Active earth pressure on retaining wall for c-phi soil backfill under seismic loading condition

This technical note describes the derivation of an analytical expression for the total active force on the retaining wall for c-phi soil backfill considering both the horizontal and vertical seismic coefficients. The results based on this expression are compared with those obtained from earlier analytical expressions for the active force for c-phi soil backfill under seismic conditions, and found to have a similar trend of variation. The parametric study shows that the inclination of the critical failure plane with the horizontal plane decreases with the increase in values of seismic coefficients; the decrease being more for their higher values. The total active force increases with the increase in value of horizontal seismic coefficient; while it decreases with the increase in value of vertical seismic coefficient except for a very high value of horizontal seismic coefficient. Design charts are presented for various combinations of horizontal and vertical seismic coefficients (kh and kv), and values of cohesion and angle of shearing resistance for estimating the total active force on the retaining wall for c-phi soil backfill for practical applications.