The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure
<p>Boulder bars are a common form of riverbed morphology that could be affected by landslide dams. However, few studies have focused on the formation and geometry characteristics of boulder bars due to outburst floods triggered by landslide dam failure. In such a way, eight group landslide dam...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2021-09-01
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| Series: | Earth Surface Dynamics |
| Online Access: | https://esurf.copernicus.org/articles/9/1263/2021/esurf-9-1263-2021.pdf |
| _version_ | 1819063753428172800 |
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| author | X. Jiang H. Cheng L. Gao W. Liu |
| author_facet | X. Jiang H. Cheng L. Gao W. Liu |
| author_sort | X. Jiang |
| collection | DOAJ |
| description | <p>Boulder bars are a common form of riverbed morphology that could be affected by landslide dams. However, few studies have focused on the formation and geometry characteristics of boulder bars due to outburst floods triggered by landslide dam failure. In such a way, eight group landslide dam failure experiments with a movable bed length of 4 to 7 times the dam length with 25 boulder bars were carried out. In addition, 38 boulder bars formed in the field triggered by four landslide dam failures were investigated. The aim of this paper is to study the formation and geometry characteristics of boulder bars along the riverbeds. The results show that boulder bars are formed after peak discharge of outburst flow. The number of boulder bars is 0.4 to 1.0 times the ratio of riverbed length to dam bottom length. Besides, boulder bars have the characteristic of lengthening upstream during the failure process. A boulder bar's upstream edge has a more extensive development than a boulder bar's downstream edge. The length of a boulder bar along the channel changes faster than the boulder bar's width and height. After the dam failure, the boulder bar's length is about 8 to 14 times its width. The relationship between the ratio of boulder bar length to width and the boulder bar's dimensionless length could be described with a hyperbolic equation. The dimensionless area of the boulder bar increases linearly with the dimensionless area of the river section, and the linear ratio is about 0.5. With the field data, this demonstrates that the formation and geometry characteristics of boulder bars in tests are consistent with the field boulder bars. Therefore, the results in this paper are credible and can be applied to the riverbed's geomorphological characteristics analysis triggered by overtopped landslide dam failure. The plentiful experimental and field data could contribute to the community boulder bar research.</p> |
| first_indexed | 2024-12-21T15:19:41Z |
| format | Article |
| id | doaj.art-6d34faffde6f499aaec21c4b1c29987a |
| institution | Directory Open Access Journal |
| issn | 2196-6311 2196-632X |
| language | English |
| last_indexed | 2024-12-21T15:19:41Z |
| publishDate | 2021-09-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth Surface Dynamics |
| spelling | doaj.art-6d34faffde6f499aaec21c4b1c29987a2022-12-21T18:59:04ZengCopernicus PublicationsEarth Surface Dynamics2196-63112196-632X2021-09-0191263127710.5194/esurf-9-1263-2021The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failureX. Jiang0H. Cheng1L. Gao2W. Liu3College of Civil Engineering, Sichuan Agricultural University, Dujiangyan, Chengdu 611830, ChinaCollege of Civil Engineering, Sichuan Agricultural University, Dujiangyan, Chengdu 611830, ChinaKey Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, ChinaKey Laboratory of Mountain Hazards and Earth Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China<p>Boulder bars are a common form of riverbed morphology that could be affected by landslide dams. However, few studies have focused on the formation and geometry characteristics of boulder bars due to outburst floods triggered by landslide dam failure. In such a way, eight group landslide dam failure experiments with a movable bed length of 4 to 7 times the dam length with 25 boulder bars were carried out. In addition, 38 boulder bars formed in the field triggered by four landslide dam failures were investigated. The aim of this paper is to study the formation and geometry characteristics of boulder bars along the riverbeds. The results show that boulder bars are formed after peak discharge of outburst flow. The number of boulder bars is 0.4 to 1.0 times the ratio of riverbed length to dam bottom length. Besides, boulder bars have the characteristic of lengthening upstream during the failure process. A boulder bar's upstream edge has a more extensive development than a boulder bar's downstream edge. The length of a boulder bar along the channel changes faster than the boulder bar's width and height. After the dam failure, the boulder bar's length is about 8 to 14 times its width. The relationship between the ratio of boulder bar length to width and the boulder bar's dimensionless length could be described with a hyperbolic equation. The dimensionless area of the boulder bar increases linearly with the dimensionless area of the river section, and the linear ratio is about 0.5. With the field data, this demonstrates that the formation and geometry characteristics of boulder bars in tests are consistent with the field boulder bars. Therefore, the results in this paper are credible and can be applied to the riverbed's geomorphological characteristics analysis triggered by overtopped landslide dam failure. The plentiful experimental and field data could contribute to the community boulder bar research.</p>https://esurf.copernicus.org/articles/9/1263/2021/esurf-9-1263-2021.pdf |
| spellingShingle | X. Jiang H. Cheng L. Gao W. Liu The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure Earth Surface Dynamics |
| title | The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure |
| title_full | The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure |
| title_fullStr | The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure |
| title_full_unstemmed | The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure |
| title_short | The formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure |
| title_sort | formation and geometry characteristics of boulder bars due to outburst floods triggered by overtopped landslide dam failure |
| url | https://esurf.copernicus.org/articles/9/1263/2021/esurf-9-1263-2021.pdf |
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