Abstract:
Stone column or granular piles is one of the most effective ground improvement
techniques for soft cohesive soil to increase in bearing capacity and reduction in
settlement. This is partly due to replacement of soil by a relatively stiffer materials as
well as drainage of action of stone column. The failure of stone column may be taken
place due to the yielding of the column if the column has to support a rigid raft due to
difference in stiffness and also may take place due to yielding of the stone column
material upon loading beyond the critical state. The behaviour of such yielding stone
column can be considered to be in the triaxial state of stress due to confinement
provided by the surrounding soil or the reinforcement (encased stone column). The
behaviour of the column material can be taken as an elasto-plastic and strain hardening
and hence the yield function for the stone column material can be determined using
different model parameters which can be determined from a series drained of triaxial
tests data. This paper will present an approximate yield function for the yielded encased
stone column.