Auger Boring (Earth & Rock) - Under Road Boring
Horizontal auger boring is a trenchless technology technique DM Civil have been utilising since the mid 1980’s. DM Civil has auger boring machines, which give the capability to install steel casing from DN250 to DN2600.
Auger boring methodology cuts a hole in the ground into which the steel casing is progressively pushed by hydraulic rams on the rear of the boring machine against the back of the boring pit. The boring machine and casing are set up on tracks to the required position, line, level & grade. The cutting head is attached to augers, located inside the steel casing, which are driven by the boring machine. These augers transport the soil back into the boring pit for removal. Line and grade can also be controlled to reasonable tolerances utilising a steering head and Dutch water level or sonde, if required.
DM Civil have a range of cutting heads from closed face for sand soils, clay heads, soft rock heads for rock up to approximately 20 MPa and small boring unit roller rock heads for competent rock up to 175 MPa in strength.
Once the steel casing is installed, the service pipe can be sleeved inside on centralising brackets and the annulus grouted, or alternatively the casing can be jacked out with a product pipe such as concrete, clay, concrete coated steel gas pipe, GRP or GRC pipe.
Auger boring is typically used for bores up to 60 metres in length; however auger bores up to 100 metres have been achieved. Set up times and productivities are relatively quicker and equipment cost are cheaper compared with micro tunnelling machines. This technique is a very cost effective methodology used for bores under roads, railway lines, services and structures, in dry ground conditions, where line, level and grade are not critical.
DM Civil also offer pilot auger boring (Sand & Soft Clay) services.