Study On The Evolving Characteristics And The Dynamic Affecting Of Surrounding Rock Macro Stress Shell And Mining Induced Fracture

According to the complexity, nonlinear, dynamic of evolving and the variety of effecting factor of mining induced stress and mining induced fracture (MIF) during caving, the evolving of macro stress shell (MSS) and MIF and those effecting factors are studied comprehensively and systemically by the integrated methods of on-site tests, material simulation, numerical simulation and theory analysis etc. in the extensive three-dimensional surrounding rock. The results show that the MSS configuration is an approximate half space ellipse-sphere-shell and the MIF is an approximate half space trapezium-cone and the distribution and evolvement of MIF are nearly relative with once caving thickness and mining frame parameters. The evolvement characteristics and mining height affection of MIF are opened out. The mechanic analyzing model and the reference frame of MSS and MIF evolvement are constructed and those configuration equations are educed. Based on the integrated analysis of evolving and equations of MSS and MIF, the factors and the relation among those; the mechanism of acting on MSS and MSS and MIF evolvement by coal pillar are obtained and the instability criterions are established. The MSS evolving characteristics and the dynamic affection between MSS and MIF are synthetically opened out .The results provide some important references on the mining frame designing, abutment controlling and safety mining and so on.