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Safeguarding the leaning Minaret of Jam (Afghanistan) in a conflict scenario: State of the art and further needs
Published in Renato Lancellotta, Alessandro Flora, Carlo Viggiani, Geotechnics and Heritage: Historic Towers, 2017
A. Bruno, C. Margottini, L. Orlando, D. Spizzichino
It is clear from Figure 15 that the minaret has been recorded with severe leaning since, at least, 1974 (Bruno & Margottini, 2011). This leaning might be attributed to many causes but the most probable is related to river evolution and then the loss of bearing capacity due to flood events and fluvial erosion close to the foundation. Fluvial erosion is caused by rivers and streams, and can range from gradual bank erosion to catastrophic changes in river channel location and dimension during flood events. In order to prove such a hypothesis, a numerical elaboration of bearing capacity in various situations experienced by the monument was developed.
Evaluation of the river Padma morphological transition in the central Bangladesh using GIS and remote sensing techniques
Published in International Journal of River Basin Management, 2023
Anupom Halder, Rumman Mowla Chowdhury
The River Padma is a typical wandering river. This study applied GIS and Remote sensing techniques with multi-temporal satellite imageries to highlight the variations in channel morphology of the River Padma, which may be helpful in future management planning. The results showed a large morphological change because of the fluvial flow system alteration. This study determined that rapid changes in the erosion and accretion of river channels in the last four decades resulted in significant land development and loss and were the backdrop of the River Padma. There was more erosion during this period than accretion, and erosion in the right bank was dominant, meaning that the rivers became wider and prompted river channel migration. This analysis recognizes that the River Padma planform became sinuous-braided in recent times. For comparison with other rivers of the same scale, details on the dynamics and current state of fluvial erosion and deposition of this river may be used.
Three-dimensional flow structure at fixed 70° open-channel confluence with bed discordance
Published in Journal of Hydraulic Research, 2020
Olga Birjukova Canelas, Rui M.L. Ferreira, Sebastián Guillén-Ludeña, Francisco C. Alegria, António H. Cardoso
River confluences are key features of fluvial networks known for their interrelated complex flow dynamics and geomorphological and sediment transport processes. The study of open-channel confluences has a relatively long history supported by the studies of Taylor (1944), Webber and Greated (1966), Mosley (1976), Best and Reid (1984), Best (1987), Gurram, Karki, and Hager (1997), Leite Ribeiro, Blanckaert, Roy, and Schleiss (2012), among many others. The first two pioneering works were focused on flow hydrodynamics using one-dimensional approaches taking into account the changes of momentum. Based on flume experiments, Mosley (1976) attempted to provide a general model of confluence hydraulics. The effort was continued by Best (1987, 1988), who identified six distinct flow zones in confluences: (1) flow stagnation, (2) flow deflection, (3) flow separation, (4) maximum velocity, (5) flow recovery, and (6) shear layers. The author also stressed the importance of the shear layer between the two convergent flows in the generation of strong vertical vortices along its path.
Experiments and modelling of cantilever failures for cohesive riverbanks
Published in Journal of Hydraulic Research, 2018
Supapap Patsinghasanee, Ichiro Kimura, Yasuyuki Shimizu, Mohamed Nabi
To address the limitations of the previous experiments and to model the cantilever failure process, a series of scale experiments were conducted with the objective of fully elucidating the complex mechanisms of cantilever failure by considering geometrical and material scaling, and the sidewall correction effect. Additionally, the slump block failures that occur during the progress of cantilever failure, and the phenomena associated with the decomposition of those blocks, are discussed with reference to an experimental flume. Furthermore, a novel coupled numerical model that incorporates the effects of fluvial erosion, cantilever failure, slump block occurrence, and sediment transport was developed to simulate the cantilever failure mechanism.