Frictional characteristics of geosynthetic–geosynthetic and geosynthetic–soil interfaces determined by the inclined plane apparatus

The problem of managing the unneeded and unusable materials is a serious challenge for modern societies. The progress of civilization is accompanied by an increase of the human population. This results in a constant increase of waste production. An average EU citizen generates over 500 kg of municipal waste per year, of which less than one third is recycled. The rest is either disposed of in the landfills or incinerated. Every landfill needs to be properly protected by an impermeable barrier - a liner. Its use is necessary to prevent soil and ground water contamination. The protection barrier needs to be implemented both at the bottom and at the top of a landfill. Various geosynthetic materials are utilized for a liner design. Waste disposed of in a landfill creates high embankments with steep slopes. In these conditions, the problem of liner stability arises. The tests, the results of which are presented in this paper, were conducted to analyze the behaviour of several different combinations of geosynthetic materials used for liner design and to calculate the friction angle of the interface between them. A set of combinations, crucial for the stability of a landfill capping system was tested: geomembrane-geospacer, geospacer-geotextile and geotextile-soil. All of the tests were conducted at the LTHE Laboratory at Joseph Fourier University in Grenoble, France