Ground Improvements for Georgia Ports’ Mason Mega Rail Project

The Port of Savannah Mason Mega Rail Project is an 85-acre intermodal facility that comprises 18 tracks for simultaneous operations of six 10,000-ft long trains. Upon completion, it will be the largest on-dock rail facility for a port authority in North America, which will help boost the Garden City Terminal’s (GCT) rail capacity to one million container lifts per year. A majority of the Mason Mega Rail site was an unregulated industrial landfill over low-lying land along a major drainage canal. The banks of the canal are underlain by very soft and compressible soils. The new rails were laid over the landfill, and two new rail bridges were constructed to cross the canal. The landfill debris and the soft marine deposits present major challenges to ground stability and settlements. The following six ground improvement techniques were employed to treat the landfill material and mitigate the settlement and stability concerns: dynamic compaction of the landfill, undercut and geogrid stabilization for wetlands, driven prestressed concrete piles for rail-mounted gantry (RMG) cranes and bridges, rigid inclusions for embankment stability, surcharging with wick drains for drainage structures with high fill, and geocell MSE walls along the edge of the rail yard. This paper outlines the project design process, subsurface conditions and associated challenges, geotechnical considerations of various ground improvement options, and experience and lessons learned from their applications.