CRITICAL LIMIT OF DAMAGE OF COASTAL DIKE IN TERMS OF BEACH WIDTH AND CROSS-SHORE AREA OF BEACH

Abstract

 As the characteristic parameters to consider the damage potential of the stability of coastal dike associated with the shoreline recession, beach width in front of the coastal dike, which can be easily confirmed in the field, and cross-sectional area of the beach between the berm height h_R and the depth of closure h_c were considered. The examples at the Ryuyo, Hamamatsu-goto, and Hamamatsu-shinohara coasts were investigated. On the basis of the time changes in beach width obtained from the past aerial photographs and the cross-shore area of the beach calculated from the annual bathymetric survey, the critical limit for damage of the coastal dike was obtained.