Research on Supporting Technology for Surrounding Rock of Inclined Large-Span Open-Off Cut Roadway

In order to solve the difficult support problem of inclined large-span No. 5103 open-off cut roadway in Beixinyao Mine, China, a new long-short cable combined supporting scheme was proposed to strength stability of surrounding rock. Filed monitor results show that the deformation of surrounding rock keeps stable, and the displacements of roof and floor were 30 mm and 15 mm, and both sides were 25 mm and 17 mm after excavation, respectively. It is indicating that the surrounding rock deformation of the open-off cut under the supporting scheme was well controlled. Three dimensional model of roadway was built to calculate stress and plastic zone distribution of open-off cut roadway. Based on the numerical analysis, it is concluded that the vertical stress concentration zone, plastic development zone and peak value of principal stress difference for both sides of the open-off cut are located at 2 m depth of rock, while for the roof are located at 7 m depth. The distribution of principal stress difference varies with the positions of roadway. The principal stress difference in roof, stope side and no mining of the open-off cut first rapidly increased to a peak, and then gradually decreases and tends to be stable. But for floor, principal stress difference progressively increases and when reach to 25 m, it remains stable.