Simplified solution for calculating active thrusts on retaining walls with a broken backslope

Abstract

This paper reviewed Satyanarayana’s solution for calculating the active thrust on a retaining wall with a broken backslope. To improve Satyanarayana’s solution, a limit broken backslope height was proposed. A parametric study was conducted to investigate the influences of several key factors on the calculated active thrusts and their application point heights using the Satyanarayana solution. To simplify the calculation method, this paper proposes an equivalent infinite backslope angle based on the force equivalency between Satyanarayana’s and Coulomb’s solutions. This paper also proposes an empirical formula to estimate the equivalent infinite backslope angle and a simplified solution for calculating the active thrust. A numerical method was used to examine design examples of retaining walls with a broken backslope as compared with the Satyanarayana, Coulomb, and simplified solutions. The parametric study showed that the broken backslope height, the soil internal friction angle, the wall inclination angle, and the broken backslope angle had significant effects on active thrusts, while the wall-soil interface angle had a minor influence on the active thrust. The calculated equivalent infinite backslope angle using the proposed empirical formula well matched that calculated based on the force equilibrium. The design examples demonstrated that the simplified solution was easy and accurate for the design of retaining walls with a broken backslope.