STORAGE AND RELEASE REGULAR OF ELASTIC ENERGY DISTRIBUTION IN TIGHT ROOF FRACTURING

Rock burst is one of the severest natural calamities in coal mining;and its energy variation regular is always studied emphatically.The in-situ practices show that most rock bursts occur in the front abutment scope ahead of the coal face.Based on the study of coal mining,theoretical mechanics and material mechanics theory,the mechanical model of tight roof initial fracturing on the basis of uniform stress and increment stress is proposed;the calculation formula of energy distribution of elastic foundation beam is put forward,and the storage and release laws of energy distribution ahead of the coal face before or after tight roof fracturing are studied.The elastic foundation beam will fracture at the maximum bending moment position ahead of the coal face.As it hangs to limit distance,the elastic rebound and compression phenomenon will occur at two-sides of fracture position.The closer to coal face,and the bigger the displacement and bending moment are the more the stored energy of elastic foundation beam is,and the more the release of energy after fracturing.The scope in which compression and elastic rebound occur after tight roof fracturing is the vibrating source of rock burst.