Cyclic triaxial test results on French soils

Dynamic soil properties, in particular the strain-dependent normalized shear modulus (G/Gmax) and damping ratio (D), are key inputs for seismic site-response analyses, soil–structure interaction studies, and performance-based design in earthquake engineering. Despite influential international compilations, no homogeneous, openly accessible database exists for French soils, which limits the calibration of nonlinear site-response models in regions of moderate seismicity such as metropolitan France. This paper introduces two new datasets compiled within the SIGMA2 project from cyclic triaxial (CTX) tests performed by Cerema and EDF over the past decade. A total of 63 specimens are released, representative of clays, sands, marls, silts, crushed limestone, and molasse, covering depths from 2 to 147 m and effective confining pressures from 35 to 1590 kPa. Each record includes harmonized sample descriptors, test conditions, and derived dynamic parameters, together with a documented post-processing workflow to ensure reproducibility. The datasets are intended as a living reference resource for empirical model evaluation, uncertainty quantification, and the development of data-driven predictive approaches for French geotechnical contexts.