Hanoi Metro tunnel excavation completed: design and TBM notes for engineers
Reviewed by Joe Ashwell

First reported on Tunnels & Tunnelling International – News
30 Second Briefing
TBM Than Toc (Speedy God), a 6.6m-diameter, 100m-long, 850t Herrenknecht machine operated by Ghella, has broken through at Station S12 (Hanoi Station) after a 4km drive installing 1,720 precast segments on Hanoi Metro Line 3. The 12.5km Pilot Light Line 3, Hanoi’s first underground metro, comprises 8.5km of elevated track, 4km of twin-bore tunnels and four underground stations between Nhon and Hanoi Station, and is now over 72% complete. A second TBM, Tao Bao, is currently advancing towards Station S11, maintaining underground excavation momentum.
Technical Brief
- Four underground stations – Kim Ma, Cat Linh, Van Mieu and Hanoi – define intermediate access, ventilation and emergency egress nodes along the 4km tunnel.
- Alignment connects Nhon in Tay Tuu (Nam Tu Liem district) to Hanoi Station, traversing dense urban fabric with associated settlement and utility protection constraints.
- Elevated–underground interface over 12.5km requires transition structures managing stiffness contrast, groundwater ingress and differential settlement at portal zones.
- With >72% overall completion, remaining works are likely dominated by station fit-out, MEP integration and systems testing rather than primary excavation.
- Second TBM Tao Bao advancing toward Station S11 allows parallel headings, shortening programme and distributing settlement risk over time.
- Experience from this first underground metro in Hanoi will inform design baselines for subsequent tunnelling under similar geotechnical and urban conditions.
Our Take
Herrenknecht’s use on Hanoi’s Line 3 adds to a pattern in our database where the same supplier is also providing large TBMs and vertical shaft sinking machines for European power and metro tunnels, signalling its consolidation in complex urban underground works.
With only 4km of underground tunnel against 8.5km of elevated track on Line 3, Hanoi is following the cost-optimised alignment mix seen in several Asian metros, which typically reserve full TBM drives for the most constrained central corridors.
Among the 154 Infrastructure stories in our coverage, Line 3’s >72% completion status puts it in the more advanced tier of urban rail projects, meaning procurement and construction risk for contractors like Ghella is now largely replaced by interface, systems integration and commissioning risk.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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