Invisible wall that hits the Hokkaido Shinkansen When I visit the construction site ... April 8th, 18:38
Ten years later, the Hokkaido Shinkansen aims to extend to Sapporo at the end of 2030.
On the Shinkansen, the section from Shin-Hakodate Hokuto, which is the northernmost part of Japan, to Sapporo, is under construction for 212 km.
But the work is now facing major challenges.
In order to find out what it was, I visited the site with the special permission of the "Railway and Transportation Organization" that is constructing it.
(Sapporo Broadcasting Station reporter Keisuke Igarashi)
Steady work to challenge a long tunnel
A mountainous area about 3 km southwest of Asari Station on the JR Hakodate Line in Otaru City.
If you go down the road, you will see a semi-circular hole on the mountain surface.
It is the entrance on the Otaru side of the "Sasson Tunnel".
The long tunnel of about 26 km connecting Sapporo and Otaru starts from here and runs through the center of Sapporo.
In mid-March, when I visited "Face", the cutting edge of this construction site, I was in the middle of excavation work.
At the site, heavy machinery was spinning a drill with a metal blade to carve out earth and sand.
Compared to the size of heavy machinery, the drill was small and the speed of scraping out earth and sand was slow.
Person in charge of the Railway and Transportation Organization
"The most important thing to be careful about in tunnel construction is not to collapse it. For that purpose, delicate operation by skilled workers is required."
After digging about 1 meter to prevent it from collapsing, concrete is sprayed on the wall to reinforce it.
When it hardens, excavate the next meter again.
Repeat such steady work and move forward little by little.
Even if the work is going well, it is said that it is at most 5 meters a day.
Work started in November last year on the section we visited this time.
Only about 400 meters have progressed over four months.
The construction is scheduled to be completed in October, five years later.
Still, at this site, I was approaching Sapporo step by step.
Construction in Sapporo city that hits the wall
The invisible wall that was hitting was under construction on the Sapporo side of the Sasson Tunnel.
I was able to cover this site as well.
When I was first guided to the site, I felt strange.
This is because it was a residential area about 1 km northwest of Hassamu Station on the JR Hakodate Line in Nishi-ku, Sapporo.
The construction method is different on the Otaru side and the Sapporo side.
The Sasson Tunnel will be constructed through the mountains on the Otaru side, but will pass under the city on the Sapporo side.
For this reason, after digging a vertical hole of 50 meters, the tunnel is passed by advancing sideways.
What's going on below?
I went down the vertical hole up to 30 meters underground with the person in charge of the railway and transportation organization.
What I could see from there was a large circular iron frame mounted on the wall.
Person in charge of the Railway and Transportation Organization
"We call it the'entrance'. There will be a Shinkansen tunnel on the inner circumference of this steel material."
It is said that the machine will be installed according to this frame and the tunnel will be dug.
Construction began in January, two years ago.
Estimated completion says August after five years, but not begun yet essential of excavation work, that the prospect is also not standing.
A person in charge of the Railway and Transportation Organization asked the reporter, "Is it at the stage where preparations are ready now?", But answered plainly, "It is a situation where preparations are in progress."
"Countermeasure soil" that prevents the start of construction
Why haven't we started excavating the Sasson Tunnel in Sapporo?
The reason is that the place to receive the earth and sand generated by the construction has not been decided.
Some of the earth and sand contain naturally occurring heavy metals such as arsenic and cadmium.
For this reason, it is necessary to dispose of it in a place where special measures have been taken, and it is called "countermeasure soil".
According to the city of Sapporo, the amount is equivalent to 0.7 cups of Sapporo Dome.
Sapporo City and the Railway and Transportation Organization have asked the residents for their understanding by accepting two locations, the Yamamoto district in Atsubetsu Ward and the Kanayama district in Teine Ward, as candidates for acceptance, and holding briefing sessions.
However, the selection was stalled due to a series of cautious opinions from the residents, such as "I can't get rid of my anxiety about safety" and "I don't have enough explanation."
Sediment disposal is an unavoidable problem
The treatment of earth and sand in the tunnel is an extremely important issue for the extension of Sapporo.
The tunnel occupies 80% of the 212 km section from Shin-Hakodate Hokuto on the Hokkaido Shinkansen to Sapporo.
For the Shinkansen, where it is important to run fast, it is necessary to take a straight route in order to run without slowing down, and as a result, many tunnels run through the mountains.
For this reason, countermeasure soil is not a problem limited to Sapporo.
When completed, the "Oshima Tunnel," which is the longest on land in Japan and is about 32 kilometers long, has the same problem.
Agricultural officials are concerned about the impact on the soil and are opposed to accepting it, so only about half of the total soil disposal site has been secured.
According to the Railway and Transportation Organization, the tunnel excavation rate was 38.4% as of March 1.
More than 60% remains untouched.
If the recipient is not decided by March next year, there is a sense of crisis that the construction period should be considered.
Director Yoda, Hokkaido Shinkansen Construction Bureau
"The delay in starting is likely to affect the delay in the process. I am doing my best every day so as not to affect the opening of the business, but it is certain that it is in a very tight state."
Since everything from redevelopment of central Sapporo to management of JR Hokkaido is premised on extension at the end of 2030, there is no doubt that the impact will be enormous if it is postponed.
Understanding of candidate site residents is indispensable
In order to overcome the situation, Sapporo City and the Railway and Transportation Organization have decided to make the Yamaguchi district of Teine Ward one of the receiving places, which is different from the two places already selected, March 28 and 29. We held a resident briefing session on the day.
In addition to embankment on the countermeasure soil, he explained that taking measures such as covering with a sheet would not affect the surrounding environment, and then showed a schedule to bring in the countermeasure soil from around autumn.
There were a series of voices from the residents who were worried about the damage to the crops and who said that the explanation was acceptable.
Nevertheless, Sapporo City and the Railway and Transportation Organization said that they would set up a council in which residents would participate and give explanations, but asked for their understanding on the premise that they would proceed with acceptance as shown.
Mayor Akimoto
"I felt that I had to resolve the anxiety about the damage caused by rumors. At this briefing session, I set up a forum for sharing information with the local people in the future, not all. I would like your understanding. "
Junichi Yoda, Director General, Hokkaido Shinkansen Construction Bureau
"Please understand that the Ministry of Land, Infrastructure, Transport and Tourism has created a manual so that people can have safety and security in accordance with the technical standards so that health hazards do not occur."
Considering the timing and effect of stretching, it is easy to understand that it is "clogged".
However, the voice of inhabitants' anxiety should never be left behind.
As a major premise for proceeding with the construction, Sapporo City and the Railway and Transportation Organization need to carefully seek the understanding of the residents around the receiving area through every place.
Reporter
Keisuke Igarashi of
Sapporo Broadcasting Station
Joined in 2012
After working at Yokohama Station and Akita Station, he was in charge of the economic field at Sapporo Station.