Large-Scale Subsurface Utility Engineering Using 3D GPR Array Technology at Philadelphia International Airport

Abstract: Accurate mapping of underground utilities is a critical component of infrastructure planning and construction, especially within complex airside and landside environments such as airports. At Philadelphia International Airport (PHL), a large-scale Subsurface Utility Engineering (SUE) program was conducted to support upcoming design and infrastructure improvements across the parking facilities and adjacent airside zones. The investigation encompassed hundreds of thousands of square feet of paved areas, including active and restricted regions where minimizing operational disruption and maintaining safety were essential.

The SUE effort employed a combination of advanced nondestructive technologies, led by multichannel 3D Ground Penetrating Radar (GPR) and complemented by Electromagnetic Induction (EMI) and selective vacuum excavation test pitting. The integration of GPR and EMI provided a comprehensive detection framework capable of identifying both metallic and nonmetallic utilities, while test pits were used to confirm depth, material, and alignment at key locations within the parking lot. The high-density GPR array produced continuous subsurface imagery up to several feet in depth, with real-time kinematic (RTK) GPS positioning ensuring centimeter-level spatial accuracy. Processed data were compiled into CAD and GIS formats for incorporation into the airport’s digital utility mapping system.

This paper presents the methodology, equipment configuration, data processing workflow, and accuracy assessment associated with this large-scale SUE investigation. The findings highlight the effectiveness of combining 3D GPR, EMI, and targeted test pitting to deliver reliable, high-resolution subsurface information while maintaining safe and efficient operations in an active airport environment.