[JP] Ground Uplift Detected Above Maglev Tunnel Site in Tokyo

[Miss Maglev]

Ground Uplift Detected Above Linear Shinkansen Tunnel Site in Tokyo — JR Central Launches Investigation

Central Japan Railway Company (JR Central) announced that it is investigating a ground uplift that occurred in Shinagawa Ward, Tokyo, above the tunnel construction zone for the Linear Chuo Shinkansen (Maglev) project.

At approximately 8:30 a.m. on Sunday, Shinagawa Ward officials notified JR Central of an irregularity on a local roadway. Upon inspection, the company confirmed that the ground near an intersection in Nishi-Shinagawa had risen, creating a height difference of up to 13 centimeters between the sidewalk and the roadway.

The affected area lies roughly 80 meters above a section where a shield tunneling machine is excavating tunnels for the Linear Chuo Shinkansen, the next-generation maglev train line designed to connect Tokyo and Nagoya in about 40 minutes.

JR Central stated that it is conducting a detailed analysis to determine whether the uplift is related to the tunneling operation. The company has also begun safety inspections in the surrounding area to ensure there is no further risk to local infrastructure or residents.

“We are taking this matter seriously and will continue to investigate the cause while prioritizing the safety of the community,”

a JR Central spokesperson said.

Info based on: https://article.auone.jp/detail/1/3/6/3 ... 1196409796 Accessed 2025-10-28

[latestnews]

品川区のリニア大深度トンネル上で路面隆起、段差13cm　工事との関連調査へ
Road Surface Uplift Detected Above Linear Maglev Tunnel Site in Tokyo’s Shinagawa Ward

Tokyo, Oct. 31, 2025 — A section of roadway in Tokyo’s Shinagawa Ward experienced ground uplift of up to 13 centimeters (about 5 inches) directly above an area where JR Central is constructing a deep-underground tunnel for the Linear Chuo Shinkansen (maglev) line.

At around 8:30 a.m. on October 28, the Shinagawa Ward Office alerted JR Central to an uneven road surface. Company staff confirmed that the deformation occurred almost directly above the excavation zone, where the vehicle lane and sidewalk had shifted, creating a visible step in the pavement.

JR Central has halted all tunneling work at the site and launched an investigation to determine whether the uplift is linked to ongoing construction activities. The incident adds to growing safety and cost concerns surrounding the Linear Maglev project, already delayed and facing soaring expenses.
Info based on: Source: https://xtech.nikkei.com/atcl/nxt/colum ... 142/02438/ Accessed 2025-10-31
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PHOTO: https://xtech.nikkei.com/atcl/nxt/colum ... 142/02438/ Accessed 2025-10-31

[Parrahub1]

I doubt if that small damage would have occurred if they had used Chinese TBM technology.

[latestnews]

In Shinagawa, Tokyo, a road near the site of tunnel excavation for the Linear Chuo Shinkansen experienced an uplift measuring up to 13 centimeters in height last month.
Mayor Kyoko Morisawa of Shinagawa emphasized the critical importance of verifying the implementation of countermeasures, prioritizing the safety and well-being of local residents by adopting a firm and resolute approach. The railway operator, JR Tokai, has temporarily suspended construction activities pending a thorough investigation into the cause of the anomaly, with onsite excavation and inspection scheduled to commence on November 20.
This incident underscores the ongoing challenges associated with large-scale urban infrastructure projects and the imperative of stringent safety oversight during the development of high-speed rail systems in Tokyo.

Info based on: https://topics.smt.docomo.ne.jp/amp/art ... -000466703 Accessed 2025-11-16

[Parrahub1]

It is relativly small but what do you expect with last century drill and blast.

[Eurorapid]

リニア新幹線工事関連か 路面が隆起　JR東海が掘削調査を開始
Road Heave Near Maglev Construction Site in Tokyo Prompts Investigation

A section of roadway near the Linear Chuo Shinkansen (Maglev) construction site in Tokyo’s Shinagawa Ward has buckled, prompting JR Central (JR Tokai) to halt tunneling work and launch a detailed on-site investigation.

On the 28th of last month, officials confirmed that a stretch of road about 10 meters (roughly 33 feet) long had risen by up to around 13 centimeters (about 5 inches). The deformation was found close to an active construction area for the Linear Chuo Shinkansen, the planned Maglev line that will eventually link Tokyo and Nagoya.

