Effect of integrating memory on the performance of the fractional plasticity model for geomaterials

A fractional plasticity model for geomaterials is proposed by using the fractional derivative.Due to the integral definition of the fractional derivative,the range of load memory for calculating the flow direction may influence the subsequent model performance.Therefore,an investigation on the memory dependence of the model was conducted.It was found that the load memory affected the stress-dilatancy behavior of the geomaterial.Due to the loss of memory from zero-to confiningstress states,slightly higher strain is reported,whereas an insignificant difference in the predicted deviator stress is observed.Thus,for engineering applications,starting the memory from the zero-stress state,which avoids mathematical complexity,is suggested.