The Use of Cone Penetrometer Testing to Investigate Sand Fill Subsidence Beneath Highways

During construction of Interstate I-10 between Baton Rouge and LaPlace, Louisiana, highly organic swamp deposits were excavated and replaced with hydraulically pumped river sand. The main objective of the study reported was to evaluate the subsurface conditions and investigate the reason(s) for sand fill subsidence at cross-drain locations, utilizing the electric cone penetration test during the site investigation. Numerous conclusions were drawn from the study with the major factor for subsidence being loosely compacted sand at the cross-drain locations. It was demonstrated that the electric cone penetration test was a valuable quality control tool and should be utilized both immediately after construction, as well as in checking time related effects in subsidence and compaction studies.