Dry Mass Stabilization for Airport Taxiway and Apron Expansion in South Florida

摘要

This paper describes the design, construction, and verification testing of a mass stabilization project in south Florida as part of a taxiway and apron expansion for Marco Island Executive Airport. Resulting from a preconstruction value engineering analysis by the geotechnical specialty contractor, Dry Mass Stabilization (DMS) was used to support new taxiway and apron structures on coastal marsh soils. The soil profile included a thick stratum of very weak and wet peat and organic silt extending to a maximum depth of 6.1 m (20 feet) below the existing ground surface. Left untreated, this material would have resulted in excessive total and differential settlement of the new pavement systems. During a preconstruction site visit, such distress was observed on the existing taxiway in the form of undulating pavement surface and deep ponding of rainwater. Conventional soil replacement and deep foundation solutions were considered, but ultimately rejected due to their significant technical challenges and high costs associated with these options concerning this particular project. Instead, the specialty geotechnical contractor improved the existing subgrade soils using DMS, a dry soil mixing technique. The DMS program increased the shear strength and stiffness of the treated soil, creating a stable mass suitable for long-term support of the new pavement systems. Performance was verified using in-situ shear strength measurements and settlement monitoring of several test embankment sections during construction.