Analytical formulation of overturning moments in retaining walls under two-phase arching

Abstract

Soil arching plays a critical role in governing stress redistribution and stability of rigid retaining walls, yet its influence on overturning moment is commonly evaluated considering only the active phase of wall movement. This study presents an analytical formulation for estimating the overturning moment by explicitly accounting for both construction- and active-phase arching. The formulation uses a differential slice approach combined with a catenary representation of soil arch geometry to model vertical and principal stress distribution within backfill. Different wall movement modes, including rotation about the base, rotation about the top and horizontal translation, are incorporated in the analysis. The proposed model enables direct computation of the overturning moment while considering mobilised wall friction and initial wall inclination during construction. Predicted results show good agreement with established analytical and experimental solutions. Parametric and sensitivity analyses demonstrate that the internal friction angle of the backfill is the predominant factor influencing overturning moment across all wall movement modes. Importantly, incorporation of construction-phase arching improves the prediction of overturning moment resulting in variations of up to 38% compared to formulations considering only active-phase arching. The study emphasises the necessity of explicitly including construction-phase arching in the stability assessment of rigid retaining walls.