Mechanical Behaviour of Compacted Dutch Clays

Abstract

The Netherlands faces an urgent need to reinforce its flood defences against rising sea levels. This study investigates the potential of using locally sourced Dutch clays as a sustainable alternative to imported materials for dike reinforcement. A comprehensive experimental campaign was conducted on three types of laboratory-compacted Dutch clays, with clay content varying from 42% to 23% and differing levels of erodibility. Soil characterisation, microstructural analysis (ESEM), and mechanical testing through oedometer and triaxial tests assessed the impact of composition on engineering properties. Results showed that compression behaviour is primarily influenced by the clay content, while shear response, exhibiting both contractive and dilative tendencies, remained consistent across the different compositions. Triaxial tests revealed that samples acted as representative volume elements (RVEs) only up to a certain strain level, beyond which localised deformations occurred due to end-restraint. Additionally, mixing local soils with erosion-resistant materials proved effective in improving the erodibility of unsuitable soils, thereby reducing the quantity of imported material needed. Finally, a new advanced model, JMC-clay bounding surface, was calibrated and validated across the range of soil compositions. The model accurately captured pre-failure and failure behaviour, demonstrating its applicability for predicting geotechnical structure performance and stability.