Liquefaction mitigation in silty soils using composite stone columns and dynamic compaction

The objective of this study is to develop an analytical methodology to evaluate the effectiveness ofvibro stonecolumn(S.C.)and dynamic compaction(D.C.)techniques supplemented with wick drains to densify and mitigate liquefactionin saturated sands and non-plastic silty soils.It includes the following:(i)develop numerical models to simulate and analyzesoil densification during S.C.installation and D.C.process.and(ii)identify parameters controlling post-improvement soildensity in both cases,and(iii)develop design guidelines for densification of silty soils using the above techniques.Ananalytical procedure was developed and used to simulate soil response during S.C.and D.C.installations,and the resultswere compared with available case history data.Important construction design parameters and soil properties that affect theeffectiveness of these techniques,and construction design choices suitable for sands and non-plastic silty soils were identified.The methodology is expected to advance the use of S.C.and D.C.in silty soils reducing the reliance on expensive field trialsas a design tool.The ultimate outcome of this research will be design charts and design guidelines for using composite stonecolumns and composite dynamic compaction techniques in liquefaction mitigation of saturated silty soils.