Behaviour of encased floating stone columns

Abstract EN

In this paper, the finite element method is utilized as a tool for carrying out different analyses of stone column-soil systems under different conditions.

A trial is made to improve the behaviour of stone column by encasing the stone column by geogrid as reinforcement material.

The program CRISP2D is used in the analysis of problems.

The program adopts the finite element method and allows prediction to be made of soil deformations considering Mohr-Coulomb failure criterion for elastic-plastic soil behaviour.

A parametric study is carried out to investigate the behaviour of ordinary and encased floating stone columns in different conditions.

Different parameters were studied to show their effect on the bearing improvement and settlement reduction of the stone column.

These include the length to diameter ratio (L / d), shear strength of the surrounding soil and, the area replacement ratio (as) and others.

It was found that the important increase in strength of stone column occurs when it is encased by geogrid for (length / diameter) L / d = 8 while in case of L / d = 4, a slight increase in the bearing improvement ratio at the early stages of applying the load is obtained and then the value of (q / Cu) for both ordinary and encased stone columns is the same.