An open face TBM where the cutting head is rotated inside the main shield with bearings between the outer skin and the inner rotating ‘drum’. The cutting head is a bar or cross across the face of the drum equipped with carbide teeth to suit the ground conditions. A very simple design and cuts to the exact shape of the pipe/tunnel so that the shield edge does not have to cut the ground. It is faster than a backacter in the right ground and when equipped with point attack teeth will cut much harder ground than a backacter.
The machine is ideal for stiff clays. The excavated material is loaded into skips using a conveyor belt or an auger (for soft ground) in much the same way as a backacter. Skips are usually winched out on a pipe bogie or rails. The system includes standard Akkerman rails and skips, all hydraulic umbilicals and an Akkerman power pack. The jacking rig is a telescopic Akkerman design allowing a full 2.5m diameter pipe to pushed without spacers.
For further deatils please contact Glen Kilroy, Plant Director at;