Performance and observations of model stone column foundations

This paper reports on a series of laboratory experiments carried out to investigate the settlement performance of a rigid foundation supported on soft soil reinforced with stone columns. The results have been obtained using a large calibration triaxial cell chamber that was equipped with a dual load actuator that allowed surcharge and foundation loading to be applied simultaneously. The significant findings of the work include (i) optimisation of area replacement ratio for foundation performance at 30% for non end bearing columns, (ii) an optimum column L/d ratio for the control of settlement of 8, (iii) design flexibility of column geometry, whereby settlement can equally be control by either a long slender column or a short larger diameter column, and (iv) the important role of soil-structure interaction in providing adequate column confinement to prevent excessive column deformation.