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Forschungsprojekt aus §26 oder §27 Mitteln
Laufzeit : 2022-01-01 - 2023-12-31

In this research project, a 3D grain-scale continuum-discontinuum hierarchical multiscale computational framework is proposed to improve the deep understanding of compaction banding formations in the sedimentary porous rocks that are of strong interest and of major challenge in the modern geomechanics. The proposed grain-scale continuum-discontinuum multiscale numerical framework for porous geological media consists of three levels including FEM meshes at macro-scale, DEM grains at meso-scale and hypoplastic peridynamic points at micro-scale. Furthermore, the region partitioning search algorithm and CPU-GPU heterogeneous computing architecture both contribute to improvement of computational efficiency to construct an open-source 3D computational platform that is suitable to simulate large-scale geological and geotechnical problems. To systematically investigate the localized failure mechanism of compaction bands in porous geological media at laboratory and field scales, one laboratory-scale and one field-scale numerical models are simulated by 3D computational platform. The influencing factors of boundary conditions, stress fields, geomaterials heterogeneity, nonlocal characteristic length, granular shapes, etc. on the localization failure processes of compaction bands will be summarized and analyzed. Sequentially, effects of microstructural mechanism including pore collapse, grain debonding, intra-granular damage and grain crushing on the nucleation and propagation of compaction bands during the localized failure processes. Furthermore, localized failure mechanism of the geological tectonic phenomena, i.e., coexistence of pure compaction bands and shear enhanced bands, will be numerical explored.
Forschungsprojekt aus §26 oder §27 Mitteln
Laufzeit : 2021-10-11 - 2022-01-10

Finanzierung der Vorbereitung für die Einreichung des Projektes: Mountain geohazards and risk dynamics in a changing world (MOZARD) Within the scope of this proposal, “mountain geohazards” are understood as extremely rapid, gravitationally driven processes which typically occur in mountain areas and are potentially hazardous for society. Such processes are e.g. landslides in the very broad sense of the term, snow avalanches, glacial lake outburst floods, or process chains involving one or more of those phenomena. Mountain geohazards lead to significant losses of life, public infrastructure, and private property every year, all around the world. Disasters resulting from inadequate risk governance act against the SDGs 3, 9, and 11, among others. Whereas it is well established that societal change along with increased exposure has resulted in increasing losses and disasters, it is unclear to what extend and at what time-scale certain geohazard processes are affected by climate change. An increased understanding of all aspects of mountain geohazards now and in the future, from triggering to process dynamics and societal impact and perception, requires concerted inter- and transdisciplinary efforts and is necessary to inform risk governance and ultimately reduce losses. Austria is not only a country frequently affected by mountain geohazards, but also having developed a highly active scientific community and a powerful research infrastructure to investigate both the relevant physical processes and their socio-economic consequences. The proposed Cluster of Excellence aims at further strengthening and extending the available expertise and networks, in order to form an even stronger basis for risk governance efforts not only in Austria but also internationally, particularly in the Global South, and to strengthen the role of inter- and transdisciplinary Austrian mountain geohazards research as an international flagship.
Forschungsprojekt aus §26 oder §27 Mitteln
Laufzeit : 2021-06-30 - 2024-06-29

Dieses Projekt beschäftigt sich mit Zentrifugenmodellversuchen von Tunnelquerschlägen. Lange Tunnel bestehen i.d.R. aus zwei parallelen Hauptunneln, welche in bestimmten Abständen mit Querstollen verbunden werden. Die Beanspruchung an der Schnittstelle zwischen dem Haupttunnel und dem Querstollen stellt ein dreidimensionales Problem dar. Mit Hilfe von Zentrifugenmodellversuchen sollen die Spannungen und Verformungen an der Schnittstelle Untersucht werden. Die Bauwerksanforderungen im Querschlagbereich werden in der Ausschreibungsphase festgelegt. Die Kenntnis des Erddrucks in diesem Bereich ist unerlässlich. Aufgrund des dreidimensionalen Spannungs-Dehnungs- Feldes und der Spannungs-Singularitäten an der Schnittkante zwischen Streckenröhre und Querschlägen sind analytische Berechnungen der Spannungsumlagerung beim Querschlagsöffnung und -Vortrieb nicht zuverlässig und die akademische Literatur liefert wenig Anleitung. In der Praxis werden oft Messtubbinge im Querschlagbereich eingebaut, um die Betonspannungen zu beobachten. Mit Messtubbingen erfolgt jedoch das Monitoring nur nachträglich und die Interpretation der Messdaten ist nicht eindeutig. Daher verlassen sich Tunnelplaner häufig auf komplexe dreidimensionalen numerischen Berechnungen. Beweise für die Validierung solcher numerischen Berechnungen sind jedoch rar. Ziel dieses Forschungsprojekts ist es, diese Wissenslücke zu schließen.

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