Open-type check dams are widely used to mitigate debris-flow hazards in mountainous areas. However, the regulation function of dams is a non-trivial and still open issue. With the aim to better understand the process regulation of open-type check dam against debris flow, in this study, a series of specially designed flume experiments are conducted as well as contrast tests of closed-type dam. The effects of the debris-flow bulk density, opening form, and dam size are considered. Analysis of the flow patterns, discharge process, peak discharge, and flow duration give an insight into regulating detail. Results reveal that the regulation characteristics depend on the blocking performance of open structure. There are differences in the debris-flow hydrography after passing through an open-type or closed-type dam, and the temporary blocking phenomenon is found to play an important role in regulating the discharge process. Moreover, open-type dams produce a reduction and time lag in the peak discharge, and more effectively regulate the travel time of debris flow downstream than closed-type dam. The reduction ratio of peak discharge for narrow openings is similar to that of closed-type dam and decreases as the relative opening becomes wider. Finally, based on these regulation characteristics, the application of open-type dams for a novel form of debris flow mitigation is discussed from the perspective of balancing interception and regulation of sediment.

中文翻译：

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开放式拦阻坝对泥石流排放过程调控的试验研究

开式拦河坝广泛用于减轻山区泥石流灾害。然而，大坝的调节功能是一个重要且仍然悬而未决的问题。为更好地了解开式止回坝抗泥石流的过程规律，本研究开展了一系列专门设计的水槽试验以及闭式坝的对比试验。考虑了泥石流容重、开口形式和大坝尺寸的影响。对流动模式、排放过程、峰值排放和流动持续时间的分析可以深入了解调节细节。结果表明，调节特性取决于开放结构的阻塞性能。泥石流通过开放式或封闭式坝后水文有差异，发现暂时阻塞现象在调节放电过程中起重要作用。而且，开放式大坝在高峰流量上产生减少和时滞，比封闭式大坝更有效地调节下游泥石流的传播时间。窄口大坝峰值流量减少率与封闭式大坝相似，随着相对口的增大而减小。最后，基于这些调节特性，从平衡截流和调节泥沙的角度讨论了开放式坝在新型泥石流减缓形式中的应用。比封闭式大坝更有效地调节下游泥石流的行进时间。窄口大坝峰值流量减少率与封闭式大坝相似，随着相对口的增大而减小。最后，基于这些调节特性，从平衡截流和调节泥沙的角度讨论了开放式坝在新型泥石流减缓形式中的应用。比封闭式大坝更有效地调节下游泥石流的行进时间。窄口大坝峰值流量减少率与封闭式大坝相似，随着相对口的增大而减小。最后，基于这些调节特性，从平衡截流和调节泥沙的角度讨论了开放式坝在新型泥石流减缓形式中的应用。