Study On The Risk Of Mining Rockburst In Working Face Of Fault Zone

Rockburst is one of the serious disarsters in Chinese coalmines,When working face approaches to the fault, the mining stress concentrates and large-scale roof rocks move due to the block of the fault which is caused by the fault cutting, hence the rock bursts with the large-releasing energy might be induced easily. The distribution of the mining stress and the evolution laws of the fault slipping in the fault-affected zone are studied utilizing the physical simulation,numerical simulation and the engineering cases. The main conclusions of the study are shown as follows:(1)The movement laws of the overlying strata with the working face in footwall or hanging wall advancing through the normal fault are studied utilizing the physical simulation. According to the comparative analysis of the footwall mining and the hanging wall mining, the movement affected by the fault and the fault slipping of the former are higher than that of the latter, hence, the possibly of the rock burst caused by the violently move of the roof rocks and fault shipping of the former in the vicinity of the fault might higher than that of the latter.(2)The width effect of the fault coal-pillar and its influence on the rock burst with the working face running parallel to the fault are studied utilizing the numerical simulation. When footwall mining, the concentrated stress of the fault coal-pillar and the fault slipping values is high due to the block of the fault and the lowly transfer performance to the hanging wall, while the concentrated stress of the fault coal-pillar when hanging wall is small with the strongly transfer performance to footwall due to the stable structure of the overlying strata. And the possibility of the rock burst with the different width of the fault coal-pillar is analyzed further.(3)The influence of the fault characteristic parameters on the rock burst with the working face running parallel to the fault is studied by means of the numerical simulation. The influence of the fault dip angle on the mining stress and the fault slipping with the footwall mining is higher than that of the hanging wall mining. The smaller of the shear modulus and the larger width of the fault zone, the higher of the fault block effect which might easier induce the rock burst.(4)The conclusions of the study are verified via four engineering cases, including the microseismic activity and rock burst accidents at the panel 6303 of the Jishan coalmine, panel 2208 of Shenjiazhuang coalmine, panel 2106 of Gucheng coalmine, panel 3100 of Chaoyang coalmine.