01 / Water Tunel Drilling & Tunnel Boring Machines
02 / Continuous Operations
03 / Modernized Standards
Execution Challenge
The tunnel was driven through hard Deccan Basalt at depths of 109 metres (Kapurbawdi) and 125 metres (Bhandup), with the TBM required to safely manage incoming groundwater, especially when crossing beneath the Kasheli River and the lakes in the Thane district.
Abrasive basalt rock and fractured ground with the potential for water inflows contamination presented continuous machine wear and face stability risks throughout the drive. First-time TBM deployment in the Mumbai region added an additional layer of technology execution risk for the contractor team.
Because the alignment passes through highly populated, dense urban areas with high-rise structures, traditional drilling and blasting methods were completely avoided.
TBM Usage: TBMs were required to achieve rapid and continuous excavation (averaging over 400 meters a month) without causing surface disturbances or structural damage.
Strategic Role
Being a senior leadership at the Unity Infraprojects Limited (Joint Venture Contractor on the project), Mr Avarrsekar's responsibilities spanned bid strategy, project governance, JV coordination, and execution oversight.
He led the process of demonstrating the company's technical readiness for first-time TBM deployment in Mumbai, aligning the contractor's capability framework with the client's evaluation requirements.
His risk oversight function covered TBM procurement, shaft logistics planning, groundwater management strategy, and MCGM stakeholder engagement throughout construction.
Actions Taken
- Procured a Herrenknecht gripper TBM (6.25 m diameter, 2,100 kW cutterhead), specified for drainage capability under the Kasheli River crossing.
- Assembled the machine on site at the shaft bottom, avoiding pre-assembly at the Shanghai factory and saving time and cost.
- Installed a vertical conveyor, the largest H+E Logistik had built at the time, to lift spoil from the 109-metre launch shaft.
- Tracked the alignment across 8.3 km with a VMT guidance system.
- Applied shotcrete as primary support, with rock bolts and steel arches in fractured zones.
- Reported production and milestones to MCGM throughout, avoiding significant contractual delay.
Outcome
The TBM breakthrough was achieved in September 2013, completing the tunnelling drive within the projected 18-month window, against a conventional drill-and-blast estimate of five years for the same alignment.
Peak production reached up to 215 metres of shotcrete-lined tunnel per week. The completed tunnel enables an additional 455 million litres per day of clean drinking water to reach Mumbai's residents, supplying the Bhandup filtration plant reliably through both monsoon and dry seasons.
The project established the first successful TBM deployment record in Mumbai's water infrastructure sector, directly informing future underground tunnelling decisions in the city.
Technical Data of Record
Scope of Work
An 8.3 km bored tunnel from Kapurbawdi, Thane to the Bhandup Water Filtration Complex for MCGM, delivered in joint venture.
Key Specifications & Challenges
Hard Deccan basalt, depths up to 125 metres, groundwater beneath a river and lakes, first TBM use in Mumbai and a dense urban surface above the alignment.
Major Deliverables
TBM procurement, on-site assembly, vertical muck extraction, laser-guided navigation, shotcrete-based ground support and programme governance reporting to MCGM.
Result
TBM launch in June 2012 and breakthrough in September 2013, with peak progress of 215 metres a week and 455 million litres a day of added supply.
Client
Municipal Corporation of Greater Mumbai.
Location
Kapurbawdi (Thane) to Bhandup, Mumbai.
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