立体交叉隧道爆破动力响应和安全范围研究

Analysis of Dynamic Response and Safety Range of Crossing Tunnel Based on Blasting Vibration

研究目的:目前矿山法在隧道施工中非常普遍,在交叉隧道施工中,隧道爆破施工对既有隧道的影响是近些年人们非常关注的问题。因此,研究常规爆破方式爆破对立体交叉隧道动力响应规律,确定安全振速标准及不同影响程度的安全范围。研究结论:(1)新建下穿隧道施工至交叉位置时,既有隧道拱底和拱脚峰值振速较断面环向其他位置大,对爆破振动相对敏感,为薄弱环节,需重点关注;(2)爆破作用下位移对既有隧道的运营安全和结构安全都不会产生影响;(3)以振速作为评判标准,对新建隧道爆破施工下穿既有隧道全过程中既有隧道受到的结构破坏、影响运营和关注围岩等三种不同程度的影响范围进行了定量划分,并确定了相应程度的安全范围;(4)本研究成果可为立体交叉隧道爆破荷载作用下的抗震设计提供指导。

Research purposes:Because the current mining method is very common in tunnel construction.In construction of fly-over crossing tunnels,the influence of blasting vibration on existing tunnel has been paid more attention to in recent years.Consequently,dynamic response law of fly-over crossing tunnels of the conventional blasting method is studied,to determine criterion of security vibration velocity and safety range of different conditions.Research conclusions:(1) When a new underpass tunnel is constructed to the intersection position,the peak vibration velocity of the arch bottom and the arch foot of the existing tunnel is larger than that of the other locations in the circumferential direction of the cross section,and is relatively sensitive to blasting vibration,as a weak link of the existing tunnel,it should be paid more attention to.(2) The displacement under blasting action will not impact the operation safety and structural safety of the existing tunnel.(3) Taking the vibration velocity as the criterion,this paper quantitatively divides the influence ranges of three different degrees,such as the structural damage of existing tunnels,influence on operation and the concern about surrounding rocks,in the whole process of the blasting construction of new tunnels through existing tunnels,and determines the corresponding safety norms.(4) The research results will provide guidance for aseismic design of fly-over crossing tunnel under blasting load.