<p>Although tunnels are generally considered resistant to seismic damage, past earthquakes have demonstrated that strong ground motions can cause tunnel collapse. Soil liquefaction, in particular, has contributed to the failure of various underground structures. This study explores the performance of tunnels in liquefiable soils using two-dimensional numerical analysis. The behavior of circular tunnels was examined under two different soil conditions: a two-layer system with loose sand overlying dense sand, and a three-layer system with loose sand sandwiched between dense sand layers. The influence of lateral spreading on tunnel response was also evaluated by considering four gently sloping ground conditions (0.25°, 0.5°, 1° and 1.5°). The key responses, such as ground deformation, tunnel bending moments, axial forces and inclinations, were analyzed to identify the most critical soil conditions. The findings indicate that a two-layer profile with the tunnel located in the upper liquefiable layer poses a significant risk due to ground uplift from tunnel flotation, threatening both the tunnel and overlying structures. Furthermore, the presence of mildly sloping ground intensified the bending moments in the tunnel lining due to lateral spreading of soil. The study also indicated that a dense layer above the liquefiable soil is effective in limiting soil displacements.</p>