关键词: 二次沿空留巷, 关键块的稳定性系数, 巷旁充填体宽度, 影响因素的敏感度

Abstract: In order to solve the problem of gas accumulation and gas transfinite in the upper corner of high gassy working face, the technology of the secondary gob-side entry retaining is proposed based on existing technology of the gob-side entry retaining. Firstly, according to the activity law of overlying rock of the secondary gob-side entry retaining, mechanical model of key block in the working face tail is established, the mechanism of action between key block and surrounding rock of the secondary gob-side entry retaining is analyzed, the stability coefficients K1, K2 of key block are introduced, the stability criterion of  the key block is determined, and calculating formula of roadside supporting resistance is derived. If K1>1, then extrusion instability will emerge; If K2>1, sliding instability will emerge. By taking haulage gateway of No. 512(5) working face at Xieyi coal mine in Huainan as project background, based on stability criterion of key block, determines reasonable width of roadside backfill, and the sensitivity of influencing factors on the stability of key block are analyzed. The example analysis shows that final strength of No.1 roadside backfill and its width, mining height have great influence on the stability of key block, it is critical to improve final strength of No.1 roadside backfill and design reasonable width of No.1 roadside backfill, applying the technique of the secondary gob-side entry retaining to working face with large mining height is of more difficulty.

Key words:  , the secondary gob-side entry retaining；stability coefficient of key block；the width of roadside backfill；the sensitivity of influencing factors