Published Date
, Volume 20, Issue 1, pp 230–235
Title
Examining effects of tree roots on shearing resistance in shallow landslides triggered by heavy rainfall in Shobara in 2010
Ushio Kurokawa
Short Communication
Cite this article as:
Okada, Y. & Kurokawa, U. J For Res (2015) 20: 230. doi:10.1007/s10310-014-0470-1
Abstract
The long-term accumulation of precipitation was accompanied by a seasonal rain front (known as the Baiu front) covering wide areas of western and central Japan during the period 11–16 July 2010. In Shobara city, Hiroshima prefecture, more than a thousand shallow landslides occurred within a very limited area (9 km2 = 3 × 3 km) during the afternoon of 16 July 2010, claiming one fatality. In the source areas on steep slopes, meanwhile, volcanoclastic soil slid due to the heavy rainfall, then fluidised to flow over long distances. Landslides appeared to occur on all slopes; not only young forests but also mature forests. A field investigation revealed a case where slides occurred in young Japanese cypress (Chamaecyparis obtusa) forests, but surface water only flowed over the ground in mature Japanese cypress forest sandwiched by the young forests, while the side ends of the slides reached the edge of the mature forest. To examine the differences between both forests, simplified cone penetration tests, tests on tree root distribution in trenches, tree root pull out tests, soil samples, and geotechnical soil tests were all conducted. Although the number of lateral roots found in the trenches differed little, the root diameters in the mature forest exceeded those in the young forest. The thicker and stronger root in the mature forest would, thus, help prevent shallow landslides.
References
For further details log on website :
http://link.springer.com/article/10.1007/s10310-014-0470-1
, Volume 20, Issue 1, pp 230–235
Title
Examining effects of tree roots on shearing resistance in shallow landslides triggered by heavy rainfall in Shobara in 2010
Short Communication
- First Online:
- 06 November 2014
DOI: 10.1007/s10310-014-0470-1
Abstract
The long-term accumulation of precipitation was accompanied by a seasonal rain front (known as the Baiu front) covering wide areas of western and central Japan during the period 11–16 July 2010. In Shobara city, Hiroshima prefecture, more than a thousand shallow landslides occurred within a very limited area (9 km2 = 3 × 3 km) during the afternoon of 16 July 2010, claiming one fatality. In the source areas on steep slopes, meanwhile, volcanoclastic soil slid due to the heavy rainfall, then fluidised to flow over long distances. Landslides appeared to occur on all slopes; not only young forests but also mature forests. A field investigation revealed a case where slides occurred in young Japanese cypress (Chamaecyparis obtusa) forests, but surface water only flowed over the ground in mature Japanese cypress forest sandwiched by the young forests, while the side ends of the slides reached the edge of the mature forest. To examine the differences between both forests, simplified cone penetration tests, tests on tree root distribution in trenches, tree root pull out tests, soil samples, and geotechnical soil tests were all conducted. Although the number of lateral roots found in the trenches differed little, the root diameters in the mature forest exceeded those in the young forest. The thicker and stronger root in the mature forest would, thus, help prevent shallow landslides.
References
- Abe K (1997) A method for evaluating the effect of tree roots on preventing shallow-seated landslides. Bull For For Prod Res Inst 373:105–181 (in Japanese with English abstract)
- Abe K, Ziemer RR (1991) Effect of tree roots on a shear zone: modelling reinforced shear stress. Can J For Res 21:1012–1019CrossRef
- Cruden DM, Varnes DJ (1996) Landslide types and processes. In: Turner AK, Schuster RL (eds) Landslides, investigation and mitigation: Special report 247. Transportation Research Board, National Research Council, Washington DC, pp 501–516
- Japan Meteorological Agency (2010) http://www.datakishou.go.jp (in Japanese)
- Kaibori M, Sugihara S, Nakai S, Araki Y, Yamakoshi T, Hayashi S, Yamashita Y (2010) Prompt investigation report on the sediment-related disaster on July 16, 2010, in Shobara-City, Hiroshima prefecture. J Jpn Soc Eros Control Eng 63(4):30–37 (in Japanese with English abstract)
- Kitahara H (2010) Effect of tree root systems on slope stability. Water Sci 53(6):11–37 (in Japanese)
- Osanai N (2007) Site prediction of shallow landslides by means of simplified cone penetration tests. Found Eng Equip Mon 35(11):19–22 (in Japanese)
- Tsukamoto Y (1987) Evaluation of the effect of tree roots on slope stability. Bull Exp For Tokyo Univ Agric Technol 23:65–124 (in Japanese with English abstract)
For further details log on website :
http://link.springer.com/article/10.1007/s10310-014-0470-1
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