Performance of Granular Piles-Improved Soft Ground Under Raft Foundation: A Numerical Study

Reinforcing soft soil with granular piles improves effectively its properties. In the current research, the performance of granular piles reinforced soft soil under a uniformly loaded raft foundation has been investigated numerically utilizing Plaxis 3D. A parametric study was performed under drained loading conditions to investigate the effect of various parameters on the long-term behavior of the raft foundation such as spacing distance, diameter and length of the granular piles. The influence of the parameters has been studied on the overall settlement, bending moment of the raft and the lateral bulging of the granular piles. The results indicated that the existence of the granular piles in soft soil decreases significantly the settlement and the bending moment of the raft. The lateral bulging distribution of the granular piles is dependent on their locations. Additional improvements in the settlement and the bending moment of the raft, and in the lateral bulging also occurred due to the decrease of the spacing ratio, and the increase of area replacement ratio and granular piles length. Reinforcing soft soil using floating ground piles with length to soil layer thickness ratio of 0.75 is sufficient to achieve good improvement performance.