Numerical simulation of dynamic response of operating metro tunnel induced by ground explosion

To evaluate the effects of possible ground explosion on a shallow-buried metro tunnel, this paper attempts to analyze the dynamic responses of the operating metro tunnel in soft soil, using a widely applied explicit dynamic nonlinear finite element software ANSYS/LS-DYNA. The blast induced wave propagation in the soil and the tunnel, and the von Mises effective stress and acceleration of the tunnel lining were presented, and the safety of the tunnel lining was evaluated based on the failure criterion. Besides, the parametric study of the soil was also carried out. The numerical results indicate that the upper part of the tunnel lining cross-section with directions ranging from 0° to 22.5° and horizontal distances 0 to 7 m away from the explosive center are the vulnerable areas, and the metro tunnel might be safe when tunnel depth is more than 7 m and TNT charge on the ground is no more than 500 kg, and the selection of soil parameters should be paid more attentions to conduct a more precise analysis.