Roughly 80 meters (about 260 feet) below the affected section, JR Central has been excavating a tunnel for the new line. Starting on the 20th, the company began digging down up to about 3 meters from the surface around the buckled area to better understand what caused the uplift and whether ground conditions have changed around the tunnel.

At this stage, JR Central says the relationship between the surface heave and the Maglev tunnel construction is still under investigation. As a precaution, tunnel excavation work in that section has been suspended while engineers analyze soil conditions and monitor for any further movement.

The Linear Chuo Shinkansen is one of Japan’s largest ongoing infrastructure projects, designed to use superconducting Maglev technology to dramatically cut travel time between major cities. Because of its scale and the depth of the tunnels under dense urban areas, any sign of surface deformation is being watched closely by both authorities and the public.

For now, the focus is on confirming safety in the surrounding area, determining the exact cause of the road heave, and deciding how and when tunneling work can safely resume. Further updates from JR Central and local authorities are expected as the investigation progresses.

Info based on: https://news.tv-asahi.co.jp/news_societ ... 67650.html Accessed 2025-11-22

[Parrahub1]

リニア新幹線工事関連か 路面が隆起　JR東海が掘削調査を開始
Road Heave Near Maglev Construction Site in Tokyo Prompts Investigation

A section of roadway near the Linear Chuo Shinkansen (Maglev) construction site in Tokyo’s Shinagawa Ward has buckled, prompting JR Central (JR Tokai) to halt tunneling work and launch a detailed on-site investigation.

On the 28th of last month, officials confirmed that a stretch of road about 10 meters (roughly 33 feet) long had risen by up to around 13 centimeters (about 5 inches). The deformation was found close to an active construction area for the Linear Chuo Shinkansen, the planned Maglev line that will eventually link Tokyo and Nagoya.

Roughly 80 meters (about 260 feet) below the affected section, JR Central has been excavating a tunnel for the new line. Starting on the 20th, the company began digging down up to about 3 meters from the surface around the buckled area to better understand what caused the uplift and whether ground conditions have changed around the tunnel.

At this stage, JR Central says the relationship between the surface heave and the Maglev tunnel construction is still under investigation. As a precaution, tunnel excavation work in that section has been suspended while engineers analyze soil conditions and monitor for any further movement.

The Linear Chuo Shinkansen is one of Japan’s largest ongoing infrastructure projects, designed to use superconducting Maglev technology to dramatically cut travel time between major cities. Because of its scale and the depth of the tunnels under dense urban areas, any sign of surface deformation is being watched closely by both authorities and the public.

For now, the focus is on confirming safety in the surrounding area, determining the exact cause of the road heave, and deciding how and when tunneling work can safely resume. Further updates from JR Central and local authorities are expected as the investigation progresses.

Info based on: https://news.tv-asahi.co.jp/news_societ ... 67650.html Accessed 2025-11-22

13 cm is relatively small and if they had used Chinese TBM there would have been none.

Japan has to use Chinese TBM tech to sell their SC maglev with overnight container trains that allow daytime fares to be lower than planes.

Australia wants to be friendly with both.

[latestnews]

リニア大深度トンネル上で隆起、現場を掘削して工事との因果関係調査
Info based on https://xtech.nikkei.com/atcl/nxt/mag/n ... 121100062/ Accessed 2025-12-22
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2025-12-18_NIkkei-01

. Source: https://cdn-xtech.nikkei.com/atcl/nxt/m ... 2/8_02.jpg Accessed 2025-12-22

A road-surface heave occurred near a deep underground tunneling site in Shinagawa Ward, Tokyo, where construction is underway for the Chuo Shinkansen (Linear/Maglev). JR Tokai began an on-site excavation investigation to determine whether the tunneling work caused the heave and suspended tunneling operations after the issue was discovered.

JR Tokai said Shinagawa Ward reported a “step in the roadway” at about 8:30 a.m. on October 28, 2025. Company staff confirmed a height difference of up to 13 cm between the roadway and the sidewalk on a ward road located almost directly above the excavation line. The work in this area is being carried out by a joint venture of Kumagai Gumi, Daiho Corporation, and Tokura Construction on the Kita-Shinagawa section of the “First Metropolitan Area Tunnel.”

A mud-pressure shield machine with an outer diameter of about 14 m launched in October 2021 from the vertical shaft for the “Kita-Shinagawa emergency exit.” The machine has advanced about 500 m and is currently stopped roughly 5 m short of the heave location. The overburden at this point is about 80 m. While the project does not set a formal surface-displacement management limit, it uses 1/1000 radian as a guideline threshold; no measured displacement exceeded that guideline through the day before the heave was identified.

