Constitutive model for coarse granular materials based on breakage energy

The existing constitutive models incorporating particle breakage mainly introduce the particle breakage index to reflect the influences of the particle breakage on the mechanical properties of coarse granular materials. Because of the external display of the particle breakage index of coarse particles under external load, the measured parameters actually include the influences of the particle breakage, and the methods for the particle breakage into which by introducing the particle breakage index are not suitable. Based on the Ueng’s and Chen’s dilatancy formulae, the dilatancy equation considering the particle breakage and the relevant methods for its parameters are proposed by analyzing the energy equilibrium problems in the process of triaxial CD tests. The Rowe’s dilatancy formula and the proposed dilatancy equation considering the particle breakage are respectively introduced into the Duncan-Chang E- model and the NHRI double-yield face model by Shen Zhujiang. Through the comparison with the results of triaxial CD tests and the finite element numerical analysis of a case study, it is shown that the proposed model can satisfactorily reflect the dilatancy properties of the materials, for example, the elastoplastic model may depict the increase of the deformation and simultaneously the decrease of the strength of the materials during the particle breakage. The rationality and reliability of the proposed model are thus validated. Compared with the existing constitutive models considering the particle breakage, the proposed model has the advantages of small test workload, few parameters and clear significance of parameters, etc., and it is convenient to be popularized in projects.