Comparison between monotype and hybrid earth retaining structures

This paper studies the benefit of hybrid systems of earth retaining structures compared to using monotype systems in widening the roadsides to solve traffic congestion problems. Various innovative 2D finite element models including both monotype systems and hybrid systems were used to investigate the behavior of each system separately. The limit equilibrium approach for each system is considered the basic methodology in selecting the parameters used in the finite element analysis. The results are presented in terms of wall deformations, tensile forces in the reinforcements in case of using the soil-nailing wall or the mechanically stabilized earth retaining wall (MSE wall), anchor forces in case of using the anchored sheet pile wall, and the global factor of safety. Through the results of the analysis for each model, a comparison between monotype systems and hybrid systems of earth retaining structures has been done. It has been observed that using the hybrid cantilever/anchored sheet pile wall or using the hybrid MSE/anchored sheet pile wall has a significant effect in reducing the wall deformations and increasing the global factor of safety compared to using the full height monotype systems. In contrast, using the hybrid cantilever/soil-nailing wall or using the hybrid MSE/soil-nailing wall has no effect in reducing the wall deformations or in increasing the global factor of safety compared to using the full height monotype systems.