- Role: Construction Management, Technical Support
- Client: City of Columbus
- Construction Cost: $375 Million
- Technology: EPBM/Slurry TBM
- Geology: Karst limestone
- Diameter: 20 ft (6 m)
- Length: 23,000 ft (7010 m)
- Depth: 200 ft (50 m)
Project Elements:
- Combined Sewer Overflow (CSO) Tunnel in urban environment
- Deep shafts (access and drop shafts)
- Slurry wall construction
- Drill and blast shafts, adits, and starter tunnel
- Groundwater inflow control by rock grouting
- TBM data analysis
- Risk management during construction
