CONTROLLING EFFECT OF LONGSHORE SAND TRANSPORT BY DETACHED BREAKWATERS WITH PERMEABLE PILE STRUCTURE

Abstract

 At Mihono-matsubara on the Shimizu coast, a plan was determined to build L-shape groins in place of the ordinary wave dissipating breakwaters using concrete armor units as a measure against beach erosion with the improvement of the coastal scenery. This L-shape groin employs the detached breakwater with pile structures as the head part of the breakwater. Before the construction, it was required that the controlling effect of longshore sand transport is clarified. To this purpose, beach changes around the L-shape groins to be constructed on the Shimizu coast were predicted using the contour-line-change model including the effect of sand back pass from the north end of the Shimizu coast.