<p>This study integrated in situ tests, monitoring data, and construction records from a large deep excavation project on gravelly cobble formation in Taichung to conduct a numerical analysis of the deep excavation at the site. In the simulation, the forward analysis of deep excavation was conducted using the mechanical parameters of gravelly cobble material derived from in situ tests. For the analysis, the numerical simulation parameters were established according to the actual design and construction conditions. The excavation stages were carefully considered and simulated according to the construction records to obtain reasonable analysis results. The results were comparable with the monitoring data from anchor load cells, rebar strain gauges, and an inclinometer installed within the retaining pile and anchors. This confirms the rationality of the geotechnical parameters, numerical model, and simulation method and procedures employed in this study. The insights and data obtained from this study can be used as a reference for the design of large-scale deep excavation projects on similar geological formations.</p>