Caisson Shaft Sinking

Caisson shafts can be constructed as either complete section or segmental shafts ranging from 1.2M up to 25M diameter.
Caisson shafts are designed to support the ground with a structure made up of a number of preformed interlocking structural elements. Together these elements form a continuous self supporting structure in the ground. 
Duffy Tunnelling have extensive experience delivering shafts of various diameters and depths.

PipeJacking

PipeJacking is a technique for installing underground pipelines, ducts and culverts.  Hydraulic jacks are used to push specially constructed pipes through the ground behind a shield. 
Duffy Tunnelling utilise manual pipejack shields with working ranges from 1.2M to 3M diameter up to 250M length drives

Timber Headings

Timber headings are one of the oldest methods of tunnel construction. Timber headings involve the use of timbering to provide temporary support for the ground during tunnelling. Timber heading construction is completed in line with current industry best practice and standards including;
TRADA: Timber in excavation
BS 5975; A code of practice for temporary Works
BS 6164; health & safety in tunnelling.