Experimental Study on the Damage Process of Gentle-Slope Sea Dike Attacked by the Severe Irregular Waves for Hours Together

Abstract

The experiments on the damage of gentle-slope sea dike were conducted by using the irregular waves.The gentle-slope dikes of 1/3, 1/4 and 1/5 slope were constructed at the shoreline and the offshore side .The mutual relationship between the damage of sea dike and the relative maximum scoring (hmax/Ho) in front of dike was sufficiently estimated from the result of experiments. In the case of l t/Lo=-0.2, as the value of slope angle increase, the value of hmax/Ho becomes large and damage of dike becomes early.On the other, in the case of l t/Lo=0.0, as the value of slope angle increase, the value of hmax/Ho becomes small, but the damage of dike did not occurs within the limits of these experiments.Damage proceeded in the order as follows:(1) vanishing of sands on the slope, (2) damage of foundation works, (3)piping of backfilling stones, (4) subsidence of armor unit. This damage process agreed well with the result of experiments by the regular waves.