Numerical analysis of earthquake-induced deformation of liner system of typical canyon landfill

Integrity of composite liner system is closely related to the serviceability of Municipal Solid Waste (MSW) landfill and should be taken into account in the seismic design of landfill. Moreover, extensive application of geomembrane (GM) and geosynthetic clay liner (GCL) in composite liner system generates soil-geosynthetic interaction problem. In this study, a numerical model is proposed to analyze earthquake-induced deformation of liner system with a full consideration of the dynamic landfill-liner-foundation interactions. Rate-dependent exponential model for GM and equivalent linear model for GCL are developed. Normal and tangential behaviors of geosynthetic interface within liner system are defined with physical constitutive relationship and solved with appropriate numerical technology. The present model is validated against experimental results of centrifuge test. A series of two-dimensional dynamic finite element analyses of typical canyon landfill are performed to provide an insight into the mechanism of deformation within liner system. Results indicate that tension of GM is mainly influenced by non-uniform friction between its upper and lower surfaces, while shear strain of GCL is strongly connected to outward slippage of landfill. Resistance of the composite liner system plays an important role in the distribution of force and deformation in this dynamic interaction problem, which deserves special attention in engineering practice.