Success depends on accurate survey

As a chief engineer, I supervise the construction of the Onuma Evacuation Tunnel. My work ranges from management of the construction process, materials, workmanship, safety, post-construction quality checks, and consultation with clients, to preparation of documents and materials related to these tasks.

The construction project mainly consists of excavating the evacuation tunnel. The Onuma Tunnel has many challenges: multiple fracture zones (soft and fragile geology), low-strength ground, swelling rock, high-pressure water inflow, acidic water inflow, heavy metals and acidification. The construction of the evacuation tunnel is separate from that of the main tunnel, and by excavating the former earlier, it serves as a pilot tunnel by (1) draining the water, (2) understanding the geological information and (3) assisting the main tunnel construction (auxiliary construction method, working pit).

Geological conditions such as low-intensity ground or high-pressure groundwater can cause sudden displacement (deformation in the tunnel) or inundation which may lead to serious accidents. Therefore, getting a good grasp of the geological and groundwater conditions by survey beforehand is crucial for safety and smooth transitioning between differing ground types.

Becoming a true professional

Unlike other tunnel sites, the JV staff here doesn’t live in on-site accommodations but lives in apartments and commutes from there. Due to Japan’s work-style reform law, more workers take weekdays off in shifts but since we live away from the construction sites, it is easier for us to refresh ourselves and keep our mind and body in shape for work.

Since joining Obayashi, I have set a goal of acquiring a qualification every year for self-improvement. I would like to become an expert tunnel technician for Obayashi, obtaining a qualification of Professional Engineer in Tunnel Engineering and then in Engineering Management in the future.

My interest in civil engineering began early as my father worked in the industry, and with a special interest in concrete material, I majored in structural engineering at college. This is my sixth year at Obayashi and I have worked on both bridge and tunnel construction sites. After joining the Tunnel Engineering Department at the main office, I was transferred to the Onuma Tunnel project and have been here for almost two years. I have become a middle management with the title of Chief, but I still have a lot to learn.

At this construction site, what is needed above all is integrity. All of us involved in this project will continue to work as one to ensure that the Onuma Tunnel is completed without any accidents.