Improvement Of Caisson-Type Quay Wall To Suppress Tsunami Force

In general, the caisson-type quay walls can endure surging tsunamis with a good performance thanks to the earth pressure behind the caissons. However, the earth pressure deteriorates the situation by pushing the caissons under the backwash of the tsunamis. This stability depends on the states of the sensitive surroundings of the caissons, and its mechanism has not been comprehended sufficiently. In order to examine the stability of a caisson-type quay wall against the backwashes of the tsunamis, this study performs hydraulic experiments. And, the effectiveness of the soil solidification and influences of its damage are examined. From the experiments, the solidified backfill enhances the stability of the caisson-type quay wall against overflowing tsunamis even with a damage of the solidified part. Compensating parameters to evaluate overflowing tsunami forces are obtained from the experiments, and the sea-side parameter α_r gets stable values as 1.0 < α_r <1.0+0.1/h^*, while the land-side parameter α_f gets various values depending on the models. The solidified part gains stability and the peak force is reduced by 20% to that without the solidified part. Moreover, if the overflow depth or the sea-side water level gets deeper, the land-side force is reduced more effectively by the solidified part.