Kennett Tunnel Survey


Project: Kennett Tunnel

Scope: Survey live water 2.5 metre tunnel

Location: Eley Ouse bulk transfer tun

Following a global search for a capable pipe inspection company, in March 2014 we were commissioned by the Environment Agency, Black & Veatch and Jackson Civils to survey a 21km x 2.5m diameter bulk water transfer pipe. There were only 3 useable access shafts, which varied in depth between 35m and 85m, with 1800mm square covers and a 10m drop to water level. The distance between the hatches varied between 3000m to 12400m. Duty pumping had to be maintained throughout the survey.

Our scope was to carry out a live visual/CCTV survey that provided a full circumferential view of the pipe to facilitate pipe condition assessment which had to including hairline cracks, concrete segment displacement and to check tunnel ovality using profiling sonar. It was essential that recorded CCTV data had full resolution on playback with the capability of viewing key areas in fast forward, slow motion, with seamless pause, picture enlargement where required and the capability to screen dump specific images.

With no-proprietary equipment available we set about designing and building a self-propelled Pipe Inspection Vehicle (PIV), with an 11-camera configuration and profiling sonar, which was controlled and monitored via 8km of neutrally buoyant Micro-Fibre Optic cable, all within a 4-month window.

Testimonial: After a global search, we identified Tunnel Vision as the leading company for remotely operated pipe inspections and were delighted to work with on the inspection of the Kennett Tunnel; a 21 km x 2.5m diameter raw water transfer tunnel owned and operated by the Environment Agency. Throughout the inspection, WSSG demonstrated their impressive technical capabilities in developing a bespoke unit capable of providing a full circumferential viewing with exceptional picture quality. They also demonstrated a real “can do” attitude, overcoming all the difficulties presented and pushing the boundary for the maximum distance surveyed on a single excursion to an impressive 10km. WSSG provided a thoroughly professional service and I would recommend them for tunnel/pipe inspections.”

Emma Booth, Project Manager for Black & Veatch