GPR detection of buried steel gas cylinder; a study conducted in a sandbox

In this study a controlled medium was created to apply the ground penetrating radar technique to detect and locate a buried steel gas cylinder. The work was to demonstrate the utility of the GPR in locating underground utilities prior to excavation for civil works. The survey was carried out in a sandbox which measures 4.20 m by 2.30 m of surface cross section and has a depth of 1.10 m. The wooden box with an open bottom was filled with dry sand which had previously been sieved to rid it of organic matter and therefore to create a substantially homogenous medium. An empty LPG cylinder was buried in the sand at a measured location and depth from the sand surface. The measurement was carried out with the 800 MHz shielded GPR antennae. The experiment led to a definition of the GPR signature of the horizontally oriented empty steel cylinder. The burial depth, representing the top surface of the cylinder from the sand surface was found to be in the range of 0.58 to 0.64 m, compared with a concealed depth of 0.60 m. The bottom of the sandbox was also well imaged and located within the range of 0.95 m to 1.20 m. the actual depth of the sand was 1.10 m.