May 2005

The Highways Agency (HA) is proposing to widen the A2 to four lanes in each direction between the M25 and Bean, a distance of approximately 2km, with extra free-flow link roads at the M25/A282 Junction 2. The work will also involve a new soakaway pond to the north west of the A2 at Bean and balancing ponds by the M25.

The site investigation was awarded by the HA to Fugro Engineering Services (FES) Ltd. As part of FES's term contract with the Highways Agency. Apart from the ponds, the proposed development will generally lie within the existing highway boundary and, with 90,000 vehicles per day currently using the A2/M25 junction, the site investigation work has needed to be carried out at night with the drilling equipment transported to and from the site each night under strict traffic management control.

The HA commissioned FES to drill 45 boreholes to depths of between 10m and 35m. FES employed three rigs - a Knebel rotary rig and two Dando cable percussion rigs. The Knebel was mounted on a Unimog truck, capable of road speeds of 56 mph.

In-situ permeability tests were carried out in some of the holes. Samples recovered were subsequently tested at FES's Consett laboratory.