This paper presents and discusses the results of laboratory tests and numerical simulations carried out to assess the efficiency of slit dams (open-type retention dams) and applicability as a short-term structural mitigation measure against debris flows in steep torrential channels. Inspired by common slit dam solutions, two different layouts of piers were tested in the experimental study – aligned and V-shaped. Some of the major experimental results about the sediment control efficiency are presented, showing that aligned layout is more appropriate to mitigate stony-type debris flows than the tested V-shaped solution. Actually, it was proved that slit-check dams mitigation efficiency is influenced by various variables and parameters, most of them previously studied by several authors, but also by pier layout in plan view. Considering aligned layout, 1.0d95 to 1.4d95 slit widths shall be considered to design effective slit dam solutions. Further, a numerical study was performed, providing relevant data that greatly enriched the experimental efforts and also support future slit dam design phases. The numerical results show similar quantities of retained solid material comparing with the experimental tests, indicating that the model provides reliable results, thus being able to support engineers and decision makers regarding debris flows mitigation.
debris flow, experimental study, numerical study, sediment control efficiency, slit-check dam
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