[O-08] Poster presentations by senior high school students

[O08-P20] Research on the influence of decomposed granite soil in flowing water on the erosive force of flowing water

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

Keywords:decomposed granite soil, erosive force

We were interested in the fact that when decomposed granite soil is mixed with water, it is easier to transport the earth and soil, and when decomposed granite soil dries on land, it becomes non-slip. The purpose of this research is to investigate how the erosive force of flowting water is affected when water mixed with particles such as decomposed granite soil is flowing, focusing on differences in particle type and particle size. First, we defined erosion force as "the force necessary for particles to start moving.'' The magnitude of the erosive force is then measured by the time it took for a weight placed within the channel to travel a given distance. When the same decomposed granite soil was used repeatedly in preliminary experiments, it was noticed that its erosive force decreased. One of the factors contributing to this change is the decrease in mud with small particle sizes. Currently, We are conducting experiments mainly on mud.