Effect of Stiffness of Stone Column on Drainage Capacity during Soil Liquefaction

Abstract

Among the most used ground improvement techniques is the mitigation of soil liquefaction by installation of stone columns. To minimize soil liquefaction, the area ratio of the stone columns should be evaluated properly. The available solutions for determining the area ratio of stone columns were developed without consideration of the effects of the stiffness of the columns. However, stone columns have a larger drained elastic modulus than the surrounding soil. The aim of the present paper is to provide a simplified solution for determining the drainage capacity of stone columns during soil liquefaction considering stiffness and limited permeability of the stone columns. Equal strain condition is considered at all depths, i.e., the same vertical deformation of the stone column and surrounding soil is considered at all depths. The present solution shows that the susceptibility of soil liquefaction increases due to the reduction of the stiffness and permeability of the stone column. It is also observed that the maximum pore water pressure ratio decreases by 2–6% due to the stiffness effect of the stone column. Design charts are presented based on the results of the developed solution. Charts can be used to determine the area ratio of the stone columns. Through the presentation of a design example, the present solution is compared with available design methods and the variances between these methods are discussed.