NUMERICAL ANALYSIS OF GROUND DEFLECTION AND SETTLEMENT DUE TO DIAPHRAGM WALL INSTALLATION: A CASE STUDY AT EGYPTIAN METRO STATION

This study investigates ground movements resulting from diaphragm wall (D-wall) excavation during the construction of an underground metro station in Heliopolis, Cairo. In a densely populated urban environment, horizontal soil displacement and additional pressure on support systems present major geotechnical concerns. Influencing factors include subsurface conditions, excavation depth, wall stiffness, construction sequence, nearby infrastructure, and surface loading. Field data collected over two years were analyzed and compared with numerical simulations using both Mohr-Coulomb and Hardening Soil models through two-dimensional (2D) and three-dimensional (3D) finite element methods. The study aims to assess the predictive accuracy of these models and evaluate the potential risks to surrounding structures. Findings indicate maximum horizontal wall displacements between 0.04% and 0.06% of excavation depth, with surface settlements ranging from 6% to 32% of lateral wall movement. The outcomes enhance understanding of soil-structure interaction and contribute to safer design, planning, and monitoring of deep excavations in urban metro development.