The　freeway　embankment　linking　Meizhou　Island　with　Putian　City　in　Fujian,　China,　passes　through　a　shallow-sea　area.　Sand　columns　distributed　in　regular　triangles　and　sand　cushions　reinforced　with　geogrids　were　employed　to　accelerate　the　consolidation　of　the　soft　ground　beneath　the　embankment　and　improve　its　bearing　capacity.　In　this　study,　three-dimensional　(3D)　finite-element　analysis　was　carried　out　using　the　modified　Cam-clay　model　to　enhance　the　level　of　design　and　analysis　of　this　complicated　practical　engineering　problem　of　softground　improvement　in　terms　of　accurate　prediction　of　the　settlement,　horizontal　displacement,　period　of　surcharge　preloading,　and　variation　of　excess　pore-water　pressure.　The　predicted　settlement　and　horizontal　displacement　of　the　embankment　subgrade　were　found　to　agree　well　with　the　actual　measurements.　In　line　with　the　prediction　of　a　consolidation　degree　of　95%,　ultimately,　the　340th　day　was　determined　to　be　the　optimal　date　on　which　to　remove　the　surcharge.　In　addition,　the　3D　effect　of　the　variation　of　excess　pore-water　pressure　was　clearly　revealed.　The　results　prove　that　the　3D　nonlinear　numericalmethod　presented　in　this　paper　is　scientific　and　reliable　for　complicated　practical　engineering　problems　involving　soft-ground　improvement.　©　2017　American　Society　of　Civil　Engineers.