Protective Characteristics of Nonwovens in Geocomposite for Landfill Cap Cover

There is a need for landfill cap cover to suppress water infiltration to waste while simultaneously promoting rapid gas permeation. We have developed geocomposites (GCs), comprising a micro-porous sheet which is waterproof but have gas permeability, coated with nonwovens to protect it, and investigated the characteristics of GCs as a landfill cap cover. In this study, the protective characteristics of nonwovens in GCs were evaluated by examining the resistance to water penetration (RTWP) of GCs and porous sheet after puncture deformations. Puncture tests on GCs and their constituents were also carried out when they were laid out and fixed on compacted soil. Results showed that the RTWPs of GCs remained unchanged even when displacement due to puncture deformation reached approximately 60-70% of that at the maximum puncture load. In addition, GCs exhibited a higher allowable puncture load and higher allowable displacement in puncture deformations than porous sheet when laid out on highly compacted soil. It was suggested that GC would remain waterproof even if gravel having a maximum grain size of 40 mm deformed GC on compacted soil and became half-buried it.