締固めた凝灰岩の透水性

The permeability tests were performed on compacted tuff using triaxial cells and the effects of consolidation pressure σ'_<3c> and back pressure u_b for coefficient of permeability k were experimented.
From these tests，the following results are obtained that k of 47% specimen is decreased with increment of σ'_<3c> , but k of 34% specimen is increased with increment of σ'_<3c> , and k of 19% specmen is decreased with increment of u_b from 0 to 1.0kgf/㎝^2 on condition of σ'_<3c> = 1.0kgf／cm^2. Moreover, the relation between k and compacted moisture content or void ratio is different from that of normal sand or cohesive soil. It is considered that these results are come from the migration of soil particies in soil．