一軸圧縮応力下にある石炭のAE震源分布
1988 年 104 巻 1201 号 p. 163-168
詳細
1988 年 104 巻 1201 号 p. 163-168
Hypocenters of AE in coal under uniaxial compression test were determined. AE waveforms and strains were simultaneously detected by 16 PZT transducers and 4 strain gauges attached to the sample surface. The sample fractured with fracture planes nearly parallel to the loading axis and local failure region. Hypocenters were determined for 223 events thatoccurredd uring loading.
The hypocenters were randomly distributed below about 20% of the fracture strength. Just above this stress, AE events began to swarm around one of the fracture planes. In the stage when the coal sample approached to the ultimate fracture, the hypocenters concentrated on the ultimate fracture planes. Near the AE swarm region, anomalous decrease of local volumetric strains were observed. Temporal variation of the anomalous behavior seems to be fairly consistent with the AE activity in the swarm region.
