Study on deformation and failure mechanism and control technology of deeply gob-side entry driving

In order to solve the large deformation problems of the deep gob-side entry driving at No.15 coal seam in Yangquan Mining Area, its geological character istics, geological mechanical parameters characteristics and original supporting design were analyzed, which revealed the laws of deep roadway deformation, relatively stable initially, roof by the rib bends and subsides subsequently, large inverted trapezoid deformation, roof destabilizes.It pointed out that the high in situ stress, big prin cipal stress difference, and multiple mining were the fundamental factors which affected the stability of the roadway, and low strength of initial support of and weak side support were the deciding factors. Combination with analysis of relation between coal pillar size and stress of surrounding rock, the high pre-stress control technology w as put forward, which was lay its focus on supporting the strong coal side with auxiliary support between roof and coal side.The results showed that the initial support in tensity increased by 149% and sectional convergence rate decreased by 48%.The technology ensured the roadway stability, and met production requirements.