An analysis of the cause of karst collapses near the Dapipo-Zhongcun section of the Xiuning tunnel of the Guangzhou-Kunming railway

The Dapipo-Zhongcun tunnel in Yunnan is an area where karst collapses frequently occur. The karst collapses have an important impact on the local industry and agriculture production, the daily life the local residents. It is of important significance to grasp the development regularity and formation mechanisms of the karst collapses. Based on the basic characteristics of geological environment of the study area, this article analyzes the temporal and spatial distribution of the karst collapses and reveals three emergence periods of the karst collapses: the slow emergence period, concentrated outbreak period and subsequent influence period. According to the standard of the main influence factors, the karst collapses in the study area are divided into four basic stages: the initial stable stage, initial change in stress stage, collapse stage and periodically stable stage. The formation mechanisms of the karst collapses are analyzed and grouped into two types. The corresponding prevention and control measures are also proposed. The research results may provide references for the improvement of local environmental conditions and control of geological disasters.