Abstract
An influence f soil compression on the pF of soil moisture must be considered in using the centrifuging method. Soil used is a volcanic ash soil (Kanto Loam) and the results are as follows.
1. Stress caused by centrifugal force does not hardly affect the pF-moisture of undisturbed soil but it affects that of disturbed one. Furthermore the pF-moisture of disturbed soil changes due to the methods of preparation. So experiment was done under the condition of same preparation and the effect of the compression was expressed in terms of dry density (Fig.8). The pF-moisture curves which are obtained from the soil with different dry density intersected at about pF=2.
2. A phenomenon of soil consolidation in the sample tubes of centrifuge was appeared. The more rotation velocity increases, the more expands the susceptible range of consolidation.
3. It is seemed that the upper limit of pF, which can be determined by the centrifuging method, is about 2.5 according to the experimental data which are obtained under uniform dry density. This value of pF=2.5 is equivalent to the moisture of rupture of cappillary.
