TBM S-1075 Makes a Breakthrough for Mumbai Metro Line-3 at Worli
Just a few moments ago, Tunnel Boring Machine S-1075 operated by the Continental Engineering Corp – ITD Cementation – Tata Projects JV made a breakthrough at Worli Station’s northern-end on Mumbai Metro’s 33.5 km Aqua Line (Line-3).
This was S-1075’s second breakthrough, 6.08 km package UGC-04’s sixth breakthough, and overall Line-3’s 26th breakthrough.
This Herrenknecht TBM, nicknamed Krishna-3, successfully passed factory acceptance testing (FAT) in October 2017, and was first commissioned on July 19, 2018 to build the 1305 m up-line tunnel of the Siddhivinayak – Worli section. After its breakthrough in March 2019, it was brought back to Siddhivinayak for its final assignment to build the 1284m down-line tunnel towards Worli Station.
Package UGC-04 now has just 2 more breakthroughs pending, both at Dadar Station. Here’s a table displaying its tunneling plan (best viewed on a desktop device) and the status of each tunnel –
| TBM | Line | From | To | Distance | Status |
| 1 | Up | Nayanagar Shaft | Dadar | 2491m | Completed April 1 ’19 |
| 1 | Up | Nayanagar Shaft | Dharavi | 589m | Completed Nov 21 ’19 |
| 1 | Down | Siddhivinayak | Dadar | 1126m | In Progress |
| 2 | Down | Nayanagar Shaft | Dadar | 2472m | Completed Mar 1 ’19 |
| 2 | Down | Nayanagar Shaft | Dharavi | 589m | Completed Oct 11 ’19 |
| 2 | Up | Siddhivinayak | Dadar | 1106m | In Progress |
| 3 | Up | Siddhivinayak | Worli | 1305m | Completed Mar 15 ’19 |
| 3 | Down | Siddhivinayak | Worli | 1284m | Completed Today |
Upcoming breakthroughs in March-April include:
• Package UGC-02: CST → Mumbai Central (up-line tunnel, 3825m)
• Package UGC-05: BKC → Dharavi (down-line tunnel, 1504 m)
For more updates, check out the Mumbai section of The Metro Rail Guy!
– TMRG
The balloons look like popcorn 😀
What is that white stuff coming out of the TBM?
It’s a foaming agent. Helps to treat the ground for better pressure control. Results in lower friction and wear of cutting tools.
For the underground metro, how it is being insured that it don’t get flooded in monsoon during construction and after construction?
Flooding can’t be prevented during the construction stage, so they’ve had to make do with pumps to drain out the sites.
To prevent flooding after construction, they’ve planned all entry structures to be 60-90 cms above the historic 100 year flood level recorded at each location. Tunnel ring segments have special gaskets between them that will swell in contact with water to prevent seepage.
All station roof slabs will/are being sprayed with a waterproofing solution. Here’s an image: https://twitter.com/TheMetroRailGuy/status/1228880649190334464
NATM built tunnels are/will be lined up with a synthetic membrane. Here’s an image:
https://twitter.com/TheMetroRailGuy/status/1236470405076062208