General information on tunnelling and underground work is given in the preceding chapters, mainly in part three. The case histories developed in this chapter concern the Kariba South Bank and the Kariba North Bank underground works, excavated in igneous rock and the Waldeck II machine house in sedimentary rock. In all three cases the rock required support. The methods used were very different in each case. It is interesting to compare designs, excavation techniques and rock support.

The Kariba South Bank power scheme (fig. 16.1)

The geology of the site (figs. 16.2 and 16.3)

The most impressive element of the Kariba power scheme is the high double-curvature arch dam impounding water in the Kariba Reservoir. Most of the geological investigation on the site was concentrated on the dam foundations and on the rock abutments on both sides (see section 11.4.3) and on the reinforcement work on the South Bank.

The geology of the Kariba area was recorded and interpreted by the late Dr Francis Jones and Dr Dubertret (Paris). Dr J. L. Knill and Dr K. S. Jones have published an extensive geological description of the area, including the areas where the South Bank and the North Bank underground power houses had to be located. They reported that: