Finite-Element Study for Seismic Structural and Global Stability of Cantilever-Type Retaining Walls

This paper investigates the structural and global stability of a cantilever-type retaining wall under seismic loading using numerical modelling. A new and robust approach is proposed to compute the seismic earth pressure behind the stem and along a virtual plane passing the heel of the wall. The results show that under different earthquake characteristics and wall geometries, the seismic earth pressure forces may be out of phase, leading to different seismic responses of the wall. The critical scenario for the structural stability is observed when the maximum acceleration is directed toward the backfill soil, and the earthquake frequency content is close to the natural frequency of the wall. In contrast, the critical scenario for the global stability occurs when the maximum acceleration is directed with minimum frequency content. Further, the natural frequency of the wall does not affect the global stability of the wall. However, the duration of the applied earthquake acceleration does affect the global stability of the wall, whereas the structural stability remains unaffected by it. In contrast with the current understanding, the possibility of failure of a cantilever-type retaining wall by horizontal sliding is remarkably increased with time of the applied earthquake acceleration.