爆破地震波穿越不同介质结构面的衰减效应

为探索爆破地震波穿越不同充填介质结构面的振动速度、频率和能量分布的衰减规律,采用混凝土边坡相似模型进行爆破振动试验。通过分析爆破地震波的峰值振动速度、边际能量谱和各频带能量百分比,获得了爆破地震波穿越无结构面与结构面充填泥、细沙、水和空气的衰减规律。结果表明:当充填介质波阻抗越小,地震波的峰值能量和峰值振动速度衰减越快,频率上表现出高频滤波作用越强,在频带间能量分布变窄,主频带有往低频带0～20 Hz聚集的趋势;值得注意的是,当水作为充填介质时,不仅水的波阻抗会影响地震波的衰减,而且水的微压缩连续性也会使峰值能量和峰值振动速度衰减更慢,能量在频带间分布更广,水的流动性则会造成爆破地震波的主频带在各传播方向上分布不一。在相同充填介质条件下,随着结构面倾角增大,峰值振动速度在各传播方向上均减小。

Attenuation effect of blasting seismic wave passing through different media structure plane

In order to explore the attenuation law of vibration velocity, frequency and energy distribution of blasting seismic wave passing through the structural planes of different filling media, blasting vibration test was carried out on a concrete slope similar model. Based on the analysis of the peak vibration velocity, marginal energy spectrum and energy percentage of each frequency band of blasting vibration signal, the attenuation law of blasting seismic wave passing through non-structural plane and structural plane filled with mud, fine sand, water and air were obtained. The results show that the smaller the wave impedance of the filled medium, the faster the attenuation of the peak energy and peak vibration velocity of seismic wave, the stronger the blocking effect on high frequency wave in frequency, the narrower the energy distribution between frequency bands, and the trend of main frequency band gathering to low frequency band 0～20 Hz. It is worth noting that water is used as a filled medium, not only the wave impedance of water affect the attenuation of seismic waves, but also the continuity of micro-compression of water, which makes the peak energy and vibration velocity attenuate more slowly and the energy distributes more widely among frequency bands, the fluidity of water causes the difference of the main frequency band of blasting seismic wave in different propagation directions. Under the same filling medium condition, the peak vibration velocity decreases in each propagation direction with the increase of the inclination angle of structural plane.