Study on Catastrophe Mechanism of pipe-type Karst Water Inrush Disaster

Abstract To study the catastrophic mechanism of water inrush and mud outburst disasters encountered during tunnel excavation involving pipe-like water-rich structures, the research combined theoretical analysis with model experiments to construct a three-dimensional experimental model. This study investigated the catastrophic mechanisms of water inrush and mud outburst in pipe-like water-rich structures, analyzed the evolution laws of these disasters during their formation process, and achieved the following main results: 1) Throughout the entire process of water inrush and mud outburst disasters, the evolution of the disaster mainly consists of three stages, including the initiation of water-conducting channels, erosion and enlargement of water-conducting channels and instability stage, reflecting the formation, development, and disaster-causing evolution of water inrush and mud outburst. 2) Tunnel excavation caused a gradual decrease in the permeation water pressure of the surrounding rock under the initially stable water pressure field. Meanwhile, as the disturbance from tunnel excavation progressed, the permeation water pressure in the filling medium also gradually decreased, with an increasing rate of decline. 3) During the occurrence of water inrush and mud outburst, there were noticeable stage-like changes in displacement, permeation water pressure, and stress-strain parameters in the tunnel and karst channels. The displacement and stress-strain information of the surrounding rock before the occurrence of water inrush and mud outburst in the tunnel was particularly sensitive, serving as a predictive standard for the precursory information of tunnel water inrush and mud outburst.