Settlement and pile response in a long-term vertically loaded piled raft foundation model on saturated clay - Experimental study

Abstract

This paper aims to investigate long-term behavior of a piled raft (PR) through small-scale physical modelling. In the experiment, the model ground was prepared by consolidating a slurry mixture of Kasaoka clay and Silica sand. The model foundation consisted of a square raft and 9 piles with a pile spacing of 3D (D: pile diameter). For the loading test of PR, vertical load was increased by multiple steps and each load step was maintained for a sufficient duration to observe the long-term behavior. The results show that, when small loads were applied, the piles carried a major part of the load. For larger applied loads, the increment of the load was mainly supported by the raft. In primary consolidation period, the pile resistance increases with elapsed time. The rate of settlement was basically proportional to the dissipation rate of pore pressure beneath the raft base. In secondary consolidation period, the pile load was slightly reduced under smaller applied load, and stable under larger applied load.