CATASTROPHIC MECHANISM AND ITS PREVENTION AND CONTROL OF SEEPAGE DEFORMATION AND FAILURE OF MINING ROCK MASS Ⅱ: A REVIEW OF WATER INRUSH FROM SEAM FLOOR

This paper examines the typical types of disasters caused by groundwater seepage deformation and failure in underground mines. They include water inrush or water-sand mixture inrush from the roof,water inrush from the floor,and seepage failure of the interface between water retention bulkhead and surrounding rock,etc. The paper introduces the important role of Professor Guochang Liu in laying the foundation for the development of mine hydrogeology and engineering geology in China. It further reviews the mechanism of major engineering geological disasters caused by groundwater seepage failure of rock masses in mines and their development of prevention and control technologies. This paper also reviews the history of the proposal,improvement and application of the water inrush coefficient for the evaluation of water inrush from seam floor,and reinterprets the physics of the water inrush coefficient from the seepage mechanical mechanism of the generation of the seepage failure of the seam floor. Based on the critical hydraulic gradient of the floor rock mass structure,a water inrush discrimination method was established. The critical hydraulic gradient of the floor rock mass can be estimated by semi-empirical method. A dynamic evaluation method of water inrush risk from the seam floor based on the safety factor against seepage failure is proposed after the analysis of the evolution of evaluation methods for floor water inrush. The prevention and control principle and efficiency evaluation method of the active prevention and control measures for the flood water inrush catastrophe are analyzed. Finally,the scientific issues that require further in-depth study in the seepage stability of the seam floor are proposed.