In order to maintain their supply of raw water to Sutton Hall Water Treatment Works, United Utilities (UU) required LiMA, (a Laing O'Rourke, Imtech and Atkins) AMP6 partnership to install an 800mm polyethylene (PE) pipe under the A483, which is one of the busiest roads leading in to Chester city center.
Visser & Smit Hanab were contracted by LiMA for the Horizontal Directional Drill (HDD) and welding of the free issue 800mm PE product. The purpose of the drilling was to upgrade the existing raw water supply from the River Dee which supplies the industrial areas in Chester, Ellesmere Port and the Wirral.
The scheme included a HDD wtih horizontal drilling length of 433 meters in order to install the 800mm PE100 SDR 11 pipe. This project provided us with several challenges. The first one was having to deal with an elevation difference of 15 meters between the entry and exit points.
For this project Visser & Smit Hanab mobilised their 450T drilling rig and utilized the forward reaming technique. This was crucial to facilitate the transportation of drilling fluid from the higher elevated exit point back through the borehole to the entry point, where the drilling fluid could be recycled and reused.
The second significant challenge was drilling through varying ground conditions. Visser & Smit Hanab used their in-house expertise to determine when to change the reaming assemblies to match the actual formation that was encountered.
Despite the varying soil conditions, difference in elevation and rig site being a busy public area, the drilling was completed successfully with minimal impact on the local environment and community.
On completion of the HDD works, Visser & Smit Hanab also grouted the drilled bore and pressure tested the pipeline installed to satisfaction of the client.