The Instability Characteristics and Displacement Law of Coal Wall Containing Joint Fissures in the Fully Mechanized Working Face with Great Mining Height

Coal wall rib-spalling is regarded as a key technical problem influencing safe and efficient mining of fully mechanized working face with great height (FGH) while the coal stability influenced by strength body, which internal joint fissures have crucial impact on body. This research attempted to explore how FGH occurrence fissures. paper uses physical numerical simulations systematically analyze instability characteristics displacement law FGH. Research results show that form scope depend state seam development area, related combination joints; under condition hard coal, better at inclination angle 90°, less stable 45° 135°; medium-hard surface 135°, smaller spacing surface, larger area rib-spalling, wall.