19-06-2023, 08:32 AM
![[Image: 01.JPG?__scale=w:500,h:333&_sh=0808607508]](https://cdn-xtech.nikkei.com/atcl/nxt/column/18/00142/01619/01.JPG?__scale=w:500,h:333&_sh=0808607508)
![[Image: 02.JPG?__scale=w:500,h:375&_sh=0590403a0a]](https://cdn-xtech.nikkei.com/atcl/nxt/column/18/00142/01619/02.JPG?__scale=w:500,h:375&_sh=0590403a0a)
19-06-2023, 08:34 AM
GOOGLE TRANSLATED ARTICLE
"Fortress" scaffolding to prevent falling rocks, Kitanomaki tunnel rock mass removal work
Sawato Tsutsui
2023.06.02
Countless scaffolding stands like a fortress. The height of the scaffolding is 70m, equivalent to a 30-story building. It is a masterpiece volume.
On May 16, 2023, the East Japan Expressway Company unveiled the site of the rock mass removal work on the upper part of the Kitanomaki Tunnel located between the Matsuida Myogi IC (interchange) and the Usui Karuizawa IC on the Joshinetsu Expressway. It was at that site that he built a fortress-like scaffolding. Over the past five years, temporary piers and scaffolding have been constructed for transporting materials and surplus soil. Various construction methods will be adopted to prevent falling rocks, as construction will be carried out directly above the expressway.
The Kitanomaki Tunnel is 190m long, and the rock mass is located above the tunnel gate on the Nagano side. In 1996, following the Toyohama Tunnel bedrock collapse accident that occurred in Furubira-cho, Hokkaido, the East Japan Expressway began investigation in the same year. From 2000 to 2002, ground anchors were used as countermeasures against cracks in the rock mass.
After that, additional surveys were conducted from 2009 to 2014, confirming the existence of areas at risk of collapse called "wedge blocks." Decided to remove the boulders. The designer of the removal work is OYO Corporation, and the contractor is Obayashi Corporation.
Rock masses will be removed by excavation using the hydraulic rock splitting method. Cracks are generated by driving a Japanese parsley arrow into a rock mass, and then the rock is crushed by a breaker. A construction method that uses explosives was also considered, but it was abandoned because it would take nearly a year to close the expressway and it could lead to the development of cracks. Excavate the top of the rock mass from the Tokyo side and protect the slope surface with concrete. In February 2017, the construction of temporary scaffolding and piers began as a preparatory stage for excavation.
Source: https://xtech.nikkei.com/atcl/nxt/column...142/01619/
"Fortress" scaffolding to prevent falling rocks, Kitanomaki tunnel rock mass removal work
Sawato Tsutsui
2023.06.02
Countless scaffolding stands like a fortress. The height of the scaffolding is 70m, equivalent to a 30-story building. It is a masterpiece volume.
On May 16, 2023, the East Japan Expressway Company unveiled the site of the rock mass removal work on the upper part of the Kitanomaki Tunnel located between the Matsuida Myogi IC (interchange) and the Usui Karuizawa IC on the Joshinetsu Expressway. It was at that site that he built a fortress-like scaffolding. Over the past five years, temporary piers and scaffolding have been constructed for transporting materials and surplus soil. Various construction methods will be adopted to prevent falling rocks, as construction will be carried out directly above the expressway.
The Kitanomaki Tunnel is 190m long, and the rock mass is located above the tunnel gate on the Nagano side. In 1996, following the Toyohama Tunnel bedrock collapse accident that occurred in Furubira-cho, Hokkaido, the East Japan Expressway began investigation in the same year. From 2000 to 2002, ground anchors were used as countermeasures against cracks in the rock mass.
After that, additional surveys were conducted from 2009 to 2014, confirming the existence of areas at risk of collapse called "wedge blocks." Decided to remove the boulders. The designer of the removal work is OYO Corporation, and the contractor is Obayashi Corporation.
Rock masses will be removed by excavation using the hydraulic rock splitting method. Cracks are generated by driving a Japanese parsley arrow into a rock mass, and then the rock is crushed by a breaker. A construction method that uses explosives was also considered, but it was abandoned because it would take nearly a year to close the expressway and it could lead to the development of cracks. Excavate the top of the rock mass from the Tokyo side and protect the slope surface with concrete. In February 2017, the construction of temporary scaffolding and piers began as a preparatory stage for excavation.
Source: https://xtech.nikkei.com/atcl/nxt/column...142/01619/
19-06-2023, 08:35 AM
![[Image: Vwx4TeGPJCacQF2.jpg]](https://img.bohaishibei.com/2023/06/18/Vwx4TeGPJCacQF2.jpg)