Long-Term Behavior of Water Content and Density in an Earthen Liner

An extensively instrumented compacted earthen liner was constructed at the Illinois State Geological Survey facility in Champaign, Ill. in 1987. A pond of water $0.31\mathrm{m}$ deep was maintained on top of the $7.3\mathrm{m}\times 14.6\mathrm{m}\times 0.9\mathrm{m}$ thick liner for $14\text{years}$ . One of the goals of the project was to evaluate the long-term performance of a compacted earthen liner by monitoring the long-term changes in water content and density. The water content of the earthen liner showed no trend with depth or time. The liner density remained essentially constant from construction through excavation in 2002. The liner did not become fully saturated. Upon excavation of the liner, the degree of saturation was $80.0\pm 6.3\%$ after $14\text{years}$ of ponding under a hydraulic head of $0.31\mathrm{m}$ . The results imply that properly designed and constructed earthen liners may reduce the possibility of pollutants leaching from municipal solid waste containment facilities by remaining partially saturated for years and maintaining the placement density.