地铁基坑爆破中减振孔的降振效果实测研究

结合某地铁工程实际,在爆破区与受保护区之间合理布置减振空孔,孔径、孔深和孔距根据实际需要调整,对现场有无减振孔爆破进行振动测试,对采集数据进行拟合分析计算,得出本工程减振孔的减振规律。研究结果表明：减振孔的最大减振率达到22.4%,降低了振动强度,减少了对近区周边构筑物（如地下连续墙）的损害;随着爆心距的增大,减振效果越来越差,在远处时几乎与无减振孔最大振速一致。

Study on the effect of damping hole on reducing blasting vibration under the excavation of subway foundation pits

According to the practical subway engineering,damping holes were drilled between the blasting area and the reserves appropriately. The pore size,pore depth and pitch were adjusted based on actual needs. Blasting vibration was tested in-situ and vibration data with or without damping holes were collected. Then the vibration regularity of damping holes was derived in the project though a fitting analysis with the data. The research results show that when using damping holes reasonably,the maximum damping ratio reaches 22. 4%,which reduces the vibration intensity and the damage of surrounding structures（ such as the underground continuous wall）. With the increasing of blasting distance,the damping effect is gradually weakened,and the peak particle velocity of vibration in the long distance is almost the same as the one without damping holes.