下穿高速公路输水隧洞爆破振动响应分析

Study on Blasting Vibration of Diversion Tunnel Undercrossing Expressway

输水隧洞下穿高速公路爆破施工将导致路面振动,对路面结构稳定性产生不利影响,掌握爆破引起路面振动响应规律至关重要。因此,为研究隧洞爆破作用下高速公路路面振动响应特征,依托平潭及闽江口输水工程,以输水隧洞下穿既有G15高速公路为研究对象,采用现场振动监测和数值模拟方法,研究了隧洞爆破开挖引起上覆高速公路路面振动响应特征及衰减规律。研究结果表明:由于隧洞掏槽眼爆破药量最大,同时缺少临空面导致过大夹制作用,MS1段爆破引起的高速路面质点峰值振速最大;爆破引起的高速公路路面测点垂直方向峰值振速最大,可能导致路面动力沉降;隧洞已开挖部分的自由面,有效地削弱了爆破地震波效应,加快了爆破振动衰减。

The blasting construction of water diversion tunnel under an expressway will lead to pavement vibrations and adversely affect the stability of the pavement structure,so it is very important to find out the response law of pavement vibrations caused by blasting.In order to study the vibration response characteristics of the expressway pavement close to the tunnel blasting,we took the diversion tunnel undercrossing the existing G15 expressway in the Pingtan to Minjiang water conveyance project as the research object so that to study the vibration response characteristics and attenuation law of expressway pavement by field vibration monitoring and numerical simulation.The results show that the peak particle vibration velocity of the road surface caused by MS1 section blasting is due to the maximum amount of blasting charge in the cut holes of the tunnel and its lack of enough free surface,which leads to increased confinement.The largest blasting peak vibration velocity appears in the vertical direction of at the measuring point,which may lead to dynamic settlement of the pavement.In addition,the free surface of the excavated part of the tunnel effectively weakens the blasting seismic effect and accelerates the attenuation of blasting vibrations.