ABSTRACT
Nepal Himal consists of various types of rocks and geological structures. Thus the underground construction works through these domains varies in terms of excavation, support system requirement and stability. The critical issues with regard to the underground works are geotechnical. Hence investigations are necessary to clarify the type and magnitude of the risks and how they can be reduced or managed. Experiences have shown that same type and scale of ground investigation is not suitable to all the project sites. The Khimti 1 Hydropower Project (KHP) is the first project applying Q-system in Nepali Himalayan Rock. The method was found to be appropriate for drill and blast tunnels in jointed, fractured and sheared rock, which tend to overbreak. The main advantage of the NMT is that each stretch of tunnel is evaluated and it takes optimum advantage of the self-supporting capacity of the rock. Site specific modification would be necessary in determining support for the underground construction.
