Nonlinear Behavior and Dynamic Properties of Cohesive Soil Under Seismic Cyclic Loading Considering Strain History Effects

In earthquake engineering and hydraulic engineering, the dynamic mechanical behavior of cohesive soils is crucial to ensure structural stability. However, most existing dynamic constitutive models fail to adequately account for the influence of strain history, which is essential for accurately predicting soil behavior under seismic loading. This study conducted a series of cyclic single-shear tests on both in situ and disturbed Changsha cohesive soils. Hysteresis curves were obtained under varying shear strain amplitudes to investigate the degradation patterns of the dynamic shear modulus and the evolution of the damping ratio. Furthermore, multi-cycle loading tests under constant strain amplitude were carried out to clarify the correlation between damping ratio, dynamic shear modulus, and the number of loading cycles. A simplified practical dynamic model, applicable to general cohesive soils, is proposed. This model incorporates the effect of strain history and provides a valuable reference for analyzing the dynamic response of soils subjected to earthquake actions.