A nonlinear model for strut behaviour in braced excavations
File(s)
Published version
Author(s)
Taborda, David MG
Pedro, Antonio MG
Matos Fernandes, Manuel
Type
Journal Article
Abstract
Deep braced excavations are widely employed to support urban construction, with the axial stiffness of strut systems playing a crucial role in their structural performance. However, field observations have consistently shown that the effective axial stiffness of struts is often significantly lower than theoretical values, frequently attributed to slack arising from imperfections during assembly, gaps between structural elements, and initial curvatures. This paper presents a nonlinear model that captures the deformation-dependent stiffness behaviour arising from those initial imperfections. The model is governed by a single physically interpretable parameter, which controls the offset between effective and theoretical force–deformation curves and serves as an indicator of construction quality. A consistent unloading–reloading response and pre-stressing capability are incorporated within the same framework. The model is applied to a single-propped embedded wall to demonstrate its performance. The results confirm that the range of effective stiffness values reproduced by the model is consistent with instrumented case studies reported in the literature, and that pre-stressing improves average stiffness and reduces wall displacements. A straightforward calibration procedure based on monitored force–displacement data is proposed, enabling application within the Observational Method to improve predictions and inform installation practice.
Date Issued
2026-09-01
Date Acceptance
2026-05-08
Citation
Computers and Geotechnics, 2026, 197
ISSN
0266-352X
Publisher
Elsevier
Journal / Book Title
Computers and Geotechnics
Volume
197
Copyright Statement
© 2026 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
License URL
Identifier
10.1016/j.compgeo.2026.108235
Publication Status
Published
Article Number
108235
Date Publish Online
2026-05-15