ABSTRACT
The fossil energy is impacting global environment considerably. Therefore, focus on the development of renewable energy is of priority in world. Hydropower is among the favored renewal sources which many developing nations have prioritized. One such example is recently constructed Minas-San Francisco Hydropower Project in Ecuador where both drill & blast and TBM methods of tunneling were used. This manuscript highlights engineering geological conditions of headrace tunnel and evaluates TBM performance. Influence by rock mass quality in TBM penetration rate is assessed, and has been emphasized that knowledge of rock mass quality parameters and cutter technology are key factors that influence on the estimation of net penetration of TBM. Hard rock mass of high abrasivity encountered in the project resulted in very low penetration rate than that was predicted during design. Analyses further shows that throughout TBM boring the penetration mainly depended on the mechanical strength of the rock mass.
