Abstract
The measurement of pF-moisture characteristics of soils requires saturation of the soils before setting of those in an apparatus. However, it is not clear how much time it takes to saturate the soils in 5.1 cm tall samplers. Insufficient saturation of the specimens causes errors on the test results of pF-soil moisture characteristics of the soils.
This paper discusses the saturation time of undisturbed soils in 5.1 cm tall samplers. The term “saturation” does not refer to “complete saturation”, but to “the state where a soil specimen does not absorb water any more”.
Tests for saturation and permeability with undisturbed soils were carried out. The saturation processes were analyzed with the finite element method for saturated-unsaturated flow. Discussion on the experimental and numerical results has led to the following conclusions:
1. Exudation of water over the upper surface of soil in a sampler does not mean the completion of the water absorption of the soil.
2. The standard saturation time of undisturbed soils in the samplers, 5.1 cm tall, is as follows:
1) Single-grained soils
Sandy soils … about 0.5 day
Other soils … about 5 days
2) Aggregated soils … about 10 days.
