Abstract: "Doline" collapses are one of the frequent geological hazards. This paper presents the physical and chemical properties of soils from two recent collapses: Xinchang Doline of Dayi and Huaiyuan Doline of Congzhou. The specific gravity, grain size distribution, Atterberg limits and chemical properties of the soil samples were examined. The research results indicate that the two collapses were not due to bearing loss from the formation of underlying carbonate cavity. The disturbance of groundwater at both locations are the likely reasons.

Key words: Doline, Surface Collapse, Grain Composition, Atterberg limits