The investigation tests carried out as part of the rock anchor contract at Hazelmere dam are still ongoing but have already broken new ground with the installation of arguably the world’s largest sacrificial (loaded to failure) test anchor. The stressing jack (capacity of 15000kN) and the stressing chair weigh just over 4 tonnes and collectively stand at a height of 1.7m. The test anchor tendon comprised 61No strands, installed in a 355mm diameter borehole and has an overall length of 40m.
Many challenges lie ahead in this fascinating project which is being executed under the watchful eye of ground anchor expert Dr Devon Mothersille.
Figure 1: SRG Site Engineer Vutshila Mkhatshwa inspects the stressing jack during loading
Figure 2: Mark Sinclair (SRG), Devon Mothersille (GGL) and Adam Botha (ISA) discuss technical challenges encountered during the execution of the trial anchor works
Figure 3: Installation of test anchor tendon in an area on the downstream face of the dam