孔底空气间隔装药降振试验研究

Experimental study on vibration reduction of the hole-bottom air space charging

为研究孔底空气间隔装药降低爆破振动效应的最佳空气层比例，进行了现场试验。首先基于试验数据，利用小波分析与AOK分布相结合的方法，对不同空气层比例的实测爆破地震波质点振速峰值、主频、主频持续时间、频带优势频率持续时间以及频带能量比进行了研究。结果表明：随着空气层比例的增加，爆破地震波质点振速峰值降低、主频降低、主频持续时间延长、频带优势频率持续时间延长并且频带能量比向低频发展。然后以与建筑物固有频率相接近的7．8125—15．6250Hz频带能量为指标，进行了降低爆破振动效应的最佳空气层比例的选取．并结合实际工程证明了该方法的可行性与有效性。

In order to study the best air-decking ratio of the hole-bottom air space charging to reduce blasting vibration effect, a field experiment was conducted. First, based on the experimental data, using wavelet decomposition combined with the AOK time-frequency representation,peak particle velocity of blasting seismic waves, dominant frequency, duration of dominant frequency, duration of preponderant frequency and frequency-band energy ratio was studied under different air-decking ratio. The results show that, with the increase of air-decking ratio, peak particle velocity of blasting seismic waves and dominant frequency are decreasing, duration of dominant frequency and duration of dominant frequency are increasing, and frequency-band energy ratio is developing toward low frequency. Then, with 7. 812 5- 15.625 0 Hz frequency-band energy which is closed to natural frequency of buildings as the indicator, the best airdecking ratio to reduce blasting vibration has been selected, and combined with practical work, the feasibility and effectiveness of the method were proved.