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城市地下工程中常遇到近接既有隧道岩体爆破开挖的问题。乌鲁木齐市新建雅山连拱隧道为全线上穿近接既有隧道的典型工程,因其与既有隧道间距离较近,使得掘进爆破时对既有隧道结构的振动强度控制十分困难。为此,该文针对新建雅山连拱隧道掘进爆破开挖,利用LS-DYNA动力分析软件对不同掏槽爆破条件下连拱隧道中导洞掘进爆破时对既有隧道结构的动力响应情况进行了数值模拟计算,并结合现场爆破试验及振动测试数据验证了数值计算结果的正确性。结果表明:1)中导洞掘进爆破时,既有隧道迎爆侧拱肩处的振动强度最大,且振动强度与掏槽药量具有明显的线性关系;2)中导洞掏槽孔齐爆药量小于6kg时,既有隧道衬砌上的质点振动速度可控制在设定阈值4cm/s以内;3)受衬砌质点与掏槽孔间距离和边界条件的影响,中导洞掏槽爆破时隧道衬砌迎爆侧拱肩处和拱脚处的有效应力最大。但各工况下的有效应力均小于0.15MPa,不足以使隧道衬砌发生拉、压破坏。
Urban underground engineering often encounter the problem of blasting and excavation of rock mass near the existing tunnel. The new Yaqingshan multi-arch tunnel in Urumqi is a typical project of putting on the existing tunnel near the existing tunnel. Because of its close distance from the existing tunnels, it is very difficult to control the vibration intensity of the existing tunnel structure during tunneling blasting. Therefore, this paper aims at the excavation blasting of the new Ya-Shan multi-arch tunnel, and analyzes the dynamic response of the existing tunnel structure by tunneling blasting in the double-arch tunnel with different cutting blasting conditions by LS-DYNA dynamic analysis software The numerical simulation is carried out, and the correctness of the numerical calculation results are verified by combining the field blasting test and the vibration test data. The results show that: 1) During the tunneling blasting of the pilot tunnel, the vibration intensity at the blasting side of the existing tunnel is the highest, and the vibration intensity and cutting dose have obvious linear relationship; 2) The blasting of the pilot tunnel When the dose is less than 6kg, the vibration velocity of the particle on the existing tunnel lining can be controlled within the set threshold of 4cm / s; 3) According to the influence of the distance between the lining of the lining and the cutting hole and the boundary conditions, The effective stress of the tunnel lining welds on the side arch shoulder and arch foot is the largest. However, the effective stress in all conditions are less than 0.15MPa, not enough to make the tunnel lining pull, pressure damage.