Advances in geotechnical experimental techniques for unsaturated and liquefactable soils and tailings under different gravity accelerations (1g-Ng)
(English) Flow liquefaction in contractive granular materials represents one of the most complex and hazardous failure mechanisms in geotechnical engineering, particularly in tailings dams. It is characterised by a sudden loss of shear strength under undrained conditions and by the rapid mobilisatio...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2026 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | inglés |
| OAI Identifier: | oai:dnet:upcommonspor::33c7b8ea2462a3f05351ae27a1bf2351 |
| Acceso en línea: | https://hdl.handle.net/2117/460122 https://dx.doi.org/10.5821/dissertation-2117-460122 |
| Access Level: | acceso embargado |
| Palabra clave: | landslides liquefaction flow liquefaction tailings tailings dams tailings storage facilities physical modelling centrifuge modelling image-based analysis image-based measurement techniques large deformation behaviour post-failure 624 - Enginyeria civil i de la construcció en general Àrees temàtiques de la UPC::Enginyeria civil |
| Sumario: | (English) Flow liquefaction in contractive granular materials represents one of the most complex and hazardous failure mechanisms in geotechnical engineering, particularly in tailings dams. It is characterised by a sudden loss of shear strength under undrained conditions and by the rapid mobilisation of large volumes of material. Despite its practical relevance and the many documented failures, a detailed understanding of the internal processes governing the transition from sliding to flow remains limited, mainly due to the difficulty of obtaining experimental evidence during large deformations and post-failure stages. This doctoral thesis addresses the experimental study of post-failure behaviour, including strain localisation, retrogressive failure and flow liquefaction, through the development and application of non-invasive image-based measurement techniques. The main objective is to improve the observation, quantification and interpretation of deformation mechanisms and hydro-mechanical processes under large deformation conditions, and to apply these tools to the study of tailings failures. From a methodological perspective, the thesis refines the Eulerian–Lagrangian PIV-NP method. Its main limitations are systematically analysed, with particular emphasis on border-related errors, and specific correction strategies are proposed to enhance robustness and accuracy. These developments are validated using synthetic cases involving rigid motion and controlled deformation. In addition, PIV-NP is integrated with short-wave infrared (SWIR) imaging to allow non-intrusive measurement of surface moisture and degree of saturation in moving soils. This combined methodology, referred to as PIV-NP-Sr, is based on homographic transformations ensuring accurate spatial correspondence between visual and infrared images. The proposed techniques are first applied to a 1g test involving wetting-induced failure of a sand dam. Subsequently, a comprehensive experimental programme based on geotechnical centrifuge modelling is presented, conducted within the Geolab–SLIDAM project. This programme includes the characterisation of a mine tailing and seven small-scale centrifuge models tested under different acceleration levels, saturation conditions and failure activation mechanisms. Conventional instrumentation was deliberately minimised in favour of non-invasive imaging, allowing the full evolution of failure to be captured without disturbing material behaviour. The results enable detailed interpretation of shear band development, volumetric strain evolution and the progressive transition from sliding to flow-type behaviour. A novel observation is the occurrence of surface eruptions during post-failure stages, resembling miniature volcanoes. These events are shown to be preferentially located in zones of concentrated extensional strain. Based on the tracking of individual gas bubbles and their correlation with deformation fields, a preliminary interpretation involving gas entrapment, migration and pressurisation within the saturated granular medium is proposed. |
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