The Western Tehran Wastewater Transmission Tunnel is Tehran’s second-largest wastewater conveyance tunnel. The main object of this project is to collect and transfer the wastewaters of the central and western parts of Tehran to the southwest wastewater treatment plant of Tehran. The tunnel should be able to pass a maximum discharge of 17.2 m3/s. The tunnel length is about 11 km, which is completed with an EPB Tunnel Boring Machine (TBM) with the internal diameter of 3 m. For the first in this project, used the Combi-Segment as an anti-corrosion on the segmental lining.