Abstract: A typical geological model considering soil cover thickness, geological material types for the most harmful covered karst is established. The karst collapse mechanism is analyzed under groundwater fluctuating and rainfall infiltration based on this model. Furthermore, a comprehensive method for karst collapse spatial prediction that involves physical detection, engineering investigation, geological material physical mechanics experiment, numerical simulation and monitor evaluation is proposed and applied to evaluating a karst disaster area in Huangshi, Hubei province. The numerical simulation, which is based on physical detection, engineering investigation and laboratory test of rock and soil, shows that the ground settlement due to softened clay cover caused by rain permeation is larger than that induced by groundwater fluctuating. With reference to the developing tendency of building fissures and ground cracks, the spatial extent of the karst collapse area is distinguished. It is shown that this karst collapse spatial forecast method is feasible; and the prediction results are in good agreement with observations. Therefore, this method can be popularized as a general method for karst collapse prediction in similar engineering.

Key words: covered karst, collapse mechanism, prediction of collapse, comprehensive method