As the excavation progresses, the secant pile is supported with soil anchors and wallers at regular intervals.
Surat : Under the Ahmedabad-Mumbai bullet train project, the work of the first 7 km long tunnel under the sea in Maharashtra has already started. The work of 7 km undersea and 21 km long tunnel outside has already started. On the other hand, contracts have been signed for electrification of the bullet train to run at a speed of 350 with the help of electricity.A 21 km long tunnel will be constructed between Bandra-Kurla Complex and Shilphata. At present piling work has been started. In this tunnel, both up and down tracks will be built around. This tunnel will be tube shaped. The tunnel will also have 39 equipment rooms at 37 locations. Three tunnel boring machines will be used to build the 16 km section of the tunnel. The tunnel will be about 25 to 57 meters deep from the ground. In that too, a construction point 114 meters deep from the mountain will be built near Shilphata.
Along with this, an agreement has also been made for the electrification of bullet trains. The bullet train will run at a speed of 350 Now to run this train, like a normal train, power supply has to be given through electric wires, but as the speed of the train is higher, its design will be different. 14 separate sub stations, 11 sectioning posts, 17 sub sectioning posts, 1 auto transformer post and overhead equipment will also be installed along the 508 km route for electrification. Apart from this, 11 call backbones and more than 125 substations will also be constructed in Surat, Sabarmati and Thane. The land required for constructing the BKC station, which is about 4.8 hectares, has been handed over to a contractor by NHSRCL (National High-Speed Rail Corporation Limited). The station will be constructed using the bottom-up method, which means that the excavation work will start from the ground floor level and the concrete work will start from the foundation. The excavation required for this station is very extensive, reaching a depth of 32 meters, with an estimated volume of approximately 18 lakh cubic meters.
In order to carry out deep excavations safely, a basic support system must be constructed to prevent the ground from collapsing. In this foundation method, 3382 secant pillars will be constructed, each ranging from 17 to 21 meters in depth. All secant pillars are created. Excavation has started in the station area. As the excavation progresses, the secant pile is supported with soil anchors and wallers at regular intervals (from 2.5 to 3.5 m).At present 681 laborers and supervisors are working day and night at the work site. This number is expected to increase as the project progresses. According to an estimate, the maximum workforce required per day during peak hours may reach up to 6000 persons. Excavation and fixing of soil anchors and wallers is the primary activity going on at the site.