Abstract
　Experimental investigation of effects of stone backfill adjacent to the back of wall on stability of quay walls during an earthquake was performed. A l00cm-wide, 200cm-long and 75cm-deep oscillating soil bin and a 55cm-high movable wall was used. It was found that the stone backfill reduces the seismic active earth pressure against the wll but the point of application of the resultant force moved upward with increasing of the acceleration of bin. Therefore, it may come about that the overturning moment around the base of the wall is not necessarily reduced by use of the stone backfill.

*名古屋大学工学部
Faculty of Engineering, Nagoya University
**（株）熊谷組
Kumagai-Gumi Co., Ltd.
***名古屋大学工学部
Faculty of Engineering, Nagoya University