample produced cracks along the loading direction. Secondly, full-course acoustic monitoring was achieved based on the ultrasonic plane testing method, waveform comparison could well reflect the evolution process of rock damage, and waveform distortion could be used as a precursor to the evolution of rock burst. Thirdly, by monitoring the amplitude based on the ultrasonic plane testing method, the internal development changes of the whole rock could be acquired, so as to achieve recognition of rock energy accumulation, dissipation and release process. Finally, the ultrasonic plane testing method could be used to detect and monitor the separation and spallation of surrounding rocks and rockburst.