Shaft-Sinking

Irish Tunnelling Ltd. sink shafts through every type of strata, from vertical and incline shaft sinking to large underground excavations. Our vast experience in this field enables us to provide a comprehensive and complete shaft sinking service.

We construct:

• Segmental Shafts - Constructed using underpinning or caisson techniques with Kentledge or jacking employed where necessary.  Shaft diameters vary from 1.52 metres up to 25 metres and depths up to 50 metres have been installed. Segmental shafts can be smoothbore or in panels.

• Caisson Shafts - A one pass pre-cast concrete liner usually installed with machine excavation/hand trimming. Diameters range from 1.5 metres to 4 metres. Caissons can be converted to manholes. Caisson shafts are constructed using a metal or concrete cutter ring and base section with rings being added on top as excavation proceeds. The shaft normally sinks under its own weight using bentonite but kentledge or rams can be used depending on ground conditions. Excavation can be conventional 360 degree excavator with bucket and/or grab with hand trimming if required.

• Sheet piled shafts - Usually for temporary access during construction. The shafts are mechanically excavated, and constructed using conventional sheet piles carried down and supported as excavation progresses or piles can be pre-driven depending
  on ground conditions. 

Shafts are installed in various diameters/sizes and depths in ground conditions ranging from water bearing sands and gravels, silt and clay down to hard rock and in areas of a high water table.

“Learning is not attained by chance, it must be sought for with ardor and attended to with diligence”  
Abigail Adams, 1780 US wife of John Adams 1764 (1744 - 1818)