Load-Settlement Behaviour of Piled
Raft Foundation by Three Dimensional
Nonlinear Finite Element Analysis

 

Dilip Kumar Maharaj

Assistant Professor, Civil Engineering Group
Birla Institute of Technology and Science, Pilani, Rajasthan, India
e-mail: dilip_maharaj@yahoo.com, dkm@bits-pilani.ac.in

ABSTRACT

 

This paper presents the results based on three dimensional nonlinear finite element analysis of piled raft foundation which is under the application of uniformly distributed load. The raft, pile and soil have been discretized by eight noded brick elements. The soil has been idealised as a Drucker-Prager elastoplastic continuum. The load settlement curves for raft and piled raft have been presented. The effect of soil modulus and pile length on load settlement behaviour of raft and piled raft have also been presented. Based on the finite element analysis it has been found that the ultimate load carrying capacity of flexible raft increases with increase in soil modulus and length of pile. Piles of length even less than the width of a flexible raft have been found effective in reducing differential settlement. The increase in pile length has been found to reduce the overall settlement and differential settlement. The increase in soil modulus has been found to reduce the overall settlement. It has also been found that although the increase in soil modulus reduces the overall settlement, differential settlement increases with increase in soil modulus for the same overall settlement.The results based on three dimensional finite element model considered in this analysis compare well with published literature.

Keywords: Analysis, Nonlinear, Settlement, Differential -settlement, Raft, Piled raft

 

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