不均質地盤を対象とした中規模溶質輸送実験と空間・時間モーメント法による溶質分散パラメータ同定

抄録

Geological media exhibit heterogeneities in their hydraulic properties, which lead to enhanced spreading and mixing of the transported solutes. Intermediate-scale laboratory experiments on heterogeneous porous media were conducted in a 1×1×0.03 m sandbox with small blocks of fine or coarse sand. The use of visualization of dye solute and the measurement of NaCl concentration were applied to the identification of the changes in longitudinal and transverse dispersivities caused by the presence of heterogeneities. Results indicated an increase tendency in longitudinal dispersivity with the increase of travel distance and heterogeneity, while a continuous decrease in transverse dispersivity attributed to the initial solute distribution despite of the heterogeneity. Results also revealed that dispersivity estimates from temporal moments were identical to or smaller than those from spatial moments and variation of the dispersivities showed no dependency on the seepage velocity. Moreover, identified values were in good agreement with reported studies regarding laboratory experiments in heterogeneous porous media.