Can’t Let the Shale Fail!

摘要

Since 1908, the City of Rome in upstate New York State has been relying on a hand-mined, 6-ft wide by 6-ft tall subsurface shale rock tunnel for conveyance of their drinking water supply. Fed by water impounded by the Kessinger Dam on East Branch Fish Creek, water is screened at the dam’s gatehouse then diverted through the 5,450 lf flat tunnel by gravity. At the terminal end of the tunnel is a junction chamber where it enters into City’s 48-inch diameter water transmission main that conveys it to their Water Filtration Facility for treatment and distribution. Due to the age, pressure/time, weathering, and erosion acting on tunnel, the soundness and condition of shale material had degraded so the entire Raw Water Tunnel was in need of full crown and wall rehabilitation. To perform this task, it was necessary to temporarily decommission, dewater and clean the tunnel. Tunnel was scaled, surveyed, washed and anchored with rock bolts, as necessary, then sprayed with a fiber-reinforced shotcrete.