Robust design optimization of retaining wall backfilled with shredded tire in the face of earthquake hazards

A systematic robust design optimization methodology is presented in this study for cantilever retaining wall backfilled with shredded tire in the face of earthquake hazards. Regarding the merits of application of shredded tire backfill in seismically active areas, the uncertainties in properties of this material (e.g., friction angle and cohesion) as well as uncertainties in earthquake load (e.g., peak ground acceleration) necessitate examining the robustness of design along cost efficiency in geotechnical design procedures. The wall tip deflection was treated as the response of concern for which a response surface was developed based on the design and random (uncertain) variables. Coupling with Monte Carlo simulations, the optimization in terms of cost and standard deviation of response as a measure of robustness yielded a set of preferred designs, or Pareto front, and the final optimal design was determined via selection procedures based on knee point concept.