Arrays of obstacles are a potentially effective measure to manage a channel landslide run-out deposit. In this research, three kinds of debris sands with different particle sizes, 0.25–0.5 mm, 1–2 mm and 2–5 mm respectively, are investigated in a 4.28-m-long chute with a fixed incline angle of 40°. Structure from motion (SfM) and other novel image analysis techniques are proposed to analyse the deposits’ characteristics, including time histories. These allow measuring accurately the run-out distance, width, 3D topography and area of the deposits which are used to assess the effectiveness of the obstacles to manage run-out deposits efficiently. Experimental results reveal that particle size has a significant impact on the final deposition because they effectively behave as three different rheology characteristics: viscous (fine), frictional (medium) and collisional (coarse). The observations show emerging shape properties that are characterised, as well as surprising behaviours when considering time histories such as the non-monotonic area growth in fine, or viscous, landslides. Other phenomena such as airborne particle jets are observed for the coarse particle size, representing a collisional-type flow. In practical terms, the experiments show that when designing protection barriers, a compromise is needed between length, width and depth of deposition and that this can only be decided based on the structure to be protected.

中文翻译：

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快速干重力驱动泥石流与障碍物阵列相互作用的实验研究

一系列障碍物是管理渠道滑坡流失沉积物的潜在有效措施。本研究在4.28米长、固定倾角为40°的斜槽中研究了三种粒径分别为0.25-0.5mm、1-2mm和2-5mm的碎屑砂。提出了运动结构（SfM）和其他新颖的图像分析技术来分析沉积物的特征，包括时间历程。这些允许准确测量沉积物的溢出距离、宽度、3D 地形和面积，用于评估障碍物的有效性以有效管理溢出沉积物。实验结果表明，粒径对最终沉积有显着影响，因为它们有效地表现为三种不同的流变特性：粘性（细）、摩擦（中等）和碰撞（粗）。观察结果显示了新出现的形状特性，以及在考虑时间历史时的惊人行为，例如细小或粘性滑坡中的非单调区域增长。对于粗颗粒尺寸，观察到其他现象，例如空气中的颗粒喷射，代表碰撞型流动。实际上，实验表明，在设计保护屏障时，需要在沉积的长度、宽度和深度之间进行折衷，这只能根据要保护的结构来决定。对于粗颗粒尺寸，观察到其他现象，例如空气中的颗粒喷射，代表碰撞型流动。实际上，实验表明，在设计保护屏障时，需要在沉积的长度、宽度和深度之间进行折衷，这只能根据要保护的结构来决定。对于粗颗粒尺寸，观察到其他现象，例如空气中的颗粒喷射，代表碰撞型流动。实际上，实验表明，在设计保护屏障时，需要在沉积的长度、宽度和深度之间进行折衷，这只能根据要保护的结构来决定。