Microtunnelling
Robbins Double Gripper TBM Guided by NAV24 Gyro System
When Bradshaw Construction (BCC) of Eldersburg, Maryland (USA) was awarded the Niles Avenue Sewer Improvement project in Atlanta, they had to decide on the navigation system to be used.
Their 72’’ Robbins Double Shield Gripper TBM that had been selected for this project had very limited interior space, so line of sight through the TBM was difficult to guarantee at all times. Furthermore, most of the 215 m long drive was done at a radius of 300 m and the expected ground conditions were rough due to hard rock geology. These circumstances would make it even more problematic for a conventional...
