Suitability of Boulder Marl and Marsh Clay as Sealing Substrates for Landfill Capping Systems—A Practical Comparison

• Main Authors: Steffen Beck-Broichsitter, Horst H. Gerke, Rainer Horn
• Format: Article
• Language: English
• Published: MDPI AG 2018-09-01
• Series: Geosciences
• Subjects: landfill capping systems; mineral liner; shrinkage intensity and tendency
• Online Access: http://www.mdpi.com/2076-3263/8/10/356

The effects of compaction on soil shrinkage behavior need to be considered for engineering long-term durable mineral liners of landfill capping systems. For this purpose, a new three-dimensional laser scanning device was coupled with a mathematical-empirical model to simultaneously determine the shrinkage behavior of a boulder marl (bm) and a marsh clay (mc). Therefore, both materials were precompacted in 200 soil cores (100 cm3) on the basis of the Proctor test results with five different degrees of compaction (bm1-bm5; mc1-mc5). Thus, the shrinkage behavior, intensity, and tendency were determined during a standardized drying experiment. The volume shrinkage index was used to describe the pore size dependent shrinkage tendency and was classified as high to very high (11.3–17.7%) for the marsh clay and medium (5.3–9.2%) for the boulder marl. Additionally, only the boulder marl (bm2), compacted up to 88% of Proctor density, could be installed as landfill bottom liner in drier locations if the local matric potentials did not exceed the previously highest observed drying range (i.e. values below −300 hPa), to avoid crack formation and generation.