Viscoplastic modelling of rate-dependent pile penetration in crushable sand

This work examines how crushable sand responds to the different quasi-static constant rates of pile penetration. A breakage mechanics-based viscoplastic constitutive model simulates plane strain pile driving in sand, focusing on how the penetration rate affects particle crushing at the pile tip. Finite element modelling (FEM) is used to simulate the pile granular media interaction in 2D. The model, which links the macro and micro aspects of granular media, predicts the behaviour of particle crushing and material strength at different rates of pile penetration. Input parameters are calibrated based on experimental sand samples. The results show that piles driven at higher rates have greater strength and less particle breakage. In contrast, piles with slower penetration rates show more breakage and reduced strength, with stress and breakage accumulating most at the pile tip corners. Also, the impact of the penetration rate on shear resistance force is more evident along the pile length, but it is reduced at the ends because of crushing-induced particle rearrangement and resultant loss of contacts. This study provides important insights into the behaviour of granular media in geotechnical applications like pile driving, highlighting how different penetration rates can influence crushable granular media response.