Study Of The Transmutation And Destroy Character Of Surrounding Rock At Working Face Of Flap Top

The immediate roof of coal₁₃ is limes rock, hardness and thickest in Xiezhuang Colliery. The whole isn' t easy to fall. During extraction rock beam of roof is easy to form circs of flap top. This provides superior condition to break floor, and it is disadvantage to prevent and cure water for floor. Aim at 71303 (up) existing multi-actul problems of mining over containing water layer, this text discusses the transmutation character of roof and floor under flap top condition in working face.On the basis of analyzing strong rock mechanics character, utilizing flexion tansmutation of material mechanics, the text discusses utmost span of cover rock beam and utmost length of cantilever bar during working face pushing, and fetches calculating formula; Basis on principle of equivalent load to accept distribution of abutment pressure to linearization according to area, and utilizing displacement-dispel of pole coordinate under the function of centralized load of half infinitude body of elasticity mechanics, the text discusses two phases movement characters of primary weighting and periodic weighting, and gains comparatively displacement character that floor terrane perpendicularity in floor direction under three roof structures condition (before primary weighting, falling roof and flap top) :compression-tension-recompression.Considering the flexural character of rock, and utilizing rock beam flexion transmutation of material mechanical to analysize the influence of pushing speed vs the transmutation of surrounding rock in working face, gain that the transmutation of roof and floor are aggrandizement along with pushing speed of working face depress; contrarily reducing.Finally, adopting adopts 2D—σ finity buck simulation software of rock engineering, simulate transmutation of surrounding rock, stress distribution character and the influending effect of pushing speed at working.face under three...