The subsurface information model is the basis of all design and engineering processes of an underground structure and covers its entire life cycle (design, construction, operation, maintenance & deconstruction). It is an independent specialized model with a particularly high influence on the time and cost of an underground project. The information model makes it possible to obtain different views of the subsurface and can be classified according to different subjects. These include geology, geotechnics, hydrogeology and geochemistry. Based on all collected information and a combination of these, the model enables significant, comprehensible decisions to be made and supports the client and contractor in forecasting, planning and documenting the actual conditions encountered. This requires a data structure that meets the requirements of the domain and has the capacity to minimize redundancies. At the same time, the model should have the flexibility to implement future developments with minimal effort. In the course of this work, such a domain model was developed as an exemplary model and automatically converted into a standardized graphical modeling language (UML) using the tool Excel2UML.