Experimental and Numerical Modeling of Connected and Disconnected Piled Raft

Abstract

Piled raft foundations, wherein a small number of connected piles are utilized as settlement reducers, have been widely used for high-rise buildings. Recently, a new technique has been introduced by disconnecting the piles from the raft and inserting a cushion layer between them. In such cases, the piles are considered as soil reinforcement components rather than structural members. To explore the feasibility of utilizing the disconnected piled raft foundation, a series of experimental model tests were conducted to examine the load–settlement behavior and pile load sharing ratio of the connected piled raft (CPR) and disconnected piled raft (DCPR) foundation systems using cushions of different thicknesses and stiffnesses. In addition, ABAQUS 3D finite element analyses were performed to analyze the axial stress along the piles and the bending moments along the raft. The results indicated that the total settlement of the system was minimized significantly when disconnected piles were used. In addition, the disconnected technique provided a significant reduction in the axial stress along the piles and the bending moment along the raft compared with that of the CPR. These findings may be accompanied by economic and environmental benefits.