Energy and Vibration Absorption Characteristics of Damping Holes under Explosion Dynamic Loading.

There are usually many buildings near the subway. In tunnel construction, the vibration caused by explosion affects the structure of buildings. The vibration and energy absorption characteristics of damping holes caused by tunnel blasting are investigated under explosion dynamic loading, experimentally and numerically. This paper, taking Yan'an Third Road Station as a case, verified the effectiveness of the damping hole on the vibration reduction of the ground building based on the simulation and experiment. Furthermore, the article examines the effect of distance between the damping hole and charging holes, diameters of the damping hole, and material of the medium on the damping performance. The results show that an increase in diameter improves the energy and vibration absorption performances of the damping hole better than a decrease in distance. In addition, damping performance in gas and liquid medium is better than that in solid medium. The optimum scheme for vibration and energy absorption under extreme conditions of tunnel blasting is to arrange an 80 mm damping hole above the charging holes, and the distance between the damping hole and the center axle wire of the two charging holes is 0.2 m. By using this scheme, the vibration and energy absorption characteristics of damping holes are better than that of other scheme: the damping efficiency is the highest, which is 10.83%, and the pressure-relief efficiency is 10.48%. Furthermore, the medium materials of the damping hole are preferably air or water. Finally, the tunnel excavation contour line is smooth by applying this method. It is concluded that if the damping system is developed with proper design guidelines, then it may reduce the transmission of energy and vibration with effective protection of ground buildings.