Tunnelling under the M6 to keep water flowing in Standish

Most new water mains are installed by digging a trench in the road – but when a water main under the M6 needed replacing that wasn’t an option.

Instead, the water company for the North West brought in specialist contractors to go under the busy stretch of motorway near Standish using ‘no dig’ technology to bore under and install a new 10ins water supply main.

The new water supply features two new 80 metre length of pipe that have now been connected into the existing water network at either side of the UK’s longest motorway.

Senior Project Manager John Harrison explained: “The old main was showing signs of wear and tear and a leak appeared. We investigated several methods of repair but in the end the best option was to introduce a new section to replace the damaged section under the M6.

“With around 175,000 vehicles using that section of the motorway at all times of day and night, digging it up to install the new pipe simply wasn’t an option. With water we don’t usually go overhead, which meant we had to go under.”

United Utilities employed specialists from Morrison Water Services to use cutting-edge directional drilling which means motorway users could continue their journeys uninterrupted while a new pipe was being installed eight metres beneath their wheels.

The process involves drilling a pilot hole from an entry point to an exit point, after which a new pipe is pulled back through the hole.

John Harrison added: “This engineering approach allows for precise control, enabling the drill to change direction where necessary to avoid underground obstructions, including other services running beneath the motorway.

“The use of directional drilling enables the work to be carried out efficiently while safeguarding the integrity of the motorway and the environment around it.”