1,721,082 research outputs found
FLOW-LIKE MASS MOVEMENTS IN PYROCLASTIC SOILS: Geomechanical modelling of triggering mechanisms
No full textNew Advances and Challenges for Numerical Modeling of Landslides of the Flow Type
No full textAbstractLandslides of the flow types represent a worldwide natural hazard whose consequences have been largely increasing in the last decades, despite the huge efforts of the International Organizations and Scientific Communities which can provide either highly interdisciplinary approaches or enhanced sector-based studies. The former must include expertise from geology, geotechnical engineering, social sciences and economics if landslide risk reduction is pursued as final goal while the latter include detailed geotechnical analyses to simulate the multiple stages characterizing the landslides of the flow-type. Within this framework, numerical modeling has been playing an increasing role for engineering-based decisions. The present paper outlines some difficult topics recently solved or firstly tacked through advanced numerical modeling. For the failure stage, distinct modeling alternatives are applied to a relevant case study. For the post-failure stage, an enhanced numerical approach is provided to understand and forecast the transition from a slide to a flow. Furthermore, a novel numerical approach is applied for evaluating the propagation heights and velocities. Finally, open issues are outlined and possible future research developments are indicated
Geomechanical modelling of triggering mechanisms for flow-like mass movements in pyroclastic soils.
No full textFlow-like landslide mechanisms and modeling: filling the gap between hydraulic and geotechnical engineering
No full textLarge-area physically-based analysis of the triggering zones of shallow landslides for layered unsaturated deposits of Southern Italy
No full textX-ray Computed Tomography for Capillary Collapse of Loose Unsaturated Sand
No full textAbstractThe collapse of unsaturated soils consists of the reduction in volume upon wetting at constant total stress. Several studies at the macro scale outline the influence of initial void ratio, confining pressure and matric suction on the onset of collapse of standard laboratory specimens. Conversely, few observations at the micro scale are available in the literature, although the influence of the particles arrangement and intergranular bonding has been formerly supposed. The collapse of fine sand derived by a pyroclastic soil of Southern Italy is investigated in this paper at the microscale using the X-ray Computed Tomography. The experimental procedure, formerly tested on similar pyroclastic soils, consists into testing a remoulded specimen (only loaded by its self-weight), which undergoes a reduction of matric suction until the collapse occurs. The laboratory investigation aims to: i) follow the transformation of the particles arrangement; ii) measure the global variations of the specimen in terms of water content, porosity and saturation degree during the wetting stage; iii) measure the local porosity, water content and saturation degree in several representative sub-volumes of the specimen. The experimental evidence outlines that the collapse occurs at very low suction while it is not mandatory to reach the complete saturation, emphasized by the presence of macro-voids at collapse
Tipici meccanismi di innesco di colate rapide di fango in terreni piroclastici.
No full textIncontro Annuale dei Ricercatori di Geotecnica- IARG 200
Analisi fisicamente basata dell’erosione superficiale indotta da pioggia in bacini montani
No full textLarge-area analysis of soil erosion and landslides induced by rainfall: A case of unsaturated shallow deposits
No full textMPM hydro-mechanical modelling of flows impacting rigid walls
Full text linkThe study on impact mechanisms of flow-like landslides against structures is still an open issue in the scientific literature. Many researchers have employed so far either experiments or numerical methods, but the evaluation of the impact forces on mitigation obstacles remains difficult especially if the solid-fluid interaction within the flow is considered. This study shows how advanced numerical tools, such as Material Point Method, may be used in simulating those complex processes. The simulations are carried out for two well documented laboratory tests: a dry granular flow impacting a rigid wall under different geometries and testing conditions in a small-scaled flume and a saturated flow with complex propagation pattern in a centrifuge apparatus. The numerical modelling is validated against the observations and then used to explore the response of different flows impacting rigid structures in other conditions than in the experiments. The soil-fluid interaction influences the type of impact mechanism, the kinematics of the flow, and the space-time trend of the impact pressure against the structure.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
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