Effect of Settlement rate and Geogrid reinforcement on the Deformation Behaviour of Soil barriers of Landfill Covers: Centrifuge Study

Abstract

The objective of this paper is to examine the influence of settlement rate and geogrid reinforcement on the deformation behaviour of soil barriers of landfill covers subjected to differential settlements. A series of centrifuge tests were performed on soil barriers at 40 gravities. Two different settlement rates were induced using motor-based differential settlement simulator designed for a high gravity environment. Centrifuge tests on a 1.2 m thick unreinforced soil barrier subjected to two different settlement rates without provision of any overburden pressure was found to experience identical deformation profiles and cracking pattern. A slight delay in the occurrence of crack initiation and an increase in the strain at crack initiation was noticed when the soil barrier was tested at slow settlement rate. An increase in the limiting distortion level from 0.044 to 0.069 was noticed when the unreinforced soil barrier was subjected to an overburden pressure equivalent to that of cover system. When the soil barrier was reinforced with a geogrid layer without any overburden pressure, the limiting distortion level was increased from 0.044 to 0.064. An increase in the maximum mobilized tensile load of model geogrid from 77 kN/m to 120 kN/m was observed with the provision of overburden pressureequivalent to that of cover system.