Tunnel and Underground SpaceISSN:1225-1275(Print) 2287-1748(Online)한국암반공학회

Due to the limitation of national land area and the mountainous topography of Korea, the utilization of surface space is restricted, leading to active development of underground space. As underground structures become more widespread and their depth increases, it is necessary to consider in more detail the effects of blast-induced vibration on adjacent underground structures during blasting operations. Currently, various controlled blasting techniques are applied to reduce vibration; however, most of these techniques focus on reducing lateral vibration, and methods to attenuate vibration in the tunneling direction remain insufficient. In this study, to supplement this limitation, a medium with different physical properties from the surrounding rock mass was filled into the bottom of the blast hole to induce wave scattering and reflection due to impedance contrast at the interface, and to verify whether this can effectively attenuate forward-propagating vibration. For this purpose, Numerical simulations were conducted using ANSYS AUTODYN, applying sand with compaction characteristics as a filling material. The analysis was performed by varying parameters such as the length of the filling material and the type of explosive. As a result, it was found that the longer the length of the filling material, the greater the attenuation effect, and that the use of lower detonation velocity explosives showed a more distinct vibration reduction effect. This study suggests the potential of applying heterogeneous materials at the bottom of blast holes as a new design approach for forward-direction vibration control, and is expected to be utilized as fundamental data for minimizing blast-induced vibration in future blast design.