3:30 PM - 3:50 PM
[U11-05] Slope Disasters and Earth Structure Damages on Roads by 2024 Noto Peninsula Earthquake and Heavy Rain in September 2024
★Invited Papers
Keywords:earthquake, heavy rain, road, slope, earth structure
Main damages of slopes and earth structures on roads by 2024 Noto Peninsula Earthquake are embankment collapses on Noetsu Expressway and Noto Satoyama Kaido Road, and slope disasters on the coastwise section of Route 249 (north coast of Noto Peninsula).
Large scale embankment collapses on Noetsu Expressway and Noto Satoyama Kaido Road occurred at 28 sites (reported by the material of committee for restoration of roads from damages by 2024 Noto Peninsula Earthquake). However, damages of restored embankments with reinforcement and sufficient drainage after damages by 2007 earthquake were slight.
Slope disasters on the coastwise section of Route 249 occurred at 58 sites, in total of natural slope failure, cut slope failure and deep-seated landslide (reported by the material of committee for restoration of roads from damages by 2024 Noto Peninsula Earthquake). And tunnel damages at 2 sites were caused by deep-seated landslides.
One of the characteristics of damages on the coastwise section of Route 249 is the cutting of road by deep-seated landslide at many sites. Geological map of Japan, 1:50000, Suzumisaki, Noto-iida and Horyuzan (Geological Survey of Japan, AIST) indicates that the bedding plane mainly dips toward the sea in this coastwise area, and it is supposed that dip-slope landslide occurred. However, it is very difficult find the site lik this before disaster, and also it is difficult to make countermeasures by structures against these large scal phenomena. Therefore, in the Road Technology Committee of the Ministry of Land, Infrastructure, Transport and Tourism, the direction of policy to avoid these sites by selecting the road route before designing of road structures has been discussed.
At the heavy rain in September 20 to 23, 2024, 412mm of maximum rainfall depth in 24 hours and 121mm of maximum rainfall depth in 1 hour were observed at Wajima City. These observed rainfall data are maximum values from the beginning of observation. Slope disasters on the coastwise section of Route 249 occurred newly at 83 sites by this heavy rain, in total of natural slope failure, cut slope failure, deep-seated landslide and debris flow (reported by the material of committee for restoration of roads from damages by 2024 Noto Peninsula Earthquake). And 34 sites which were damaged by the earthquake were damaged again by the heavy rain. Especially, the section from north entrance of Nakaya Tunnel to 2km north toward the central Wajima were damaged severely by debris flows from slopes more than 100m high from the road, erosion by river flood and slope failures.
Large scale embankment collapses on Noetsu Expressway and Noto Satoyama Kaido Road occurred at 28 sites (reported by the material of committee for restoration of roads from damages by 2024 Noto Peninsula Earthquake). However, damages of restored embankments with reinforcement and sufficient drainage after damages by 2007 earthquake were slight.
Slope disasters on the coastwise section of Route 249 occurred at 58 sites, in total of natural slope failure, cut slope failure and deep-seated landslide (reported by the material of committee for restoration of roads from damages by 2024 Noto Peninsula Earthquake). And tunnel damages at 2 sites were caused by deep-seated landslides.
One of the characteristics of damages on the coastwise section of Route 249 is the cutting of road by deep-seated landslide at many sites. Geological map of Japan, 1:50000, Suzumisaki, Noto-iida and Horyuzan (Geological Survey of Japan, AIST) indicates that the bedding plane mainly dips toward the sea in this coastwise area, and it is supposed that dip-slope landslide occurred. However, it is very difficult find the site lik this before disaster, and also it is difficult to make countermeasures by structures against these large scal phenomena. Therefore, in the Road Technology Committee of the Ministry of Land, Infrastructure, Transport and Tourism, the direction of policy to avoid these sites by selecting the road route before designing of road structures has been discussed.
At the heavy rain in September 20 to 23, 2024, 412mm of maximum rainfall depth in 24 hours and 121mm of maximum rainfall depth in 1 hour were observed at Wajima City. These observed rainfall data are maximum values from the beginning of observation. Slope disasters on the coastwise section of Route 249 occurred newly at 83 sites by this heavy rain, in total of natural slope failure, cut slope failure, deep-seated landslide and debris flow (reported by the material of committee for restoration of roads from damages by 2024 Noto Peninsula Earthquake). And 34 sites which were damaged by the earthquake were damaged again by the heavy rain. Especially, the section from north entrance of Nakaya Tunnel to 2km north toward the central Wajima were damaged severely by debris flows from slopes more than 100m high from the road, erosion by river flood and slope failures.