Design, analysis and testing of non metallic rockbolt bearing plates.

Non metallic bearing plates have been identified as the weakest component in GRP rockbolting systems used in UK coal mines. A literature review revealed a shortage of information on the design of rockbolting components, particularly the design of the non metallic bearing plates.Over twenty parameters concerning the design and testing of non metallic rockbolt bearing plates have been investigated using Finite Element Analysis and laboratory testing. The parameters included bearing plate depth, central hole diameter, external diameter, material, coned angle for both solid and webbed bearing plates. The designs have been evaluated by comparing the load / plate volume to consider the efficient use of the material. The experiments were designed using Taguchi and one factor at a time methodologies. Interactions between some parameters have been investigated. Reasons for the observed effect of parameters have been suggested.A modification of the BS 7861 test is proposed which more closely simulates the colliery failure mechanism and hence gives a better measure of a bearing plate's suitability for use in a coal mine. The modified test uses a 100 mm hole in the steel support plate as specified by American Standard F432 for steel rockbolt bearing plates, not the 55 mm hole as specified by BS 7861.Optimum values for important parameters have been determined for a 100 mm hole in the steel support plate as proposed in this research and for the 55 mm hole diameter specified by BS 7861. The results produced can be used to design a bearing plate for use in a coal mine with optimum depth and coned angle.