Effect of artificial soil compaction in landfill capping systems on anisotropy of air‐permeability     

Steffen Beck-Broichsitter  Heiner Fleige  Horst H. Gerke  Rainer Horn 《植物养料与土壤学杂志》2020,183(2):144-154

Soil air permeability is an important parameter which governs the aeration in soils that significantly promotes the root growth of field and grassland species and leads, in turn, to higher levels of evapotranspiration. The German Landfill Directive (2009) requires a rigid or a minimal shrinking capping system that ensures a high evapotranspiration rate to decrease the infiltration rate through the underlying waste body and therefore the leachate generation. This research is focussed on the questions if compacted glacial till can ensure the required rigidity and if and how air permeability is affected by soil compaction. The objective was to compare air‐filled porosity and the direction‐dependency of air permeability of a capping soil when assuming rigid and non‐rigid conditions considering a shrinkage factor. Intact soil cores were sampled in vertical and horizontal direction in 0.05, 0.2, 0.5, and 0.8 m depths at two profiles of a mineral landfill capping system at the Rastorf landfill in Northern Germany. Desiccation experiments were carried out on differently‐compacted soils and soil shrinkage was measured with a 3D laser triangulation device, while the air permeability was estimated with an air flow meter. The results indicate that the “engineered” soil structure which was predominately platy due to a layered installation, led to a more anisotropic behaviour and therefore to higher air permeability in horizontal than in vertical direction. The compacted installation of the capping system seems to be effective and observes the statutory required more‐or‐less rigid system, otherwise, soil shrinkage would lead to vertical cracks and a more pronounced isotropic behaviour.  相似文献   

Soil type and land use effects on tensorial properties of saturated hydraulic conductivity in northern Germany     

Rainer Horn  Anneka Mordhorst  Heiner Fleige  Iris Zimmermann  Bernd Burbaum  Marek Filipinski  Eckhard Cordsen 《European Journal of Soil Science》2020,71(2):179-189

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The plant functional traits that explain species occurrence across fragmented grasslands differ according to patch management,isolation, and wetness     

Petra Janečková  Štěpán Janeček  Jitka Klimešová  Lars Götzenberger  Jan Horník  Jan Lepš  Francesco de Bello 《Landscape Ecology》2017,32(4):791-805

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Gedanken über den Gebrauch von entomologischer Literatur     

Walther Horn 《Journal of pest science》1932,8(2):17-21

Ohne Zusammenfassung  相似文献   

Mitteilungen der Deutschen Gesellschaft für angew. Entomologie E.V.     

Dr. Horn 《Journal of pest science》1931,7(8):96-96

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Effective stress and shear strength parameters of unsaturated soils as affected by compaction and subsequent shearing     

Xinjun Huang  Tusheng Ren  Rainer Horn 《European Journal of Soil Science》2023,74(3):e13384

Wheeling induced compression and shearing forces are main stresses accounting for soil deformation and changes of hydraulic, gaseous and thermal properties. There are reports about the combined effects of compaction and subsequent shearing on soil hydraulic properties, but their consequences on soil strength properties (i.e., effective stress and shear strength) need to be further analysed. This study investigated the dynamics of soil mechanical properties as affected by pore water pressure ($u_{\mathrm{w}}$) during compaction and shearing. Soil samples from an A-horizon of Gleysols derived from glacial sediment and a Stagnic Luvisol from loess were analysed. The repacked and structured samples were compressed under static and cyclic loading and then sheared at two speeds (0.3 and 2.0 mm min⁻¹) with three loading levels (50, 100, and 200 kPa). During each stress application, the $u_{\mathrm{w}}$, chi factor (χ) and effective stress (${\sigma }^{\prime }$) were measured and calculated. The shear strength ($\tau$), angle of internal friction ($\phi$) and cohesion ($c$), were determined and fitted by the Mohr–Coulomb failure criterion. The results showed that compaction and shearing increased $u_{\mathrm{w}}$ and χ in all homogenized soils while on structured soils this phenomenon only occurred when the applied loading stress exceeded the soil precompression stress. The increased $u_{\mathrm{w}}$ resulted in soil hydraulic and mechanical stresses, which ultimately reduced the ${\sigma }^{\prime }$, especially at −6 kPa initial matric potential. Soils with finer texture, higher loading stresses and faster shear speed normally exhibited more reduced ${\sigma }^{\prime }$ values. The structured soil had higher $\tau$ values with higher $\phi$ and $c$ compared to the homogenized soils. The changes of $u_{\mathrm{w}}$ at high loading stress (i.e., 200 kPa) may overlap the normal pattern of the Mohr–Coulomb failure line that results from the theoretical Mohr envelope. Thus, to minimize the destruction of soil structure and stability induced by wheeling, it is important to consider field water content, traffic loading and wheeling speed.  相似文献