Abstract
Construction on natural soft soil is considered a risk due to its low shear strength and permeability as well as its high compressibility. Stone piles technique have been utilized in soft soil to increase the bearing capacity and accelerates the consolidation. To improve the reinforcement and the drainage functions of the stone piles, the geosynthetic are used as encasement. In the current research, a case history of an embankment constructed on the reinforced soft soil with conventional stone piles has been chosen from the past research to be simulated. 3-Dimension, plane strain and axisymmetric techniques are used to simulate the embankment parts. The stone piles are reinforced by geogrid material to imply the influence of the encasement on the behavior of the stone piles-soft soil foundation. The consolidation analysis is applied to investigate the long-term behavior of the clay. There is a good agreement between the FEM results and the field measurements of the reinforced soft soil with conventional stone piles. The 3D and the axisymmetric models induces better agreement with field measurements than that of the plane strain model. The reinforced soft soil with encased stone pile has a smaller settlement and a shorter consolidation time than those of the reinforced soft soil with conventional stone piles. The reduction in the settlement is more significant with developing consolidation time. The dissipation of the excess pore water pressure in the reinforced clay with encased pile consumes shorter time in comparison with the reinforced clay with conventional piles. The effective vertical stress and the stress concentration in the encased piles are higher than those in the conventional piles. The encasement also causes reduction in the total stress of the surrounding clay which participates in the acceleration of the consolidation.