著者
Kimio INOUE Toshio MORI Takahisa MIZUYAMA
出版者
Japan Society of Erosion Control Engineering
雑誌
International Journal of Erosion Control Engineering (ISSN:18826547)
巻号頁・発行日
vol.5, no.2, pp.134-143, 2012 (Released:2012-12-27)
参考文献数
19
被引用文献数
2 3

Large landslides or debris flows caused by heavy rainfall or earthquakes often block rivers in mountainous areas and form landslide dams. The area upstream of the landslide dam is submerged under water and the downstream area is flooded when the landslide dam breaks. In recorded history, as many as 22 landslide dams have formed upstream of the Shinano River and the Hime River, in the northern part of Nagano Prefecture in central Japan, and all except three have subsequently broken. This abundance of landslide dams is probably caused by the geotectonic background of this area, which is located at the western end of the “Fossa Magna” major tectonic line. In this study, we examined three large historical landslide dams and outburst disasters in the north Fossa Magna area.
著者
Laurentia DHANIO Takahisa MIZUYAMA Ken'ichirou KOSUGI Agnes RAMPISELA
出版者
Japan Society of Erosion Control Engineering
雑誌
砂防学会誌 (ISSN:02868385)
巻号頁・発行日
vol.61, no.4, pp.32-38, 2008-11-15 (Released:2013-09-02)
参考文献数
8

The collapse of caldera walls of Mt. Bawakaraeng on 26th of March 2004 in South Sulawesi is one of the largest mass movements in the history of Indonesia. The collapsed material, calculated at approximately 232 million m3, covers 8 km of the upstream part of Jeneberang River. The main purpose of this research is to evaluate the magnitude of the impact on the change of basin and how the impact decreases over time. A given amount of rainfall produces less discharge after the collapse and peak flows which normally occurred in the months of January are now found in the months of March. Before the collapse, every daily amount of rainfall corresponds to 0.6 value of daily discharge, though in 2006, it decreased to 0.45. Daily discharges are mostly low flows (less than 5 mm/day) except in the year of the collapse (2004). After the collapse, medium flows occurred more frequently and high flows (flow of over 90 mm/day) occurred in less frequency and lower values. Analysis of turbidity and discharge relationship at Bili-bili Dam located 31 km downstream of the collapse may be applied to understand the sediment exhaustion and the basin's potential rates of recovery. Bili-bili Dam's maximum turbidity rate increased significantly from 407 Nephelometric Turbidity Units (NTU) to 125,159 NTU after the collapse and turbidity's respond to discharge alters after the collapse. Peak turbidity rates normally fall faster than the discharge falling limb ; nonetheless after the collapse, both values fall by approximately 50% daily.
著者
辰野 良秋 堀内 照夫
出版者
Japan Society of Erosion Control Engineering
雑誌
新砂防 (ISSN:02868385)
巻号頁・発行日
vol.1959, no.32, pp.21-26, 1959

(1) 霜柱は一般に土壤を混んじて上長し, これが土壤侵蝕, 斜面緑化不成功の原因になるが, 展圧された土壤面, 新しい盛土, 切土面から発生する霜柱は, 土壤中の水分を多量に析出するが, 扛起する土量は非常に少い。<br>(2) 発生する霜柱の量は, 土壤条件が一様であれば気温が零度以下にある間の積算温度に比例する。また積算温度は最低気温に比例する。<br>(3) 藁伏工は気温が低くない間は (-3°程度まで) 効果は著しいが, それ以下に低下すれば効果は半減する。しかしながら裸地に比較すると霜柱発生量は少く, 発生する霜柱も土壤表面から出るので, 侵蝕防止的にも, 斜面混播保護の面からも効果は期待出来るが, 藁の量, 伏せ方等には問題が残された。この場合3本並べが良いと考えられた。<br>(4) 霜柱, 凍上現象は斜面の方位によつて著しく趣を異にするが, 斜面の上, 下の部位によつても異る。<br>(5) 土壤改良剤の土質改良効果は粘質土に対する場合, アロンA-20pに顕著な効果が認められ, 霜柱の発生を防ぐことは出来たが, 受蝕性が却つて大となつた。