Abstract:Muddy clay from the soft ground of Huaihe River¢s levees for a flood channel to sea was retrieved and remolded to investigate the mechanism of stability of levees on soft ground after the end of construction and during rapid drawdown of water level,respectively,by centrifugal model tests. The safety factor against sliding was analyzed on the basis of slope surface displacement development while the location of slip was determined from the vector diagram of displacement on slope cross-section. It is observed from the overloading tests,by accelerating models over the predetermined g-level,that the sliding surface of the levee on soft foundation is deep seated one,which passes through the soft ground,after the completion of construction,whereas there is a failure surface,which passes through the toe of the slope but occurred earlier than the deep seated one,during rapid drawdown of water level. These test results show that the stability of the levee on soft ground is mainly governed by the bearing capacity of the soft soil layer and be influenced,to a certain degree,by action due to rapid drawdown of water level. Suggestion on more realistically modeling for stability behavior of levee on natural soft ground is also proposed on the basis of similitude consideration of inherent structure of in-situ clay.