Desiccation of mineral liners

Desiccation and Cracking of Mineral Liners Below Landfills with Heat Generation

A composite liner system consisting of a geomembrane on top of a clayey mineral liner constitutes an efficient barrier to contaminant transport, unless cracks form in the water unsaturated mineral liner because of its desiccation. Below landfills with heat generation, downward vapor diffusion due to temperature gradients might increase desiccation of the mineral liner and thus the risk of cracking.

At the Technical University of Berlin, a numerical model to assess the desiccation of landfill liners under the influence of temperature gradients was developed. Simulations for typical landfill conditions show that a critical desiccation of the base liner occurs if it is located on top of a coarse grained material (e.g. a drainage layer), unless the groundwater table is very high. However, even if the subsurface consists of a material with a low saturated hydraulic conductivity (1·10-7 m/s), nonisothermal desiccation might become so strong that cracking cannot be precluded. Therefore, a landfill-specific assessment of the risk of desiccation and cracking should be performed before a composite base liner system is planned for a landfill with heat generation. In this assessment, the numerical model SUMMIT can be used to calculate the temperature-dependent development of water suctions in the landfill subsurface.


SUMMIT (source code, executable code, manual) is available together with the Ph.D. dissertation of Petra Döll (Modeling of Moisture Movement Under the Influence of Temperature Gradients: Desiccation of Mineral Liners below Landfills). The dissertation includes measured model parameters, sensitivity analyses, simulations of nonisothermal lab and field experiments as well as simulation studies of typical landfill conditions. The price for the dissertation is Euro 15, and Euro 60 for the dissertation including SUMMIT.

For further information and orders, please contact Prof. Dr. Petra Döll.