Journal of the Japan Society of Erosion Control Engineering, Vol.63,No.4,2010

Study on hillside landslides caused by typhoon T0421 in Miyagawa]dam basin, Mie prefecture

Chie KUROIWA and Shinya HIRAMATSU


Abstract

Many hillside landslides and debris flows occurred by typhoon T OSQP in Miyagawa village ithe present Odai townj on SeptemberQX, QOOS. These caused severe sediment]related disasters. In this study, several findings on the influence of precipitation, slope angle and forest practice on hillside landslides caused by typhoon TOSQP were shown in Miyagawa]dam basin as followsFPjCorrelation between precipitation and collapsed area ratio was not clear. QjAngle of collapsed slope in deforestation sites was T|POlower than those of non]forestation and reforestation sites. RjCollapsed area in deforestation sites occupied TV in total collapsed area. SjMost of landslides were occurred since PO to QO years after deforestation. TjMore hillside landslides observed in larger deforestation area. UjA prediction model of slope stability changes considering forest practice iKuroiwa and Hiramatsu, QOOSj was applicable to Miyagawa]dam basin. As the result of this simulation, collapsed area is generally in proportion to collapsing possibility area ratio index iAPhritjj. VjAngle of collapsed slope and APhritjand collapsed area ratio showed significant correlation.


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