大跨度四连拱公路隧道的爆破动力响应分析

Blasting dynamic response analysis of long-span four arch highway tunnel

由于大跨度四连拱隧道具有复杂且特殊的受力结构,爆破荷载作用下的四连拱隧道中隔墙和先行隧道衬砌极易发生损伤甚至产生破坏。以长沙市银星路观音岩四连拱隧道作为实际工程背景,对先行隧道衬砌的爆破振动速度进行实测,通过回归分析,总结先行隧道的振动波传播规律。同时,采用数值模拟的方法,分析了爆破荷载作用下先行隧道中隔墙和衬砌的振速和位移响应。研究表明:在爆破开挖面纵向30 m范围内的中隔墙振动速度较快;中隔墙迎爆侧墙肩的位移值最大,墙顶的位移值次之,背爆侧墙脚的位移值最小;右辅道隧道爆破时,距离右辅道较近的右主线隧道迎爆侧振动速度较快,且主要分布在迎爆侧拱腰处;右主线隧道衬砌迎爆侧拱腰振速峰值约为左主线隧道衬砌迎爆侧拱腰振速峰值的16倍、左辅道隧道衬砌背爆侧拱腰振速峰值的40倍。

Due to the complex and unique stress structure of long-span four-arch tunnels,the midpartition wall and the lining of the first tunnel are prone to damage or even destruction under blasting loads.Based on the engineering context of the Guanyinyan four-arch tunnel in Yinxing Road,Changsha,the blasting vibration velocity of the advanced tunnel lining has been measured.Through regression analysis,the propagation law of vibration waves in the advanced tunnel has been established.Additionally,numerical simulation methods have been employed to analyze the vibration velocity and displacement response of the mid-partition wall and tunnel lining under blasting loads.The results indicate that the vibration velocity of the mid-partition wall is significant within 30 meters along the longitudinal direction of the blasting excavation face.The maximum displacement occurs at the shoulder on the blasting side of the mid-partition wall,followed by the top,while the least displacement is observed at the foot behind the blasting side.During blasting in the right auxiliary tunnel,the vibration velocity on the blasting side of the right main tunnel,particularly near the right auxiliary tunnel,is higher,with the highest vibration velocity recorded at the haunch of the blasting side.Notably,the peak vibration velocity of the haunch in the right main tunnel lining on the blasting side is approximately 16 times greater than that in the left main tunnel and 40 times greater than that in the left auxiliary tunnel lining.