Liquefaction potential of reinforced soil by stone columns

Abstract

Stone column installation is commonly employed to prevent liquefaction. Stone columns mitigate liquefaction by means of mainly three mechanisms which are drainage, stiffening and densification. A factor of safety against liquefaction FSis used to quantify liquefaction potential. The aim of this study was to assess the efficiency of stone columns as a liquefaction remediation based on twenty four case studies. In these cases, SPT and CPT tests were recorded before and after stone columns installation. It was found that the installation of stone columns considerably increased soil density mainly in clean to slightly silty sand. The average rate of increase in the penetration resistance N1,60,cs and qc1Ncs were about 31.13% to 69.29% and 57.10% to 318.28%, respectively. Furthermore, the cyclic shear stress ratio of reinforced soil can be reduced by 13.5% to 77.5% due to the stiffening improvement of stone columns. Densification and stiffening mechanisms have been investigated through several approaches. Their individual and combined effects have been analysed. Comparative results indicate that considering the densification and stiffening effects in liquefaction analyses improved considerably the performance of stone columns.