<p>Underground constructions play an important role in mega-cities, allowing the solving nowadays urban transportation challenges. The answer to rising transportation issues globally is the construction of underground public infrastructure including subways. To meet the demand for rapid development of underground construction the present study aims to investigate the effect of building-pile structures on twin tunnel behavior based on two-dimensional (2D) numerical modeling. The models were built considering different scenarios of tunnel excavation procedure and three constitutive soil models. The soil models used in this study include the linear elastic perfectly plastic Mohr-Coulomb model (MC), the hardening soil (HS), and the hardening soil with small strain (HSS). Due to the 2D modelling approach application, two typical deconfinement techniques, i.e., the Convergence Confinement Method (CCM) and the Volume Loss Method (VLM) have been used to consider the three-dimensional nature of the tunnelling process. Considering the presence of piles on the side of twin tunnels, the effect of tunnel excavation sequences has been investigated. Particular attention was paid to analyses of internal forces induced in the twin tunnel linings and ground surface settlements. For comparative purposes, the analyses of twin tunnels’ behavior and ground deformation were performed for the conditions when no pile foundation interactions were considered. The results indicated that the pile foundation, soil’s constitutive models, and the tunnel excavation sequence have significantly affected the internal forces induced in the twin tunnel linings as well as resulted in influencing ground surface settlements. The effect of deconfinement techniques in the 2D numerical simulations of twin tunnels, i.e., CCM and VLM, was also highlighted.</p>