New Tunnel Will Boost Canada's Hydroelectric Capacity

摘要

In 2007,justmonths after crews began drilling work for a 10.4 km tunnel intended to carry water from the Niagara River to Ontario's Sir Adam Beck hydroelectric generation complex, they ran into a problem. The underground rock they were excavating was less stable than expected, resulting in frequent overbreak that seriously impeded the progress of the world s largest tunnel-boring machine (TBM) for hard rock.