1 Assistant Professor, Civil Engineering Department, Babol University of Technology, Babol, Iran.
2 Assistant Professor, Geotechnical Engineering Research Center, International Institute of Earthquake Engineering and Seismology, Tehran, Iran.
3 Professor, Geotechnical Engineering Research Center, International Institute of Earthquake Engineering and Seismology, Tehran, Iran
*Email: tavakoli@nit.ac.ir
Online published on 1 February, 2013.
The use of clay alone or amended with aggregates as core material of embankment dams and backfill materials for nuclear waste disposal is common. Composite clay is a mixture of clay, as the main body and aggregates which are floating within the clayey matrix. The hydraulic conductivity of composite clay in its natural or compacted has great importance for geotechnical engineers. An extensive test program was conducted on clay-aggregate mixtures to investigate various effects of aggregate content, aggregate size, confining stress and fabric anisotropy on the hydraulic properties of mixtures. Test results reveal that hydraulic conductivity of clay- aggregate mixtures decreases with increase in aggregate content up to an addition of 40% aggregate. With the addition of more than 40% aggregate, hydraulic conductivity increases. In addition, the presence of aggregate may induce a heterogeneous field of hydraulic conductivity in the clayey matrix, after specimen preparation in compaction mold, compaction and isotropically or anisotropically consolidation.
composite clay, hydraulic conductivity, heterogeneous field, clayey matrix
