基于Wigner-Ville分布的黄土中爆炸地运动信号传播分析

PROPAGATION ANALYSIS OF GROUND MOTION INDUCED BY EXPLOSION IN LOESS BASED ON WIGNER-VILLE DISTRIBUTION

在黄土中进行7次100kgTNT当量的地下封闭爆炸试验,在1000m范围内共布设了4个测点对爆炸近区地运动信号进行测量。对实测地运动信号应用Wigner-Ville分布进行分析,给出地运动信号的时频特征和能量的分布情况。通过分析发现,黄土中爆炸地运动信号主要有2个中心频率,分别为4～10和11～16Hz;信号能量分布在30Hz以内,优势频率在8～15Hz。地运动信号Wigner-Ville分布的特征参数随爆心距的变化规律比较明显,地运动信号时频分布能量峰的大小随爆心距的增大以指数规律衰减,其能量峰对应的频率随爆心距的增大以对数规律减小,能量峰对应的时间随爆心距的增大大体以线性规律增大。

Seven underground explosion experiments that explosion equivalent is 100 kg TNT are carried out in the loess, and the ground motion signals are measured by four acceleration sensors laid in the range of 1000 m away from the explosion source. By applying Wigner-Ville distribution to analysis the measured signals, the time-frequency characteristic parameters of the signals and its energy distribution are gained. The analysis shows that the ground motion signal in the loess is mainly composed of two center frequencies, respectively, in 4 - 10 and 11 - 16 Hz. The signal energy lies within 30 Hz, and the dominant frequency is in 8 - 15 Hz. According to the results, there are the obvious relations between the characteristic parameters＂ value of Wigner-Ville distribution of the ground motion signal and the distance away from the explosion source. Based on the analysis of the signals, as the distance away from the explosion source, it is found that the energy of the Wigner-Ville distribution＇s peak attenuates exponentially, the frequency corresponding to the Wigner-Ville distribution＇s peak reduces logarithmically, and the time corresponding to the Wigner-Ville distribution＇s peak increases linearly.