ABSTRACT
Analyses of rock bolt pull-test data are therefore still applicable to these current construction practices. Two important aspects are: torque-tension relationship and displacement-load ratio, particularly anchor tightening. The tests were performed on randomly selected rock bolt installations during construction of the underground excavations for the Churchill Falls underground hydro-electric power facility in Labrador, Canada, completed in the early 1970s. Some causes of excess frictional resistance to torque recognized from the Churchill Falls testing, other than non-lubricated or rusty threads and washers, are: Observing the latter emphasized the importance of having a pair of bevelled washers or a spherical seating in the bearing assembly. Examination of values of anchor tightening determined from pull tests for various makes, designs and sizes of anchors allows an effective evaluation of rock bolt performance. However, the wedge/serrated anchors showed more anchor tightening at low tensions.
