The Ballandaz landslide (Le Planay, France) has been studied for years. Geotechnical characterization, geophysical surveys and geomechanical modelling have been performed to characterize its behaviour, but these different approaches were not deeply analysed in a common way. This work aims to study what kind of contributions geophysical data could provide in geomechanical modelling. In particular, seismic and borehole data, obtained during previous campaigns, are used for taking into account the soil variability in a finite element modelling. Instead of constructing the slope model from geological interpretations, themselves derived from geophysical sections – as it is generally done – we use the P-wave velocity distribution obtained from seismic tomography computations to fill the mechanical mesh with different mechanical properties. Simulations are carried out with the GEFDYN code. A parametric study is also performed for determining the optimal number of materials, the optimal element size, the velocity classification algorithm, etc. Finally, our results are compared to a classical 3-layers model for discussion.