| DOI: | 10.1002/2015GL064723
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| 论文题名: | Fragmentation and boosting of rock falls and rock avalanches |
| 作者: | De Blasio F.V.; Crosta G.B.
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| 刊名: | Geophysical Research Letters
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| ISSN: | 0094-9593
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| EISSN: | 1944-9324
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| 出版年: | 2015
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| 卷: | 42, 期:20 | | 起始页码: | 8463
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| 结束页码: | 8470
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| 语种: | 英语
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| 英文关键词: | boosting
; fragmentation
; modeling
; rock avalanche
; rock fall
; runout
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| Scopus关键词: | Geometry
; Landforms
; Landslides
; Models
; Rock bursts
; boosting
; fragmentation
; Rock avalanche
; Rockfalls
; Run outs
; Rocks
; collision
; complex terrain
; discrete element method
; fragmentation
; geometry
; kinematics
; momentum transfer
; numerical model
; rock avalanche
; rockfall
; slope angle
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| 英文摘要: | Fragmentation has been proposed as an important dynamical process in the propagation of rock avalanches. The occurrence of an intense block fragmentation inside a rock avalanche traveling on smooth inclined terrain followed by a flat region (a geometry common to many landslides) is first studied numerically by means of a discrete element 2-D code in which blocks are subjected to mutual collisions and impact with the terrain. This numerical model confirms that the locations where fragmentation is more likely to occur are those in correspondence of abrupt slope changes. We thus analyze this geometry of impact in two cases: low- and high-impact energy. In the first case, where recent experimental data are available, a kinematic analysis shows that the energy released at impact causes high velocities of the smallest fragments, a highly probable scenario in rock avalanche dynamics. When the impact is so energetic to disintegrate the landslide, we find that explosive fragmentation at the slope break provides an extra horizontal boost to a rock avalanche via a peculiar mechanism coupling the geometry of the slope path to the dynamics of the rock avalanche. As a consequence, a net momentum gain (boost) results along the horizontal direction due to the terrain asymmetry. However, under normal field conditions, only when the slope angle is greater than 70° and fragmentation produces clasts of fairly uniform size, the momentum and runout distance are significantly enhanced. Allowing for a spectrum of fragment sizes and velocities, we find a relationship between the degree of fragmentation and the magnitude of the extra boost. Key Points Excessive runout of granular flows on steep slopes Impact energy effect on rock fragmentation Topographic and geometric effects on fragmentation and mobility © 2015. American Geophysical Union. All Rights Reserved. |
| URL: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-84946542181&doi=10.1002%2f2015GL064723&partnerID=40&md5=3b08f96499b54c91f20edbbf63f86a32
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| Citation statistics: |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/9208
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| Appears in Collections: | 科学计划与规划
气候变化与战略
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作者单位: | Department of Earth and Environmental Sciences, University of Milano Bicocca, Milan, Italy
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| Recommended Citation: | |
De Blasio F.V.,Crosta G.B.. Fragmentation and boosting of rock falls and rock avalanches[J]. Geophysical Research Letters,2015-01-01,42(20).
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