Long-term and short-term disposal of landslide dams at steep V-shaped valleys

• Published in: Landslides 2024, Vol.21 (1), p.135-153
• Main Authors: Wang, Jingwen, Wang, Rui, Zhang, Chong, Ma, Zihao, Tan, Guangming, Shu, Caiwen, Han, Shasha, Shang, Haixin, Zhang, Guangyue, Zhan, Yizheng
• Format: Article
• Language: English
• Subjects: Agriculture; Channels; Civil Engineering; Dam breaching; Dam failure; Dams; Damsites; Data collection; Direction; Disaster management; Diversion channels; Dredging; Earth and Environmental Science; Earth dams; Earth Sciences; Emergency preparedness; Emergency response; Energy dissipation; Energy exchange; Environmental risk; Excavation; Experimental research; Field investigations; Field tests; Flood risk; Geography; Laboratory experimentation; Landslides; Landslides & mudslides; Mountains; Natural Hazards; River beds; Riverbeds; Rivers; Rockfill dams; Technical Note; Valleys
• ISSN: 1612-510X; 1612-5118
• DOI: 10.1007/s10346-023-02145-0

Landslides often occur in V-shaped valleys exhibiting strong river incisions and large elevation differences between the riverbed and surrounding mountains. This study expounded upon the topographical and flow conditions of typical landslide dam sites through field investigations and data collection and established a small-scale physical model for experimental research. The formation conditions of landslide dams, an important part of the long-term management of such events, were studied. Simultaneously, the experiments verified a series of engineering measures proposed based on calculus theory and implementation principles according to their experimental disposal effects to mitigate short-term flood risks. Results showed that the dam formation is mainly related to topographic characteristics, upstream flow, and dam compositions. Specifically, steep V-shaped valleys should be considered when establishing physical models as they provide great conditions for landslide mass blocking the river completely. In addition, for earth dams, the effects of the position and direction of excavated diversion channels were compared; it showed that when there are multiple passes on the dam crest, priority should be given to lateral excavation of channels from the pass to restrict the lateral development process. The dam-break flow direction should better be orthogonal rather than be parallel to the river bend, which can reduce peak flow discharge by natural energy dissipation. For earth and rockfill dams with wide particle distributions, piles and flexible nets were instead utilized to coarsen the dam breach and reduce peak flow discharge. Finally, applicable values and research significance were summarized based on the obtained results. This research enriches studies of mountain disaster management and provides guidance for on-site emergency response.