Ground Penetrating Radar for Detecting Underground Pipe Buried in Different Type Materials

摘要

Ground Penetrating Radar (GPR) propagate electromagnetic (EM) wave that reacts to electromagnetic properties changes across the subsurface materials, for example, sand, granite, concrete, beach sand, clay, plastic material, etc., use to profile underground material. Before GPR invented, engineers, rely on the excavation process to determine what lies beneath the ground surface. Excavation is an expensive and time-consuming endeavour, but it does not always detect every object underground. GPR, by comparison, is faster, more accurate, and less costly than enable to penetrate most materials with few exceptions. This study meant to evaluate whether different types of material underneath, can cause an impact on the image display of the underground profile for human interpretation. GPR with a central frequency of 250 MHz - used to capture the image of pipes buried in six samples of different soil types and one of it is a ready mix concrete. There are two metals and two plastic pipes running through the material at the depth 0.5m and 1m respectively were buried on site. A few pieces of plywood used as the separator between them. Each GPR data, of pipes buried in six different soil material displayed as a two-dimensional array of value called radargram. The array with a specific value and location show the intensity of the reflected wave for each soil that reflected the signal. The vertical direction of radargram displays it travel time for depth measurement, once the signal velocities are known and the horizontal direction is linear distance on the ground surface.