A centre shaft drive D series machine. The D series has a chamber for a “bentonite bubble” to minimise settlement in changing face conditions. It is not usually necessary at this size of machine and we have never used it. Rollers on the rock head can still be changed underground but access is above the drive shaft rather than through the centre bearing as in the 1500T. This is a full system with its control cabin, power pack, jacking frame and pumps.
The machine can be equipped with a tail can where rings can be built behind the TBM rather than pipes, but the machine is normally used in pipejacking mode. The 1800D is configured to operate interjacks and has a push module and has been pushed over 400m. It also has a heavy duty soft ground head which works very well in mixed conditions. This is a large machine with a 1200t jacking rig and needs at least a 7m diameter shaft to launch from.
It also has a new Sulzer Computer System.
For further details please contact Glen Kilroy, Plant Director at;