抄録
The purpose of the study is to find out the factors relating to the permeability of the decomposed granite soil with special consideration on the physical properties of soil particles. Specific surface area was taken first for a criterion of the degree of weathering and was determined by means of Nitrogen adsorption test. The relationship between specific surface area and free energy level of soil water was examined in detail.The permeability test was also carried out on the soil specimens to find the influence of the physical properties on permeability.In conclusion, fundamental properties of soil particles have a close connection with specific surface area by Nitrogen adsorption, which gives a strong effect on water retertion capacity of the soil mass. Soil water with pF value higher than 3.3 is assumed to be firmly held within or around the soil particles and is not involved in permeation of water. Coefficient of permeability can be examined in detail by such parameters as void ratio, specific gravity, apparent specific gravity and medium grain size.
