引水隧洞下穿既有铁路隧道爆破施工振动影响及对策

Vibration Influence on the Existed Railway Tunnel by Blasting Construction of Underpass Diversion Tunnel and Countermeasures

结合云南省盐津县白水江三级电站引水隧洞下穿内昆铁路手扒岩隧道爆破施工工程,采用LS-DY-NA显式动力数值模拟方法及现场爆破振动监测,研究钻爆法施工产生的振动对既有铁路隧道的影响。结果表明:爆破振动影响大小与单段起爆药量、爆源距考察点距离关系密切,随药量的减小、距离的增大而减小;在掌子面接近、远离既有隧道相同的距离时,接近时产生的竖向振动速度大于远离时的;振动速度方向和爆源与考察点的方位有关,当两者为左右关系时,水平方向为主,当两者为上下关系时,竖直方向为主;数值模拟与现场监测所得规律和数值均有较好的一致性,证明了采用该方法研究隧道工程爆破振动影响的可行性和正确性。

Based on the practical situation of the diversion tunnel for Baishuijiang third class power station in Yanjin county of Yunnan province, underpass of Shoubayan tunnel of Nei-Kun Railway, LS-DYNA explicit dynamic numerical simulation and in-situ blasting vibration monitoring were used to study the vibration influence on the existed railway tunnel by drilling and blasting construction of underpass diversion tunnel in short distance. The result indicates that the scale of blasting vibration has a close relationship with the dose of single-dose initiation, explosion sources distance from the inspection point. The vibration goes down when the dose decreases and the distance increases. When towards the existing tunnel, the vibration is stronger than far from it at the same distance. The direction of vibration velocity is related to the positions of explosion sources and inspection points. When the positions of the two are from left to right, the horizontal direction dominates, and when from top to bottom, the vertical direction dominates. The insitu data agree with the computing results, so it is feasible and proper to study the vibration influence by adopting this method.