JR Tokai to Begin Linear Tunnel "Survey Digging" at Three Sites in Kawasaki and Machida by the End of the Fiscal Year, Raising Concerns of Residents Along Line
JR Tokai plans to begin excavation of the first Metropolitan Area Tunnel of the Linear Central Shinkansen Line in Kawasaki City and Machida City, Tokyo, in fiscal 2022 to investigate vibrations above the ground and their impact on the ground. The company plans to dig with three shield machines over a period of about six months, and then move to full-scale excavation this fall or later. The results of the investigation will be reported to residents in the area.
Tunnel with a diameter of 14 meters, more than 40 meters underground
Since October 2020, sinking accidents have occurred in the deep underground tunnel construction of the Tokyo Outer Ring Road (Outer Ring Road) in Chofu City, Tokyo, and residents along the linear rail line have voiced their concerns.
According to JR Tokai, investigations were conducted at the Kajigaya emergency exit (Miyamae-ku, Kawasaki City), Higashi Yurigaoka emergency exit (Aso-ku, Kawasaki City), and Onoji emergency exit (Machida City). All of these tunnels, 14 meters in diameter, will be excavated for 150 to 350 meters toward Nagoya to investigate the impact on the surrounding area.
After that, full-scale construction will begin in the fall at Kajigaya and Onoji, and at the end of FY2011 at Higashi Yurigaoka, with 200 to 400 meters of tunnel excavation each month. From Kajigaya, full-scale excavation will also begin in the direction of Shinagawa.
JR Tokai decided to conduct investigative excavation following the sinking accident in Chofu, and began excavation at the Kitashinagawa emergency exit (Shinagawa Ward, Tokyo) in October 2009. However, due to a breakdown of the excavator, the planned 300-meter dig was halted after 50 meters. The excavation of another deep tunnel near Nagoya City, from the Sakashita emergency exit (Kasugai City, Aichi Prefecture), has not progressed since July last year, when the excavator blade chipped during preparation work.
The Linear Central Shinkansen Line is planned to connect Shinagawa and Nagoya (285.6 km) in about 40 minutes. The project has been delayed until 2015 due to the unresolved conflict with Shizuoka Prefecture, which is concerned about the negative environmental impact of the line. (The project has been delayed until 2015 due to unresolved conflicts with Shizuoka Prefecture, which is concerned about the negative environmental impact of the line.)
◆"Vibration Concerns" and Concerns about the Ground Surface Caving in
The construction of the first Metropolitan Area tunnel for the Linear Central Shinkansen, which will be excavated to a depth of more than 40 meters, will begin by the end of March at three new sites in Kawasaki City and Machida City, Tokyo, using shield machines (excavators). Although the tunnel is called "investigation," the excavators will finally pass under the feet of the residents along the tunnel, and they are concerned about vibrations during the construction.
From November last year to January this year, JR Tokai held a total of eight explanatory meetings for residents near three emergency exits, including Higashi Yurigaoka (Asao-ku, Kawasaki City). The plan was to dig a tunnel where linear trains would actually pass through while collecting data on vibration and other issues during the survey excavation, and to take countermeasures if any problems were found before moving on to full-scale excavation.
The briefing was closed to the press. At a briefing held near the Higashi Yurigaoka emergency exit in late January, participants expressed concern about vibration, sinking and rising of the ground surface, and impact on groundwater, in contrast to JR Tokai's assertion that "adverse effects from the construction are unlikely.
There are still many people who do not know that the Linear Line will pass nearby. The company's stance was also questioned.
The digging began in response to the sinking of the Tokyo Outer Ring Road (Gaikan Expressway), but two of the preceding sites, including one in Shinagawa Ward, Tokyo, have been halted due to equipment malfunctions and other problems. A man in his 80s from Asao Ward, Kawasaki City, who attended the briefing said, "I am worried because the tunnel is underground and cannot be seen by anyone. There is no such thing as safe and secure construction. I want to ask again whether it is necessary to take the risk of building a linear Shinkansen line. (Jo Watabe, Mitsuharu Umeno)
The cause was a mistake in adding an additive to the excavator.
Info translated from Japanese News:
https://www.tokyo-np.co.jp/article/228523 Accessed: February 1, 2023 06:00