Study on bolt-mesh-anchor support technology of open-off cut with compound roof and large cross section

In order to solve the support problem of open-off cut with compound roof and large cross section, based on the geological conditions of No.20106 working face of Wangjialing Coal Mine, physical simulation was carried out to analyse the failure characteristics of surrounding rocks. Results showed that the corner and roof of open-off cut were easy to deform and destroy.The deformation and damage of surrounding rock during the second excavation were obviously higher than that during the first excavation. The counter measures for surrounding rock were pointed out. It was determined that the combined support of tunneling in twice+bolt-mesh-anchor+hydraulic pillar should be adopted in the open-off cut.The results of field obserbation showed that the maximum separation of open-off cut was 9 mm and the maximum section shrinkage was 6.6%.The support scheme effectively controlled the deformation of surrounding rock of open-off cut with large section.