The dynamic behavior of a caisson-type quay wall resting on a pile foundation during the 1995 Hyogo-ken Nanbu Earthqtuake was evaluated numerically by liquefaction analysis, which was based on an effective stress model. The effective stress model used for liquefaction analysis during the earthquake gound motion was based on the strain space multiple mechanism theory. The effect of the application of a pile foundation to a caisson-type quay wall was studied by liquefaction analyses. The deformation during the earthquake ground motion was caused by an increase in the excess pore water pressure in the ground behind the caissontype quay wall. The displacement of the caisson-type quay wall with a pile foundation was smaller than that of the caisson-type quay wall without a pile foundation. However, the deformation was mainly induced by the increase in the excess pore water pressure, regardless of the existence of the pile foundation under the caisson structure.
The investigation of the disaster damage from the 1995 Hyogo-ken Nanbu Earth-quake showed that the damage to the quay walls was mostly triggered by the strong acceleration force of the earthquake, which exceeded the maximum horizontal force of the waves allowed under the design of the facilities inside the harbor. The harbor facilities that lacked 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 severe damage from liquefaction, which was induced by the increase in the excess pore water pressure 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 restoration of disaster damage.