Geological and hydrogeological reference conditions for rock engineering: An example for grouting design at äspö hard rock laboratory, Sweden

Paper in proceeding, 2017

© 2017 International Society for Rock Mechanics. All Rights Reserved. The observational method includes the idea that rock engineering design can be modified as construction progresses, and that identification (confirmation or rejection and updating) of e.g. rock classes can be used in order to choose from predefined design classes. To facilitate rock engineering design, we suggest that geological and hydrogeological reference conditions are used as a basis. Fundamental to a reference condition approach is the identification and sampling of reference sites. Attributes, in this case geological and hydrogeological attributes, are selected and used to define the reference conditions. The reference conditions should be defined and described early on in a project, using relevant engineering parameters, and grouped together into rock classes with similar engineering characteristics. The reference conditions are subsequently used to define e.g. grouting design classes, to adapt to project-specific flow requirements. In this paper we suggest and give examples of geological and hydrogeological reference conditions for grouting, and present an example where reference conditions were used to define the grouting design for a site in crystalline rock, located at a depth of 400 m at the Äspö Hard Rock Laboratory, Sweden.