Experimental investigation of the nonlinear evolution from pipe flow to fissure flow during carbonate rock failures

Abstract

Fissure flow (FF)-induced disasters are a basic scientific difficulty in the fields of rock mechanics and geological engineering disasters. Based on large collapse and landslide disasters in China’s southwestern mountainous karst region, this study focused on the nonlinear evolution of the transition from pipe flow (PF) to FF during the process of carbonate rock rupture, with a view to determining the mechanism by which the interactions between geological structures and karst PF cause disasters. An experiment was designed and conducted to visualize the PF–FF transition in a carbonate rock by X-ray imaging at a material scale. Multiple mechanical metrics for the carbonate rock as well as X-ray imagery of the flow were obtained. The effects of multistage loading on the PF regime and the fractal characteristics of the PF–FF morphology were investigated. On this basis, the mechanism of the nonlinear evolution from PF to FF during the carbonate rock rupture process was determined. The experiment result demonstrates the fractal characteristics of the nonlinear evolution from PF to FF during the carbonate rock rupture process.