The dynamic interaction between granular flowing masses and obstacles is a very complex phenomenon involving large displacements and high strain rates. To numerically simulate the event in a continuum-based framework both advanced numerical tools and constitutive relationships are required. In this work, the impact of a dry granular mass against a rigid wall is numerically simulated using the open-source Material Point Method code ANURA3D, where the multi-regime constitutive model proposed by Marveggio et al., 2022, has been recently implemented. This constitutive model has been conceived to describe the behaviour of granular materials under both solid and fluid-like regimes, depending on their current void ratio and strain rate. The comparison with DEM data has shown the potentiality of the numerical tool to reproduce impact with different initial porosities and velocities, using a single set of constitutive model parameters. The numerical MPM simulations have then allowed to highlight the different mechanical processes occurring after the impact (waves propagation, solidification and fludization in the granular mass, jet and dead zone formation).