Multi-scale analyses of granular flows for disaster resilience enhancement
Author(s)
Liu, Fangzhou
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Abstract
A study that overlaps the fundamentals of granular flows with human responses to disasters at the community or regional scale is considered to be a strategic approach that advances existing methods in natural and human-induced hazard research in light of global-scale changes in earth systems. This study aims to improve the understanding: 1) on the mechanical behaviors of fluidized loess flowslide using centrifuge modeling as well as in-house designed laboratory testing and elastic wave characterization techniques (i.e. natural systems), and 2) on the cascading impacts of geohazards on local communities, assessing disaster resilience associated with reconstruction strategies and the performance of debris flow mitigation systems (i.e. natural-human systems interactions).
The current work reveals the state-dependent effects of structure on flow behavior of loess and proposes modified criteria to predict the flow behavior. Laboratory tests show the changes in the mechanical behavior due to decementation of loess and indicate the needs to study loess within the scope of geotechnical analysis. The failure mechanism of loess flowslide is better understood from the study on the deformation process that shows the compounding effects of increasing pore-water pressure and reducing confining stresses on static liquefaction. The earthquake and post-earthquake impacts are documented after the 2008 Wenchuan earthquake, which permits a pilot study on quantifying the recovery processes of two communities of different reconstruction modes in light of Bayesian-based learning method. The design and performance of post-earthquake debris flow mitigation systems are reviewed; it offers a simple and robust data-driven approach to evaluate the effectiveness of debris flow mitigation systems at the regional scale.
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Date
2019-11-12
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Dissertation