Seismic analysis of landfill considering the effect of GM-GCL interface within liner

Geomembrane (GM) and geosynthetic clay liner (GCL) are extensively used in liner system which are placed beneath the landfill to isolate waste material from the surrounding environment but the geosynthetics can also be the weak interface, so analysis of seismic response and permanent deformation of landfill should be performed considering the influence of liner interface reasonably. In this study, a displacement-softening nonlinear elastoplastic constitutive model is established to describe the dynamic friction behavior of GM-GCL interface under various normal stress conditions and is validated against experimental results of cyclic shear tests and shaking table tests. Two-dimensional time-domain dynamic finite element analyses of typical above ground landfill incorporating the newly proposed dynamic interface friction model are conducted to provide an insight into the dynamic response and slip displacement along the GM-GCL interface. Neglecting the nonlinear elastoplasticity and displacement-softening property of the geosynthetic interface generally induces significant errors. The liner layer should be designed with full attention to restrict the seismic response and permanent deformation caused by earthquake. Extreme caution is required when using simplified dynamic analysis methods for seismic design or assessment of landfill.