模型试验单孔爆破振动信号时频分析

以地下工程常见的直墙半圆拱形硐室为原型,借助胶结砂相似材料开展单孔爆破相似模型试验,并监测爆破过程中相似模型试件顶面的爆破振动信号,随后采用HHT法对3个方向爆破振动信号的时频特征进行分析。爆破振动监测表明,在3个方向爆破振动信号中,竖向爆破振动峰值最大,水平径向次之,水平切向最小。3个方向爆破振动信号IMF分量能量分布表明,爆破振动信号优势能量集中分布于主振频率所在的几个IMF分量。HHT分析表明,3个方向爆破振动信号集中分布在0.03~0.07 s时域内;爆破振动信号频域成分丰富,但其在频域内分布不均匀;对于水平径向,爆破振动信号集中分布在111~312 Hz频域内;水平切向集中分布在171~323 Hz频域内;竖向则集中分布在128~209 Hz频域内。

Time-frequency characteristics of single-hole blasting vibration signals in model experiment

With common arch wall chamber in underground engineering as the prototype, single-hole blasting model test has been carried out with cemented sand similar materials. And the blasting vibration signals on the top surface of cemented sand model have also been monitored. Then time-frequency characteristics of blasting vibration signals in three directions have been investigated with HHT method. Blasting vibration signals indicate that in three blasting vibration signals, peak particle velocity in vertical direction is the biggest of all, and peak particle velocity in horizontal tangential direction is the smallest of all. Then peak particle velocity in horizontal radial direction is between them. Energy percentage of IMF components for blasting vibration signals show that most of blasting vibration signal energy is distributed in a few of IMF components where main vibration frequencies locate. HHT analyses indicate that blasting vibration signals in three directions are centralized distribution in time domain, in the range of 0.03 to 0.07 s. And blasting vibration signals in three directions are rich in frequency components, but they are distributed unevenly in frequency domain. In horizontal radial direction, blasting vibration signal is mainly concentrated in frequency range of 111 to 312 Hz, while it is 171 to 323 Hz in horizontal tangential direction and 128 to 209 Hz in vertical direction.