Distribution of seismic earth pressures on gravity walls by wave-based stress limit analysis

A closed-form stress plasticity solution is presented for earthquake-induced earth pressures and distribution of these pressures on inflexible retaining walls. The solution is essentially an approximate yield line approach that over-and under-estimates active and passive pressures, respectively. Results are presented in the form of dimensionless graphs and charts that elucidate the salient features of the problem. Compared to Mononobe-Okabe equations, the proposed solution is simpler, more accurate and safe. In addition, it provides a rational means for determining the distribution of limit thrusts on the wall. It is shown that the pseudo-dynamic seismic problem does not differ fundamentally from the gravitational one, as the former can be derived from the latter by means of a revolution of the reference axes. In the second part of the paper, the solution is extended to determine the distribution of limit pressures on a gravity wall by means of simple wave equations. The proposed approach has advantages over earlier efforts by Steedman and Zeng, as it satisfies the stress boundary conditions of the problem.