For successful project execution of underground constructions, ÖNORM B 2203-1 requires, in addition to the engineering geological and geotechnical documentation, a continuous tunnel constructional documentation. The tunnel constructional documentation serves for the preservation of evidence of rendered services. A detailed record is indispensable for a successful reward of the performed constructional services. Based on the documentation, various statistics, target-actual comparisons and post-calculations can be carried out. This gives rise to a knowledge database for future projects. Currently, documentation on tunnel construction sites is only carried out in a digital form in the broadest sense. The data are digitized by scanning the documents. However, this has the consequence that the data cannot be processed. In order to store the data in long-term in an effective way, a data model is modelled with the graphical modeling language Unified Modeling Language, UML. Class and object diagrams were chosen for this purpose. These diagrams represent the data structure of the documentation process on tunnel construction sites in a graphical way. This data model is the basis for the implementation of an IT application including underlying databases. The data model describes which construction data are relevant for construction documentation and how these data are linked to each other. For an automatized transfer of the data to the monthly settlements the work deals with the abstraction of the bill of quantities. The structure of the bill of quantities and its contents are modeled with the help of class diagrams. Based on this, the recorded quantities can automatically be assigned to the corresponding bill of quantities. The thesis is the basis for designing of a software application for the tunnel construction documentation and for transferring the data into the accounting.