2013 Volume 19 Pages 51-56
The torrential rainfall by seasonal rain front caused rivers to severe flood at the north region of Kyushu in July 2012 and the right bank levee at 7.3km from the mouth of the Yabe River had been breached.
For identifying the mechanism of the levee breach, Ministry of Land, Infrastructure, Transport and Tourism (MLIT) conducted a series of surveys including geotechnical investigation and seepage analysis. It is found that sand stratum on the foundation ground had crossed the levee from riverbank to landside area. In this paper, it is presumed that the major cause of the levee breach is piping through the sand stratum due to lasting high water level along the levee.
