基盤漏水に伴う噴砂及びパイピング進行条件の検討

抄録

A river levee of the Yabe River was breached due to piping failure induced by prolonged high water levels following heavy rains in Northern Kyushu in 2012. The piping failure was caused by water infiltration into the highly permeable sand and gravel foundation under the clay levee body. However, some levees with similar foundations were deformed but did not fail. In addition, the current judging method for determining the breaking point, is necessary to provide a new evaluation. Therefore, it is necessary to scrutinize the piping system. Piping phenomenon from the results of previous studies and model experiments are divided into three stages, boiling, piping and penetration of the pipe hole. It was carried out to verify the dominant factors for each of the phenomenon. In this report, we clarified the factors that govern the respective phenomenon, and summarized about the piping mechanism as a flow chart.