The dynamic behavior of a caisson-type quay wall resting on a pile foundation against the 1995 Hyogo-ken Nanbu Earthquake was numerically evaluated by an effective stress liquefaction analysis. The deformation during the earthquake ground motion was mainly due to an increase in the excess pore water pressure in the reclaimed land behind the caisson-type quay wall. We also studied the effect of liquefaction countermeasures in the reclaimed land on the dynamic behavior of the caisson structure using some numerical examples. The feasibility of using non-liquefied material in the reclaimed land was investigated from the viewpoint of deformation control during the earthquake motion. Further, we considered the differences in the connection condition between the caisson structure and the pile foundation and also on the pile length. The application of non-liquefied material to the reclaimed land behind the caisson structure has a significant effect on the final residual deformation of the caisson structure.
The investigation of earthquake damage due to the 1995 Hyogo-ken Nanbu Earthquake shows that the damage to the quay walls was mostly triggered by the strong acceleration force of the earthquake. This acceleration force exceeded the maximum horizontal force of the waves used in the design of the facilities inside the harbor. The harbor facilities without a structurally resistant design against severe waves were greatly damaged by the acceleration force of the strong earthquake. In addition to the direct damage from the acceleration force of the earthquake, many of the port and harbor structures suffered sever damage from liquefaction. It is economically impractical to make all harbor facilities seismically resistant to strong earthquakes. Port and harbor structures, such as the quay or the jetty, are important for moving goods to/from overseas, and they also play a key role in the emergency response in case of disaster.
