盾构隧道涌水涌砂问题已成为隧道结构安全的主要威胁。然而传统数值方法无法合理模拟涌水涌砂引起的隧道周围土体大变形，难以揭示隧道结构内力变形响应机理。基于两相物质点法建立隧道涌水涌砂模拟分析方法，研究了涌水涌砂引起的隧道表面水土压力发展规律，并进一步分析了隧道涌水涌砂过程中隧道力学性态的演化规律。结果表明，涌水涌砂的“快速涌砂阶段”，流失孔处的隧道表面压力急剧降低，而隧道底部的表面土压力显著增大。这导致隧道衬砌的剪力和弯矩显著增大，最大值增幅分别达到114%和82%。此外，流失孔附近的2号接头的张开量和转角变形均有明显的增大，极可能会导致严重的纵缝错台甚至混凝土压碎，因此需要格外关注接头处的变形发展。

Water-soil gushing in shield tunnels has been a major threat to the safety of tunnel structures. However, traditional numerical methods cannot reasonably simulate large soil deformation around the tunnel caused by the water-soil gushing. Therefore, it is difficult to reveal the evolution of the internal force and deformation of tunnel structures. Based on the two-phase material point method, the numerical analysis method for the water-soil gushing was established to investigate the development of water-soil pressure acting on the tunnel surface, and then the evolution of the tunnel mechanical behaviors in the process of water-soil gushing was further studied. The results indicate that during the "rapid gushing stage", the tunnel surface pressures around the leakage point decrease sharply, whereas those on the tunnel invert increase significantly. This gives rise to a significant increase in the shear force and bending moment of the tunnel lining, with increase rates of 114% and 82%, respectively. In addition, the axial and angular deformation of Joint 2 near the leakage point increased significantly, which may lead to serious longitudinal joint dislocation or even concrete crushing. Thus, close attention to the joint deformation is required.