It is the supplementary data for publications and the PhD thesis of Ching-Yu Chao. The research aims to address significant gaps in the understanding of the behaviour of Dutch soft organic clays under both monotonic and cyclic loading conditions. It focuses on stress-induced plastic anisotropy, the role of organic matter, and the impact of initial stress states in Dutch soft organic clays. Further, it aims to contribute to the field by: conducting experimental tests, Refining existing models, and Developing advanced testing apparatus: Setting up an innovative cyclic shear apparatus called CYC-DoSS. This apparatus aims to provide high-frequency, multi-directional, and complex cyclic loading patterns. Equipped with state-of-the-art measurement systems like bender elements, accelerometers, and pore pressure transducers, it will yield a unique and reliable dataset for model development, calibration, and validation. This addresses existing limitations in current equipment, which cannot control or measure lateral ...