What is Pipe Ramming?
Pipe ramming is a trenchless method for installation of steel pipes and casings over distances usually up to 30m long and up to 500mm in diameter, although the method can be used for much longer and larger installations. This method is the most useful for shallow installations under railway lines and roads, where other trenchless methods could cause surface settlement or heaving. The majority of installations are horizontal, although the method can be applied for vertical installations as well.
- Pipe ramming employs the method of using pneumatic percussive blows to drive the pipe through the ground.
- The leading edge of the pipe is almost always open, and is typically closed only when smaller pipes are being installed.
- Its shape has to allow a small overcut (to reduce friction between the pipe and soil and improve load conditions on the pipe) and to direct the soil into the pipe interior instead of compacting it outside the pipe. These objectives are usually achieved by attaching a soil-cutting shoe or special bands to the pipe.
- Further reduction of friction is typically achieved with lubrication, and different types of bentonite and/or polymers can be used (as in horizontal directional boring) for this purpose.
- Spoil removal from the pipe can be done after the whole pipe is in the ground (for shorter installations). If, however, the pipe with the spoil becomes too heavy before the installation is completed, the ramming can be interrupted and the pipe cleaned (for longer installations).
- Spoil can be removed by auger, compressed air or water jetting.
Some photos of Pipe Ramming in progress
Recent Job at Ballykelly Power Station
Recently we completed a pipe ramming job at Ballykelly Power Station, Co. Louth. This involved inserting two 500mm steel pipes underneath the main road within the site to facilitate multi ducts carrying cables to the power room.
We drove the pipes open ended just underneath the concrete. The job was completed within two days.