Shi Zhenming, Zhang Gongding, Peng Ming, Zhang Qingzhao, Zhou Yuanyuan, Zhou Mingjun
Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China.
Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China.
Materials (Basel). 2022 Mar 9;15(6):2029. doi: 10.3390/ma15062029.
Landslide dams are dangerous because the outburst floods produced by dam failures seriously threaten life and property downstream. In this study, a series of physical flume tests were conducted to investigate the breaching process of landslide dams with fine-grained, well graded, and coarse-grained material under different inflow conditions. The effects of dam material and inflow discharge on the breach development, outflow discharge and erosion characteristics were studied. The erosion resistance of materials and lateral collapses were also discussed. Experimental results reveal that the whole breaching process is determined by the water-sediment interaction. For the fine-grained dams, a general constant downstream slope angle is maintained during the breaching process. For the well-graded dams, a step-pool structure is generated due to the scarp erosion. For the coarse-grained dams, they can remain stable under normal circumstances but fail by overtopping in a short duration under the extreme inflow condition. The final breach of the dam with higher fine content or larger inflow discharge is deeper and narrower. In addition, many fluctuations are observed in the changing curve of the erosion rates along the flow direction for the well-graded and coarse-grained dams. The erosion resistance of materials increases along the flow direction, which needs to be further considered in physically based breach models. Furthermore, the lateral collapse is affected by the dam material instead of inflow discharge. The lower fine content causes more lateral collapses with smaller volumes.
滑坡坝很危险，因为坝体溃决产生的突发洪水会严重威胁下游的生命和财产安全。在本研究中，进行了一系列物理水槽试验，以研究在不同入流条件下，由细粒、级配良好和粗粒材料构成的滑坡坝的溃决过程。研究了坝体材料和入流流量对溃口发展、出流流量和侵蚀特性的影响。还讨论了材料的抗侵蚀性和侧向崩塌情况。实验结果表明，整个溃决过程由水沙相互作用决定。对于细粒坝，溃决过程中下游边坡角度基本保持恒定。对于级配良好的坝，由于陡坎侵蚀会形成阶梯-深潭结构。对于粗粒坝，在正常情况下它们可以保持稳定，但在极端入流条件下会在短时间内因漫顶而溃决。细粒含量较高或入流流量较大的坝最终溃口更深更窄。此外，对于级配良好和粗粒坝，沿水流方向的侵蚀速率变化曲线存在许多波动。材料的抗侵蚀性沿水流方向增加，这在基于物理的溃口模型中需要进一步考虑。此外，侧向崩塌受坝体材料影响，而非入流流量。细粒含量较低会导致更多体积较小的侧向崩塌。
