Protective effect of overlying geosynthetic on geomembrane liner observed from landfill field tests and inclined board laboratory experiments

Abstract

Geosynthetic liner systems are generally installed in landfill sites to prevent toxic leachate from escaping into the adjoining environment by utilizing their impervious characteristics. Therefore, it is important to protect the geomembrane from being damaged or destroyed during all phases of landfilling, namely landfill construction, waste tipping and landfill closure. This paper presents firstly the observed performance of a geomembrane liner from a landfill site where the geomembrane liner was installed on the slopes of a Korean landfill; and secondly the results of an inclined board laboratory test. Two types of experiments were conducted to identify the protecting effect of the overlaying geosynthetic on the geomembrane liners. At a testing landfill site, the slope consisted of three different sub-inclines and two 2-m-wide intermediate levels. The sub-inclines were each 8 m in vertical height and their angle of inclination was 1: 1.5 (vertical: horizontal). The reported observations were made for a time period of approximately 1 year, until the landfill was filled with wastes to the top of the uppermost slope. In addition, inclined board laboratory tests were carried out. During the inclined board test, a base table is inclined slowly and steadily until the block located on the base table starts to slide, when the tension and displacements of two geosynthetics, namely the geomembrane liner and protecting geotextile, are measured. In conclusion, test results showed that the down-drag force generated by waste accumulation and sliding of upper material was to a large extent dissipated through the elongation of the protecting geosynthetic overlying the geomembrane and thus was not transferred to the geomembrane. Unless the protecting geosynthetic undergoes structural failure, this stress relaxation phenomenon continues to occur so that the magnitude of tensile force to be applied on the geomembrane remains marginal.

Tensile Failure Mechanism of Antiseepage System for Slope with Solid Waste Underground Landfill

“…Excessive tensile force will tear the membrane and invalidate the antiseepage system consequently [9,17,18]. In the existing researches, the interface characteristics of geosynthetics in landfill antiseepage systems [19][20][21] have been tested frequently, but the interface friction characteristics were seldom analyzed. Due to the lack of reasonable and effective theoretical support for the mechanism of interaction between the landfill body, the antiseepage membrane, and the cushion, the design and construction usually rely on experiences.…”

A novel risk assessment method for landfill slope failure: Case study application for Bhalswa Dumpsite, India

“…Unit weight, cohesion and friction angle are the three key MSW material properties for this analysis, all of which contain a large degree of uncertainty (Blight, 2007;Choudhury and Savoikar, 2010;Chung et al, 2006;El-Ramly et al, 2002;Gharabaghi et al, 2008;Park and Lee, 2005). However, the probabilistic approach for slope stability analysis assumes a Gaussian distribution for FoS where the probability of failure is calculated as a probability that the FoS could be less than one (El-Ramly et al, 2002;Kremen and Tsompanakis, 2010;Savoikar and Choudhury, 2009).…”