Print

Construction Crew Sprays Concrete, ritchiewiki.com

Temporary Support Systems

Temporary support is defined as any system designed and installed to support the perimeter of an underground opening between the time it is first excavated up to the time that a permanent lining is in place.

We can divide these supports into 4 main categories :

Permanent support

Permanent support is defined as the support that is designed and installed to guarantee the long term stability of the underground structure.

On some occasions, the permanent support is taken into consideration for the long term, being considered in such case also as permanent support. This is the case of precast concrete segments placed by TBMs or certain rockbolts.

Other temporary support elements might suffer degradations over time (corrosion on steel rockbolts, loosening of sprayed concrete, etc) and therefore their contribution is often neglected for the long term.

 

In these occasions, permanent support is normally guaranteed by means of a concrete shell that is cast in place with movable formworks.

Sometimes, permanent support also plays an important functional role. This can be the case of traffic tunnels (smooth surfaces needed for ventilation, visibility and esthetic qualities), or hydraulic reasons (smooth surfaces for less hydraulic charge losses).

To know more