Tunnel Construction Professionals
Shield Tunneling
Civil Engineer, Nanbu Mainline Shield Tunnel Project OfficeAkari TAKADA
“Never content with the current situation and always move forward“
Proactive approach toward accuracy improvement
In the Nanbu Mainline shield project, I oversee order placement of materials and equipment such as segments, backfill grouting material, and dump trucks for soil removal, as well as surveying and safety management.
There are basic procedures for all of these tasks, but I strive to improve them, such as a list of checking items to prevent disruptions in the construction work.
As for backfill grouting material, its shortage will delay the construction, while its excess will overflow the tanks, so the right timing of the order is important. I used to check the excavation data to predict the timing, but to be more accurate, I started checking with my eyes the remaining amount of material in the tanks.
Also, shield surveying requires attention to detail that is different from other types of construction, so I ask the senior staff for guidance as needed to improve accuracy. In terms of safety management, as the inside of the tunnel is narrow this time, I need to watch out for the items that are difficult for others to see such as whether the wires that fix the air ventilation pipes are sticking out on the aisle side, whether the protrusions or other objects that may hit people are protected with cushions, and whether there are any gaps in the scaffolding boards in the tunnel, and If something needs adjustments, we take action immediately.
Actively visiting other sites
Before coming to this site, the first shield construction site I was involved in had a large section with a diameter of 16m, and I thought that was normal. However, this Nanbu Mainline has a small cross-section of 2m in diameter, requiring workers to bend down in the tunnel. Also, for this project, the URUP method is used to launch the machine from above the ground directly into the ground at an angle. I felt that I should learn more from different construction sites.
Luckily, the director arranged a visit to another shield construction site for me and I had the opportunity to visit other companies' case studies at the "women's group" of the company group. I make the most of those opportunities.
When I saw the launching base gradually being built on what had been a vacant lot, and the shield machine entering the ground after the removal of a retaining wall of the launching shaft, I felt that shield construction progresses with the involvement of so many people, each making mindful efforts. And now that the current excavation is progressing smoothly, every time I enter the tunnel for surveying, the distance I walk through increases, which makes me happy.
The day and night shifts change every two weeks, but as a responsible and good-spirited member of this construction team, I will take good care of myself, eating and sleeping well.
