The Ground Engineering Award 2014 has been awarded to the United Utlilities Piethorne & Wickenhall Water Treatment Works Access Road Stabilisation project. PaSCoE provided the Geotechncial Design for the scheme with Eric Wright Civil Engineering Ltd providing the construction services.
An existing access road to the Piethorne Water Treatment Works had started to fail, and tension cracks were observed in the road surface. PaSCoE were commissioned by Eric Wright Civil Engineering to design a temporary access track to maintain access for deliveries to the Piethorne & Wickenhall Water Treatment Works. The intention was for the temporary road to be installed whilst United Utilities investigated the options for a permanent solution (bored pile anchored wall).
As site investigation results were received during the initial mobilising works it became apparent that the probable cause of the failure was high ground water level, further exacerbated by a damaged culvert which ran beneath the road. Our role was then expanded to design an effective drainage scheme to manage the water from the embankment above the road and design land drains to reduce ground water levels. Slope stability modelling undertaken by PaSCoE showed that the drainage improvements increased stability. Upon completion of these works further monitoring showed that the slope had stabilised, avoiding the expense of the proposed bored pile anchored wall.
In announcing the winner of the Editor’s Award, Smith said “The approach taken on this scheme resulted in a value engineered solution that cut costs during the design stage and was further revised during the site work through application of the observational method in order to deliver the scheme in time to allow major planned work on the Haweswater Aqueduct to go ahead on time.”
The judges said the project showed a real understanding of geotechnics and the mechanisms of failure to value engineer the work and avoid a heavily engineered solution to deliver a 50% reduction in costs.