Numerical Analysis of Piled Raft Foundations in Alluvial soil

Abstract

In this age of rapid urbanization, population is rapidly increasing in urban area, therefore a new concept of vertical cities has been introduced in form of high-rise building, and there are many conventional methods for design of foundation systems for high rise buildings. In most of the conventional methods pile foundations have been given preference for high rise buildings, all the loads of the building are transferred to the soil by piles. Some of the pressure of the building can also be transfer by raft directly to the soil by contact pressure which is neglected in most of the conventional designs of pile raft foundation system. But from last decades, optimised way of designing of pile raft foundation system have been started by engineers, in which raft foundation is allowed to transfer some of the total load directly to the ground by contact pressure. This optimised way of designing has made the foundation system more economical and sustainable. This type of foundation system in which some part of the load is transfer by raft and some by piles are called as pile raft foundation system. Soil–structure interaction in this pile raft foundation system is very complex in nature and to study this soil–structure interaction we need some numerical techniques or numerical methods. So, in this paper, we are going to use one of the numerical methods for numerical analysis of pile raft foundation system. There are various factors that influence the behaviour of pile raft foundation, some of the important factor that we are going to see in this paper are raft thickness, pile length, pile spacing and number of piles. All these factors are very important for optimize and economical design of pile raft foundation system. In this paper, numerical analysis has been done by using finite element software that is GEOTECH 3D Foundation to find out the influence of above factors on pile raft foundation system in alluvial soil.