On the morning of August 28, information from the Hanoi Urban Railway Project Management Board (MRB) said that by the end of August 25, the entire "Thanh Speed" TBM machine including cutting head and auxiliary machinery was in the tunnel. . The TBM has dug about 100m (total underground length is 4km - PV), installed 7 temporary tunnel lining segments and 58 permanent tunnel lining segments.
After nearly a month of tunneling, the project encountered some difficulties due to the TBM drilling in the hardened clay layer, so the speed had to be reduced. After adjusting the ratio of soil conditioner (a substance sprayed in front of the TBM head to make the geological layer softer, making it easier for the TBM cutting head to cut this soil layer), the TBM's digging speed returned to normal. Normal is about 35-40mm/min.
Wherever the drilling is done, the project will proceed with construction and installation of the tunnel lining. With a modern robot arm, the tunnel shell installation time will be about 30 to 35 minutes for a tunnel segment consisting of 6 pieces. In the first phase, the first 200m is the initial drilling phase, the TBM operator will try to optimize the steps to shorten the progress for the following sections.
Currently, the project site is working 24/24, with each shift of 15 - 17 employees.
According to the plan, the project will drill the "Thanh Speed" TBM1 machine from Station S9 - Kim Ma at a depth of 17.8m. When the TBM1 excavator has drilled about 200m, the TBM2 - "Bold" machine will begin the tunnel drilling process.
Completing the launch for the first 240m, the tunnel boring machines will accelerate to a standard speed of about 10m/day to approach the next stations. According to the plan, the total time from the start of drilling for the first TBM until the end of TBM No. 2 is 16 months.
After finishing drilling at station S12, the TBM machines will be dismantled at this station, the auxiliary equipment system will be pulled back and dismantled at Station S9 - Kim Ma. The total number of personnel for construction work is more than 150 people. The main tasks include operating the TBM machine, operating the robot arm to install the tunnel cover, replacing the cutting head...
On the ground, the Project has designed and installed a geotechnical monitoring system to ensure regular monitoring and monitoring of ground displacement and subsidence. Below ground, the Project has established a drainage system during the push phase.
In parallel with the process of constructing the tunnel using TBM, other construction items of the underground section (underground ramps, underground stations, garages and lane changers) continue to be implemented in parallel according to plan. .
