3D geologic modeling for digital twin applications: insights from the Bedretto Underground Laboratory

Accurate 3D geological models are instrumental to the development of reliable digital twin frameworks for underground research and engineering, yet their development is hindered by the complexity of integrating multi-scale, multi-source, and heterogeneous datasets. Here, we present a set of comprehensive, multi-scale geological models of the area surrounding the Bedretto Underground Laboratory for Geosciences and Geoenergies (BULGG - Bedretto lab; Central Swiss Alps). Using an implicit geological modeling approach, we computed three interconnected models that capture the regional geologic and tectonic framework, the distribution of the main deformation structures, and domains with different structural and petrophysical properties along the Bedretto tunnel. These models integrate geological data from regional maps, remote sensing lineament analyses, field surveys, and tunnel-scale observations to produce georeferenced 3D meshes and visualizations. Our models can be adopted to visualize the geometry of deformation structures affecting the Rotondo granite and the Gotthard nappe, hosting the Bedretto Lab. These models are instrumental for efficient outreach activity and communication in multidisciplinary research environments, such as those characterizing underground research facilities. They also provide a quantitative, georeferenced, and geologically-sound framework to understand the spatial distribution of anisotropic properties in the underground. The models offer a high-resolution foundation for investigating hydro-seismo-mechanical processes, informing experimental design, and enabling advanced simulation workflows within a digital twin environment. 3D geological models are meant to be dynamic representation of the underground environment, evolving with the increasing amount of available knowledge resulting from geological, geophysical, monitoring, and modeling efforts.