2134/21991
Francisa Tano
Francisa
Tano
Daniel Dias
Daniel
Dias
Gary Fowmes
Gary
Fowmes
Franck Olivier
Franck
Olivier
Guillaume Stoltz
Guillaume
Stoltz
Nathalie Touze-Foltz
Nathalie
Touze-Foltz
Numerical modelling of the nonlinear mechanical behavior of multilayer geosynthetic system for piggyback landfill expansions
Loughborough University
2016
Geosynthetics
Numerical modelling
Interface strain softening
Nonlinear stiffness
Built Environment and Design not elsewhere classified
2016-07-18 09:40:00
Journal contribution
https://repository.lboro.ac.uk/articles/journal_contribution/Numerical_modelling_of_the_nonlinear_mechanical_behavior_of_multilayer_geosynthetic_system_for_piggyback_landfill_expansions/9448220
Numerical modelling techniques have been increasingly used to assess the integrity of engineering works, such as landfills, that involve interactions between multiple geosynthetics GSYs). In piggyback landfill expansions (PBLEs), where a new landfill is built over an older one, such interactions are particularly important because multiple GSYs, natural materials, and waste interact with each over. To obtain reliable numerical results, the real mechanical behavior of the GSYs and of the interfaces between GSYs must be considered. Designers, however, often use simplistic assumptions without further analyzing the implications of these assumptions on the results. Such simplifications mainly concern the nonlinear axial stiffness of GSYs, the strain softening at interfaces between GSYs, and the difference between the compressive and tensile behavior of GSYs. By, considering these key aspects, the present study aims to understand the extent to which the results of numerical calculations can be influenced both by the differing compressive and tensile behavior of GSYs and by the assumption of strain softening at interfaces between GSYs. For this purpose, several numerical models are implemented by using the finite-difference code FLAC 2D on a typical PBLE that involves four GSYs and six interfaces. The present work also applies comprehensive, state-of-the-art numerical modelling to study the interactions between multiple layers of GSYs. This study also investigates the nonlinear axial stiffness of GSYs through a series of uniaxial tensile tests. The numerical results show that, if the GSY axial compressive and tensile characteristics are the same, then tensile force is minimized, which induces significant compressive force in the GSYs. The results also indicate that neglecting strain softening at the interface between GSYs affects interface shear stresses, displacements of GSYs at the interface, and the GSY force distribution, potentially rendering the model unrealistic. Including strain softening, however, allows the assessment (location) of unstable areas along the interface where large displacements occur.