The safety of adjacent existing tunnels under the effect of tunnel blasting is a key concern in blasting construction.This paper takes the blasting excavation of the tunnel between Hongshan Road Station and Xiaohongshan Station interval of Wuhan Metro Line 8 as an example to study the dynamic effect of the upper existing civil air-defense tunnel under the blasting action of the underlying subway tunnels.A finite-element numerical model of the tunnel blasting was established by LS-DYNA,and the reliability of the numerical model was verified by field vibration monitoring data.Then,the dynamic response characteristics of the civil air-defense tunnel were studied.Field tests and numerical simulation studies reveal that with the increase of the distance to blasting center,the peak particle velocity(PPV) of the civil air-defense tunnel lining decreases gradually with the maximum PPV point located directly above the explosive.The results show that the stability of the civil air-defense tunnel lining is controlled by tensile stress.Specifically,the main tensile stress of the tunnel floor and vault is in circumferential direction,and the main tensile stress of side wall is in vertical direction.The most dangerous section of the lining structure is located above the source of the explosion,and the most likely location of damage to this section is the foot of the arch facing the blast.The damage mode is tensile failure from the inside to the outside.In addition,the safety threshold of vibration velocity of the tunnel lining structure calculated by the ultimate tensile strength criterion is 14.9 cm/s.