## 4 Case Analysis  
### Project Overview  
This paper takes the Kunming Changshui International Airport Project as an example to analyze. The project area is widely distributed with carbonate rocks such as bioclastic limestone, tiger porphyry limestone mixed with arenaceous limestone, dolomitic limestone, etc. The single layer of carbonate rocks is relatively thick, strongly affected by geological structure and joint fissures have developed. Under long-term weathering, denudation and water action, it easily forms dissolution ditches, dissolution channels, karst caves, stone buds and stalagmites. The engineering geological and hydrogeological conditions of karst morphology such as karst depressions and funnels, as well as surface collapse and soil caves caused by karst development are very complex. The geomorphic features of the site can be divided into denuded peneplain and denuded hill. The overburden layer is composed of Quaternary artificial fill layer, Quaternary vegetation layer and Quaternary eluvial layer. The alluvial-proluvial layer is hard plastic to soft plastic secondary red clay, which is generally distributed in karst depressions. The eluvial-diluvial layer is hard plastic to soft plastic red clay, which is widely distributed in the eroded and denuded plains, eroded hills and slopes. The bedrock includes the limestone of the Qixia section of the lower Permian Yangxin Formation, the mudstone of the lower Permian inverted stone formation, the limestone of the middle Carboniferous Weining Formation, the dolomite of the upper Devonian Zaige Formation and the structural breccia near the F10 fault. The occurrence forms of groundwater in rock mass are pore water, fissure water and karst water. According to the burial conditions and the distribution characteristics of the aquifer, it is divided into layered fissure water and weathered fissure water. According to the difference of the space and form of the underground water, the karst water is divided into karst fissure cave water and karst fissure water. Its task is to find out whether there are adverse geological phenomena, and provide geotechnical technical parameters and treatment plan suggestions required for the prevention and treatment of adverse geological phenomena.  
Since the karst in this area is relatively developed, and there are adverse geological problems such as soluble rock and a large-scale fracture zone, in order to further investigate and analyze the distribution, burial depth and development degree of karst caves, and carry out targeted research, a special geological survey of karst has been carried out. In order to further explore some geological features of the area, entrusted by the engineering survey unit, the borehole optical imaging technology, borehole directional acoustic scanning technology and borehole radar technology are used for comprehensive survey of some boreholes. This paper takes three boreholes (ZK I, ZK II, ZK III) as examples to analyze and elaborate. The borehole multi-source data acquisition equipment is shown  
Figure 10: Echo curve extraction and estimation in borehole A, B or C.  
in Figure 11. Among them, borehole optical imaging technology and borehole directional acoustic scanning technology were independently developed by the Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. The borehole radar technology uses the SIR200 borehole radar system produced by the GSSI company and is equipped with a 100 MHZ antenna.