The construction of an underground metro system in India involved a crucial aspect of the excavation of a shaft, a 20 m× 20 m box structure, for the launch of Tunnel Boring Machines (TBMs). Diaphragm walls (D-walls) were selected as one of the preferred shoring methods as they not only provide shoring support during excavation but also contribute to the permanent structure of the metro system. To comprehensively analyze the behavior of the excavation process, both PLAXIS 2D and 3D analyses were conducted. Initially, PLAXIS 2D was employed to assess the response of the excavation in the given geological conditions. However, it indicated higher than anticipated deformations for a shaft box. One critical aspect that PLAXIS 2D failed to capture was the box effect of the launching shaft. In the PLAXIS 3D simulation, the excavation of the launching shaft was modeled, allowing for a more accurate representation of the box effect. The results obtained from the PLAXIS 3D analysis demonstrate that the deformations and the settlements are comparatively less to 2D, indicating the effective simulation of the launching shaft's box. This comparative study between PLAXIS 2D and 3D provides a thorough understanding of the benefits and limitations associated with numerical modeling.