THE EFFECT OF VOID RATIO, MOISTURE CONTENT AND VERTICAL PRESSURE ON THE HYDROCOMPRESSION SETTLEMENT OF COPPER MINE TAILING
Keywords:
Copper Mine Tailings, Embankment, Hydrocompression, ConsolidationAbstract
Copper mine tailing (CMT) has the potential to be used as embankment material but this
waste material contains plasticity. Soils containing plasticity are highly reactive to any form of liquid and
considered to have greater compressibility when exposed to water. As an embankment material, CMT is
susceptible to different environmental condition which can cause significant settlement. One possible cause
of volume loss is the compression due to wetting or hydrocompression. This study aims to determine the
consolidation properties and hydrocompression settlement of waste materials with plasticity like copper mine
tailing when used as embankment material. One-dimensional consolidation tests were performed on
reconstituted specimens. The obtained consolidation properties indicate that CMT is very slightly
compressible under over-consolidated condition to moderately compressible under normally consolidated
condition. The hydrocompression settlement of CMT in relation to initial void ratio, moisture content and
vertical pressure was investigated. The hydrocompression settlement increases with increasing pressure until
the preconsolidation pressure is reached, then decreases with pressure beyond the preconsolidation pressure.
Samples with lower density and initial water content less than its optimum exhibit greater hydrocompression
settlement. The determined hydrocompression strain in every condition is less than 5% which means that
CMT has a degree of collapsibility classified as low to negligible despite of having plasticity. CMT when
used as embankment materials should be prepared with initial moisture content slightly more than its
optimum, it should be in its very dense condition and preloaded with vertical stress more than its
preconsolidation pressure to make hydrocompression strain negligible.