Study on overlying strata movement in gob-side entry retaining by roof cutting pressure relief based on quantitative fracture characterization

XI Zetao; GUO Junqing; ZHANG Baisheng; LIU Xiaowang; REN Xiaoyang; YANG Yongyong; LI Jianfei

doi:10.11799/ce202510018

Abstract：To quantitatively analyze the development of fissures in the overlying strata of gob-side entry retaining by roof cutting and determine a reasonable roof cutting height,a method based on Avizo software for quantitative statistical analysis of overlying strata fractures was proposed.Taking the gob-side entry retaining of the No.8104 return air roadway in Nianyan Coal Mine as the engineering background,theoretical analysis,numerical simulation,and field industrial tests were comprehensively employed.Based on Avizo software,the movement and fissures development of the overlying strata in the retained entry under no roof cutting and different roof cutting heights were studied,and the strata behavior and effectiveness of gob-side entry retaining by roof cutting were analyzed.The results show that after roof cutting in the retained entry,compared to no roof cutting,the height of the caved zone increases with the roof cutting height,while the height of the fractured zone remains the same as that under no roof cutting.Under roof cutting conditions,as the roof cutting height increases,the fissured area in the entry roof and the compacted void area of the goaf gangue both decrease exponentially.When the roof cutting height is 12 m,the roof cutting effect is optimal.Compared to no roof cutting,the fissured area in the entry roof and the compacted void area of the goaf gangue decrease by 49.2%and 33.5%,respectively.The roof-to-floor and rib-to-rib convergence of the gob-side entry retaining by roof cutting exhibit three distinct stages:slow deformation,rapid deformation,and deformation stabilization.Beyond 300 m behind the working face,both the roof-to-floor and rib-to-rib convergence stabilize within 400 mm.