Waikaremoana Power Scheme – Piripaua penstock engineering geology Study and risk assessment

ECNZ wished to have an engineering geology and risk assessment study undertaken of the Piripaua penstock slope, part of the Waikaremoana Power Scheme. This paper presents the method used for geological and statistical analysis and the conclusions made. Aerial photograph interpretation as well as field mapping of the geology was carried out to determine the likely failure mechanisms. Three dimensional analysis of wedge failures was performed with variation of input parameters such as strength and earthquake magnitude to allow probabilities of failure to be evaluated.