Large wood (LW) in debris flows during flooding can cause significant damage to check dams, bridges, and other major infrastructure in its flow path. When LW accumulates and forms logjams, large volumes of sediment can be deposited, resulting in increased backwater. The logjams can then suddenly collapse, with the deposited sediment and accumulated water increasing the magnitude of debris-flow peak discharge. To better understand the characteristics of debris flow discharge caused by LW accumulation and collapsed logjams, as well as the associated magnitude amplification effects, a series of experiments was carried out in a laboratory experimental channel. The main purpose of this study was to analyze the process of LW accumulation and collapse and to determine the magnitude amplification ratio of the debris flow peak discharge with LW. The results revealed three types of debris flow movement with LW: flow with no clogging or breakage, flow with clogging but without breakage, and flow with both clogging and breakage. The results indicated a significant effect on the magnitude amplification ratio caused by LW clogging and breakage. The maximum magnitude amplification ratio was 1.60 in the experiments, with a relative LW length and volume of 0.875 and 0.75, respectively, during the clogging and breakage process.

中文翻译：

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裂隙坝大型木材和泥石流过程特征的室内研究

洪水期间泥石流中的大木头 (LW) 会对其流动路径中的检查水坝、桥梁和其他主要基础设施造成重大损坏。当 LW 堆积并形成僵局时，会沉积大量沉积物，导致回水增加。然后，僵局会突然崩溃，沉积的沉积物和积水增加了泥石流峰值排放量。为了更好地了解长波堆积和倒塌的泥石流排放特征以及相关的震级放大效应，在实验室实验通道中进行了一系列实验。本研究的主要目的是分析LW堆积和坍塌的过程，并确定LW泥石流峰值流量的幅度放大率。结果揭示了三种类型的泥石流随LW的运动类型：无堵塞或破碎的流动，有堵塞但无破碎的流动，以及有堵塞和破碎的流动。结果表明，LW 堵塞和破损对幅度放大率有显着影响。实验中最大放大倍数为1.60，在堵塞和破损过程中相对LW长度和体积分别为0.875和0.75。