<p>Simulation data.</p>

The comparisons show that the proposed model can reasonably reproduce the main characteristics of interface shearing, including the evolution of shear stress, the increase in normal stress, and post-peak strength degradation. Parametric analyses indicate that the critical-state-line parameters and the initial void ratio primarily govern the initial dilatancy potential of the interface; the dilatancy coefficient has the most significant influence on the peak shear strength and the magnitude of normal-stress increase; and the shear-band thickness mainly controls the rate of state evolution and the post-peak response.

The proposed model provides a concise constitutive framework for describing the coupled evolution of dilatancy, normal stress, and shear strength of dense sand–structure interfaces under CNS conditions.</p></div>