Abstract
By means of the λ/4 resonance method, the velocity (√<E/ρ_s>) and the absorption coefficient (α) of longitudinal waves in soil are measured as functions of water content (W) and frequency (n) in the range of 0. 1-2. 0 kc/s. For the comparison of different soils, the parameter gamma γ = (volume of air / vol. of air + vol. of water. ) is chosen in place of water content. Typical soils subject to comparison are Kanto Loam (natural state), Mitaka Sand Silt (obtained as sediments at well-boring) and White Clay (semi-moulded). Results of measurements made by this method show that: (1) √<E/ρ_s> is not so closely related to n, but log α is proportional to log n in the mentioned frequency range. (2) Both √<E/ρ_s> and α are affected deeply by W. √<E/ρ_s> is an increasing function of γ and α is decreasing function of γ. (3) Kanto Loam, a thick stratum of fine volcano ash, contracts little as W decreases. Its √<E/ρ_s> varies between 180 m/s and 400 m/s. α_<500> varies from 10^<-2> cm^<-1> to 10^<-3> cm^<-1>. (4) White Clay, sampled at Mt. Hakone (volcano), contracts greatly as W decreases. Its √<E/ρ_s> varies from 40 m/s to 1000 m/s and also α_<500> varies from 10^<-1. 5> cm^<-1> to 10^<-4. 5> cm^<-1> as γ increases. (5) Mitaka Sand Silt is very soft when it is saturated with water out becomes very hard when it is dried. Its √<E/ρ_s> varies from 30 m/s to 800 m/s and α_<500> varies from 10^<-0. 5> cm^<-1> to 10^<-3> cm^<-1>.
