| This paper aims to clarify the characteristics on the stability of gravity type quay wall during earthquake by investigating the damages caused by earthquakes. Close examinations on the damages and stability factor of quay walls were carried out for the recent two big earthquakes in Hokkaido Island. As a result、 the damages were large at the quay walls where liquefaction occurred in the backfill ground. On the other hand、 the quay walls whose backfill ground had not been liquefied、 could have survived the severe shakes which exceeded their stability limit in earthquakes. Here the stability limit had computed by seismic coefficient method in which Mononobe-Okabe’s formula was applied to seismic earth pressure acting on the quay walls. From the results mentioned above、 the interaction between caisson and backfill ground might improve the availability of seismic coefficient method for gravity type quay wall. And it is considered that there is a possibility that the seismic force acting on gravity type quay walls whose backfill ground had been improved against liquefaction could be lessened in the seismic coefficient method. |
