The development of innovative flexible protection barriers against shallow landslides with 1:1 scale prototype field testing raised the need for a numerical model that accounts for the complex interaction during the filling process. It was possible to represent the barrier with high quality using specially developed discrete elements. All parameters of the barrier model were bound to small scale test results or material properties and the model was validated by high-energy rock fall testing. To gain the same quality on the modeling of the landslide impact there is a demand for a model allowing for phenomena like shear thinning rheology, free face flow, turbulence in complex geometry and fluid-structure interaction with dynamic mesh movements. The focus of this article is on the realization of the impact model, leading to a simulation with bounded parameters more or less universally usable.