Assessment of Stone Column Technique as a Mitigation Method Against Liquefaction-Induced Lateral Spreading Effects on 2 × 2 Pile Groups

Two shake table experiments were conducted on two 2 × 2 pile groups to investigate the efficacy of stone column technique as a mitigation method against liquefaction-induced lateral spreading. The experiments were performed employing a designed and manufactured laminar shear box by Sharif University of Technology. Two separate 2 × 2 pile groups (with and without superstructure weight) were installed in the models to investigate the effects of superstructure weight on the behavior of pile groups in treated and untreated liquefiable layers as well. The models were shaken with a sinusoidal base acceleration having a frequency of 3 Hz and amplitude of 0.3 g. The piles and the soil at far field were instrumented to measure various parameters during and after shaking. The results including acceleration, pore water pressure, displacement at free field and bending moment of the piles are briefly presented and discussed in this paper. The results illustrate that stone column technique significantly decreased lateral displacemnts in the free field and bending moments in the piles, while increased the accelearions in the pile caps and rate of dissipation of excess pore water pressure in the liquefiable layer.