Experimental study of dynamic shear stiffness decay characteristics of interbedded soil: a case study in Yangtze River floodplain

To explore the characteristics of the dynamic shear modulus of river-phase (as opposed to estuarine) floodplain interbedded soil, undisturbed interbedded soil from the floodplain of the Yangtze River in Nanjing was subjected to strain-controlled cyclic triaxial tests to investigate how the initial effective confining pressure ( σʹ m ), consolidation ratio ( k c ), and degree of consolidation ( U ) influence the maximum dynamic shear modulus G max and the dynamic shear modulus ratio G / G max . The results show that for this soil, G decreases with increasing strain amplitude, and for a given strain amplitude, G increases with increasing σʹ m , k c , and U . Compared with soil from the Yangtze estuary, k c has a greater effect on G max of the floodplain interbedded soil. Finally, a modified Martin-Davidenkov model is proposed for predicting G / G max of river-phase floodplain interbedded soil under different σʹ m , k c , and U.