下穿既有环城公路的隧道爆破减振研究

Study on Vibration Reduction of Tunnel Blasting under Existing Ring Road

针对下穿既有环城公路隧道爆破产生的振动效应,同时考虑隧道上方公路车辆载荷耦合作用,运用LS-DYNA分别对设置减振孔和未设减振孔两种工况下的隧道爆破进行数值模拟,对比分析对公路的缓冲减振效应。模拟结合实测结果表明:减振孔可使应力大幅波动的时间延后且持续时间缩短,降低应力波和地震波的叠加效应;在减振孔周边,最大减振率约为41.7%,水平方向减振率明显高于垂直方向减振率;公路路面的最大减振率发生在中部,约为19.1%;设置减振孔使公路振速大幅波动的持续时间减少了50%。

Aiming at the vibration effect caused by the tunnel blasting under the existing ring road,and considering the coupling effect of the vehicle load above the tunnel,LS-DYNA was used to numerically simulate the tunnel blasting under two working conditions of with or without vibration damping holes.And then,compare and analyze the vibration reduction on the ring road.The results show that damping holes can delay the time and shorten the duration of stress wave and reduce the superposition effect of stress wave and seismic wave.The maximum vibration reduction rate around the vibration damping holes is about 41.7%,and the reduction rate in the horizontal direction is significantly higher than that in the vertical direction.The maximum reduction rate of the ring road occurs in the middle of the road surface,which is about 19.1%.The duration of large fluctuation of highway vibration speed can be reduced by 50%by setting damping holes.