A review of the research on karst and sinkhole of red beds in China

The karst area in China is spacious and the karst types are diverse. The karst phenomena in the red beds area of south China are special. In the region, the occurrence of karst collapse has become a problem that cannot be avoided in recent years. So it is necessary to make a systematic analysis of the present situation of the research on the red-bed karst and associated karst collapses, particularly occur in red-bed area in the country. Red-bed karst mainly occurs in South China where the red clastic rocks are cemented with soluble substances or contain carbonate gravels. The characteristics of the karst red beds can be summarized as follows: 1) karst types are complex and their dissolution mechanisms are diverse; 2) the red rock is not fully cemented, with low mechanical strength and being easy to be weathered and collapse; 3) it is closely related to the geological structure. In karst red-bed area, not only soil collapse but also the bedrock collapse may occur. According to the geological structure, the red beds collapse mode can be generalized into three categories: the overburden layer collapse, the red beds cave roof collapse, and the collapse of the whole red beds. At present, the research on the karst collapse of the red beds is relatively limited. It is necessary to study the mechanism of the soluble red beds on the karst collapse in the future. Further, control measure of the red beds corrosion on the karst collapse development and distribution and impact of the soluble red beds on the karst collapse development and evolution need to be investigated, which will provide scientific basis and technical support for risk assessment and prevention treatment of the karst collapse geological hazard in red beds areas.