Prediction of triaxial drained creep behaviors of interactive marine-terrestrial deposit soils by fractal derivative

The mechanical properties of interactive marine-terrestrial (IMT) deposit soils differ from those of other deposits as a result of the complex sedimentary environments in which they are found. The creep behaviors of IMT deposits in Ningbo, China were studied via triaxial drained creep testing. The theory of fractal derivatives was then applied to develop a fractal merchant model, in which a fractal dashpot replaces the conventional Newtonian dashpot, to characterize the triaxial creep behaviors of IMT deposits. The model results indicate that Ningbo deposits demonstrate typical nonlinear creep behaviors. As the creep time and stress level increase, the creep process shows characteristics of transient creep attenuation and shear contraction. To validate the proposed fractal model, its predictive results were compared with the experimental results and those of conventional and fractional merchant models. It was found that the fractal merchant model results agree closely with the experimental results and that it was more accurate and efficient than the other models even though it applies the same number of parameters and has a simpler computational approach than the fractional merchant model.