Seismic Damage Investigation for River Levees Reinforced by Steel Sheet Piling Method Due to the 2016 Kumamoto Earthquake

As for ground reinforcement technology, there are a conventional steel sheet piling method (called “the CS method”) penetrating steel sheet piles to support layer, a floating steel sheet piling method (called “the FS method”) not penetrating to support layer, and partial floating steel sheet piling method (called “the PFS method”) that is combined the FS method and the CS method. These piling methods has been widely used for river levees in Kumamoto prefecture, Japan. In April 2016, earthquakes occurred in Kumamoto prefecture that recorded a maximum magnitude of 7.3, causing damage such as ground settlement and liquefaction in the Kumamoto plain, Japan. The objective of this study is to investigate the damage of river levee caused by the 2016 Kumamoto earthquake and to evaluate the effectiveness of the steel sheet piling method as a countermeasure against earthquake. Seismic damage of the river levee reinforced with the steel sheet piling method was analysed in terms of both liquefactions of river levee body and foundation ground.