75 m Deep Diaphragm Wall Element for Patna Subway Project

With roughly 1.43 billion people, India has become the most populous country on earth. To accommodate the continually growing population and the increased traffic load associated with this growth, especially in major urban areas, infrastructure expansion is increasingly prioritized. This is also the casein Patna, the capital of the state of Bihar in northeastern India. The goal of the Patna Metro subway project is to provide the metropolis with an efficient public transportation system that will improve the traffic situation and reduce road congestion. Apart from subway lines and stations, the construction project also includes elevated railway routes along with train depots and the associated infrastructure. In June 2023, the deepest barrette foundation element ever constructed at Patna Metro was installed at a depth of 75 m using a hydraulic grab
Credit/Quelle: Bauer Gruppe

Foundations for Subway Stations

Bauer Engineering India Private Limited was awarded the contract for diaphragm wall work at four stations as well as for a retrieval shaft. “We are excited to contribute to this groundbreaking project,” says Yogeshwaran Purushothaman, Project Manager at Bauer India. “Our diaphragm wall elements act as permanent foundations on which the new subway stations will be constructed.” The work started in November 2022 and is expected to be completed by March 2024. Over this period, a total of 636 diaphragm wall/barrette elements will be constructed for all four subway stations. They act as watertight barriers to provide stability and structural support. Among other equipment, a Bauer GB 34 hydraulic grab, a GB 50 and a DHG grab on a Bauer MC 96 duty-cycle crane are being used.

75 m Deep Barrette Foundation Element

An extraordinary task within the scope of this project was completed in June 2023: The deepest barrette foundation element ever constructed at Patna Metro was installed at a depth of 75 m using a hydraulic grab. “This is a milestone in the history of Bauer India,” remarks the project manager enthusiastically, since this depth is extremely unusual for excavation with a hydraulic grab. The remaining diaphragm wall elements will be installed up to a depth of 55 m. The Bauer India team are confronted with a range of challenges in the process: For instance, the very different geological soil profiles across the four sites and retaining verticality during work require the utmost attention. What’s more, all work must be executed under very limited spatial conditions within the city.