With the increase of the traffic and the over-load vehicles

the failure of the subgrade retaining structure is always being reported. For a failure earth retaining wall of the Renminglu grade separation bridge in Hezhe City of Shangdong Province

the dynamic effect of the vehicles has been firstly analyzed. Based on the finite difference method of FLAC

the failure mechanism and the failure development under the dynamic vehicles load have been researched. It is concluded that the effect of vehicles dynamic load is a time-spatial process

and the displacement of the strip net induces the wall failure. The failure mechanism of the retaining structure can be shown as the tensile failure in the upper part and the shear failure in the lower and medium parts. At the same time

a comparing study on the height of the retaining wall and non-symmetric dynamic load has been done. The result indicates that in the reinforcement of the failure retaining wall both controlling the deformation and increasing the soil strength are important for a comprehensive engineering project. The conclusion of this paper will be a useful reference for the analogous failure of earth retaining structures.