Abstract

• The present research is carried out slope geology, geotechnical characteristics of rocks and slope stability analysis of spillway slope cutting at the Tha-Htay Hydropower Project, Thandwe Township, Rakhine State. This area is tectonically situated at the Central part of the Rakhine Coastal Belt. The rocks comprise the medium to thick bedded, indurated and moderately jointed sandstone intercalated with thinly laminated, fissile, partly carbonaceous shale and mudstone of Ngapali Formation (Middle Eocene). Most of the rock units are trending nearly NW SE in direction. The fracture system shows as closely spaced and moderately to highly jointed nature in the map of lineament analysis. According to geotechnical investigation, the rocks exposed along the spillway slope cutting site govern fair, poor and very poor rock classes respectively where the rock classes display CL and CM rock classes in this spillway slope site. Therefore, the supporting system should be installed with wire-mesh and rock bolt covering together shotcrete and systematic drained pipes. Moreover, some of the slope failures can be observed by kinematic analysis. Slope monitoring systems should be prepared on these slope sites. Hence, the selection of systematic supporting systems should be done on surface geological, geotechnical properties of rocks combined with design modeling.