Evolution Characteristics Analysis of Displacement and Seepage Pressure of Water Inrush in Karst Tunnel Face with Layered Structure

To study the disaster process of water and mud resistant rock mass with layered structure and the accompanying catastrophe information of water inrush in karst tunnel, a new method based on the discrete element method and fictitious joint technology was adopted to really simulate the evolution process of water inrush process in karst tunnel face and study the evolutionary characteristics of displacement and seepage pressure of water and mud resistant rock mass with different layered structure. Results show that as the excavation of the karst tunnel progresses, the extrusion displacement of the water and mud resistant rock mass transitions from single unloading to the joint influence of unloading and karst water pressure, and the displacement of each measuring point on the karst tunnel face increases. As the water in the cavity continues to pour into the joints and fissures, the water pressure continues to rise. When the water inrush channel of tunnel face is formed, the karst water flow rate rises sharply, which provides significant water inrush precursor information. With the continuous increase of the inclination angle of the layered structure, the maximum lateral displacement of the face moves downward from the front, and the water pressure at each position of the water and mud resistant rock mass shows a trend of first increasing and then decreasing. The conclusions obtained in this study have a great significance to early warning and prevention of water inrush in karst tunnels. © 2022 School of Science, IHU. All rights reserved.