Project: Otterbourne Water Treatment Works
Scope: Adit surveys and shaft refurbishment (potable water)
Location: Otterbourne Works
To establish accurate shaft dimensions, shaft verticality and the number, shape and orientation of the adits running off the bottom of the shaft, we designed and built a bespoke shaft inspection system (SIS). The shaft survey revealed deterioration and partial collapse of the existing chalk retaining steel and timber cladding, which we subsequently removed as a diving operation.
To stabilise and prevent further collapse of the shaft structure we designed and installed a stainless steel weld-mesh and, circumferential rolled angle-iron, expanding hoop system that was secured into the chalk wall by stain-less steel ground anchors.
The entire system and all underwater plant including a bespoke diver work platform had to pass through a 1m square shaft reduction near the top of the shaft below water level.
The entire operation was carried out in potable water and the site was an Site of Special Scientific Interest.
Upon completion of the refurbishment works, we then utilised a Pipe Inspection Vehicle (PIV) to inspect and measure the adits running-off from the bottom of the shaft.
Testimonial: When we were first approached by Southern Water with the project brief, our initial enquires failed to come up with a company that could provide any of the specialised services required for what was a complex and technically challenging project. We were recommended to contact Tunnel Vision by Southern Water who had used them with great success on other projects and against the odd’s Tunnel Vision were able to provide a complete package for the entire project from designing and building a bespoke shaft inspection tool to remote vehicle adit surveys to technical and complex diving operations under stringent working conditions. Their service was second to none and they brought the project in on time and on price, despite complications and running changes to the work scope.
Brian Ellis – Project manager – Nuttall Hynes