Determination of Active Earth Pressure on Rigid Retaining Wall Considering Arching Effect in Cohesive Backfill Soil

A new simplified method is proposed to compute the active earth pressure acting on the backface of a rigid retaining wall undergoing horizontal translation. The effect of soil arching for cohesive backfill soil and friction mobilized along the wall–soil interface was considered. Analytical expressions to determine the slip surface angle and the coefficient of active earth pressure were obtained using the limit-equilibrium approach. These expressions were used for the horizontal flat-element method to obtain theoretical formulas for the active earth pressure, active thrust, and its point of application. Additionally, an implicit solution was derived for the depth of the tension crack in the backfill. A parametric study was undertaken to assess the effects of cohesion, unit weight, friction angle, surcharge pressure, and wall–soil friction angle on the active earth pressure, as well as the effects of the friction angle of backfill soil and wall–soil friction angle on the slip surface angle. The results of the proposed method were then verified against the existing test data and the predictions from the Coulomb and Rankine theories. The results show that the proposed method yielded satisfactory results.