Study on reasonable width of isolated coal pillar based on rock outbursting-mine seismicity coordinated control

In view of the current situation that rockburst and mine earthquake frequently occur in the working face of Shaanxi and Inner Mongolia deep mining area due to unreasonable design of coal pillar width, by means of case study, theoretical analysis and field monitoring, the mechanism of rock burst and mine earthquake in isolated coal pillar area and the reasonable width of isolated coal pillar are studied. Three typical rock burst and mine earthquake events occurred in isolated coal pillar area in the working face of Shanxi and Inner Mongolia deep mining area in recent years are taken as engineering background, according to the different dynamic characteristics and induced mechanisms, they can be divided into three types: rock burst caused by local failure of coal pillars, rock burst caused by overall instability of coal pillars, and mine earthquake induced by thick hard-strata breaking under the support of isolated coal pillars. The goaf lateral abutment pressure estimation model, the goaf transfer stress estimation model, the bearing stress estimation model of coal pillar and the deflection and bending deformation mechanical model of key stratum are established respectively, the mechanism of local rock burst, overall instability type rock burst and mine earthquake induced by different width isolated coal pillars are revealed. The results show that, the width of isolated coal pillar between 2101 working face and 2201 working face without local rock burst is 5～6 m or not less than 128 m; the width without overall instability type rock burst is not less than 138 m; the width of no mining earthquake is 498 m. On this basis, the influence of coal pillar width on rock burst instability and mine earthquake is discussed, and the reasonable design basis of coal pillar width based on the cooperative control of rock burst and mine earthquake is proposed, in order to provide reference for the design of coal pillar width in similar conditions.