Seismic lateral earth pressure distribution on a hunched-back retaining wall under pseudo-static conditions

Prior research on the determination of seismic lateral earth pressure distribution along hunchedback walls is limited. In this study, limit equilibrium principles were used to derive a novel analytical expression for computing the lateral earth pressure distribution, resultant force, and its line of action for vertical, inclined, and hunched-back retaining walls subjected to seismic loading conditions. A horizontal cohesionless soil was used with a wall movement model involving rotation about the top of the wall. The proposed method accounted for backfill soil friction angle, unit weight, wall roughness, failure plane inclination, wall inclination, and horizontal and vertical seismic ground accelerations. The horizontal slice method and pseudostatic approach were used to derive the closed-form solution. Seismic loading contributions to the total resultant force were examined. Calculations of the lateral earth pressure distribution, based on the proposed method, were illustrated with numerical examples. In addition, a parametric study was conducted to investigate the influence of different parameters on the seismic lateral earth pressure distribution and resultant lateral earth force magnitude and position. Results showed a non-linear distribution of lateral earth pressure decreasing to nearly zero at the wall base and were in agreement with the experimental results of earlier studies. Raising the hunched point to a higher elevation significantly reduced both lateral earth pressure intensity and resultant force under static and seismic loading conditions. Compared to vertical or inclined walls, the resultant lateral force in hunched-back walls was positioned higher, within the middle third of the wall height, along with a lower critical failure plane angle. In conclusion, hunched-back retaining walls were subjected to lower lateral earth pressure and a reduced lateral thrust compared to vertical walls, making them more economic, stable, and efficient alternatives to conventional walls.