The observational method applied to a high embankment founded on sulphide clay

• A case study discussing the observational method (OM) and its definitions in EC7
• The design methodology used in the case partly follows the OM definitions in EC7.
• The OM definitions in EC7 are not suitable for embankment design in all aspects.
• For embankments, a combination of “design by calculation” and the OM is recommended.
• Clarification of the OM definitions in EC7 is desired.

Since its introduction, Eurocode 7 has acknowledged the observational method as a valid design approach for geotechnical structures. The observational method is defined in five paragraphs. Although several case studies have concluded that the observational method is useful, the method is still sparsely used. This study compares the actual implementation of the observational method in the Veda embankment project according to the definitions given in Eurocode 7. The outcome of the observational method as a design approach, and the major deviations compared to the definitions in Eurocode 7 are discussed. It is concluded that the design of a multi-staged embankment, where the building process is governed by consolidation in the subsoil, can only partly be adapted to the observational method as defined in Eurocode 7. Furthermore, when this is the case, the possibility of combining “design by calculations” and the observational method is discussed.