Improved Estimation of the Seismically Induced Active Earth Thrust on a Cantilever Retaining Wall at the Preliminary Design Stage

Abstract

Numerical investigation of free-standing cantilever walls subjected to horizontal seismic loads was carried out using nonlinear elastoplastic finite-element approach. The numerical model was validated using centrifuge tests and a numerical study. This study emphasizes the acceleration response, deformation mechanism, and active earth thrust (Pae) of seismically induced cantilever retaining walls. A detailed parametric study was conducted to analyze the effect of the entire earthquake motion, wall dimensions, and soil characteristics on the active earth thrust behind the wall stem (Pae_stem) and along the virtual plane passing through the wall heel (Pae_vp). The study found that the Pae_stem and Pae_vp decrease with an increase in peak ground acceleration (PGA) up to approximately 0.55 g because they are impacted significantly by the translational and rotational displacement of the cantilever wall. In addition, the magnitude of Pae_stem is smaller than that of Pae_vp. Based on the parametric investigation and regression analysis, an equation for Pae_stem and Pae_vp is proposed and was verified by comparing it with the results of the finite-element study and existing numerical work. The proposed equation provides improved prediction of the active earth thrust of a cantilever wall at an early design stage.