Investigation of the structural damage caused by blasting activities in tunnels to surrounding buildings: The case of Gümüşhane belt highway

Tunnels are road transport structures that reduce traffic and expropriation problems, noise, and possible damage to animals and plants, and provide safer, more comfortable, and faster transportation for vehicles compared to highways. However, some environmental problems occur during tunnel construction. These problems such as vibration, noise, rock throwing, etc. caused by the blasting process used during tunnel excavation on buildings and people should be well investigated. In this study, two buildings located close to the exit and entrance of two tunnels (T2 and T3 tunnels) on the Gümüşhane belt road were chosen to investigate. Firstly, the existing damages in the first building, which is 7 m away from the T2 tunnel exit, and the second building, which is 60 m away from the T3 tunnel entrance, were analyzed by considering criteria such as the geological and ground condition of the land and the building materials used during the construction of those building. In addition, the negative effects on the buildings were evaluated by calculating the vibrations after the blasting process in the tunnel with the help of various empirical formulas. Investigation on site showed that building 1 was built of masonry and building 2 was built of reinforced concrete, and that deep cracks had formed in the bearing systems of both buildings, spills occurred in the walls, and fractures in the windows. Also, calculations with empirical formulas showed that the vibration rates caused by blasting process in the 1st and 2nd buildings were as 385.68 mm/sec and 6.91 mm/sec, respectively, and these vibration values were above the standard values. The data obtained through examination on-site and empirical approaches show that it would be dangerous for people to be resident in both buildings.