Based on the mechanical model of a simply supported beam, this study investigates the influence of periodic construction disturbances from a close upper tunnel on the vibration characteristics of the roof of a lower tunnel. The mathematical expression for the dynamic response of vertical displacement at the top of lower tunnel is deduced. The mathematical expression can provide a theoretical basis for determining the occurrence time and peak displacement, and provide a method for determining the safe distance between the two tunnels. The law of the action of influencing factors such as the disturbance force on maximum displacement is explored with a specific example. The results show that when the disturbance amplitude and the tunnel span increase by 1 and 2 orders of magnitude, respectively, the corresponding peak displacements increases by 1 and 23.9 orders, respectively and when the vertical distance between tunnel layers and the elastic modulus of soil increase by 2 and 3 orders, respectively, the corresponding peak displacements reduces by 88.2% and 70%, respectively. When the main affecting factors change, the maximum displacement and its oscillations increase, which influences the top stability of the tunnel.