The dynamic response of Tunnel–Soil–Pile (TSP) systems under seismic loading plays a pivotal role in determining the structural integrity of underground constructions. This study focuses on the seismic interaction among tunnels, surrounding soil, and nearby pile foundations by employing advanced numerical modeling through RS2 software. The subsurface conditions were modeled using a till soil formation composed of mixed clay, sand, and gravel, characterized with the Mohr–Coulomb failure criterion to represent stiffness degradation under low-strain seismic excitation. The ground was treated as an infinite, homogeneous, and isotropic elastic medium, with a uniformly distributed load of 70 kN/m applied at the pile head to simulate earthquake-induced structural forces. Seismic input was provided through the scaled acceleration time history of the 1985 Mexico City earthquake, applied at the model base, with free-field boundaries introduced along vertical edges to mimic lateral wave propagation. Rayleigh damping was incorporated into the dynamic simulation to represent energy dissipation effects. Results show a notable influence of damping ratios on system response: At the tunnel invert, horizontal displacement peaks at nearly 60 mm under 0.2% damping, reducing to 51.9 mm at 5%, and further dropping to around 50 mm at 10%. Similarly, vertical displacements recorded at a depth of 8 m beneath the tunnel show a decrease from 58.2 mm at 0.2% to less than 55 mm at 10%. These findings confirm that increasing damping mitigates displacement and stress transmission, thereby improving seismic resilience. The study underlines the importance of considering damping mechanisms in the design of tunnel and pile systems to enhance safety during seismic events.