Finite element analysis of geosynthetic reinforced soil retaining walls subjected to seismic loading

A review of the available data from the literature relating to the behavior and analysis of reinforced retaining walls under static and seismic loading is presented in this dissertation. A comprehensive methodology to analyze and design these systems under static conditions has been recently introduced by the National Concrete Masonry Association (NCMA) in North America. However, the stability of these systems subjected to seismic loading has not been adequately addressed.; A finite element method is employed to analyze the geosynthetic reinforced soil retaining wall when subjected to seismic loading. Seismic response analysis of a typical geogrid reinforced retaining wall constructed with and without facing units are carried out. The walls are designed using Pseudo-Static method of analysis incorporating a factor of safety recommended by the NCMA.; The finite element method uses the Drucker-Prager model to characterize the constitutive behavior of sand. Nonlinear elastic behavior is assumed for the reinforcement material. The interface shear between geogrid and the soil is simulated using the contact pair option in ABAQUS code.; Presented in this dissertation are the responses of the wall subjected to a typical seismic spectrum. A geogrid reinforced retaining wall with and without facing units are analyzed in this study. Of particular interest in this study are: (1) the acceleration response along the height of the wall, (2) the wall displacement, (3) the tensile stress developed in the reinforcement, and (4) the relative displacement between the soil and the reinforcement. In addition to investigating the responses, the probable failure models are also sought in this study. Specifically, three possible failure mechanisms are investigated subjecting the wall to earthquake acceleration in conjunction with surcharge loading.; Having designed using a factor of safety of two, the walls withstood a base excitation of peak acceleration of 0.25g without the failure criteria corresponding to the three responses, namely, the lateral displacement, the tensile stress in the reinforcement, and the slippage at the soil-reinforcement interface, not exceeding the criterion (tentative) for failure. While imposing a surcharge load, however, those three responses tend to be cumulative over the duration of the simulated seismic event, indicating imminent failure. Slippage at the interface seems to be the probable failure mode of the wall without facing whereas the wall with facing would fail by breakage of the reinforcement. In addition, facing units inhibit the lateral deformation of the wall.