Completed in 2003 by Mole Constructors, the Cahaba River Trunk Sewer, Contract 3 project consisted of the excavation of approximately 5,000 linear feet of 12 foot diameter tunnel for a sanitary sewer through sandstone and shale including shaft excavations to depths of 120 vertical feet. Mixed face conditions were encountered. Tunnel excavation performed via a Robbins Tunnel Boring Machine (TBM) for the 12 foot tunnel. The initial tunnel support consisted of rock dowels, rock dowels with welded wire fabric and mine straps, or steel ribs and wood lagging. The final lining consisted of 84-inch diameter reinforced concrete pipe. The shafts were supported via soldier piles and wood lagging within the soft ground, and rock dowels, welded wire fabric and shotcrete within the rock. Standard drop structures were constructed within the shafts.
Project Details
- Owner: Jefferson County Commission; Environmental Services
- Location: Birmingham, Alabama, United States
- Performed as: Mole Constructors, Inc.
- Project value: $12,215,135.00
- Completion Date: March 2003