Substantiating Parameters of Reinforced Rock Supports

Abstract

In this work, we focus on the technology of stabilizing roof rocks by constructing separate rock supports reinforced with metal grids. Their parameters are specified using the results of physical structural modeling. The reinforced and non-reinforced rock supports with different fractional compositions are arranged and tested. Their initial shapes are similar to rectangular parallelepipeds with the base width-to-length ratios of 1:1, 1:1.5, and 1:2. Their shrinkage is determined by loading the supports regarding the rock particle size and the reinforcement density. Increasing the reinforcement density leads to reducing the linear dimensions without losing loadbearing capacity. It is proved that using the grids conduces the self-wedging of the rock particles. They are most effective at the initial stage of the formation of the loadbearing core. The exponential power dependence of the relative support shrinkage on the grid partitions number is obtained. The bearing core sizes in different supports are determined. For the non-reinforced supports, the core width is about 60% of the initial support width, and for the reinforced ones, it is about 90%. The exponential dependence of the core width-to-height ratio on the number of grid partitions is established. The expression for determining the reinforced support width is obtained. The support stability depends on the smallest initial base size. The size of the rock material has a little effect on the shrinkage. Reinforcement by three metal grids leads to reducing the pliability by 21% and 24% for the supports with the side ratios of 1:1 and 2:1, respectively.