By Lynda Myer
In order to advancing the Mumbai Sewer Disposal Project (MSDP) Stage II, a rock EPBM has been delivered by Terratec which is a 3.14m diameter machine and is due to build the 4.7km Priority Sewer Tunnel (PST-2). Additionally, this is the second TBM that Terratec has provided to J Kumar and Michigan Engineers Private Ltd (MEPL) Joint Venture for the project, whereas excavating process of the 5.8km Priority Sewer Tunnel (PST-1) was commenced by a 3.85m diameter rock slurry TBM in January 2024.
Comprising of a mixed type cutterhead, 27 back-loading 432mm disc cutters as well as a high-speed main drive capable of eight RPM, this rock EPBM is designed to operate under a range of geological conditions, including silty sand, silty clay, boulders, breccia, basalt, clay with gravel and thyolite.
Considering that the intended TBM has been engineered to function within a wide horizontal radius to meet the challenges of the tunnel alignment, which includes a 90-degree road intersection and working around piles supporting an overhead metro line, this modification has eliminated the need to dig a shaft at the congested intersection, resulting in time and cost savings while preventing traffic disruptions during construction. The approach, being used for the first time in India, includes using different segment ring lengths (1000mm and 650mm) to enable the TBM to navigate sharp curves with a radius of up to 95m.
Including 17 decks, the 122m-long machine is equipped with a single-track gantry type back-up system, while they are using the locomotive and muck cars to removal muck and segment transport and also logistics supply.
The MSDP – Stage II includes the construction of a sewer tunnel to the existing Malad Pumping Station, a branch sewer tunnel, and shafts and upstream connections.
In addition to providing new pumping stations, wastewater treatment facilities and treated effluent disposal systems, the Brihanmumbai Municipal Corporation project is slated to expand sewage collection networks. Recycling 2,464 million litres of sewage per day, decreasing water pollution levels and improving water quality in Mumbai’s Mithi and Oshiwara rivers, will be the scheduled contents of these treatment plants.
In a related development, a refurbished Terratec TBM operated by MEPL has achieved its second breakthrough for the 6.4km Mithi River Quality Improvement Project’s Package IV.
