Interface shear strength for multilayered liner systems - some problems in determination

摘要

The aim of this paper is to determine the interface shear strength between textured HDPE or LLDPE geomembranes, used for artificially sealing waste disposal sites, and fly ash as a mineral layer. Fly ash was compacted by the Standard and Modified Proctor methods at various water content ranging over w_(opt)±5% to reach dry densities corresponding to compaction curves. Tests were conducted in a classic direct shear apparatus, with the aid of a modified bipartite cylindrical box. The box was equipped with an additional part, which enabled interaction testing between compacted waste and polyethylene geomembranes. The fly ash-geomembrane interface strength results in reference to horizontal displacement in direct shear apparatus were presented in the paper. The results of vertical deformation versus shear displacement were shown as well. For both tested geomembranes interface contact resistance was satisfactory. Deformation of LLDPE geomembrane was stated during shearing test under normal stress of 300 kPa. In some cases an insignificant decrease in density of contact zone was established in the initial phase of the shearing.