Tunnel Stability Analysis Based on Temporary Support Modeling in The Construction of Hasang Hepp in Toba Samosir District North Sumatra Province

Abstract

Excavation at the tunnel of Hydroelectric Power Plant along 2,650 m has been conducted in Nassau Sub-district Toba Samosir District North Sumatra Province. To determine an appropriate supporting to the tunnel, simulation of supporting system variation using Phase2 and Unwed must be taken. Displacement analysis is conducted at four point, likes at the point at the roof of the tunnel, point b between roof and the tunnel wall, point c on the tunnel wall, and point d on the corner side of the tunnel floor. There are 16 variation of supporting system that implemented to the model. Conclusion from the simulation shows the appropriate supporting system is recommended 1 rockbolt along 6 m, random space, and shotcrete with thickness 50 mm on floor and the wall.