The tunnel consists of two 0.75 mile-long tunnels, each containing two traffic lanes, curbs, walkways, ventilation fans, and additional safety features, that are approximately 41 feet in diameter (OD) and approximately 120 feet below the surface of Government Cut at their deepest point. They connect Watson Island and the Port of Miami beneath Government Cut, the main shipping channel in Biscayne Bay, moving traffic eastbound (to) and westbound (from) the Port. The comprehensive port improvements included connecting the MacArthur Causeway on Watson Island and the Port of Miami on Dodge Island, as well as road improvements around the port of Miami to reduce congestion. The tunnels carry passenger vehicle traffic to the port and cruise terminals and tractor-trailers receiving cargo from the port. These improvements capitalize on newly established direct connections to the port with I-395 and I-95, which will ultimately serve to decongest downtown streets and aid future development.

H2R Corp, at the time known as Gannett Fleming, provided geotechnical engineering, drilling, inspection, laboratory testing, and construction verification services to Malcolm Drilling, Nicholson Construction, and Bouygues Construction. Additional services provided include soil mix designs, developing a laboratory management database to facilitate those designs, and quality control. H2R’s verification coring services were integral in the QC process and provided the key link to make the crucial adjustments necessary during soil mixing to ensure a quality plug. The project required unconfined strength testing on both cored soil cement and wet grabs, as well as permeability and triaxial tests on soils and soil cement. Meaningful management and interpretation of the data were integral to the performance of the geotechnical construction elements of the TBM entry/exit pits. Services also included downhole camera inspection and deploying piezometers for field permeability testing in critical plug areas and entry of the tunnel wall.