Controlling and influencing factors of the karst collapse caused by withdrawing of groundwater in carbonaceous limestone area:A case study of Xing'an County, Guangxi Province

For the study of the model of pumping collapse in carbonaceous limestone area, through the combination of electrical geophysical prospecting, geological drilling and pumping collapse test, this paper conducted the correlation analysis of karst collapse in carbonaceous limestone area of Lower Carboniferous Yanguan formation (C₁y) in Xing’an County, and established the correlation curves between drawdown water level and time and recovery water level and time. The results denotes that: The main supply source is water stored in small karst caves and the transfer passage are cave and karst fissures when pumping in calcareous limestone area. The karst fissures in the calcareous limestone area are irregular, so the permeability coefficient and influence radius measured in similar strata are quite different. The location of collapse caused by pumping in the study area is obviously affected by geological structure. When pumping produces excessive drawdown, the karst collapse often occurs at the fracture zone of aquifer. The collapse caused by man-made pumping is affected by many factors, and the rise and fall of groundwater level is the main factor.