Behaviour of a Highway Embankment on Stone Columns Improved Estuarine Clay

Abstract

Soft estuarine clays are found in many expressway and motorway projects in Queensland, Australia. The strengths of these clays are very low and as such embankment failures can be encountered during construction. Presently, there are very few case studies presenting projects on estuarine clay in Australia. This paper presents the details of a trial embankment with stone columns in Southeast Queensland, Australia. The trial embankment incorporated 3 separate sections i.e. 2 sections with stone columns of 2m and 3m spacing (square pattern), and a section without stone column. It was constructed on estuarine clay with high sensitivity. Undrained shear strength measured from field vane tests varied with depth, ranging from 5 to 20 kPa. Further, the sensitivity of the estuarine clay reduces with depth, ranging from 5 to 12. Analysis of this case study was undertaken using field measurements. The pore pressures responses and deformations below the embankment were investigated. The effectiveness of stone column is also evaluated. This paper gives the details of the ground improvement plan, and presents the findings from measured field values