Abstract: The classic MononobeOkabe theory is widely used in the calculation of the seismic earth pressures, but its assumption of the earth pressure distribution and the action point of resultant force are inconsistent with the observed. This paper considers a wedged block with the top surface parallel to the backfill surface from the sliding wedge behind the wall. The analytical solution of the lateral earth pressure can be obtained from the moment equilibrium equations on the wedged block. The nonlinear lateral earth pressures distribution and the location of the point of action can be determined from the MononobeOkabe theory. In this formula, the lateral earth pressure magnitude changes with the rotation of the retaining wall. The formula was then verified with the model testing results and the results are consistent. The modified MononobeOkabe theory can reasonably predict the lateral under the static as well as seismic conditions.

Key words: Retaining Wall, Seismic Earth Pressure, PseudoStatic Method, Mononobe-Okabe Theory, Nonlinear Distribution, Action Point of Concentric Force