Stability issues associated with the construction of underground caverns of Super Dordi Hydropower Project, Nepal

Abstract

The rock mass is heterogeneous and makes underground space construction a challenge to engineers. The rock formation, mineralogical composition, degree of schistosity, and weathering, are the major factors that determine the stability condition and rock support requirements. This manuscript deals with the stability situation of the underground settling basin caverns of Super Dordi Hydropower Project (SDHP) in Lamjung district of Nepal which is located at the lower boundary of the Higher Himalayan rock formation. The two parallel underground settling basins are 120m long and have an approximate cross-sectional area of 113 sq. m. The manuscript further discusses geological and rock mass quality conditions and evaluates the stability of the underground settling basins using 2D numerical modeling. The outcomes of the analysis presented in the manuscript have been helpful for the optimization of applied rock support.