A Unified Arching-Based Framework for Predicting Active Earth Pressures on Retaining Walls under Different Wall Movements

Abstract

Arching is the fundamental mechanism governing the development of earth pressures on retaining walls. This phenomenon, driven by soil rearrangement, initiates during construction and therefore comprises two components: construction-phase arching and active-phase arching. Although several studies have addressed arching under active conditions, the contribution of the construction phase remains underexplored. This study develops an analytical framework that incorporates the combined effects of construction-phase and active-phase arching into the prediction of normal stress distribution, total active thrust, and resultant point of application on retaining walls. Three principal modes of wall movement, namely, rotation about the base and translation (producing concave soil arches) and rotation about the top (inducing convex arches) are examined. Both planar and parabolic failure surfaces are employed to derive the loci of soil arches corresponding to each movement mode. Design charts are formulated to determine the arch coefficient and curvature factor for varying degrees of wall–soil friction mobilization and different backfill friction angles. Furthermore, a comprehensive formulation for evaluating the stress ratio is proposed using a differential slice approach that accounts for the bin coefficient and explicitly incorporates construction-phase arching. Results demonstrated that construction-phase arching substantially influences the stress distribution and increases the magnitude of active thrust by a considerable margin, whereas the height of thrust application remains relatively unaffected. Additionally, comparison with existing theories and available experimental data demonstrated satisfactory agreement. These findings highlight the necessity of accounting for construction-phase arching in design practice for retaining structures to avoid underestimation of earth pressures.