Static Analysis and Safety Assessment of Tilted Circular Sinking Wells

Sinking wells (open caissons) are widely used deep foundation structures whose installation by the cut-and-sink method may lead to unintended deviation from verticality due to heterogeneous soil conditions and construction irregularities. While tilting is a frequently observed phenomenon, quantitative criteria for assessing the admissibility of an inclined well after completion of sinking remain insufficiently defined. This study presents a static analytical framework for evaluating stress redistribution beneath the concrete plug of a tilted well. The analysis is based on eccentric vertical load transfer and derives closed-form relationships linking the permissible inclination angle to well geometry (radius r, height H) and the ratio of total weight to shaft weight (Gc/G). A practical admissibility criterion is proposed by limiting the increase in maximum contact stress to 20% relative to the vertical configuration (σ1 ≤ 1.2σ). Parametric calculations performed for typical well dimensions (r = 2–5 m, H = 4–9 m) indicate that admissible inclination angles vary approximately from 1.6° to 11.6°, depending on geometric proportions and load distribution. The results demonstrate that stress amplification is governed primarily by bending moment induced by eccentricity rather than by axial load increase. The proposed formulation provides a transparent engineering tool enabling rapid assessment of whether a tilted sinking well may remain in service without exceeding acceptable soil stress amplification.