Research and application of pre-stressed continuous surrounding rock control technology

Abstract

Pre-stressed continuous surrounding rock control technology was proposed to solve the problem of serious deformation and destruction of the return air lane of No. 5 working face of Ⅱ2-1 coal in Lingdong Mine. First of all, the mechanical model of the anchor bolt pre-stress transfer in the surrounding rock was established through theoretical analysis. Next, based on the geological conditions of Ⅱ2-1 coal surrounding rock, FLAC3D numerical simulation was used to analyze the prestress diffusion law under different preloads, and the effect of M5 steel strip on prestress diffusion was simulated. Finally, the designed prestressed continuous surrounding rock control plan is implemented on site. The results show that the prestresses can be superimposed on each other when the row spacing between the anchor rods is 900 mm × 900 mm, and the anchor rod pretension is above 100 kN. In addition to the surface protection function, M5 steel can further diffuse the prestress of the anchor rod. After reasonably reducing the size of the roadway cross section, using strong prestressed continuous control scheme of the “bolt+anchor cable+anchor net+M5 steel belt” can reduce the surrounding rock deformation of the coal roadway by more than 70%.

Keywords

• roadway support
• prestress
• surrounding rock control
• numerical simulation
• bolt support