| Deep mining has become the development trend of world resources development with the gradual depletion of shallow resources. However, the deep mining is a complex subject, it has a clear distinction for shallow mining and some theory is not yet perfect, especially the research of deep rise mining relatively small, the law of face overburden destruction in deep rise conditions not comprehensive understanding thus insufficient to guide the actual production.Therefore,it has a great significance for deep rise mining study of overburden deformation fracture. Based on geological date of Tangshan Mine of Kailuan Group in this paper, the main research work and conclusions:(1) The mechanism study of deep rise mining study of overburden deformation fracture, include: inferred when the inclination of the coal layer is small(12° or less), deformation and destruction in the form of overburden strata can be divided into caving zone, fractured zone and bend zone,when the inclination of the coal layer is large, deformation and destruction in the form of overburden strata can slip into rock collapse, bending and along bedding planes;breaking draw position when the basic roof pressure on the upper end surface of the support, calculated for the first time the basic roof to initial pressure and pressure cycles step were 112.68m、35.4m in based on mechanical model basic roof initial pressure and pressure cycles; drawn work surface above rock beamthere fracture may occur in the square in front of the work and cracks appeared ahead by analyzing the face of the deep rise mining coal above the work by the rock mining and influence along the downward component of the layer to the seam.(2) Analysis promoting different form collapse distance overburden rock displacement and stress utilize similarity simulation, reach conclusion:①Main roof initial caving step distance of about 120 m, the impact height of about 30 m,cycle caving step distance of about 30 m, affect the height of about 45 m,by seam along the downward slant to the component layer, the shape of the upper roof caving cyclical body parallelogram, a pair of parallel lines and consistent seam inclination direction, the direction of advancing a pair of parallel lines forming an obtuse angle with the face, that collapse has body seam inclined in the direction towards the goaf side of the sliding trend. ② Dip mining face in advancing the process, ahead of the working face 30-90 m position will produce crack and face advance direction of 110°-130°, the impact of fracture height of about 105-199 m, overburden rock subsidence increases overlying rock stress fracture near the sudden release decreases due to the generation of cracks. ③Overburden showing the evolution ladder in mining and the role of the damaging effects of lead fractures.④Protection pillar and a certain position at the front of the face will be concentrated stress occurs in the main roof breaking down at first when the most obvious stress concentration, stress values were33MPa、29.9MPa, stress concentration coefficients were 2.06、1.87.(3) Using numerical simulation method to promote different forms from the collapse of overburden, displacement and stress changes in the study, reach conclusion:①Main roof initial caving step distance of about 115 m, the impact height of about 25 m, cycle caving step distance of about 35 m, affect the height of about 40 m. Rock has collapsed backward to the goaf slip trend.②A range of face and rear face in coal and rock protective pillar will occur stressconcentration, protect the border pillar has been in a state of stress concentration.When the main roof first collapse stress reaches the maximum stress protection at the front pillar of coal were 35Mpa、32Mpa.(4) Put forward several key issues in deep rise mining combined with theoretical analysis, numerical simulation, similarity simulation and experimental study of the actual situation of coal mine. Proposed the corresponding control measures. |
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