Multi-Factor Influence Analysis on the Liquefaction Mitigation of Stone Columns Composite Foundation

To optimize the design of stone columns composite foundation for liquefiable ground improvement in the Tibar Bay Port Project, a 3D Finite Element (FE) analysis is implemented on the earthquake response and liquefaction mitigation effect. Nine improvement schemes are designed with the orthogonal design method. Taking peak ground acceleration and peak excess pore pressure ratio as the target indicators, the influences of four factors, including diameter, replacement ratio, stiffness, permeability ratio, of stone columns are analyzed by means of range analysis, and subsequently, the optimal ground improvement design is obtained. The analysis results indicate that the responses of ground acceleration and excess pore pressure ratio are relatively sensitive to stone columns' permeability ratio and a little sensitive to the replacement ratio. The stiffness and diameter ranging in the prescribed boundary only have negligible effect. The mitigation effect of drainage is rather significant when the ratio of the stone columns' permeability to the soils' permeability is greater than 100.