Delineating Cavities Underneath Constructed Sites – Case Study in Al Ain City

The presence of cavities and buried falajs (ancient irrigation system) in Al Ain city has direct impact on human's activities, especially when geo-hazard maps are unavailable. Therefore, a 3D presentation of such geological features will provide an exact location in any study area considered for future site development. Most cavities in Al Ain City are generated in the Limestone formations, which are the most predominant geological formation in Al Ain region. The study area represents the investigation of a subsidence under a recently constructed villa, which is 26m × 24m. The geotechnical boreholes drilled in the site did not reveal the presence of any subsurface weak zones. However, several months after finishing the construction of villa, a subsidence started to affect the whole structure of the villa and cracks appeared on the walls. Because Al Ain City is known for its Limestone formations and many cavities have been located in the city, therefore it was decided to conduct a geophysical survey to investigate the reasons for the subsidence. Based on the drilled geotechnical boreholes in the site, the geological formations in area are mainly weathered Limestone to Silty-Sandy and Clays.