Subsurface Investigation of Voids using Ground Penetration Radar in Bismayah Site, Southern Baghdad, Central Iraq

Abstract

Ground Penetration Radar investigation was used to survey the Bismayah pumping station site in Baghdad. The survey includes fifteen Ground Penetration Radar survey lines inside and outside the site, an antenna of 250 MHz was used. The total length of survey lines was about 706 m. The results of Ground Penetration Radar lines in outside station's radargrams exhibit reverberation events in the Ground Penetration Radar signal, it might be interpreted as the inverse of existing voids or noise near the surface. Grouted materials could be understood as the refractor. The results of the radargrams along the paths inside the pumping station revealed that the station collapsed in the north because the reflector of soil creep was visible in the north line path direction. After 4 m from the ground surface and right beneath the foundation base, there was a layer of loose dense river sand filled with water. It is expected that the process of soil creep caused the rush and drift of the pumping station structure towards the withdrawal of water from the well. The results show the efficiency of the Ground Penetration Radar technique in the near-surface investigation of the current study, due to the easy and time saving survey with reasonable results.