Study on mechanical characteristics and supporting parameters of asymmetric support in gob-side entry driving with narrow coal pillar

In order to study the deformation and stress distribution characteristics of surrounding rock under the asymmetric support of gob-side entry driving with narrow coal pillar, the theoretical analysis method was used to study the mechanical mechanism of symmetrical and asymmetric support of gob-side entry driving with narrow coal pillar. Based on the field engineering practice of Madaotou Coal Mine, the mechanical characteristics and stability of roadway surrounding rock under asymmetric support were studied by combination of numerical simulation and engineering effect verification methods. The theoretical analysis show that the asymmetric support can effectively reduce the bending moment of the roadway roof and reduce the deformation of the roadway roof and floor and the two sides. The simulation results show that the internal stress-concentrated area and elastic core zone in the coal pillar ensure the bearing performance of the coal pillar. The field measurement results show that under the asymmetric support of "anchor cable+channel steel", the maximum deformation of roadway roof, narrow coal pillar side, and solid coal side is 100 mm, 79 mm, 62 mm, respectively. Besides, the development of roadway loose zone and the fissure is at a medium level.