This paper presents a numerical model based on Discrete Element Method (DEM) used to reproduce a series of tests of dry granular flow. The flow was composed of poly-dispersed coarse-grained angular particles flowing in an inclined flume and interacting with a divided rigid wall. The normal impact force against the wall has been studied in details considering the force on each part of the wall. The model has been calibrated based on the flow thick-ness measurements. By quantitative comparison with experimental data, the model showed good agreement in terms of peak force on each part of the wall, the time of the peak and also the residual force values at the end of the tests.