玄武岩中裂隙分布形式对声波传播的影响

复杂岩体含有大量的裂隙,这些裂隙尺寸及其分布形式等对弹性波传播都有很大的影响.本文加工了含单个裂隙、双裂隙和三个裂隙的玄武岩岩样单元对其进行组合,进行了25kHz、 50kHz、 400kHz、 600kHz和1000kHz 等5种频率的声波测试.通过考虑垂直或平行波传播方向的裂隙长度,来探索裂隙分布形式和不同裂隙长度对弹性波传播的影响,研究玄武岩的频散效应和波的衰减.结果表明:裂隙方向与波传播方向夹角对弹性波传播有很大的影响.当裂隙方向与波传播方向垂直时,散射效应最大;而当裂隙方向与波传播方向平行时,影响最小.上述结果可为理论模型和数值分析提供依据.

Study of Crack Distribution Effects on Sound Wave Propagation in Basalt

Engineering rock mass contains lots of cracks and defects, whose size and distribution form have strong influence on elastic wave propagation. In this paper, wave velocities in basalt specimens with single, two and three prefabricated cracks were measured by using five different frequencies that is 25kHz, 50kHz, 400kHz, 600kHz and 1000kHz. Taking into account the cracks vertical or parallel to the wave propagation direction, the influence of different crack lengths and different crack distributions on elastic wave propagation, the dispersion effect and wave attenuation in basalt were analyzed based on these experimental results. Results show that the included angle between crack direction and wave propagation direction has intensive effect on wave propagation: when the crack direction is vertical to the wave propagation direction, the attenuation effect is most intensive; when the crack direction is parallel to the wave propagation direction, the attenuation affect is minimum. Above results may be helpful for theoretical and numerical analysis of elastic wave propagation in basalt.