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Experimental Study of Sinkhole Failure Related to Groundwater Level Drops

Sinkholes are natural geohazard phenomena that cause damage to property and may lead to loss of life. They occur in very distinctive karst settings, where carbonate, limestone, dolomite, or gypsum are encountered as the bedrock. Predicting the formation and the collapse of a sinkhole based on current ground investigation techniques is limited by the high uncertainties level of the soil’s properties and behavior. A laboratory-scale sinkhole model was constructed to physically simulate the sinkhole phenomenon. This model is spatio-temporal in nature. The physical model was designed to monitor a network of radially distributed groundwater wells over time around a predetermined sinkhole location. The physical model proved experimentally that the groundwater forms a water cone of depression that is related to the sinkhole development. It is postulated that this phenomenon may be used to identify the potential location of the sinkhole at an early stage of the underground cavities formation. In addition, an abnormal pattern of the groundwater table readings, which is due to the presence of the sinkhole, was observed and analyzed utilizing time–frequency analysis technique. It is observed, based on the model, that sinkhole development is accompanied by progressive drops of groundwater table readings punctuated with certain time lags. These progressive drops and time lags are analyzed and correlated to the time and location of the collapse of the sinkhole.