Seismic Behavior of the River Embankment Improved with the Steel Sheet Piling Method

抄録

In recent years, the steel sheet piling method is used as a countermeasure against soft ground for the purpose of reducing the subsidence of the surrounding ground and lateral displacement. Among them, the partial floating steel sheet piling method (called “the PFS method”) constructs a stress blocking wall by alternately placing short-length floating steel sheet piles and long-length conventional steel sheet piles, and is a new construction method to decrease settlement of the embankment side. In addition, it is possible to decrease the subsidence of the ground around the embankment, and it is excellent in terms of workability and economy. This method has been applied as a subsidence countermeasure for river embankments in Kumamoto Prefecture, Japan. However, in April 2016, a massive earthquake occurred in Kumamoto prefecture that recorded a maximum magnitude of 7.3, causing damage such as subsidence in the embankment of the rivers in Kumamoto plain where the PFS method was used. From these backgrounds, the objective of this paper is to report the damage of river embankment caused by the 2016 Kumamoto earthquake and to evaluate the effectiveness of steel sheet pile structure including the PFS method as an earthquake countermeasure.