Abstract: This paper presents test results of stressstrain properties of the undisturbed Zhoushan marine soft cohesive soils under cyclic dynamic loadings. Laboratory tests were focused on the dynamic stresses, strains and pore pressures in relation with the loading cycles. The results indicate that, the dynamic strength decrease with the increase of load cycles and the strength indices are correlated with the magnitude and cycles of dynamic loadings. The stressstrain relationship can be characterized with an incomplete closed hysteresis loop. Under cyclic loading conditions, the magnitude of both tensile and compressive strains are affected by the intensity of the dynamic stress. The failure mode of samples under the dynamic loading is compressive failure. The magnitude of tensile and compressive strains tend to similar with the increase of loading cycles and the development of plastic strains. The development of the dynamic strain can be characterized by the modified Monismith model.  

Key words: Marine Soft Cohesive Soils, Dynamic Strength, Dynamic Deformation, Monismith Model