Bethell utilises no dig techniques to safely navigate commuter railway line and canal for sewer upgrade in Lancashire
Bethell hold over 65 years of historic practical knowledge and a good business awareness of no-dig operations, following the establishment of The Kilroe Group in 1967 as a specialist tunnelling operator, operating nationwide.
Today, that same tunnelling expertise remains in Bethell’s DNA, as we are involved in early engagement sessions with water authorities to alleviate the risk of river pollution, utilising our in-house capabilities to provide additional added value for our clients.
Throughout periods of heavy rainfall, the existing sewer network in Cottam, Lancashire would reach capacity and cause internal and external flooding to properties on Hoyles Lane.
Bethell were contracted by United Utilities to deliver a sewer upgrade project which would mitigate flooding risks to properties along Hoyles Lane. In addition, the proposed upgrades would create long-term infrastructure resilience by increasing network capacity for multiple planned housing developments in the area.
Project delivery involved the installation of approximately 4.2km of new 600mm to 900mm sewer pipes, including a 150m-long tunnel beneath Savick Brook using a 
Tunnel Boring Machine (TBM) named ‘Billie’, after a student at the nearby Lea Endowed Primary School.
A 1200mm micro-tunnel was installed beneath Savick Brook, reducing surface disruption and environmental impact on the stream. The tunnel contained two inverted syphons: one to carry dry weather flow and the other to carry increased flows in storm conditions, consisting of 500mm and 300mm Amiblu GRP pipe.
Complex engineering was required to safely navigate under Network Rail and Canal & River Trust assets, using Guided Auger Bore (GAB) tunnelling. The GABs were both approximately 60m long, and 6m deep.
The scheme involved an Under Track Crossing (UTX) beneath the Preston-Blackpool commuter railway line, requiring early engagement with Network Rail in the design phase to provide a detailed understanding of the design parameters. This smoothed the way when the route of the crossing changed, as we kept Network Rail informed throughout to avoid delays to our submissions, programme and consents.
As a result of the excellent standards demonstrated by our delivery team, the Considerate Constructor Scheme (CCS) awarded Bethell with a Bronze National Site Award for achieving full marks in all three categories. In addition, United Utilities presented 3 WOW awards to our staff for supporting the community.
