Application of Ground Penetrating Radar to Detect Sinkholes and Ground Subsidence in Beryanak, Tehran

Abstract

After occurring two dangerous subsidence in both Arab and Pahlavani Streets located at Beryanak in the 10 districts of the municipality of Tehran, the GPR Department of Geotechnical & Strength of material study centre of Tehran had decided to use ground penetrating radar method to detect possible sinkholes and aqueducts on the site. The GPR data acquisition had been performed by a 50 MHz GPR antenna made by MALA Company. GPR data gathered in 7 longitudinal profiles parallel to the street directions. In the processing of the GPR data, different filters such as background removal, Migration, Band pass filter, and horizontal and vertical smoothing are applied to the data. The final result shows that the most of detecting sinkholes which cause to the subsidence were created due to the scouring. GPR profiles from Arab Street indicate that those anomalies were detected at shallow depths (between 2/5 to 5 m) are due to the subsidence caused by excavation and placement of sewer pipeline. But at some areas were identified from depths 8 to 15 meters can be some sinkholes and may lead to a big subsidence. These areas are very important for both studying and reconstructions.