The Mumbai-Ahmedabad High Speed Rail project is likely to achieve a major milestone on Saturday with the final breakthrough of its NATM (New Austrian Tunnelling Method) tunnel. WHAT IS NATMUnlike machine-driven tunnelling, NATM uses the surrounding ground as a natural support system.Concrete is sprayed on tunnel walls to stabilise the structure as work proceeds. Package C2, which includes this tunnel, is being executed by Afcons Infrastructure Ltd.BULLET TRAIN CORRIDOR
- 156km is the Maharashtra section of the entire 508km corridor.
- 135km of elevated track between Shilphata and Zaroli (MaharashtraGujarat border)
- 21km tunnel starting from BKC.
THE FULL TUNNEL
- Total tunnel length: 21 km
NATM tunnel : 4.9 km- Tunnel boring machine stretch: 15.5 km
- Side tunnel: 394 m (completed)
NATM Tunnel (Horseshoe-shaped)Dimensions: 10.5 m high, 13.6 m wideWork split in 3 parts:
- Shilphata stretch – 1.6 km
- First junction point stretch – 1.6 km
- Second junction point stretch – 1.5 km (to be completed July 2025)
Next milestone:Final breakthrough between Ghansoli and Shilphata on Sept 20, 2025Challenges:
- Hard rock strata
- Low soil cover
- Utility
WORK STATUS INMAHARASHTRAStations | Work on Thane, Virar, and Boisar stations is progressing. First slabs for Virar and Boisar are complete.BKC station | 83% excavation complete. Base slab casting at 100 ft depth underway at both ends.Viaducts | Pier foundations ongoing across multiple sites; 48 km of piers cast. Full-span box girder launching started in Palghar district.Mountain tunnels | Excavation of 7 tunnels in Palghar underway; 2.1 km of 6 km heading completed.Bridges | Construction has begun on Vaitarna, Ulhas and Jagani river bridges.
