By adjusting longwall top coal caving panel,gateroads on either end of the LMSG (longwall mining with split-level gateroads) panel are arranged at different levels within a coal seam,gateroads of the adjacent panels are offset spatially,unconventional gateroad pillar was developed.A structural model of trapezoidal pillar in is established using limit equilibrium theory and stability of the pillar is analyzed.An analytical equation of the depth of plastic zone of the gateroad pillar is derived,and distributions of supporting stress are obtained.New division of the gateroad pillar is obtained according to the above results.The result shows that the depth of limit equilibrium zone within the gateroad pillar is tremendously reduced but the stability of coal pillar and recovery ratio are significantly increased.In addition,two additional zones within this coal pillar were found,stress free zone (where only subjected to no or slightly weight of gangue) and self-weight action zone resulting from immediate roof.The reseach has some significance in gateroad design and increasing recovery ratio,etc.
