Omaha CSO project celebrates TBM breakthrough9 August 2017
USA - The South Interceptor Force Main tunnel project in Omaha made its final breakthrough on August 5, following a year-long delay due to a stuck TBM in unexpected ground.
City of Omaha Public Works awarded a USD 21.5M contract to Super Excavators for the South Interceptor Force Main Project - North Segment and North Gravity Sewer in September 2014, and the contractor launched a 102-inch-diameter Lovat TBM the following September.
During the 3,500ft (1km) drive, the TBM designed for rock got stuck last year, Scott Aurit, project manager at HDR told local media at the breakthrough, when the machine encountered boulders and groundwater conditions.
The approximately 70ft (21m) deep tunnel was mined in a limestone shale mix. The contractor excavated a rescue shaft to remove the stuck machine and launched another machine from the opposite direction in order to complete the remaining 900ft (274.32m) of the drive.