<p>Accidental surcharge, a type of uncertain manmade hazard, poses a huge threat to the safe operation of shield tunnels. In this regard, a vulnerability assessment framework is proposed in this paper to evaluate the damage state of a shield tunnel subjected to sudden extreme surcharges, accounting for the effect of soil uncertainty and tunnel burial depths. A two-dimensional numerical model of the shield tunnel in soft soil under surcharge loading is established and verified by the field monitoring data. Then, joint opening and horizontal convergence of the shield tunnel are chosen as damage indices, and the corresponding fragility curves and vulnerability curves are established based on the Monte Carlo calculation. The influences of surcharge loading and buried depths on the vulnerability are discussed. Finally, the proposed vulnerability assessment framework is applied in a real case in Shanghai to make a quick judgement on the dangerous sections of shield tunnels. The research results show that the vulnerability of shield tunnels increases with the surcharge loading. Deep shield tunnels have higher initial vulnerability but are not sensitive to surcharge loading. The study sheds light on the robust design, post-hazard decision-making, and rapid risk identification for shield tunnels subjected to surcharge loads.</p>