Sustainable and resilient reinforced soil structures: insights into interface mechanics

Geotechnical engineering is fundamental to sustainable development and the resilience of infrastructure against natural hazards. Sustainability, prioritising ecological protection and societal well-being, is intrinsically linked to resilience, the capacity of structures to withstand and rapidly recover from disruptive events. Achieving resilient geotechnical designs requires a dynamic approach integrating technical robustness with environmental, social, and economic considerations. Geosynthetics have become essential in civil engineering, significantly enhancing structural safety, durability, and serviceability while minimising ecological impact. As reinforcements, geosynthetics enhance structural resilience under cyclic, seismic, and sustained loading conditions. However, fully leveraging these benefits requires a comprehensive understanding of soil-geosynthetic interface mechanics and load transfer mechanisms. Drawing from the keynote lecture at the 12th International Conference on Geosynthetics, this article synthesises over 15 years of experimental research on soil-geosynthetic interfaces under various pullout conditions. Results highlight the critical influence of reinforcement extensibility, confinement, and loading history on interface behaviour. Long-term tests indicate that creep reduction factors derived from in-air tests may be overly conservative. New interface-specific isochronous curves offer more realistic and safer serviceability limit state assessments. Additionally, cyclic pullout tests reveal reduced post-cyclic resistance at lower confinement pressures, an aspect not currently addressed by existing design standards.