A damage and elastic-viscoplastic constitutive model of frozen soil under uniaxial impact loading and its numerical implementation

Abstract

We analyzed the uniaxial impact compression due to different strain rates on frozen soil specimens at different temperatures using split-Hopkinson pressure bar (SHPB) and obtained the dynamic stress–strain curves under the corresponding conditions. The experimental results showed that the dynamic mechanical behavior of frozen soil under impact loading shows an obvious strain-rate effect and temperature effect, as well as obvious elastic-viscoplastic deformation characteristics. Furthermore, the dynamic stress–strain curves of frozen soil showed instability with the evolution of internal micro-cracks, micro-voids, and shear bands in frozen soil. The dynamic mechanical behavior of frozen soil was described by introducing an advanced rate-dependent continuous damage evolution model and an elastic-viscoplastic constitutive model based on the Chaboche unified viscoplastic constitutive theory and using the Drucker–Prager yield criterion. To obtain a numerical solution of the elastic-viscoplastic constitutive equation, the constitutive equation was discretized into an incremental form by Euler's method, and the closest point projection algorithm was used as the numerical integral to update the stress state during the deformation process of frozen soil. The constitutive model was numerically solved, and the theoretically calculated curves agreed well with the experimentally measured curves. Thus, we verified the rationality and applicability of the uniaxial dynamic constitutive model constructed for this study and developed its numerical integral algorithm.