千曲川堤防における裏のり尻付近の基盤漏水・噴砂発生箇所の土質・地下水位と旧河道特性の関係

抄録

The distribution of former river beds in alluvial fans and floodplains has been investigated in the Chikuma river. Relations between levee, soil characteristics, groundwater level, and former river beds at the landside levee toe are studied for prevention of levee breach. The soil characteristics are investigated by simple field tests of Swedish weight sounding along the landside levee toe. Based on the spatial relation of the levee and the former river beds and height difference among groundwater, ground surface, and Swedish sounding tests, locations of foundation leakage and sand boilings were able to be found.