Determining the optimal method of excavation of the Zenica tunnel as a function of minimal damage to rock mass of poorer quality outside the excavation profile

: Corridor Vc enhances the connection of Bosnia and Herzegovina with neighboring countries and improves the potential for economic development. The Corridor Vc motorway in Bosnia and Herzegovina stretches from the northern border with the Republic of Croatia from Svilaj to Čapljina on the southern border with the Republic of Croatia, in Bijača. The Zenica tunnel is part of the Corridor Vc motorway in the municipality of Zenica and is currently the longest excavated tunnel with a total length of 3,330 meters. Excavation works were performed by a combination of blasting and machine excavation. The excavation of the tunnel was performed in sedimentary formations (flysch-like Upper Vranduk series 2 JK). Excavation of tunnels by blasting with adjusted drilling and blasting parameters in rock mass of poorer quality achieves better results in relation to machine excavation.