Shield Construction Site Visit by 2007 AISF Scholars

July 3rd was an unforgettable day for AISF scholarship recipients of fiscal year 2007. This is because of being able to visit the site for the underground construction of the Metropolitan Express Central Loop Shinjuku Line, something which ordinary people are not able to do. This project of building an urban underground expressway, which would be very significant in improving the transportation as well as environment in Metropolitan Tokyo, uses world-leading technology in shield tunnel construction.

At 2:00 PM, AISF Managing Directress Imanishi, Secretary General Shimazu, and the international students from all over the world arrived at the construction site operation center and were warmly welcomed by the people at Kajima Construction.

The participants were not necessarily specializing in civil works. They were not familiar with the method of creating infrastructure for such things as roads, water, and electric utilities and, therefore, were apparently bursting with curiosity. The Chief of Kajima Construction operation, Mr. Moriguchi, was scheduled to give a 30-minute briefing that eventually was very much extended due to the many questions from the participants. Moreover, the participants were deeply impressed since they were able to actually touch the cutter bit and special segment bolts being used in the construction site.

According to Mr. Moriguchi's explanation, Kajima was in charge with the construction of the segment of the Metropolitan Express Central Loop Shinjuku Line stretching 2660 kilometers from Hatsudai up to Matsumizaka. Our on-site visit started from the Kamiyama ventilation area, where we went 50 meters underground, and walked about one kilometer up to the Shibuya shaft.

Various questions asked were: "How do you dig a hole?" "What do you do with the dug out soil?" "How does the machine move forward?" "How do you make a tunnel?" Mr. Moriguchi was kind enough to give convincing answers to all such questions. Eventually the mode turned from question asking to discussing. Mr. Deng of the University of Tokyo proposed the use of a pioneering material called CFRP, which he is now researching for used in aircraft, as a way of protecting the shield machine's body from the pressures of the deep underground. Unfortunately, the ensuing discussion's conclusion was that it was too costly to adopt.

At 3:00 PM, we finally were able to start the tour of the site, and everyone started putting on their helmets and gloves. We reached the Kamiyama ventilation area and from there we descended 50 meters underground using the stairs. The first thing I sensed was the cool temperature and the smell of soil. We listened to Mr. Moriguchi's explanation as we headed on foot towards Matsumisaka shaft. A question was raised about how each segment was assembled, to which the polite answer was that the segments were first assembled on both sides bottom-up and finished off to form a ring tunnel.

Upon arrival at the endpoint, the visitors couldn't help hiding their surprise and awe at the 15-meter diameter cutter head of an actual shield machine while listening to the explanation of Chief Moriguchi. A lot of souvenir photos were taken.

At 5:00 PM, the tour ended, and we returned to the construction site operations center where we expressed our gratitude to the Kajima folks as we left the construction site.

During this trip I got to learn more about underground road tunnel construction, and once again was impressed with Japan's craftsmanship. On behalf of 2007 Atsumi Scholars, I would like to express my deepest gratitude to Kajima Construction and Atsumi Foundation for providing this meaningful and educational opportunity.

by Wang Jian Hong (2007 Raccoons)

Translated by Max. Maquito (1995 Raccoons)

For information about the construction site, please refer to the following URL

After the construction visit, participants recovered from long walk with beers on the roof of Keio Department Store in Shinjuku. The hottest topic of the day was "Does China need democracy now?"

The photos of our visit can be found in the following URL