Abstract
Geophysical and borehole investigations were carried out to explore the sites of subsurface buried cavities and related subsidence in Ar-Riyadh city, Kingdom of Saudi Arabia (KSA). Traditional ground probing practices were not adequately conducted in the city due to various reasons including lack of technology at a time, economic factors, the ambient general culture, and time constraints. Consequently, locations of near-surface buried hazardous cavities for proposed development projects in the studied area are essentially unknown. The geophysical studies are represented by the interpretation of ground penetrating radar (GPR) images, while the borehole investigations were done through five drilled boreholes (BHs). A good match between the results of the two methods has been found indicating the usefulness of radar techniques to identify the ground conditions prior to major engineering projects in karstic regions such as Ar-Riyadh. In addition to locating major cavities in a city underlain by limestone bedrock, crucial recommendations have been proposed to be implemented before and/or during the design and construction of major foundations in the area.