Metro Aqua Line 3 in Mumbai Conducts Trial Runs Beneath Mithi River
The Mumbai Metro Aqua Line 3 has recently kicked off trial runs on a section of the line that passes under the Mithi River. This significant development marks the beginning of train movement on the Dharavi to Acharya Atre Chowk stretch, covering a distance of 9.77 km and spanning across six stations. The ultimate goal is to open this stretch for commercial operations by March 2025, pending thorough inspection and safety certifications by the commissioner of metro rail safety.
Phase 2A Progress and Future Plans
Referred to as Phase 2A, this milestone in the Metro Aqua Line 3 project was showcased in a social media video that captured the trials and showcased the upcoming stations. The final phase of the line, which is expected to reach Colaba by the end of 2025, will connect commuters seamlessly across the city. Once the line is operational up to Acharya Atre Chowk, travelers can expect a streamlined journey of 39 minutes from JVLR to Acharya Atre Chowk.
Navigating Challenges Under the Mithi River
Undertaking a project of this magnitude beneath the Mithi River posed significant challenges for the project officials. The construction of twin tunnels under the river between Bandra Kurla Complex and Dharavi stations required innovative solutions due to the unique soil conditions and the absence of any previous similar endeavors in the area. The use of tunnel boring machines (TBMs) named Godavari 3 and Godavari 4, along with the New Australian Tunneling Method, facilitated the excavation process in this complex terrain.
Advanced Earth Balance Machines and Water Seepage Management
Approximately 2 km of the 3 km twin tunnel section passes under an expanded water body, including a 500-meter segment of the active Mithi River channel. To address the challenge of tunnelling beneath the water, custom-designed earth balance machines were deployed to maintain natural pressure at the tunnel face, prevent land settlement, and efficiently manage the removal of excavated material while controlling water seepage.
Understanding the Geological Layers
Delving beneath the Mithi River bed, the railway line is situated at a depth of 9.57 meters. The layers below the water flow consist of slush, Grade 3/4 brecciated basalt rock, and Grade 1/2 brecciated basalt rock, where the tunneling activities were focused. The intricate design of the system includes watertight gaskets, precast concrete segment rings with mushroom-type gaskets, and hydrophilic gaskets that swell upon contact with water to ensure the joints remain watertight.
Depth and Station Details
Dharavi station, adjacent to the Kotak BKC station, is positioned at a depth of 18 to 18.5 meters below the ground level. The stretch between Kotak BKC and Acharya Atre Chowk encompasses six stations, namely Dharavi, Sitaladevi, Dadar, Siddhivinayak, Worli, and Acharya Atre Chowk. Each station plays a crucial role in connecting various parts of the city and enhancing the overall transportation network for residents and visitors alike.
As the Metro Aqua Line 3 project progresses under the Mithi River, the innovative techniques and meticulous planning employed by the project team set a new standard for underground construction in Mumbai. The future of urban transportation in the city looks promising with the upcoming operational phases of this transformative metro line.
