Dynamic characteristics and damage constitutive model of cemented sand and gravel materials

Cemented sand and gravel (CSG) material is a novel dam construction material with promising applications. However, the dynamic characteristics of CSG materials remain inadequately understood. Cyclic triaxial dynamic shear tests were conducted to investigate the dynamic characteristics of CSG materials. The results indicate that confining pressure and cement content significantly influence the shape of the hysteresis curves. With increasing confining pressure and cement content, the dynamic shear modulus increases while the damping ratio decreases. A dynamic damage constitutive model was constructed by integrating damage elements into a generalized Kelvin model. The damage variable D was defined based on the energy interaction principle, and theoretical formulas for the dynamic shear modulus and damping ratio were modified accordingly. The stiffness matrix of the damage constitutive model was derived, and the model demonstrated good fitting performance for the triaxial dynamic shear tests of CSG materials. Additionally, the acceleration response and damage distribution patterns of a CSG dam under dynamic loading were analyzed using a case study.