Design Procedure for Arch Canopies for Rehabilitation of High-roof- fall Areas.
Proc Fifth Conf on Ground Control in Ming Morgantown West Virginia, 1986 Jun; :51-61
This report describes an arch canopy design for rehabilitating a high-roof-fall area. This procedure is specifically developed for evaluating an unbackfilled arch canopy that is subjected to an impact load (roof fall). Only dynamic line loading of the arch canopy at its crown is considered, and the procedure does not account for an unsymmetrical loading condition. A general evaluation can be based upon a comparison of the arch's maximum crown deflection and a prescribed allowable crown deflection. A single spring-mass system is used as an idealized model to represent the dynamic behavior of the arch canopy at its crown. An energy approach is taken to determine the maximum crown deflection of an arch rather than solving a differential equation of motion derived from dynamic equilibrium. The design procedure is based on the concept that when an arch canopy is subjected to impact loading at its crown and deflects from its unloaded state to maximum crown deflection, the structure absorbs strain energy, both elastic and plastic. The significance of this design procedure is that it gives mine personnel an analytical tool to select an arch canopy to meet the dimensional and functional requirements of a mine entry and a prescribed allowable crown deflection.
Proc. Fifth Conf. on Ground Control in Ming., Morgantown, West Virginia, June 11-13, 1986, PP. 51-61