seismic analysis of lateral earth pressure and retaining walls

eart pressure problems are encountered in retaining walls, bulkheads, sheeting and bracing in cuts,culverts, tunnels, and cofferdams. in many cases, the lateral pressure is determined by use of classical earth pressure theories, such as coulomb's, where the equilibrium conditions of a failure wedge of soil is considered. excessive dynamic lateral earth pressure on retaining structures resulting from earthquake has caused several major damages in the past. the increase of lateral earth pressure during earthquakes induces sliding and/or tilting to the retaining structures. the majority of case histories of failures reported in the literature until now concern waterfront strustures such as quay walls and bridge abutments. in this parer the major aspects of this problem, such as, variation of earth pressure due earthquake motion, point of application of the dynamic increment, and displacements of the wall, have been highlighted. based on the several theoritical and laboratory studies it was found that the lateral earth pressure on retaining structures is increased during an earthquake, and the amount of this increment depends on the magnitude of the ground acceleration. furthermore, it was found that the pressure distribution behind a retaining wall is not linear, as it is coridered in static case. the point of application of the total dynamic pressure is higher than one third of the heiqht of the wall from its bottom, as it is considered in static case.