Suffosion is a hydromechanical process that describes a rearrangement and transport of fine particles in soil as a result of water flow In order to understand the effects of material loss due to suffosion on material behaviour, the influence of density on the mass of material loss, volumetric deformation and the change in permeability was investigated. For this purpose, the structure (contact and contact force distribution) of a soil susceptible to suffosion was qualitatively simulated and analysed with help of DEM The effects of different densities were investigated experimentally by means of laboratory tests under isotropic load and constant flow. A decrease in material loss, a decrease in deformation and a decrease in permeability due to suffosion with increasing material density were found. In order to be able to describe the change in mechanical behaviour, drained triaxial tests were carried out on non-eroded and eroded samples, respectively. It was shown that the drained shear strength mainly depends on the void ratio of the coarse material before shearing, regardless of whether this was created artificially or as a result of flow.