Effect of aging on the physical properties of landfill cover layers

Year 2014, Volume: 3 Issue: 3, 212 - 219, 21.11.2014

Ruediger Anlauf Andreas Reichel

https://doi.org/10.18393/ejss.30326

Cited By: 1

Abstract

Physical properties of soil material are essential criteria for the suitability of material to be used as cover layers or water retaining (ET) layers of landfills. Important parameters, such as available water capacity and saturated hydraulic conductivity, are usually derived from easily measurable properties (such as soil texture) with the help of tables, or are measured on artificially compacted samples in the laboratory. Both methods do not consider structural changes taking place mainly in the first years after installation. Key factors for the development of the soil structure are freeze-thaw cycles, swelling and shrinkage due to moistening and drying, and the influence of root growth. The investigation was carried out with dredged material (river sediments) which was planned to be used for a landfill cover layer. Freeze-thaw cycles were simulated for a few days each in a laboratory freezer; swelling and shrinkage was simulated by alternating between water saturation and complete drying in a drying oven. The vegetation experiment was carried out in the open on a site filled with 20 cm dredged material. The effects of the environmental factors result in a modification of the pore system. All variants showed a significant increase in air capacity and a significant decrease of the available water capacity at constant total pore volume. With respect to the suitability of the material for landfill cover layers, the results imply that that the legally specified minimum values for available water capacity should be rather increased due to a possible decrease over time. However, the average decline of the available water capacity of 6%v/v with time due to aging, and the assumed penetration depths of the aging processes in the upper third of the cover layer, would result in a rather small increase of a few decimeters in layer thickness necessary to achieve the water storage targets. More important seems the increase in air capacity due to aging processes, which is of considerable importance for the growth of plants especially in the upper part of the cover layer. The risk of too high soil density associated with too low air capacity for optimum plant growth, thus, is somewhat reduced due to the increasing air capacity with aging.

Keywords

Freeze-thaw-cycle, swelling/shrinkage, available water capacity, air capacity, soil structure, dredged material, landfill

References

• Berger, K., Schroeder, P.R., 2011. The Hydrologic Evaluation of Landfill Performance (HELP) Model. Version HELP 3.90 D. (CD with program and documentation in German and English)
• Blume, H.P., Brümmer, G., Horn, R., Kandeler, E., Kögel-Knabner, I., Kretzschmar, R., Stahr, K., Wilke, B.M., 2010. Scheffer/Schachtschabel – Soil Science Textbook (Lehrbuch der Bodenkunde), 16. Edition, Heidelberg: Spektrum kademischer Verlag, Heidelberg [in German].
• Blume, H.P., Horn, R., Thiele, S., 2011. Soil Protection Handbook (Handbuch des Bodenschutzes). 4. Edition. Weinheim: WILEY-VCH Verlag GmbH & Co. KGaA [in German].
• Boden, A.G., 2005. Mapping Guidelines (Bodenkundliche Kartieranleitung) , 5. Auflage, Hannover [in German].
• Bronick, C.J., Lal, R., 2004. Soil structure and management: a review. Geoderma 124 : 3–22.
• DEPV, 2009. DepV – Ordinance on Landfills and long term deposits (Verordnung über Deponien und Langzeitlager) [in German]. http://www.gesetze-im-internet.de/bundesrecht/depv_2009/gesamt.pdf
• DIN 11274, 2011. Soil Quality – Determination of the Water Retention Characteristics – Laboratory Methods. Beuth-Verlag, Berlin/Köln.
• DIN ISO 11272:1998, 2001. Soil quality - Determination of dry bulk density. Beuth Verlag GmbH, Berlin.
• DIN ISO/TS 17892-11, 2005. Geotechnical Investigation and Testing – Laboratory Testing of Soil - Part 11: Determination of Permeability by Constant and Falling Head. Beuth-Verlag GmbH, Berlin.
• GDA, 2006. Deutsche Gesellschaft für Geotechnik E 2-31 Rekultivation layers (Rekultivierungsschichten) [in German]. http://www.gdaonline.de/download/E2-31.pdf
• Mischra, A.K., Dhawan, S., Rao, S.M., 2007. Analysis of Swelling and Shrinkage Behavior of Compacted Clays. Geotechnical and Geological Engineering 5, 289-298.
• Nagel, T., 2011. Physical evaluation of dredged material of the Bremen ports as material for landfill covers (Physikalische Bewertung von Baggergut der Bremer Häfen als Material für Deponie- Rekultivierungsschichten und andere mögliche Nutzungen), M.Sc. thesis, Osnabrueck Universiuty of Applied Sciences [in German].
• Schneider, P., 2005. Alternative Methods in mine recultivation – Concept of reactive cover layers at the example of the Schlüsselgrund landfill (Alternative Methoden in der Bergbausanierung – Konzeption von reaktiven Abdecksystemen am Beispiel der Halde Schlüsselgrund). Ph.D. Dissertation, Technical University Freiberg [in German].
• Tresselt, K., 2000. Field experiments on the effectiveness of a cover layer made of dredged material (Feldversuche zur Wirksamkeit von Oberflächenabdichtungssystemen mit Dichtungen aus Hafenschlick). Hamburger Bodenkundliche Arbeiten 46, 280 S. [in German]