Real 3D geotechnical modeling in engineering geology: a case study from the inner city of Aachen, Germany

A comprehensive three-dimensional geological and geotechnical modeling procedure is proposed that combines many useful technologies in order to reduce the uncertainties associated with geological and geotechnical models of the shallow subsurface in urban areas and facilitate sustainable city development. An approach that couples geostatistical analysis with discrete smooth interpolation to describe a reliable geological boundary was first developed. This can support attribution models with more reliable geological frameworks. Then a more informative geotechnical modeling method was proposed that consisted of three steps: assigning discrete property values to the geological model at real positions, analyzing the spatial variability of the property, and predicting the property across the whole model. These two methodologies were applied, as an example, to the inner city of Aachen, Germany. The shallow subsurface of the modeled area is characterized by a fault system and discontinuous distribution. Three-dimensional soil fraction models were constructed and visualized using the proposed methodology. The resulting models demonstrate the feasibility of the presented methodology and provide a robust way to solve some engineering geology problems.