Soil particle size-dependent constitutive modeling of frozen soil under impact loading: Fid-Bau Portal

Soil particle size-dependent constitutive modeling of frozen soil under impact loading

Zhang, Fulai / Zhu, Zhiwu / Li, Bin

Abstract In this study, the soil particle size dependence of the impact dynamic mechanical properties of frozen soil was investigated using a split Hopkinson pressure bar, and the meso-deformation mechanism of frozen soil was analyzed via electron microscopy. Under impact loading, the dynamic stress-strain curves of frozen soil showed strain hardening, strain softening, strain rate-temperature sensitivity, and soil particle size dependence, and the soil particle size dependence of frozen soil was considered to be significantly influenced by non-uniform meso-deformation, which primarily appeared in the form of microcracks surrounding the coarse particles. A constitutive model comprising a multiplicative hardening law was proposed, and soil particle size dependence was introduced through the equivalent strain gradient of the soil cell element. The impact compression process of frozen soil was simulated in ABAQUS/Explicit using the proposed model, and the mechanism of frozen soil deformation was summarized by the finite element analysis: the stress concentration around coarse particles induces the initiation of microcracks, the propagation of microcracks forms a crack network, eventually leading to the softening behavior of frozen soil.

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Highlights • The impact dynamic mechanical properties of frozen soil is particle size dependent. • The impact deformation mechanism of frozen soil is summarized. • A constitutive model considering the influence of the particle size effect is proposed. • The temperature and strain rate sensitivities of the intrinsic length are analyzed.