Numerical Modelling of Deep Shaft Excavations: Bridging The Gap Between 2D And 3D Analysis
DOI:
https://doi.org/10.21467/proceedings.7.7.25Abstract
It is widely recognized that two-dimensional (2D) analyses for deep shaft excavations tend to be conservative, primarily due to their inability to fully account for corner effects and the arching behavior around shaft walls. Overdesign resulting from 2D analysis can lead to oversized excavation and lateral support (ELS) systems, increasing construction costs and causing greater disturbance to the surrounding environment. This paper presents a comprehensive study on the application of both 2D and 3D numerical modelling in the design and analysis of shaft excavations. The study focuses on how the dimensions, such as breath, length, and depth, influence the comparative outcomes of 2D and 3D analyses. Key outputs, including bending moments, shear forces, wall deformations, and adjacent ground settlements, are analyzed and compared. The paper also evaluates computational efficiency, cost implications, and the trade-offs between model complexity and accuracy. Practical recommendations are provided for selecting appropriate modelling approaches in design practice. The findings support the integrated use of 2D and 3D models to enhance design reliability and efficiency for complex urban excavations.
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