Evolutionary approach for optimal stability analysis of geosynthetic-reinforced stone column-supported embankments on clay

Stone columns and geosynthetics are being used to increase the stability of embankments constructed over soft clays. The column into the soft soils acts as flexible vertical reinforcing element that increases the bearing capacity; reduces the settlement of the soil and also increases the stability of the embankments. Use of geosynthetic reinforcements is also very useful to reduce the settlement, increase the bearing capacity and improve the stability of the embankments resting on soft foundation soil. The present paper deals with the combined use of stone columns and geosynthetic reinforcements to improve the stability of embankments constructed over clays. A combined simulation-optimization based methodology has been developed for analyzing the stability of geosynthetic-reinforced embankments resting on stone column-improved ground by using an Evolutionary Genetic Algorithm NSGA-II (Non-Dominated Sorted Genetic Algorithm-II) to locate the critical surface and optimize the corresponding factor of safety under various conditions. In order to obtain critical failure surface, some constrains have been imposed on design variables. It has been shown that a genetic algorithm can be successfully employed to locate the critical failure surface in geosynthetic-reinforced stone columnsupported embankments. The variation of optimum factor of safety with area ratio, stiffness of the geosynthetics under various conditions has been studied. The proposed methodology has been validated by comparing the results of the present methodology with the results obtained by various other methods.