Assessing carbon emissions for alternative ground improvement methods in peat soils at N56, Glenties, Co. Donegal, Ireland

¹ Atlantic Technological University, Galway, Ireland
² ROD Consulting Engineers, Dublin, Ireland

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

The N56 project near Glenties, Co. Donegal utilised staged construction of surcharged, basally reinforced embankments up to 5.5 m high on very soft blanket peat soils in northwest Ireland to improve a 2.5 km length of national road. The 4.5 km long scheme commenced construction in March 2021 and was completed in December 2022. The adopted ground improvement methods resulted in greatly reduced requirements for peat excavation in an ecologically sensitive environment and consequent reductions in carbon emissions. The paper briefly describes the project setting, earthworks design and the Life Cycle Assessment framework and methodology adopted to estimate related carbon emissions for earthworks & pavement construction. A representative 1 km long section of embankment was assessed for comparison of the constructed surcharge treatment versus traditional excavate and replacement methods. Improved peat management alternatives including native woodland planting and deposition into bermed restoration areas are also discussed. Some conclusions are drawn about the carbon emissions from these earthworks and peat management alternatives for road construction on peat soils.