Earth Pressures of Clayey Backfilled Retaining Walls Under Seismic Loading

摘要

One of the classic approaches to find out reasonable earth pressure applied to the retaining walls for seismic condition is Mononobe-Okabe method. Although this method has a wide range of application in dynamic analysis of the retaining walls in cohesionless material, the method has some limitations for cohesive soils and for dynamic computation with different seismic parameters. In this study an investigation was carried out to evaluate lateral earth pressures for retaining wall backfilled with clayey soils under seismic condition. A numerical model of a cantilever wall was conducted with finite difference method using staged construction and installation of different layers of backfill. A 0.6 m thick cantilever wall with the height of 6 meter and width of 4 meter was used for numerical modeling. Mohr-Coulomb constitutive model was used to simulate foundation and backfill soil material. Furthermore, a bilinear elasto-plastic model was used to characterize interaction of wall and soil medium. A full dynamic analysis was conducted to determine lateral earth pressure during the earthquake. Kobe earthquake (1995) was selected for applying dynamic loading. Various clayey backfill materials were examined for this study. The results were compared to lateral earth pressures estimated by limit-equilibrium Mononobe-Okabe method. A comparison between the results of the two methods indicates that there is an inconsistency between lateral earth pressure estimated by two methods and the reasoning is discussed in detail.