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Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully

In recent years, debris flows have frequently erupted in the narrow-steep gully of the earthquake-hit Wenchuan region, displaying high flow velocities and powerful scouring abilities. However, few scouring studies in the narrow-steep gully have been conducted. A model experiment simulated the debris...

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Autores principales: Wu, Yu, Ji, Jiejie, Qi, Shunchao, Wang, Xiekang, Li, Dong, Li, Hongtao, Yang, Xingguo, Yao, Qiang
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10492852/
https://www.ncbi.nlm.nih.gov/pubmed/37689777
http://dx.doi.org/10.1038/s41598-023-41589-1
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author Wu, Yu
Ji, Jiejie
Qi, Shunchao
Wang, Xiekang
Li, Dong
Li, Hongtao
Yang, Xingguo
Yao, Qiang
author_facet Wu, Yu
Ji, Jiejie
Qi, Shunchao
Wang, Xiekang
Li, Dong
Li, Hongtao
Yang, Xingguo
Yao, Qiang
author_sort Wu, Yu
collection PubMed
description In recent years, debris flows have frequently erupted in the narrow-steep gully of the earthquake-hit Wenchuan region, displaying high flow velocities and powerful scouring abilities. However, few scouring studies in the narrow-steep gully have been conducted. A model experiment simulated the debris flow scouring process in a narrow-steep flume, in which several important physical parameters, including the debris flow density (ρ), flume slope (θ), and grain size of the sediment (D), were varied to investigate their influences on the erodible strength. The experimental flows were composed of 50 L of water and grains, which scoured 2.3 m of erodible bed down a steeply inclined flume. A high-speed camera photographed the scouring processes, while a 3D laser device captured the final bed shapes. The experiments show that the debris flow first collides with the sediment at the head of the gully to form a pit, which is enlarged by continuous impact; the velocity of the debris flow out of the pit is significantly reduced due to the change in flow direction, resulting in a much lesser scouring effect after the pit; and finally, the gully bed presents the shape of a pit at the entrance and a groove in the middle and rear. The critical scour slope, where the gully bed shows scouring, increases with increasing debris flow density but decreases with increasing grain size of sediment. Following scouring, the maximum scouring depth is further positively correlated with the flume slope. In narrow-steep gullies, the gully bed is extremely susceptible to scouring by debris flow with a low density, and even headward erosion appears, at which the maximum scouring depth only increased from 148.04 to 149.97 mm, but the erosion amount had a significant increase of 36.9%. The research results have an important significance for revealing the disaster-causing phenomena and mechanisms of debris flows in the narrow-steep gully.
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spelling pubmed-104928522023-09-11 Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully Wu, Yu Ji, Jiejie Qi, Shunchao Wang, Xiekang Li, Dong Li, Hongtao Yang, Xingguo Yao, Qiang Sci Rep Article In recent years, debris flows have frequently erupted in the narrow-steep gully of the earthquake-hit Wenchuan region, displaying high flow velocities and powerful scouring abilities. However, few scouring studies in the narrow-steep gully have been conducted. A model experiment simulated the debris flow scouring process in a narrow-steep flume, in which several important physical parameters, including the debris flow density (ρ), flume slope (θ), and grain size of the sediment (D), were varied to investigate their influences on the erodible strength. The experimental flows were composed of 50 L of water and grains, which scoured 2.3 m of erodible bed down a steeply inclined flume. A high-speed camera photographed the scouring processes, while a 3D laser device captured the final bed shapes. The experiments show that the debris flow first collides with the sediment at the head of the gully to form a pit, which is enlarged by continuous impact; the velocity of the debris flow out of the pit is significantly reduced due to the change in flow direction, resulting in a much lesser scouring effect after the pit; and finally, the gully bed presents the shape of a pit at the entrance and a groove in the middle and rear. The critical scour slope, where the gully bed shows scouring, increases with increasing debris flow density but decreases with increasing grain size of sediment. Following scouring, the maximum scouring depth is further positively correlated with the flume slope. In narrow-steep gullies, the gully bed is extremely susceptible to scouring by debris flow with a low density, and even headward erosion appears, at which the maximum scouring depth only increased from 148.04 to 149.97 mm, but the erosion amount had a significant increase of 36.9%. The research results have an important significance for revealing the disaster-causing phenomena and mechanisms of debris flows in the narrow-steep gully. Nature Publishing Group UK 2023-09-09 /pmc/articles/PMC10492852/ /pubmed/37689777 http://dx.doi.org/10.1038/s41598-023-41589-1 Text en © The Author(s) 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Wu, Yu
Ji, Jiejie
Qi, Shunchao
Wang, Xiekang
Li, Dong
Li, Hongtao
Yang, Xingguo
Yao, Qiang
Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
title Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
title_full Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
title_fullStr Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
title_full_unstemmed Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
title_short Experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
title_sort experimental study of erodible bed scoured by the debris flow in the narrow-steep gully
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10492852/
https://www.ncbi.nlm.nih.gov/pubmed/37689777
http://dx.doi.org/10.1038/s41598-023-41589-1
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