Designing Steep Stable and Sustainable Retaining Embankments in Weak Saturated Ground Using the Stable-Earth^TM Technique

Abstract

Shallow sloped embankments, vertical concrete structures or steel retaining walls, are methods typically used in the construction industry to provide support to road, rail, basement and many other projects which require safe and stable open excavations. These traditional methods have disadvantages in terms of cost and sustainability. For example, a vertical wall is expensive to construct and requires the use of non-sustainable concrete or steel materials. Alternatively, whilst a shallow embankment is less costly and is more sustainable, a larger tract of land is required, which may not be available in an urban environment. This paper describes the Stable-Earth^TM technique which was developed by OGI to provide a safe and stable, steep sloped solution, with greater flexibility than the methods described above. This technique combines groundwater management, slope reinforcement and erosion control. The soil embankment is strengthened using a combination of pore water pressure relief and soil reinforcement with anchors or soil nails. This enables steep soil batters to be constructed, resulting in a structure which is more cost-effective, environmentally sustainable and visually attractive. This paper will present two case studies where the Stable-Earth^TM technique was used on construction projects in the United Kingdom. 1. The construction of a steep road embankment in County Durham, England. 2. An open excavation with steep batters required for the construction of a storm water tank in Royton, Manchester, England.