Test Analysis on Blasting Vibration of Xiaoyu Three-lane Neighborhood Highway Tunnel

Abstract

Due to the extremely small thickness of interlaid rock in the small clear spacing tunnel, blasting construction is easy to have a certain impact on the tunnel structure, so it is particularly important to explore the dynamic law of tunnel structure under blasting load. Based on the Xiaoyu Tunnel in Qinhuangdao, the blasting vibration of the first tunnel was monitored during the blasting process of the rear tunnel of the tunnel, and the vibrational attenuation law and spectral characteristics of the first tunnel under blasting were analyzed. The results show that the vibrational velocity at the horizontal radial side wall is the largest in the three-dimensional vibrational velocity. The blasting vibration velocity decreases with the increase of the distance from the explosion source, and the attenuation rate also decreases, which can be attenuated by more than 50% at 15m. At the same section position, the blasting side wall is the position with the largest vibrational velocity, followed by the arch waist; the vibrational velocity of the front explosion side is much larger than that of the back explosion side, and the vibrational velocity of the front explosion side at the side wall position can reach 6∼7 times that of the back explosion side. The research results of this paper can provide a reference for the safe construction of similar tunnel small clear spacing tunnel projects.