Karst collapse characteristics, disaster factors and risk analysis in Xiamao Village, Baiyun District, Guangzhou City

Xiamao Village has been suffered from serious karst collapse geological disasters. The geological environment conditions in the collapse area are extremely complex. Karst soil caves of hidden limestone have strong development, and karst caves and soil caves are large in scale. Moreover, there are many karst caves with good connectivity among karst caves. The bedrock surface of karst collapse area fluctuates greatly, elevation changes sharply, the Quaternary overburden is thick, and the bottom silty clay layer soil is very large in saze. The cave development, the large-scale cave in the soil is the material foundation of karst ground collapse. In the bedrock fault structural zone and its influence zone, the rock is broken, and the water guide fault is formed. There is groundwater runoff channel. The groundwater circulation along the fault zone is active and the dissolution is strong, forming a strong karst development zone, which provides a good dynamic condition for the occurrence of karst collapse. The construction of the building foundation in the area disturbed the balance between groundwater and soil cave, which became the inducing factor of ground collapse. The risk assessment of karst ground subsidence is carried out by using seven geological environmental conditions and five economic and demographic indexes respectively. The results show that the potential geological disaster risk is large in Xiamao Village. Only by strictly controlling the dynamic conditions of groundwater can avoid karst ground collapse.