Basic Experimental Study On Water-Inrush Mechanism Of Floor In Deep Mining

In this paper by analyzing the depositing environment of deep coal resources, according to high karst hydraulic, high ground stress, strong mining disturbance and new mechanical properties of deep rock presented in deep mine, deformation and failure of floor aquifuge and formation of underground watercourse caused by tectonic activation as the main clue, with the comprehensive application of laboratory test, theoretical analysis, numerical analysis and field measurement and so on, a series of related basic experimental studies on floor water-inrush mechanism in deep mine are carried out.Based on laboratory experiment on the physics mechanical property of typical floor rock which from lower coal seam of Geting coal mine and complete stress-strain seepage properties test of floor rock under high or low confining pressure, combined with analysis of water-proof property of floor strata in deep mine, we preliminarily obtained the influence law of lithology and confining pressure to rock seepage property. By laboratory experiment on rock mass joint and cracks seepage coupling property under conditions of compression and shear, researched on the influence of normal stress, roughness of joint face, seepage pressure to samples’stress, displacement seepage property under constant normal load(CNL) or constant normal stiffness(CNS), we got the trend and regularity in shear process shear stress, normal displacement, jointed hydraulic aperture and transmissivity changed with shear displacement. Researched on the dilatancy property of rock joint fractures had shear deformation, analyzed the influence of joint shear deformation to seepage property, criterion formula about joint fractures had shear deformation are obtained. Based on the present laboratory condition’s limit to rock fracture stress seepage property, according to the actual situation of rock mass under 3d stress and the environment specificity of deep rock mass, rock stress-seepage coupling true triaxial test under high pressurized water was preliminarily designed and developed. The evolution rule of deep mine floor’s deformation and damage with the working face advanced and the features of floor’s destruction under different mining depth are analyzed though numerical experiment using FLAC-3D, the fluid-solid coupling damage characteristics of floor which influenced by fault and above pressurized water in deep mine were analyzed, some regularity cognition is obtained and verified by field test results, the reasonable size of fault waterproof coal pillar under simulation condition is put forward. The influence factors, characteristics and the reasons of floor water inrush in deep mine is analyzed and deep stope floor water inrush types are classified. According to the formation of water inrush passageway, three modes are put forward as inherent passageway water inrush mode, normal floor strata water inrush mode and discontinuous joint fissure extension water inrush mode, and then their water-inrush mechanism are researched. Catastrophe characteristics of floor water-inrush are studied with the help of the method of catastrophic theory, necessary and sufficient conditions of floor catastrophe water-inrush are derived. Some concepts as Water-proof variables factor, feature leading parameter and coefficient are put forward. Through establishing catastrophic models respectively, one model is floor water-inrush for shear failure instability, and the other is floor water-inrush for vertical and horizontal force and destroy instability, floor system state is calculated and obtained, and it can provide a new method and idea for predicting water-inrush from floor in deep mine.