Evaluation of wood packwall supports

CIM Bulletin, Vol. 84, No. 951, 1991

Thomas M. Barczak, U.S. Bureau of Mines, Pittsburgh Research Center, Pittsburgh, Pennsylvania, Carol Tasillo, Corps of Engineers, Pittsburgh, Pennsylvania, and William D. Gallant, Cape Breton Coal Research Laboratory, Sydney, Nova Scotia

This paper describes the results of full-scale testing of several multi-layered wood crib configurations that were tested in the Bureau of Mines mine roof simulator in cooperation with the Cape Breton Coal Research Laboratory and Cape Breton Development Corporation of Sydney, Nova Scotia. Nine different crib configurations currently being used as wood packwall supports for advancing longwall applications in Canada were evaluated. Configuration parameters understudy included the aspect ratio (height-to-width relationship) and percentage of solid material used in the crib construction. Test results and generalized wood crib behaviour are discussed in detail. Recommendations are made concerning crib constructions to maximize strength and stability. A cost benefit analysis of multi-layered wood crib configurations is made. A comparison of laboratory results and underground observations of several wood packwall supports in the Sydney coalfield suggest in situ load capacity is less than that measured in laboratory testing. Reasons for the apparent decrease of in situ load bearing capability are described.
Mots Clés: Rock mechanics, Packwall support, Wood packwall support