Author(s): Zhixian Cao; Zhiyuan Yue; Gareth Pender
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Abstract: Landslide dams are usually unconsolidated and when they act to impound water can be subject to failure that triggers catastrophic flooding in the downstream. However, the flood hydraulics due to landslide dam failure has remained poorly understood and cannot at present be reliably predicted. Inevitably, this militates against effective flood risk management in areas prone to landslides. Recently, we have conducted an experimental investigation of a single landslide dam failure and the resulting flood flow and also a coupled 2D computational study. Here we present an extended work along this line, i. e., an experimental and computational study on the flood flow induced by cascade landslide dam failure. A total of 12 experiments have been completed in a large-scale flume of 80 m×1. 2 m×0. 8 m, with differing inflow discharge and dam composition. An array of twelve automatic water-level probes is deployed to measure the stage hydrographs along the flume. The coupled shallow water hydrodynamic model calibrated with recent experimental data for cases of a single landslide dam failure is demonstrated to perform reasonably well for modelling the flood flows due to cascade landslide dam failure. Most notably, under appropriate conditions, the occurrence of streamwisely progressive enhancement of the flood induced by cascade landslide dam failure is demonstrated for probably the first time, which poses a higher risk of flooding in the downstream and therefore warrants careful consideration in flood risk management.
Year: 2010