engleski

Preliminary test results of gas permeability measurements for soils and GCLs

Permeability is a measure of the ability of a porous media to transmit fluids. Fluids that flow through porous media can be both in liquid and gaseous form. The movement of fluids occurs due to two major transport mechanisms i.e. advection and diffusion. Hydraulic conductivity of soils is commonly obtained by numerous testing methods that are currently available for laboratory and field measurements, where fluid transport is described by advective flow. However, the aforementioned test methods are not completely appropriate for the gas permeability measurements of soils. There is a growing interest for gas permeability determination mostly for environmental applications but also for geotechnical engineering in general. Besides, gas permeability of geosynthetic clay liners (GCLs) that have been used as hydraulic or gas barriers in many geotechnical and hydrotechnical applications, landfills and liquid waste lagoons for quite a while, is of major importance. Special consideration is given to the large quantities of biogas produced in landfills, which is most prominent in the early stage of a landfill lifetime. GCLs were already recognized as a highly effective hydraulic barrier a long time ago. Lately, there has also been a growing interest in assessing the efficiency of the GCLs as a gas barrier. In this article, the results of previous studies of soil and GCLs gas permeability are summarized at the beginning. It is followed by the description of a modified triaxial cell and gas permeability determination. Also, through the analyses of preliminary test results, the main parameters that affect gas permeability of soils and GCLs are identified.

gas permeability ; soil ; GCL ; triaxial cell ; water content

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