Effect of Dynamic Interaction of Two Neighboring Tunnels on Vibrations from Underground Railways in the Saturated Soil

This paper analytically investigates the dynamic interaction of two neighboring tunnels in the saturated soil. The twin tunnels are simulated using the Flügge shell theory, and the surrounding soil is modelled by the Biot’s theory. The solution for cylindrical waves in saturated porous media is derived by applying the potential decomposition. The addition theorem is subsequently introduced to translate cylindrical waves, thereby satisfying the boundary conditions at the interfaces between the twin tunnels and saturated soil. Numerical examples are presented to analyze soil vibrations under different loading conditions calculated by different tunnel models. The neighboring tunnels have strong dynamic interaction, resulting in the insertion gain up to ± 20 dB. It is recommended to account for the interaction between neighboring tunnels when calculating the vibrations from underground railways.