Bulk Fill Modification, M77 Renfrewshire
M77 South (Fenwick to Kingswell Section), Renfrewshire, Scotland
Client: East Renfrewshire Council
Principal Contractor: Morrison Construction
Engineers: Scott Wilson
Morrison Construction was awarded the works for the Fenwick to Kingswell section of the M77 South extension, and they appointed CON-FORM to help them overcome geo-technical issues encountered on the planned route.
These issues included the top 1 - 2 metres on some of the cutting areas containing materials, which in their natural state were not suitable for re-use within the works. This was due to the materials having a moisture condition value (MCV) of between 2% - 8%, which was outside the project's acceptable limits of between 8% – 12%.
Areas designated for fill also required treatment, prior to the fill being placed, to address a less than 2 metre soft layer of saturated boulder clay. This was one of the reasons why CON-FORM had been selected by Morrison's, as the high frequency of boulders in the clay made it a very difficult material to treat.
CON-FORM had a proven track record of being able to handle Scottish boulder clays, having procured specialist equipment from around the globe enabling it to deal with the unique challenges presented by materials of this type.
In both cases these materials were modified through the addition of lime and brought within 8% - 12% MCV range required for the project.
CON-FORM also worked closely with Morrison's earthworks contractor, enabling tight controls to be implemented over the lime used throughout the project.
This resulted in powder savings of around 20% versus the original tender projection, with significant savings being passed to Morrison's, due to a partnership agreement being put in place at the start of the contract.
Key Benefits of the CON-FORM Solution
- CON-FORM's specialist capability and track record enabling it to treat Scottish boulder clays.
- Disruptions to the smooth working of the site kept to a minimum through the application of lime stabilisation which provided a firm working platform throughout the wet, winter months.
- Over 200,000m3 of geotechnically unsuitable soils modified and made fit for purpose, eliminating the need to offsite and replace.
- Partnership approach provided both parties with incentive to optimise powder application.