Abstract: An active seismic pressures acting on a retaining wall is derived with differential thin layer method. The retaining wall has vertical face and horizontal level, the backfill material is cohesive and the interface between the back of the wall and the backfill material follows cφ  soil relations. The vertical and horizontal seismic accelerations are acting on the failure plane. It is concluded that the conventional seismic and static active earth pressure formulas are this generic formula under special conditions. The force equilibrium method applying at the toe of the retaining wall (Rankine Earth Pressure), has the same total earth pressures as the value derived from the differential thin layer method. However, the point of acting obtained from the differential thin layer method is higher than the conventional method.

Key words: Differential Layer, Active Earth Pressure, Implicit Treatment under Seismic Conditions