[O-11] Senior high school student poster presentations

[O11-P48] The effect of Decomposed granite soil in flowing water on the erosive power of flowing water

*Shunya Yamazaki¹, *Hiroyuki Saito¹, *Haruki Itabashi¹, *Ryo Minagawa¹, *Shuta Komano¹ (1.Ibaraki Prefectural Hitachi Daiichi High School)

Keywords:Decomposed granite soil, Erosive force, Landslide disaster

In areas with decomposed granite, it is known that weathering of granite separates the decomposed granite soil and corestones, increasing the likelihood of landslides. Flowing water and decomposed granite transport corestone that fell into the river as a huge boulder, triggering debris flows. Therefore, the effect of running water containing decomposed granite on erosive force was investigated. In this study, “erosive force” was defined as the force required to initiate movement of stationary particles in water, and experiments were conducted under two flow velocity conditions: 1.95 m/s and 2.49 m/s. The results showed that in water only, the erosive force was smaller at lower flow velocities, while in water containing decomposed granite, no significant difference in erosive force was observed between the two velocities. In the future, the relationship between flow velocity and erosive force in water containing decomposed granite will be examined in more detail by narrowing the range of flow velocity variation.