Volume 33, Issue 1 (January 2005)
Evaluation of Permeability of Tire Shreds Under Vertical Loading
A concern in the use of tire shreds as drainage media in landfill leachate collection systems is the impact of compression strains on the permeability of the waste material, as earlier work has reported that these materials experience large (25 to 50 %) axial strains when subjected to vertical loading. This study examines the changes in permeability of a tire shred sample after being subjected to 30 to 50 % axial strain from average vertical stresses of 75 to 330 kPa. The maximum vertical stress of 330 kPa approximated 40 m of waste overburden. A constant-head permeability apparatus was fabricated to measure the permeability of the tire shred sample under different axial strains. Further, the fabricated assembly was capable of measuring permeability of the sample at various sample locations at a given strain level. Experimental results showed that despite experiencing large axial strains, the average permeability of the tire shred sample consistently remained two to three orders of magnitude higher than the design performance criterion of 0.01 cm/s for landfill drainage layers, suggesting that the compressible nature of tire shreds will not interfere in their use as a leachate collection drainage layer in municipal solid waste landfills.