ABSTRACT
To predict the performance of engineered structures such as composite liner systems in landfills, constitutive modelling of soil–geosynthetic interfaces is required. This paper presents a numerical model that was developed to simulate the shear stress versus shear displacement responses of single and multi-layer soil-geosynthetic interfaces. A series of large direct shear tests were initially carried out to investigate the behaviour of the interface of a typical composite liner system made up of compacted clay and three geosynthetics: Geotextile (GTX), Geomembrane (GMB), and Geosynthetic Clay Liner (GCL). The numerical model developed in MATLAB R2022a was then utilised to simulate the behaviour of the soil-geosynthetic interfaces using the experimental data. The shear stress–displacement response of the soil-geosynthetic interfaces was modelled by dividing it into two parts: pre-peak and post-peak behaviour. The modelling parameters were then determined based on the results of the large direct shear tests performed on these interfaces. Subsequently, the shear stress–displacement response of the interfaces was evaluated and compared with the experimental results. For both single and multi-layer soil-geosynthetic interfaces, the predicted shear stress–displacement response was shown to be in good agreement with the experimental results.
