Numerical Study of Sinkhole Formation and Its Impact on the Stability of an Isolated Footing

Abstract

Sinkholes is a depression in the ground caused by the collapse of the surface layer often forming in areas with soluble bedrock such as limestone dolomite or gypsum. This phenomenon poses notable dangers to the environment and any structures constructed above them. The current study aims to comprehend the behavior of an isolated footing carrying a load and built on soil containing void. An analytical study was conducted on the failure mechanism of an isolated footing positioned over void soils. The ability of an analytical model to accurately predict system behavior evaluated, through verification analysis of existing research. The analysis was conducted using finite element software (PLAXIS 2D) utilizing an elastic perfectly plastic soil model. In the present study, the impact of sinkhole the depth, location, and size of voids causing sinkholes on the stability of the footing is being examined. The findings indicate that as the size of the void increases, the load intensity decreases and when the depth of the void above the footing increases, the load intensity increases. However, when the depth of the void to the width of the footing ratio is 3.5, the void has no more impact on the footing's stability. Similarly, regarding the void's location effect on the footing's stability, the location can indeed affect it. With an increasing horizontal distance between the void and the foundation's centerline, the load-carrying capacity also increases. However, when the ratio of the horizontal distance from the void to the footing's centerline to the width of the footing is 2.5 or greater, there is no significant decrease in load intensity capacity. The current research focuses solely on circular voids despite the fact that voids can also take irregular shapes. The study also only takes into account isolated footings and normal loading systems. Further research is necessary to comprehensively comprehend sinkhole behavior and their impact on different structures, and to explore ways to minimize these effects.