In Japan, the heavy rain disaster that occurred in July 2018 revealed that about 70% of the streams affected by debris flows that resulted in human casualties were small, steep mountain streams with a catchment area < 0.05 km2. Generally, many streams that are close to residential houses or roads do not have a constant flow of water and are known to pose a high risk of human fatalities when a debris flow occurs. This study aimed to promote sediment control as debris flow countermeasures in non-flowing mountain streams, utilizing secondary manufactured products (permeable debris flow barriers) with excellent constructability, focusing on the mechanism of sediment outflow from the gaps between a permeable debris flow barrier and mountain stream side banks. The necessity and effectiveness of preventative measures based on preliminary experimental results are presented. When impermeable structures were installed at both ends of the permeable debris flow barrier side, compared to using only a permeable debris flow barrier (covering the entire width with permeable debris flow barriers), we found that the capture function improved significantly, achieving a 200% increase in effectiveness.

中文翻译：

---

无流山溪防沙对策建议

在日本，2018年7月发生的暴雨灾害显示，受泥石流影响并造成人员伤亡的溪流中，约有70%是流域面积<0.05平方公里的小而陡的山溪。一般来说，许多靠近住宅或道路的溪流没有持续的水流，并且众所周知，当发生泥石流时，造成人员死亡的风险很高。本研究旨在利用具有优良可施工性的二次制造产品（渗透性泥石流屏障），促进泥沙控制作为非流动山溪的泥石流对策，重点研究泥沙从渗透性泥石流屏障与山体之间的间隙流出的机制。溪边河岸。根据初步实验结果，提出了预防措施的必要性和有效性。当渗透性泥石流屏障一侧两端安装防渗结构时，与仅使用渗透性泥石流屏障（渗透性泥石流屏障覆盖整个宽度）相比，我们发现捕获功能显着改善，实现了200%提高效率。