Paterson, B.R. 1988 Engineering geology of the Paerau tunnel, Maniototo project. Lower Hutt: New Zealand Geological Survey. New Zealand Geological Survey report EG 389 46 p.
Abstract: The Paerau tunnel is a major feature of the Maniototo combined irrigation and hydro-electric project which is located about 70 km northwest of Dunedin. The tunnel is 1.4 km long, 2.5 m diameter, and is one of the first major tunnels excavated in schist for which comprehensive geotechnical investigations were carried out, followed by detailed documentation of construction. A geological ground classification system was used as a basis of payment for tunnelling. This report gives a summary of the engineering geological investigations carried out prior to and during construction. A more detailed account is presented of engineering geological aspects of construction including a comparison between actual and predicted tunnelling conditions. (auth)