Constitutive model of frozen-soil dynamic characteristics under impact loading

Abstract

To reveal the dynamic mechanical behavior of frozen soil under impact loading, nine groups of frozen-soil samples (the initial moisture content was 20%) under different experimental conditions are tested using the split Hopkinson pressure bar. In this study, a constitutive model for predicting the dynamic strength and compression deformation of frozen soil subjected to impact loading is developed. The model is derived from continuous fracture mechanics, and we assume that frozen soil is a continuous medium with preexisting microcracks. According to the modified Drucker–Prager criterion, a dynamic constitutive model coupled with the plastic and damage phase is established to describe the dynamic mechanical behavior of frozen soil before the peak stress. Considering the post-peak curve, the statistical significance of the uniform stress–strain relationship is not established; therefore, a cohesive crack model is used to model the frozen-soil softening process. Using a comparison, we find that the results of the experiment agree well with the calculated results; thus, the feasibility of the model is proven.