The works were split into three drives in varying lengths. Working from 2.4 metre caisson shafts with trench sheets at a depth below 4 metres a 74-metre drive was installed before rotating the GAB machine and installing a 24-metre drive from the same caisson shaft. Following installation, the pipelines were connected in the drive shaft and fully tested in accordance with EN610.
The third pipeline required installation from another 2.4 metre caisson shaft at a depth of 5 metres which was required so the installed pipeline was 3 metres beneath a CLH pipeline (CLH-PS) fuel pipeline. To ensure that the ground movement beneath the CLH pipeline was inside the acceptable limits the pipeline had to be exposed and monitored by authorised personal wduring the installation of the jacking pipes. Following the installation of the jacking pipes the ground around the CLH pipeline was reinstated under supervision.
The ground conditions for the third drive changed to chalk with a high level of flint, water was added during the auger process which slowed the installation rate from 12 metres per shift to 5 metres. As installation progressed the full 18,000Nm of rotary torque was required, to rotate the flight augers in the hard ground encounted.
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Allen Watson Limited
- Horsham, West Sussex
- Harlow, Essex
- Barnsley, South Yorkshire
Wessex Water Engineers site visit
Allen Watson Limited latest project was visited by Wessex Water Engineers to witness the installation of DN225 Naylor Denlok VC pipes by guided Auger boring
Press release - Allen Watson Acquisition
Trenchless contracting services added to The Cappagh Group's technical capabilities following Allen Watson Limited acquisition.
Drive Shaft under construction
Allen Watson Limited are currently on a Southern Water project titled Ebbsfleet green, Swanscombe subcontract works which requires the installation of pipelines.
Allen Watson complete another deep pipe installation for a prestigious housing development on the banks of the rive… https://t.co/54WUphtQUe
AWL continue to invest in new equipment with the delivery of the first of four new vans complete with full livery.… https://t.co/wYU8AEy4rh