Underground structures are proven to be one of the vital part of modern transportation system. With the growing importance of tunnels for mobility, they are being subjected to threats of severe terrorist activities. Urban tunnels are mainly located in the upper few kilometers and are highly susceptible to deformations even at very low strain rates. Therefore, in the present study, an attempt is made to understand the behavior and pattern of tunnel damage subjected to the different dynamic loading conditions, through the simulation of natural as well as artificial stress states such as loads due to overburden, impact, and blast. The new methodology is proposed to overcome the difficulties of field test during a surface blast. In the present study, the combination of experimental and numerical approaches is used to analysis and design tunnels under impact and blast loads. The investigation is carried out in four steps; firstly, the impact testing is performed in the laboratory on small-scale physical models of tunnel prepared using proper scaling laws. Secondly, the numerical investigation of the physical model is performed under laboratory conditions, and then the experimental and numerical results are compared for the validation purpose. Thirdly, the numerical analysis of impact loading on prototype is carried out. The tunnel deformation results of small scale model and prototype under impact loading are compared for the validation of the prototype model. Finally, the effect of blast loading on the tunnel deformation of the prototype is investigated. It is found from the numerical simulations that the deformation at the tunnel crown in prototype under impact loading is 10 times more than that of a small scale physical model. It is also observed that the deformation of tunnel crown in prototype under impact load is equal to that of blast load due to 500 kg TNT. Therefore, it can be concluded that the methodology proposed in the present work can be utilized by the practicing engineers and academicians for the safe and economical design of tunnels subjected to impact and blast loading.

地下结构被证明是现代交通系统的重要组成部分之一。随着隧道对于机动性的重要性日益提高，它们正遭受严重恐怖活动的威胁。城市隧道主要位于上游几公里，即使在非常低的应变率下也极易变形。因此，在本研究中，试图通过模拟自然应力状态和人工应力状态（例如由上覆，冲击和爆破引起的荷载）来了解在不同动态荷载条件下隧道破坏的行为和方式。 。提出了新的方法来克服表面爆破过程中现场测试的困难。在目前的研究中，实验和数值方法的结合被用来分析和设计冲击和爆炸载荷下的隧道。调查分四个步骤进行：首先，在实验室中使用适当的定标定律对隧道的小型物理模型进行冲击测试。其次，在实验室条件下对物理模型进行数值研究，然后将实验和数值结果进行比较，以进行验证。第三，对原型冲击载荷进行了数值分析。比较了小模型和原型在冲击载荷作用下的隧道变形结果，以验证原型模型的有效性。最后，研究了爆炸载荷对原型隧道变形的影响。从数值模拟中可以发现，在冲击载荷下，原型中隧道顶部的变形是小尺寸物理模型的10倍。还可以观察到，在500吨TNT的作用下，原型在冲击载荷下的拱顶变形与爆炸载荷相等。因此，可以得出结论，本工作中提出的方法可以由实践中的工程师和院士使用，以安全，经济地设计遭受冲击和爆炸载荷的隧道。