In the normal rock conditions, conventional type surface power houses have been built, whereas in structurally sound rock with sufficient rock cover, underground power houses have been attempted in India. The geological uncertainties plays major role in deciding the type of power house at a particular site. While in the surface type conventional power house huge excavation and concreting are involved, the access to the power house involves major work in the case of underground power house. There are very little examples when semi underground type of power houses have been attempted in India. The Mahi power house-II of Rajasthan is the sole attempt of shaft type of power house after the successful completion of small Giri power house in Himachal Pradesh. This paper presents the case study of this shaft type semi underground power house. Important features about its layout, design and construction have been discussed here
