Development of a modified hypoplastic model for calcareous sand considering particle crushing

In the field of ocean engineering, calcareous sand is frequently employed. However, particle breakage can significantly reduce its strength and dilatancy while increasing its compressibility, leading to potential safety and stability issues for foundations. Traditional constitutive models have limitations in accurately describing the mechanical behavior of calcareous sand. To address this issue, a modified hypoplastic model is proposed in this study, incorporating the quantified indicator of relative particle breakage rate, Br. The established stress-strain relationship is intricately linked to the Br index, effectively connecting it with the effective stress and deviatoric stress. The effect of particle crushing on the critical friction angle, CSL parameters and α parameter of the hypoplastic model were systematically analyzed. A VUMAT subroutine is developed to assess the precision and applicability of the proposed model by simulating triaxial drainage tests under three different densities. The simulation results exhibit good agreement with experimental data, demonstrating the superiority of the modified model over the conventional hypoplastic model. This modified model proves suitable for calcareous sands with varying densities, making it a valuable tool for enhancing stability and safety in ocean Engineering Geology. •Established a modified hypoplastic constitutive model for calcareous sand that considers particle breakage.•For calcareous sand, there is a hyperbolic function relationship between the relative breakage rate Br and the effective stress, and deviatoric stress.•The critical friction angle, initial void ratio, and parameter α of hypoplastic constitutive mode decreasing with increasing relative breakage rate Br.•Used the modified hypoplastic constitutive model to simulate conventional triaxial drained shear tests on three different densities of calcareous sand.