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Investigation excavation of Higashi Yurigaoka emergency exit 'completed without problems' JR Tokai's linear tunnel construction

　JR Tokai announced on October 2 that the construction of the first Metropolitan Area Tunnel of the Linear Central Shinkansen, to be dug more than 40 metres underground, was completed on September 29, after the excavation of the Higashi Yurigaoka Emergency Exit (Asao Ward, Kawasaki City) began in March. JR Tokai will compile the results of the survey and hold a briefing for local residents.
　JR had previously announced that the excavation from the emergency exit towards Nagoya would be 150 metres, but the actual excavation distance was 133 metres. JR claims that there are no problems because the excavation was completed at the distance necessary to install equipment behind the shield machine.
　Of the total length of the First Metropolitan Tunnel, which is about 37 kilometres, 33 kilometres are deep underground. The tunnel was excavated 124 metres from the Kitashinagawa emergency exit in Shinagawa Ward, Tokyo, 75 metres from the Kajigaya emergency exit in Miyamae Ward, Kawasaki City, and 17 metres from the Onoji emergency exit in Machida City, Tokyo.
The Kitashinagawa Emergency Exit, which will be reopened in May, was excavated 124 metres for the linear survey.

Source: Translated info from https://www.tokyo-np.co.jp/article/281229 Accessed: 2 October 2023

Linear Tunnel "Survey Digging" Suspended Again; Excavator Dents in Shinagawa, Shifting Inner Wall; JR Tokai: "No Safety Issues"　

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Source: https://www.tokyo-np.co.jp/article/282146 Accesssed October 6, 2023

　JR Tokai announced on October 6 that it has found damage to a shield machine (excavator) and will temporarily suspend excavation of a 300-meter section of the Linear Central Shinkansen tunnel from the North Shinagawa emergency exit (Shinagawa Ward, Tokyo) to the Nagoya direction. This section was scheduled to be excavated by March 2022 as an "exploratory excavation," but the excavation has been suspended twice, including this time. Only 124 meters have been dug, and the completion of the excavation is expected to be delayed until the end of 2012.

　According to JR Tokai, a part of the excavated soil gradually adhered and hardened at one spot on the outside of the excavator, and the pressure caused a 7 cm-deep dent toward the inside of the tunnel. This made it difficult to assemble the reinforced concrete segments (wall blocks) that would form the tunnel's inner walls, and some of the segments were assembled up to 3 cm inward. The company claims that it has no safety problems because it allows an error of up to 5 centimeters in assembly.

　This section of the Linear Central Shinkansen Line has the steepest curve between Shinagawa and Nagoya (curve radius 900m). The company believes that the cutter's method for digging out the curve can be improved to prevent soil from sticking to the curve, and after repairing the dents, excavation will resume next spring. The excavated section will be part of the First Metropolitan Tunnel, where linear trains will run in the future.
　The excavation began in October 2009 to investigate the effects of the construction of the Tokyo Outer Ring Road (Outer Ring Road) Tunnel, which, like the Outer Ring Road, is excavated at a depth of 40 meters or less below ground level, after sinkholes and cavities were found in the construction of the tunnel in Chofu City, Tokyo. Construction was suspended in March 2010 due to damage to the excavator, and resumed in May of this year. (Mitsuharu Umeno)

Source: https://www.tokyo-np.co.jp/article/282146 Accesssed October 6, 2023

Kitashinagawa emergency exit of the Linear Central Shinkansen (right) and stacked segments (wall blocks, bottom)
Source: https://www.tokyo-np.co.jp/article/282146 Accesssed October 6, 2023

JR Tokai announced on April 6 that the construction of a tunnel near Shinagawa Station in Tokyo, the starting point of the Linear Central Shinkansen Line, has been suspended again due to a problem with a shield machine, a large excavation machine. A part of the steel casing that houses the machine's equipment has been found to be deformed, and the work is expected to resume next spring. The shield machine is scheduled to be used in the Kazakoshi Tunnel in Iida City.

　Construction has been suspended at the Kitashinagawa section of the First Metropolitan Tunnel, where excavation of the "deep underground" began in October 2021 as part of an investigation excavation.

Source: Translated info from Japanese: https://www.shinmai.co.jp/news/article/ ... 3100700131 Accessed: 2023-10-07

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Source: https://www.shinmai.co.jp/news/article/ ... 3100700131 Accessed: 2023-10-07

Tokyo: linear maglev tunnel construction resumes

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Source: https://trafficnews.jp/post/132125 Accessed 2024-04-14

　On Monday 8 April 2024, JR Tokai resumed shield machine excavation of the First Metropolitan Area Tunnel (Kitashinagawa construction section) between Shinagawa Station and Kanagawa Station (tentative name) on the Linear Central Shinkansen Line. Excavation of this section had been suspended since July 2023, as the shield machine was being inspected underground near Yamate-dori Avenue, 124 m ahead from the Kitashinagawa emergency exit.

　The tunnel has a radius of 900 m after leaving Shinagawa Station, which is the steepest curve on the main line of the Linear Chuo Shinkansen between Shinagawa and Nagoya. The shield machine that proceeded through the curve was partially deformed due to excavated soil clogging the back of a steel cylinder called a skin plate, making it difficult to assemble the circular reinforced concrete wall to be constructed inside it.

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Source: https://trafficnews.jp/post/132125 Accessed 2024-04-14

　After an investigation by experts into the cause of the problem, work to restore the shape of the skin plate and confirmation that there was nothing wrong with the tunnel that had already been built, the shield machine was put into operation for the first time in about nine months. As a measure to prevent a recurrence, JR Tokai has stated that when excavating curved sections, the extra space outside the curve will be enlarged, and the positional relationship between the skin plate and the constructed wall and their respective shapes will be measured and confirmed.

　The total length of the First Metropolitan Tunnel is approximately 37 km, of which the Kitashinagawa section is approximately 8.2 km between the Kitashinagawa emergency exit and the Todoroki emergency exit, where the tunnel becomes almost straight from around the basement of JR East's Tokyo General Rolling Stock Centre.

Source: Translated news from https://trafficnews.jp/post/132125 Accessed 2024-04-14
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Source: https://trafficnews.jp/post/132125 Accessed 2024-04-14

Was it made in Japan or China?

Parrahub1 wrote: ↑

16. Apr 2024, 05:54

Was it made in Japan or China?

100% Japanese.

That explains it.