Highways England awarded Costain the contract of delivering the smart motorway scheme across the 16km length to increase capacity and improve journey reliability for commuters.
The scheme also includes road-side technology and new infrastructure, such as CCTV, queue detection and automatic signalling systems, and refuge areas where drivers can stop in an emergency.
Aarsleff Ground Engineering were awarded the drilling works by Costain at the end of 2019, with the works commencing on the 27th January and completed on 26th February 2020.
Specifically, Aarsleff were contracted to drill 42no. probe boreholes across the 11 mile stretch of the north and southbound motorway to establish any shallow coal mine workings that would require further treatment.
Each hole was positioned to target the base of the new gantries to be constructed, with a total of 1294m of drilling carried out and 173m of temporary steel casing being installed. Aarsleff utilised its Klemm 806-3G and Casagrande C6XP-2 drilling rigs (the latter being one of two new machines the company has invested in since December 2019) for the works, which were carried out in the hard shoulder and
in some cases, lane one of the motorway.
The rigs were split into two operations, with one rig working on the Southbound carriage way heading north, and the other working on the northbound carriageway heading towards the south.
For each operation, Aarsleff had a low-loader and flatbed, along with mobile site facilities for the teams carrying out the works.
Aarsleff also sub-contracted a geoenvironmental engineer for each operation,acting as a third-party, to validate the findings of the drilling works.
Aarsleff developed a bespoke recirculation system to capture the water flush off the drilling operations and store it on the back of a flatbed trailer in IBC tanks.
The captured water was taken back to the site compound, where Aarsleff filtered the coarse particles using a gravitational filtering process, allowing them to reuse the water on the following night shift.