​Seismic Investigation of Cantilever Retaining Walls Based on Pressure and Motion Approaches

​In this investigation, the seismic response of retaining walls constructed with cohesive and cohesionless backfill materials was studied. Fully dynamic analysis based on the finite difference method was used to evaluate the performance of retaining walls during the earthquake. The analysis response was verified by the experimental study conducted on a retaining wall system with cohesive backfill material in the literature. The effects of cohesion and free-field peak ground acceleration (PGA) on seismic earth thrust, the point of action of earth thrust, and maximum wall moment during the earthquake were compared with analytical and experimental solutions. The motion characteristics of the retaining wall during the earthquake were also considered. The relative displacement of the walls with various backfill cohesions, under different ground motions, and free-field PGAs were investigated. Current analytical and empirical correlations developed based on Newmark sliding block method for estimating retaining wall movement during earthquakes were compared with the numerical approach. Consequently, fragility analyses were conducted to determine the probability of damage to the retaining walls during an earthquake event. To evaluate the fragility of the studied models, specific failure criterion was chosen for retaining walls based on the suggested methods in practice. It is demonstrated to what extent a small amount of cohesion in backfill material can influence displacement of a retaining wall and the probability of damage in seismic conditions. According to the findings, practical correlations were presented for conducting the seismic design of retaining walls.