Optimizing roof bolt properties for a full-height coal seam roadway

Using a roadway in a coal mine greatly reduces the cost of mining. Because the coal seam is weaker than the overlying strata, high mine pressures cause large ruptures in roadway sidewalls and these are threats to the support system. Using the “multi-block beam” model, this paper derives equations to analyze the stresses and deformation in the rock and the coal seam, to determine the overburden pressure on a roadway roof and sidewalls and to define the rupture range. On the basis of that analysis and by following the stability principles of geotechnical engineering, the anchoring forces required to maintain sidewall stability are examined. This provides a theoretical basis for determining support parameters. Finally, for a field test, the bolting parameters were calculated after determining the physical and mechanical properties of the rock surrounding a roadway in a working coal mine. A support system was designed using the equations generated for this paper. That system was installed in the mine and the results were good.