Digitization in the design and implementation of underground structures is progressing steadily and has now reached widespread application in many projects. There are several challenges to be mastered with respect to geological / geotechnical prognosis and the implementation of underground excavation and support in BIM models. The article shows on the example of the current draft for the IFC schema extension, proposed by IFC Tunnel/buildingSmart international, how geological/geotechnical data required for
the underground design can be organized and represented in BIM models, and how, on this basis, a coordinated design and construction model can represent the geotechnical design (definition of excavation and support) and take forecast uncertainties into account.