Stability of reinforced steep soil slopes to Eurocode 7

This study presents an analysis of internal slip circle analysis of reinforced soil slopes with different geometries and varying soil parameters. The stability of the reinforced soil slopes was quantified in an overdesign factor. Angle of friction of the fill was found to have the greatest influence on stability of the slope; stability increased linearly with angle of friction. The pore pressure coefficient also influenced stability, with stability reducing as the pore pressure coefficient increased. Applying a surcharge to the crest of the slope had a more pronounced effect on stability of lower height slopes than higher slopes. The slope face angle and the height of the slope had only a moderate affected on stability. The analysis indicated, that of the currently design codes, SANS 207 (2006) produced the most conservative designs. Eurocode 7 Design Approach 1, Combination 2 and Design Approach 3, were found to be the next most conservative. Replacing SANS 207 (2006) with a Eurocode 7 approach is likely to result in more economic reinforced soil slopes, with the economic benefit dependent on which Design Approach is ultimately adopted. Updating BS 8006-1 (2010) to include Design Approach 1 for the design of reinforced soil slopes could increase the conservatism of UK designs. The analysis presented here indicated that Design Approach 1 is more conservative than BS 8006-1 (2010). This may increase the cost of constructing reinforced soil slopes in the UK.