Study On Floor Heave Mechanism Of Gob-side Entry Retaining In Zhongxing Colliery

The superiority of gob-side entry retaining is self-evident, as the process and thesupporting method on innovation, the application scope of gob-side entry retainingalso increasingly widespread. But along the gob-side entry retaining itself flawed,experience the two mining influence make the roadway maintenance problems, thedeformation of the surrounding rock is extremely serious, especially the roadwayfloor heave, long duration, large deformation. Based on current research andgeological conditions of Zhongxing Colliery, combined with the mechanicalproperties, mechanical model, numerical simulation of gob-side entry retaining,research floor heave mechanism of gob-side entry retaining, for the control of floorheave of gob-side entry retaining to provide a theoretical basis. The main contents areas follows:(1)According to the floor heave for monitoring data, the variation of the floorheave with the mining face is divided into five periods: excavation and the stability,first mining front support influence period, frist mining post influence period, fristmining after stabilization and second mining front support influence period.(2)By elastic-plastic theory and limit equilibrium theory, respectively calculatethe supporting stress of entity coal roadway, roadway lateral bearing stress andworking face front abutment stress, according to the superposition of three stress withthe two sides of roadway concrete stress, the stress distribution of roadway can beobtained in each period, combined stress distribution of floor rock, deformation andfailure process of rock, analysis the deformation and failure process of roadway floor.(3)The amount of floor heave of roadway by elastic-plastic deformation,expansion, the hulking, creep deformation and caused by the expansion under theinfluence of water, the deformation of the elastic-plastic deformation and dilatancydeformation generated is very small, the post peak dilatancy and post peak creep is amajor component of heave part, water swelling deformation is associated with bottomwater and floor lithology. The roadway as the circular roadway as an isotropic biaxialcompression, combining the elastoplastic theory, the theory of limit equilibrium, thesurrounding rock loose circle theory were gained heave components analyticalsolution.