<p>This study investigates the substructure-induced barrier effect on confined aquifers through integrated experimental tests, numerical simulations, and theoretical analyses. The results indicate that the barrier effect in an unconfined aquifer is approximately 10% to 20% lower than that in a confined aquifer. Subsequently, theoretical analysis indicates that a convex parabola head variation pattern has the greatest impact on the blocking effect, followed by a concave parabola and a straight line. Finally, a parametric study on the barrier effect considering different soil and barrier properties was carried out. A parametric study focusing on the influence of different soil and barrier properties was conducted, highlighting that the hydraulic conductivities of the barrier and the soil beneath significantly influence the barrier effect. The anisotropy coefficient of soil hydraulic conductivity and the spatial location also play notable roles in this process. This study also reveals that the barrier effect should be seriously considered when the difference in permeability coefficient between the barrier and soils is more than 3 orders of magnitude. This study will provide valuable reference for the analysis and engineering practice of groundwater barrier effect.</p>