水下爆破振动特征及衰减规律研究

Study on vibration characteristics and attenuation law of under water blasting

针对传统质点峰值振动速度公式因没有考虑水体波动对爆破振动传播的影响导致预测结果精度较差的问题,以某核电站水下爆破实验为背景,分析了水下钻孔爆破时地面质点振动特征和水下爆破地震波的衰减规律。由现场实测爆破振动速度数据分析结果可知,水下爆破产生的地震波具有振幅小,衰减慢等特点,传统的质点峰值振动速度公式不适用于水下爆破振动传播的预测,鉴于此,对其进行修正。修正后的预测公式考虑水深比的影响,将拟合系数从0.45提高到0.92,由此可见,修正的预测公式能够更好地反映水下爆破振动衰减规律。由于爆破振动的频谱特征也是决定其灾害程度的重要因素,因此通过傅里叶变换,对比分析了水下爆破与露天爆破的频谱特征。结果表明,水下爆破具有明显的滤频效应,具有主频小,频带窄,能量小等特点。研究结果可为水下爆破灾害的有效控制提供依据。

To solve the problem of the poor prediction of blast vibration based on the traditional formula without considering the effect of water fluctuation, the characteristics of particle vibration on the ground is analyzed in underwater blasting under the background of underwater blasting test of a nuclear power station and the attenuation law of underwater blasting seismic waves. According to the in situ monitoring data, the particle vibration velocity induced by underwater blasting has obvious characteristics such as lower amplitude,slower decay,etc,the traditional formula of particle peak vibration velocity is not suitable for the prediction of vibration propagation in underwater blasting, so it is modified. Compared to the traditional formula,the proposed prediction formula is more suitable to describe the blasting vibration propagation characteristics, and the resulting correlation coefficient is improved from 0.45 to 0.92. Because the spectrum characteristics is an important factors influencing blasting disaster, the contrastive analysis between the underwater blasting and surface blasting arc madeby Fouricr-transform. The results show that the underwater blasting has obvious filtering effects, which include the small corresponding dominant frequency,the narrow band and the small energy. The research results provide the basis forcontrolling disaster in underwater blasting engineering.