AN OVERVIEW OF THE CONSTRUCTION OF TURKEY'S LONGEST ROAD TUNNEL FOCUSING ON GROUND SUPPORT USING MACRO SYNTHETIC FIBERS AS SHOTCRETE REINFORCEMENT

Mount Ovit Tunnel (Turkish: Ovit Dagi Tuneli), is a highway tunnel under construction through Mount Ovit which is 2600 m in height and 12.6 km in length. Initially the project faced many problems caused by highly unstable portal batters, and fault zones with high water inflows and difficult rock conditions. Macro synthetic fiber reinforced shotcrete FRS lining was considered to use instead of steel mesh to increase the excavation speed of the NATM tunnel so as to form a fast shotcrete lining and keep tunnel deformation within the specified limits. This paper examines the design of macro synthetic FRS lining for the projects different NATM support categories, FRS quality control test result including EFNARC plates, convergence monitoring, together with the back calculations and their analysis. A comparison between the advance speeds of the excavation for each of the trial tubes using different reinforcement methods will be analyzed.