Improvement of the Behaviour of Embankment on Soft Soil by Stone Columns

Abstract

Stone column supported embankments are non-time dependent foundation technique used to increase the structural stability and to reduce the structural deformations. In the present study, the finite element method is utilized as a tool for carrying out different analyses of embankments on soft ground with different conditions. The program GEO-SLOPE is used in the analysis of these problems. A parametric study was carried out in which an embankment on soft ground is analyzed by using different numbers of stone columns with different spacing between them, diameters, and lengths. It was concluded that improvement of the soft clay with stone columns leads to significant effect in the behavior of the soft clay, both the undrained condition and during consolidation stages. Increasing the stone column’s diameter leads to a considerable decrease in the settlement beneath the embankment, especially below the center line. When the embedment length of the stone column in clay layer (L/H) was 0.65, a reduction in the settlement of about 67% was obtained. Consolidation analysis showed that the presence of stone columns leads to a decrease in the differential settlement below the embankment. The reduction in settlement continues during the consolidation process. When the stone column’s diameter is 1.0 m, the maximum settlement is reduced by about 180% at the end of construction but it is reduced by about 250% after 200 days.