Roof falling and rib spalling occurred in any times. To predict roof falling, AE field tests have been conducted and AE monitor holes are laid out based on the block analysis.
为了预报冒落事故，开展了声发射（AE）现场试验，并在块体分析的基础上布置了AE监测孔。
2
To predict roof falling AE field tests have been conducted and AE monitor holes are laid out based on the block analysis.