Rock burst model of typical coal seam under thick alluvium

The process of rock burst can be described as the instability of surrounding rock structure driven by external force sources or the mutation of system equilibrium state under stress disturbance. The stress plays an important role in the process of rock burst. The regional feature of rock burst in Chinese collieries can be obtained based on the origin or type of main controlling stress. The rock burst controlled by the thick overburden is a characteristic of Juye coal mining area. The characteristics of rock burst behavior are associated with the stratum structure. The characteristics of rock burst in the typical coal seam under thick alluvium are investigated by means of case studies and in-situ monitoring da- ta analysis. Combined with the analysis of coal seam stress evolution,the process of instantaneous burst and delay burst in the coal seam under thick alluvium has been characterized. Finally,the relationship between coal seam stress evolu- tion and overlying strata movement and ground deformation is revealed by similar material simulation test,and the rock burst model of typical coal seam under thick alluvium is verified. The results show that the whole overlaying rock failure impels coal seam stress to reach the critical stress of rock burst rapidly,while ground deformation and movement result in slow increase of coal seam stress and rock burst when the stress reach the critical stress of rock burst. The de- velopment height of overlying separation is related to face advancing distance,and has an obvious platform effect. The coal seam stress evolution is related to overlying separation development,and has an obvious stagnation relative to face advancing distance. The instantaneous burst process is described as “overlying strata structure moving→coal stress e- volving→rock burst”,while the delay burst process is “ground deforming→coal stress growing→rock burst”. Monito- ring technology of rock burst in coal seam under thick alluvium is put forward in the end.