Sustainability Assessment of Reinforced Soil Wall Options Frictional Versus Fine-Frictional Fill

In transportation infrastructure projects, earth-retaining structures are required to enable grade separation between assets. Globally, the reinforced soil wall (RSW) is a popular solution. Current design standards provide requirements for the reinforced fill (R-Fill) material, most notably grading and plasticity limits. In general, a coarse-grained soil with less than 10–15% fines is required. Such material is in high demand for use as an engineered fill but is not abundant in nature. As such, the standard requirements pose a hurdle for transport projects that lack a nearby source. Many projects choose to import R-Fill over the use of locally available fill. While this streamlines the geotechnical aspects, it increases cost and produces negative environmental and social externalities. This paper presents RSW models designed using R-Fill varying by fines content, reinforced by HDPE geogrids. Sustainability of models is compared using a simple method that can easily be replicated to suit project-specifics. The assessment showed that R-Fill with fines content up to 45% can be used to provide similar operational performance with enhanced sustainability, provided special conditions are met.