Optimizing the Mechanical Stabilization of Earth Walls with Metal Strips: Applications of Swarm Algorithms

This research investigates the optimization of mechanically stabilized earth wall (MSEW) with metal strips. Three metaheuristic algorithms based on swarm intelligence are employed consisting of two novel algorithms including Salp swarm algorithm and grey wolf optimizer and the classic algorithm of particle swarm optimization. To this end, a code was developed to model the MSE wall according to FHWA regulations. Due to the significance of MSE wall height in the design, four different heights of wall were considered in different parts of the study. The performance of the algorithms is assessed according to the amount of cost reduction resulted from optimization compared to the costs of design by the common code of practice. Influence of variations in unit costs of major MSEW construction materials on cost function is evaluated. It is found that the unit cost of steel is more effective on the total optimum cost in contrast to the unit cost of earthworks. Moreover, sensitivity analysis of the objective function is accomplished for the main input parameters of the design problem. The results reveal that changing the angle of internal friction of the reinforced soil has quite an identical effect on the optimum costs of walls with different heights. In addition, it is shown that by increasing the height of wall, the effects of variations in reinforced soil unit weight and angle of backfill slope on the optimum cost are increased.