Experimental study on Glacial Lake Outburst Floods Due to Waves Overtopping and Erosion of Moraine Dam
Experimental study on Glacial Lake Outburst Floods Due to Waves Overtopping and Erosion of Moraine Dam
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发表时间：
2010-06
影响因子：
3.8
通讯作者：
R. Awal;H. Nakagawa;M. Fujita;K. Kawaike;Y. Baba;Hao Zhang
中科院分区：
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作者：
R. Awal;H. Nakagawa;M. Fujita;K. Kawaike;Y. Baba;Hao Zhang
冰湖溃决洪水可能在下游河段引发特大洪水。大约80%的GLOFs（基于20个已知破坏机制的案例）是由冰崩引起的位移波引起的，这些冰崩是由悬空或崩解的冰川和岩崩崩塌到湖泊中的。因此，一个综合的模型对于i)预测冰/岩雪崩产生的波浪，ii)预测由于波浪漫顶和冰碛坝侵蚀引起的流出线，以及iii)下游的水流和沉积物走向进行洪水风险评估至关重要。本研究在建立一体化模型的基础上，着重进行了波浪冲过和侵蚀作用下冰碛垄溃坝的实验研究。广泛的实验室实验是通过不同的冰/岩雪崩的大小，水坝的形状，水坝材料和湖泊水位进行的。波浪冲过和冲刷形成的流出线由多个峰组成。对于相同的落块和湖泊水位，三角形坝和梯形坝的初始峰值是相似的。然而，随着坝型和坝体材料的不同，后续峰值的大小和时间也不同。
Synopsis Glacial lake outburst floods (GLOFs) may cause floods of great magnitudes in the downstream river reaches. About 80% of GLOFs (based on 20 cases with known failure mechanisms) were initiated by displacement waves from ice avalanches that collapsed into the lakes from hanging or calving glaciers and rock avalanches. Therefore, an integrated model is essential for the i) prediction of waves generated by ice/rock avalanche, ii) prediction of outflow hydrograph due to waves overtopping and erosion of moraine dam and iii) flow and sediment routing in the downstream for flood risk assessment. Toward development of an integrated model, this study focuses on experimental study of moraine dam failure due to waves overtopping and erosion. Extensive laboratory experiments are carried out by varying size of ice/rock avalanche, shape of the dam, dam material and lake water level. The outflow hydrographs produced by waves overtopping and erosion consist multiple peaks. For the same falling block and lake water level, the initial peaks are similar for both triangular and trapezoidal dams. However, magnitude and timing of subsequent peaks are different according to dam shapes and dam materials.