The Netherlands, known for its extensive coastal regions and significant portions of land below sea level, faces escalating flood risks due to climate change and sea level rise. To address these threats, the country relies on the construction of dykes founded on soft soils like peat. Traditionally, peat has been regarded as the critical soil layer for infrastructure stability; however, recent studies suggest that the interface between peat and clay is crucial for assessing failure mechanisms. This research focuses on the mechanical response of peat-clay interface samples to better understand the interaction between these two materials.

The study integrates comprehensive laboratory experiments with advanced numerical modelling to investigate the peat-clay interface. The findings underscore the critical role of the clay layer in the mobilised shear strength, which is essential in dyke stability assessment. The study highlights that accurate modelling of the interface requires considering the volumetric fractions of peat and clay and the reinforcing effects of fibres. This research enhances the understanding of peat-clay interfaces in dyke systems and contributes to improving geo-infrastructure assessment.