Bala Balasubramaniam

Limiting Capacity of Piled Raft

The piled raft foundation is based on a skillful geotechnical concept wherein the pile group does not have any accountability for the safety and stability of the structure but performs the role of settlement reducer. In the design of piled raft, the capacity of the overall foundation system gains more importance than the capacity of individual constituting elements. Hence it becomes necessary to establish the limiting capacity of the piled raft so that the factor of safety for the overall system stability requirements can be assessed. The paper presents the details of the work done to establish a procedure to fix the limiting capacity of the piled raft based small scale 1g model tests and an independent numerical study.

Parametric Study on the Interaction Factor of Piled Raft

The performance of the piled raft foundation system depends upon the interaction level between the raft-soil-and the pile group. Understanding of this process is more complicates than the conventional pile group as the raft in contact with the ground influences the confining pressure, making the interaction behaviour more complicated. This paper presents a qualitative and a quantitative assessment of the interaction behaviour through a non dimensional interaction factor, through the results of a series of 1g model studies. The effect of various important parameters like pile length, pile raft area ratio and spacing on the interaction factor are discussed.