海底新建隧道爆破对既有隧道的振动影响研究

Study on blasting vibration of new undersea tunnel affecting existing tunnels

以青岛地铁1号线海底隧道和胶州湾海底公路隧道为工程背景,应用ANSYS/LS-DYNA建立数值模型进行研究,分析爆破作用下既有隧道的振动响应特征,建立4个模型分析海水深度对爆破振动的影响。结果表明:既有隧道中,最大爆破振速出现在对应掌子面迎爆侧上方,迎爆侧振动速度大于背爆侧,前者为后者的1.6~2.7倍;在既有隧道横断面上,三向振速及其衰减速率均表现为径向振速>切向振速>垂向振速,表明既有隧道空间对垂向振速的削减作用最小。在既有隧道轴向上,合振速关系表现为迎爆侧拱腰>迎爆侧拱脚>拱顶,对应掌子面前方振速大于后方,前者为后者的1.07倍。在隧道拱顶与海平面距离相同的条件下,既有隧道中各向振速随海水深度的增加而增大,但海水深度对爆破振速衰减速率的影响并不明显。

Taking the Qingdao Metro Line-1 undersea tunnel and the Jiaozhou Bay submarine highway tunnel as the engineering case studies,ANSYS/LS-DYNA was used to establish a numerical model in this research.The vibration response characteristics of existing tunnels under blasting are analyzed,and four models to analyze the influence of seawater depth on blasting vibration is established.The results show that in the existing tunnel,the maximum blasting velocity appears above the blasting side of the corresponding face.The vibration velocity on the burst side is greater than the back explosion side,and the former is 1.6 to 2.7 times of the latter.In the cross section of the existing tunnel,the three-way vibration velocity and its attenuation rate are expressed as:Radial vibration velocity>tangential vibration velocity>vertical vibration velocity.It shows that the existing tunnel space has the least effect on reducing the vertical vibration velocity.In the axial direction of the existing tunnel,the combined vibration velocity is expressed as:Side of the bursting side of the tunnel>side arch of the bursting side>the vault.The vibration velocity in front end of corresponding face is greater than the rear end,and the former is 1.07 times of the latter.Under the same conditions that the tunnel vault is at the same distance from the sea level,the vibrating velocity in the existing tunnel increases with the increase of seawater depth.However,the influence of seawater depth on the decay rate of blasting vibration velocity is not obvious.