Abstract: A rigid retaining wall with a vertical back face backfilled with a cohesionless soil is analyzed. By assuming that the soil arch behind the retaining wall has a form of circle, the active earth pressure formulation of horizontally layered soil is modified with considering the shear stress between the soil layers; and a set of theoretical formulae are proposed for calculating the active earth pressure, the total earth pressure and its action point for the retaining wall under translation mode. In order to check their accuracy, the predictions by the proposed formulae are compared with the results of full-scale test and existing theories. The calculated results show that the mean shear stress between level soil layers is related to the wall-soil friction angle and the internal friction angle, and it is distributed nonlinearly along the wall height. The coefficient of lateral active earth pressure and the resultant of active earth pressure are both independent of the shear stress between level soil layers; while the position of action point of the resultant earth pressure by the proposed formulae considering the shear stress is higher than that of Coulomb’s solution, and lower than that of existing theories in which the shear stress is neglected.

Key words: soil mechanics, retaining wall, soil-arching effect, shear stress, active earth pressure, differential level layer method