An approximate approach for quantifying the effects of deep well excavation on nearby masonry buildings

Excavation activities, ranging from the construction of on site sanitation systems in developing countries to deep foundations and tunnels in urban cities, can induce ground displacements that adversely affect nearby structures. This study presents a semi analytical approach for evaluating the effects of excavation induced ground movements on adjacent masonry buildings, with a particular focus on deep well excavation. The ground displacement resulting from excavation is assumed to be resisted by the strip foundation of the masonry wall, which is modeled as a beam resting on an elastic foundation. Two foundation models, Winkler and Pasternak, are employed to capture the soil structure interaction. The governing differential equation is solved using the Galerkin method, with polynomial shape functions used to approximate the displacement profile. After verifying the proposed solution against a published study and finite element results, a detailed parametric study was carried out to examine the influence of key parameters, including soil stiffness, foundation stiffness, and excavation depth and location, on the structural response. The results show that excavation depth and location are the most critical factors influencing both the magnitude and the mode (sagging or hogging) of differential settlement (∆) and, consequently, the ∆/L ratio. When the excavation is located far from the foundation, its effect is minimal; however, as it moves closer, the risk of structural damage increases significantly, particularly along the foundation’s longitudinal axis, where hogging deformation may lead to siginificant cracking in the masonry wall. The proposed method provides valuable insights into potential crack patterns and damage mechanisms and can be extended to cases where the equivalent beam stiffness accounts for the combined stiffness of the foundation, walls, and slabs, without requiring further refinement.