The design of stone column applications to protect against soil liquefaction

Abstract

Soil liquefaction is one of the leading causes of earthquake-induced damage to buildings. Several ground improvement techniques can protect against soil liquefaction. One such measure is the construction of stone columns using a vibro-compaction technique. The construction of stone columns not only enhances the ability of clean sand to drain during tremors but also increases the relative density of the adjacent soil. The amount of improvement in the relative density likely decreases as the distance from the stone column increases. A finite element computer program was developed to analyze the distribution of the excess pore water pressure (EPWP) around stone columns that develop during an earthquake. The literature review indicates that a threshold EPWP is the boundary for the liquefaction to initiate. The computer program was designed to effectively adjust the diameter and spacing of the stone columns in order to reduce the EPWP below the critical level. The computer program is capable of analyzing the undrained condition before the installation of stone columns as well as the drained conditions in the existence of stone columns.