ABSTRACT
Low-pressure compressed air is an important option for tunnelling. The presentation described the development of transportable, quickly assembled compressed air systems which provide additional flexibility and economy in use. The systems are suitable both when compressed air is the basis of the tunnelling method and when it is a standby or emergency facility. The components of the systems and typical installations were illustrated by slides. The planning needed to achieve the greater advantages from these systems was discussed. The points particularly stressed were that:
A high proportion of tunnelling is for infrastructure works at shallow depth for which low-pressure (< 1 bar) compressed air is sufficient.
At these pressure there are not the health hazards of higher pressures.
Many of these projects are relatively small in scale and the headworks are set in places awkward of access and restricted in area.
The compressed-air systems described can be tailored to suit specific situations.
