Analysis on the formation mechanism and development process of karst collapses in Lijia Village, Gaoming District of Foshan City

Abstract

Taking natural-induced Lijia Village karst collapses as the research object, on the basis of systematically collecting the data of regional geology, tectonic geology, engineering geology, hydrogeology, environment, meteorology, historical disasters, combined with the drilling data, the geological environment conditions and karst development characteristics of Lijia Village karst collapses come to a conclusion, and its formation process is analyzed. Finally, the genetic mechanism is discussed. The results indicate that: (1) The overburden in the area where the Lijia Village karst collapses located is an alternate geological structure with “Skylight” and “Separation”, and the content of calcite in rudstone is high and easy to dissolve, which plays a decisive role in the formation and development of soil caves and karst caves. The intersection and superposition of the NE fault and NW fault, closing to Xijiang River and the existence of ancient river channels, provide a channel for groundwater erosion and strong runoff and frequent exchange, and play a leading role in karst development. Good connectivity between surface water and groundwater directly leads to rain-induced karst collapse. (2) The process of karst collapses in Lijia Village is divided into three stages: water pressure stage in the early stage, softening collapse in the middle stage and vibration group collapse in the later stage. The collapse model is Osmotic Pressure-Gravity-Softening. (3) The karst collapses in Lijia Village is formed by a series of natural collapses induced by heavy rainfall under the special geological environment of “rock soil water gas” combination.

Keywords

• karst collapses
• karst developmental features
• formation mechanism
• development process
• fuwan town gaoming district of foshan city