An elastoplastic constitutive model considering local damage mechanism for granular materials

Particle shape and local breakage significantly affect the deformation characteristics of crushable granular materials. However, in the existing constitutive model research, there is less introduction of particle shape on particle breakage. A quantitative parameter for the three-dimensional particle shape(Average spherical modulus ■) is proposed in this study. Combined with ■, the triaxial compression test of granular materials with different particle shapes was carried out, and the particle size distribution before and after the test was determined. The results indicate that the local damage mechanism governs the macroscopic deformation behavior of granular materials, as influenced by the particle gradation of the samples before and after the triaxial compression test. Based on these findings, a binary medium model with a friction element weakening factor is proposed. This model incorporates the effects of particle shape and breakage behavior, significantly enhancing its calculation accuracy. Experimental results demonstrate that the model effectively predicts the deformation of crushable granular materials, accounting for particle shape.