Mass wasting events and failures on the earthworks adjacent to trunk roads are becoming more frequent as a result of climate change and increased volume of transport. This paper describes the geotechnical aspects of stabilisation of a 750 m long and up to 55 m high coastal slope in Scotland bisected by a former trunk road with a history if instability and subsidence. Ground investigations, monitoring, specimen and detailed design considerations are discussed in the light of geo-environmental, financial, temporal, sustainability and risk considerations. The geotechnical design had to consider the local and global stability of the slope as well as the effect of potential climate change, land use and traffic volume changes. Additionally, the stabilisation options for the earthworks supporting the road were constrained by the requirements of the local authority and statutory undertakers. The detailed design for landslide and erosion prevention comprised extensive drainage measures and soil nailing designed to be installed within the existing slope surface, utilising an innovative head assembly, recessed within the slope and covered with pre-seeded biodegradable ‘grow bags’ making them ‘invisible’, providing a green slope finish, and minimising the visual impact of the works on the natural surrounding. The sustainable use of vegetation for slope stabilisation is highlighted through the use of eco- and ground bio-engineering strategies in the design and construction of stabilisation measures against shallow slope instability and erosion.

sustainability; eco-engineering; soil nailing; slope stability; asset management