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Model to demonstrate how rockbolts workIn the 1960s I visited the laboratories of the Snowy Mountains Authority in Cooma,

Australia and I was shown a model used by Mr Tom Lang to demonstrate how rockboltswork. He had used many innovative rock engineering concepts in the design of thecaverns and tunnels of the Snowy Mountains Project and this model was oneof hiseducational tools. I was so impressed by this model that I used aversion of it in teachinga graduate course on rock engineering at the University of Toronto. As one of theirprojects the students would assemble this model from scratch and sodiscover forthemselves how the rockbolts work. The series of photographs included in

this documentwere taken during one such project. The model in these photographs wasbased on aversion of Tom Langs model constructed by the U.S. Army Corps of EngineersWaterways Experiment Station in Vicksburg, Mississippi.Figure 1: The rockbolt model inTom Langs office in Cooma,Australia. The inverted galvanisedbucket contained gravel which was

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held together by means of a patternof miniature rockbolts. In additionto binding the gravel together andcreating sufficient friction to hold itin the bucket, a 40 lb (18 kg)weight was suspended from a smallbeam attached to the rockbolts.Rockbolt model2Figure 2: Tom Langs explanation of how rockbolts work. A zone of compression isinduced in the region shown in red and this will provide effective reinforcement to therock mass when the rockbolt spacingsis less than 3 times the average rock piecediametera. The rockbolt lengthLshould be approximately 2s. Note there is no supportbetween the washers (unless mesh or shotcrete is applied) and the rock

pieces will fall outof these zones on the underside of the beam.Figure 3: The empty frame of the rockbolt plate model.More Information Less InformationClose