閉塞単一砂層への雨水浸透に関する研究

Abstract

In order to research the effect of pore-air on infiltration phenomenon of water into the con-fined sand column, the experiments of pounded infiltration were carried out by the use of sandcolumn formed in the lucite cylinder with bottom plate. The changes of the water contentsat various depths, the air pressure at bottom and the infiltration rate of water at top of the sandcolumn were continuously recorded.After analysing the results obtained by experiments, the following was disclosed.(1) In the first stage of infiltration, the pore-air pressure, Pa, is approximately expressedby Pa=αlogt+β(α and β are constants), whereas the infiltration rate of water, f, and themovement of infiltrated water are experimentally given by f=S/2√t and ψ(θ)=x/√trespectively, (S is a constant and ψ(θ) is a function of water content, θ).(2) In the next stage of infiltration, since the rate of infiltration and the rate of change of pore-air pressure become nearly constant, the profile of water content in the neighbourhood of wettingfront is unchanged, its phase velocity being constant, and also the space distribution of pore-airpressure in such a region shows approximately uniform.