In situ dynamic strength properties of the 3rd Meiji fortress reclaimed sands

Abstract

Construction of the 3rd Meiji fortress, at a depth of approximately 40 m near the Kannon promontory in Kanagawa Prefecture, was started in 1921 and lasted for 29 years. However, 35% of this 3rd fortress was submerged and all its functions suspended due to the liquefaction caused by the Great Kanto Earthquake of 1923. The measured relative density (Dr(m)) and stress ratios (RL20(m)) in a 20-cycle time frame values were 4.5% and 0.006, respectively, in mean values greater than those of the estimated in situ Dr(i) and RL20(i) values obtained with the economically feasible (EF) method. Thus, the Dr(m) and RL20(m) values overestimate the in situ values.