What It Takes (Geostructurally) to Extend the Plane Train Tunnel Under the World's Busiest Airport-Video

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Video Summary

The presentation covered geotechnical work for extending Atlanta airport’s automated Plane Train tunnel about 600 feet west, reducing travel time by 13 seconds. The project required construction in a restricted, nonpublic terminal area with limited overhead clearance, nearby foundations, and high groundwater near the construction shaft.<br /><br />A key task was underpinning 19 columns so the tunnel could pass beneath them. The team installed micropiles in tight spaces, managing drilling spoil and addressing casing-thread issues while meeting strict verticality requirements. Column loads were transferred to temporary steel support frames during excavation and later returned to the foundations. A production tension pile was proof-tested to verify capacity.<br /><br />The work also included micropiles and bracing for egress and ventilation tunnel excavations, plus dewatering wells along roughly 150 feet of alignment. The presentation highlighted coordination among designers, contractors, and specialty crews, as well as the logistical challenges of performing major construction within an operating airport.

Keywords

Atlanta airport tunnel extension

geotechnical engineering

micropile underpinning

dewatering wells

airport construction logistics