EFFECT OF THICKNESS OF HYDRAULIC BARRIER ON THE INTEGRITY OF A COVER SYSTEM SUBJECTED TO DIFFERENTIAL SETTLEMENTS

摘要

The objective of this paper is to study the performance of a compacted soil barrier of the cover system of municipal solid waste landfills. The risk of initiation and propagation of cracks of the soil barrier subjected to differential settlements due to underlying waste particularly was examined. Centrifuge tests were performed on model soil barrier subjected to continuous differential settlement at 40 gravities. The model soil barrier material has been selected in such a way that it envelopes the material characteristics of the soil barriers available in various parts of the world. Model soil barriers were moist-compacted towards the wet side of its optimum moisture content. The thickness of soil barrier varied is 0.6, 0.8 and 1.2 m. With the help of extensive instrumentation and the digital image analysis, the deformation profile, strain distribution and the water breakthrough of the soil barrier were analyzed throughout the deformation process to assess their performance. Soil barrier of 0.6 m thick registered a catastrophic nature of water breakthrough when the distortion level approaches 0.075 whereas 1.2 m thick soil barrier had a progressive failure once the distortion level approach 0.112 and 0.8 m thick soil barrier tends to fail when distortion level approach 0.093. All the three model soil barriers were observed to lose their integrity when subjected to maximum level distortion of 0.125.