近区爆破下梁桥振动频带能量的小波分析

Wavelet Analysis on Vibrational Frequency Band Energy of Beam Bridge under Near Blasting

近区爆破引起的连续梁桥产生振动，评估爆破震动对桥梁产生的影响，为桥梁的抗爆设计提供参考依据。基于小波变换方法，采用db8小波基对振动测试信号进行分解与重构，计算爆破震动在各个频带的能量分布。以厦漳跨海大桥南汉南引桥施工期爆破监测项目为依托，建立桥梁的空间动力分析模型并进行模态分析，计算桥梁的前10阶自振频率。对23次爆破振动信号进行小波分析，结果表明，爆破振动信号的主震频带在15．625—62．5Hz内，桥梁的前9阶固有自振频率所在频带能量小于总能量的5％。

Near blasting cause the vibration of continuous beam bridge. The influence of explosion vibration on the bridge was evaluated which was helpful for the anti-explosion design of bridge. The vibration original signal was decomposed and reconstructed by the db8 wavelet basis based on the wavelet transform method. And the energy distribution of blasting vibra- tion in each band was calculated. Based on the blast monitoring project under construction for South Branch Approach Bridge of Xia-Zbang Sea-Crossing Bridge, the space dynamic model of bridge was established and the modal was also ana- lyzed to calculate the 10th natural frequency. Signals related total 23 blasting were all processed by wavelet analysis. The re- suits show that the main shock frequency band of the blasting vibration signal is in 15. 625-62.5Hz, and the energy propor- tion in the first 9th natural vibration frequency band of the bridge is less than 5% of the overall energy.