Browsing by Subject "electromagnetic wave velocity"

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Access status: Open Access ,
Application of the ground penetrating radar (GPR) method in the detection of underground utilities above the Kobilja Glava Tunnel
(Wydawnictwa AGH, 2026) Bektašević, Ekrem; Filipović, Satko; Bojić, Mirnes; Crnogorac, Luka; Gutić, Kemal; Skrzypkowski, Krzysztof
Accurate detection and mapping of underground utilities in complex urban environments, particularly in intensive construction zones such as tunnel sites, presents a significant engineering challenge. This paper investigates the application of ground penetrating radar (GPR) integrated with high-accuracy real-time kinematic (RTK) GNSS positioning to identify and spatially define a damaged sewer pipeline above the Kobilja Glava tunnel construction site in Sarajevo, Bosnia and Herzegovina. Non-destructive investigation was required due to the lack of reliable underground utility documentation and wastewater ingress into the tunnel during construction. The study was conducted under complex urban and geotechnical conditions, including asphalt pavement, high soil moisture, heterogeneous subsurface layers, and proximity to the tunnel. GPR surveys were performed using a dual- channel Leica DS2000 system with 250 MHz and 700 MHz antennas, combining grid-based and free-profile measurements. Spatial georeferencing was achieved with a Topcon Hiper HR RTK GNSS receiver, which provides centimeter-level positioning of identified reflectors within the national coordinate system of Bosnia and Herzegovina. Data processing and interpretation followed standard GPR procedures. Results show that the sewer pipeline was reliably identified through hyperbolic reflections, with the depth of the pipe crown ranging from 1.1 to 1.7 m. Integration of GPR and GNSS data enabled precise reconstruction of the pipeline’s position and depth, supporting the design of a new pipeline and reducing construction risks. The study demonstrates the high effectiveness of the integrated GPR-GNSS approach in complex urban environments near tunnel structures. These findings suggest that the integration of GPR and GNSS technologies serves not only for object detection but also provides a critical methodological framework for real-time risk assessment during underground construction. The study demonstrates how precise spatial definition of damaged infrastructure can prevent broader geotechnical instabilities, elevating the work from a local case study to a universal model for monitoring urban infrastructure under stress.