Mr. Le Trung Hieu - Deputy Head of the Hanoi Urban Railway Management Board together with the consulting unit and contractors had a meeting with the State Acceptance Council at the tunnel shell factory in Ha Nam province.
Representative of Hanoi Urban Railway Management Board welcomed the State Acceptance Council
The cellar shell factory is located in Ha Nam province.
The manufactory produces tunnel shells with modern technology and a closed production line to produce each tunnel with the best quality. Every product in production has to go through stages of thorough testing.
Here, the State Acceptance Council checked the specifications, production methods, production lines, production materials, etc. before the project entered the phase of mass production of cellar shells.
Mr. Nguyen The Phung - member of the State Acceptance Council
Members of the State Council inspect everything from input materials to test tunnel shell products to assess the quality.
The shell ring is a universal type, consisting of 6 pieces. The tunnel shell ring has an inner diameter of 5.7m, an outer diameter of 6.3m, a ring width of 1.5m, a thickness of 0.3m. The prefabricated tunnels will be manufactured at the contractor's factory in Ha Nam province.
The production steps of prefabricated tunnels are carried out by the production unit through closed stages including:
The first is to process the reinforcement, check the reinforcement combination for every small detail. Prepare formwork, install reinforcement and accessories and pour concrete into the form. Then the tunnel shell panels will be covered with sealed chambers to perform steam curing until the concrete of the tunnel shell plate reaches 60% specified compressive strength, equivalent to 30 MPa (time about 4-6 hours).
Then the cellar shell panels will be transferred to the water curing area within 7 days. The product will then be hoisted from the soaking tank to the storage area and carefully stacked. Next is the stage of epoxy coating and marking to serve the installation and construction. In the final stage at the factory, products will be moved to the storage area, where EPDM gaskets, guide rails and gaskets are installed.
After going through a strict production process, continuously checking each stage, the product is transported to the construction site. This is an important step that needs to be properly regulated, to avoid affecting the structure of the product, to prevent cracking and to ensure product safety when transported to the place of installation and completion of the tunnel.
It is expected that the unit that directly manufactures the tunnel shell will begin to produce the shell from April 2021. The expected capacity is 12 rounds of tunnel shell/day, equivalent to 72 slabs of tunnel shell. The tunnel has a length of 1.5m. The total number of tunnel shell rings is: 3488 burning. The total number of tunnel slabs is: 20928 slabs.
Source: Hanoi Urban Railway Management Board – https://mrb.hanoi.gov.vn/tin-tuc/-/view_content/4103784-thang-4-2021-du-kien-bat-dau-san- xuat-vo-ham-cua-tuyen-duong-sat-do-thi-so-3-doan-nhon-ga-ha-noi.html
English 
Vietnamese