2020 年 8 巻 4 号 p. 109-114
One strategy currently being explored in the development of a technically simple and practical countermeasure when utilising geogenic contaminated soils as fill materials in an embankment involves the installation of a compacted soil layer with attenuation capacity underlain the contaminated geomaterials. Water retention property, which is one of the important soil hydraulic properties in the simulation of water flow, needs to be better understood for selecting a suitable composite of base material and stabilizing agent as the attenuation layer. In this study, the water retention characteristics of six composites with different sandy soils and calcium-magnesium composite sizes were investigated. It was found out that mixing the sandy soil with the mineral-based agent improves its water retention characteristics, especially when the soil is a well-graded type. The highest residual saturation (Srf) was found for the decomposed granite soil mixed with the powder agent of under 2 mm, which reached 87%. Poorly-graded sandy soils like the silica sand were found not to be suitable base material for the attenuation layer, because they drastically become impermeable, where k reaches nearly 1×10-14 m/s from very small changes in negative pressures.
