Conference Agenda

The settlement of the ground surface due to active or abandoned mining activity may lead to unwanted effects such as building misalignment. The description of settlements caused by underground cavities in unconsolidated soils is primarily based on studies of circular or rectangular geometries. In contrast, cavities with complex geometries, as encountered in abandoned mining or engineering applications, have only been investigated to a limited extent experimentally. The objective of this study is to develop an experimental setup for analysing settlement processes above such geometries and to establish an appropriate measurement method.

A model box (0.8 × 0.8 m) was constructed using aluminum system profiles and acrylic glass panels. The cavity is simulated by a water-filled cushion with plan dimensions of 160 × 160 mm and a maximum height of 70 mm and the settlement is recorded using photogrammetry. Based on image datasets acquired before and after settlement, three-dimensional models and digital surface models were generated. Raster datasets derived from these models enable quantification of the settlement.

A series of tests was carried out in loosely deposited fine sand for varying cover-to-height ratios. The results show that with increasing cover-to-height ratio, maximum settlement decreases, while the lateral extent of the settlement trough increases and a plateau forms near the maximum. Furthermore, the influence of cavity geometry diminishes and the settlement trough approaches a circular shape.

The methodology enables detailed investigation of settlement processes above complex cavity geometries and provides a basis for further analyses in different soil types and relative densities.

The geoscientific archives of the State Geological Services represent a vast treasure of knowledge that has not yet been fully harnessed as part of the digital transformation. The Hessian State Agency for Nature Conservation, Environment, and Geology (HLNUG) has therefore launched a project in cooperation with Verus Digital GmbH (Darmstadt) to 3D-scan “unusual information carriers.” The goal is to make selected objects from the well over 40,000 archival records available in Hesse publicly accessible as digital twins. In addition to creating high-end 3D scans, the project also aims to enable high-performance 3D visualization on the internet and to enrich the digital twins with additional information such as object descriptions, further reading, and key parameters. These parameters are derived at Johannes Gutenberg University Mainz through high-resolution analysis of image data. To make the developed content available via the state-specific geodata and IT infrastructure, it is also necessary to consider and implement requirements for IT baseline protection in accordance with the BSI. As of May 2026, approximately 280 3D scans (soil cubes, rock samples, fossils, drill cores) have been created, enriched, published online, and thus made easily accessible. With this initiative, the HLNUG aims to reach the general public as well as industry and educational institutions at schools and universities. We expressly encourage other institutions to follow our example!

Energy sustainability and future readiness are increasingly focused on subsurface energy storage to enhance security. The northern Upper Rhine Graben (URG) in central Germany, with its porous reservoirs, has the potential to complement the salt caverns planned for the North German Basin to the south, thereby completing the necessary nationwide infrastructure for underground hydrogen storage (UHS). While porous reservoirs provide larger volumes for strategic storage, they offer less operational flexibility than salt caverns, which have greater flexibility but smaller volumes.
In the 2010s, interest in the URG grew, leading to the acquisition of 3D seismic data, including the notable Schwarzbach discovery. A decade later, the government made this data public under the Geological Data Act, enabling a feasibility study to convert old gas fields into UHS. Despite limited data, the study aimed to develop a regional structural reservoir model by integrating geological and geophysical datasets. The model was created using well data, seismic interpretations, and geological maps, utilizing various software tools for data integration and visualization. This study demonstrates how to effectively create a subsurface model from incomplete datasets.
The resulting model provides a geological framework for dynamic reservoir simulations, UHS evaluations, and thermo-hydro-mechanical (THM) studies. The focus was on establishing a clear, flexible workflow to integrate subsurface datasets into a 3D framework for energy storage research and reservoir management, providing a foundation for future enhancements as more data becomes available.

The complex architecture of Lower Saxony’s geological subsurface can be vividly visualised using a variety of 3D underground models. These models are essential tools for planning and scientific research.

The current modelling landscape includes statewide overview models, such as TUNB3D-NI and GTA3D, which provide a comprehensive structural framework of the deeper underground of the North German Basin. In addition to these large-scale datasets, specialized regional models focusing on unconsolidated rocks (“Lockergesteinsmodelle”) offer detailed insights into shallower strata critical for groundwater management. Furthermore, recent publications include a high-resolution Quaternary Base model and TUNB Velo 2.0-NI, a new velocity model of Lower Saxony. Some of these 3D models are available as both surface models and volume models, offering flexibility in subsurface representation. At the same time, optimising these datasets is crucial, as complex geological models often require simplification, efficient structuring and performance-oriented processing for effective use in visualisation and web-based applications.

These diverse data sets are harmonised into a unified web-based environment by leveraging modern software and the NIBIS3D web interface. This provides a powerful tool for generating virtual boreholes, customized cross-sections, and numerical simulations. This 3D approach bridges the gap between classical mapping and modern digital geosciences and serves as a critical decision-support system for the sustainable use of the underground.

A common challenge is storing geomechanical discontinuity data in a searchable, safe and sustainable format for long term conservation. Therefore, a system was created that streamlines the digitalisation process of data on discontinuities and additionally enhances the management, overview and analysis of larger data sets.
The frontend is a web based intuitive user interfaces composed of a semi-automatic upload feature that allows the user to drag in their files. It is designed for scanline data, therefore it scans for common parameters and assigns them automatically but can be applied to any discontinuity data. Missing entries can be left blank or filled in during the upload process. Picking of the outcrop location can be done via a map tool or by adding GPS data.The data gets assorted to a project, named and stored in a unified form in the backend SQL-database.
It is possible to edit the data in the UI, which might be helpful to fill in blank cells, e.g. labels, or add missing GPS-data for the start and end location of a scanline.
The overview and analysis tab enables users to get a quick overview of otherwise unwieldy datasets by displaying all outcrops of a project in a map, and to plot the data in a stereographic projection. The projection is rudimentary, but for further in depth analysis there is an export feature that transforms the dataset in an easy to load file for third party programs.