基于压电信号的水下钻孔爆破损伤监测试验

Test of Underwater Drilling Blasting Damage Monitoring Based on Piezoelectric Signal

借助水下爆炸容器模拟40 m水深环境,通过两组不同装药结构的水下混凝土模型进行同药量的单次爆破损伤试验。在爆破前、后分别采用压电陶瓷传感器主动监测法对混凝土试样沿炮孔中轴线方向进行了关键点的主动信号采集。通过对监测点信号的峰值、能量统计分析发现,沿炮孔方向接收信号逐渐增强,在炮孔底部近区接收信号的峰值和能量出现明显突变,对比不同装药结构下的突变点位置可看出炮孔底部装有高阻抗球和粗砂的试样,其突变点明显提前,表明其对炮孔下部保留混凝土部分的损伤深度小。最后结合EMD方法探究了爆破前后压电信号的频率规律。研究表明:水下消能爆破技术能够有效减弱钻孔爆破对基岩岩体的损伤,基于压电信号的损伤监测方法可用于水下钻孔爆破中岩体损伤深度监测。

The underwater explosion vessel was used to simulate the water depth of 40 m,and two sets of underwater concrete models with different charge structures were used to conduct a single blasting damage test with the same charge amount.Before and after blasting,the active signals of the concrete samples along the central axis of the hole were collected by using the active monitoring method of piezoelectric ceramic sensors.Through the statistical analysis of the peak value and energy of the signal at the monitoring point,it is found that the signal received along the direction of the hole gradually increases,and the peak value and energy of the signal received near the bottom of the hole appear obvious mutation.By comparing the position of the mutation point under different charge structures,it is found that the mutation point of the sample with high impedance ball and coarse sand at the bottom of the hole is significantly advanced,indicating that the damage depth of the retained concrete part at the bottom of the hole is small.Finally,the frequency law of piezoelectric signal before and after blasting was studied by EMD method.The research showed that the underwater energy dissipation blasting technology can effectively weaken the damage to bedrock rock mass caused by borehole blasting,and the damage monitoring method based on piezoelectric signal can be used to monitor the damage depth of rock mass in underwater borehole blasting.