A tunnel is an underground passageway, dug through the surrounding soil/earth/rock and enclosed except for entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods. there were 76mm thick short concrete grade M20 with wiremesh, payline, minimum excavation line, 20mm backfill concrete grade M15 with including lagging, 150mm thick M15 grade concrete etc. are included. for for details and information download drawing file.
