Waterway Improvement Work with Underwater Tubular Pile Walls Driven by the Press-in Piling Method

Self-standing, underwater, tubular, pile retaining walls were constructed as part of Japan's Port of Miike waterway improvement project to protect the foundation of the existing breakwater and levee structures from failure as well as to keep the dredged seafloor from being filled in. The design pile top elevation was 0.5 meter below Datum Level, or more than 5 meters below High Water Level due to the wide tidal range of up to 6 meters at the project site. In order to achieve the underwater piling operations, the press-in piling method with specially developed tools was adopted to drive the tube piles all the way to the seafloor. The piling work was conducted safely and accurately from above water. The method also made it possible to shorten the construction period, as well as to minimize disruptions to vessels' navigation during the construction period compared with other piling methods considered.