In response, Shinagawa Ward formally requested that JR Tokai quickly identify the cause and not resume shield advance until the cause is known. The ward cited residents’ concerns, referencing two previous tunneling suspensions due to shield-machine issues and reports of bubble formation in the Meguro River believed to be related to the construction.

2025-12-18_NIkkei-02

Normally, air underground is blocked by clay layers, but it can rise through boreholes and other openings. (Source: Created by Nikkei Cross Tech based on JR Central materials)
Source: https://cdn-xtech.nikkei.com/atcl/nxt/m ... 2/8_03.jpg Accessed 2025-12-22

The first shield-machine problem in this section was identified during “survey advance” work intended to confirm construction impacts on the surrounding area. After reduced advance efficiency was observed, the machine was stopped in March 2022 and part of the additive injection system was found to be faulty. After a suspension of more than a year, tunneling resumed in May 2023. Soon after, segment alignment difficulties occurred; the machine was stopped again in July 2023, and an indentation up to about 7 cm deep was found in the steel outer shell. This second suspension lasted about nine months, with tunneling resuming in April 2024.

Following the October 2025 heave, JR Tokai started an excavation survey near the site on November 20, 2025. The company is restricting lanes during weekday daytime hours over a roughly 40 m stretch and excavating to depths of about 0.5–3 m to check ground conditions and the status of utilities and other lifeline infrastructure.

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2025-12-18_NIkkei-03

. North Shinagawa Emergency Exit of the Launch Shaft (Photo: Nikkei Cross Tech)
Source: https://cdn-xtech.nikkei.com/atcl/nxt/m ... /8_04p.jpg Accessed 2025-12-22

A geotechnical engineering specialist, Associate Professor Shoji Kamao of Nihon University, suggested the heave may be related to foaming agent used during tunnel excavation. In mud-pressure shield tunneling, a cream-like foaming agent is injected to increase soil flowability; he noted that bubbles and/or compressed air could migrate upward, accumulate near the surface, and then rapidly lift pavement. JR Tokai reported that radar surveys after the event found no voids down to 1.5 m, but Kamao cautioned that compressed air could still accumulate in gaps within sand layers or road base materials even without a detectable void.

Info based on https://xtech.nikkei.com/atcl/nxt/mag/n ... 121100062/ Accessed 2025-12-22

[Parrahub1]

I think they will try any way to stop it.

[latestnews]

Shinagawa Ground Heave Above Maglev Tunnel: JR Tokai Cites Air Leak, MLIT Calls Management “Inadequate”

On December 30, 2025, lawmakers and local officials urged Japan’s Ministry of Land, Infrastructure, Transport and Tourism (MLIT) to more aggressively press JR Tokai to clarify responsibility for the ground-surface heave that occurred in October 2025 above the Linear Chuo Shinkansen tunneling site in Shinagawa, Tokyo.

According to the article, JR Tokai has acknowledged that the construction work caused the heave. The company says that air accumulated in a “chamber” used to control pressure at the tunnel face and then leaked out in a large amount over a short period, pushing up the pavement. JR Tokai also stated that its frequency and volume of air release (venting) were insufficient.

MLIT officials reportedly responded that construction management was inadequate and said they would instruct JR Tokai to respond carefully to local residents.

Japanese Communist Party representatives—Senator Taku Yamazoe, Tokyo Metropolitan Assembly member Ryoko Fujita, and the party’s Shinagawa Ward council members—argued that JR Tokai should attend such meetings directly and pressed MLIT on why construction management failed. They also criticized the lack of disclosure, saying that even survey data had not been made public, and urged MLIT to demand clarification of the facts rather than defend the company.

Participants further criticized JR Tokai’s plan to resume tunneling after an explanatory meeting in February (next year), arguing that the company’s outreach is inadequate—citing, for example, a classroom-style briefing lasting only a little over one hour and an on-site office that reportedly limits entry to three people at a time. MLIT indicated it would convey concerns, saying it would tell JR Tokai that the “three-person” limit should be reconsidered and that it would relay feedback that the meeting duration is too short.

Info based on / translated from https://www.jcp.or.jp/akahata/aik25/202 ... 1_01_0.php Accessed 2025-12-31

[Parrahub1]

It seems to me the Japanese communist party want the SC maglev stopped because if China cannot do it nobody else can.