Analytical Study on the Effect of Moving Surface Load on Underground Tunnel

Abstract

To investigate the influence of the surface moving load on the underground tunnel, an analytical solution for calculating vibrations from a circular tunnel buried in a half-space due to a surface moving load was firstly given in this paper. The surface load was represented by a moving harmonic point load, and the half-space with a circular tunnel was visco-elastic with a cylindrical hole. The analytical solution of the half-space foundation and tunnel were obtained in the frequency domain based on the fundamental solutions of governing equation of elastic ground in Cartesian and cylindrical coordinate systems. Also, the transformations between the plane wave functions and the cylindrical wave functions and the surface boundary conditions should be used. Then response in the time domain was obtained by inverse Fourier transform. The influence of surface moving loads on the vibration of underground tunnel can be investigated by using the analytical model. The displacement and acceleration of the tunnel surface under different load velocities and tunnel buried depth are analyzed in this paper. The results show that both the dynamic stress and the acceleration responses above the vault of the tunnel increases significantly as the moving speed of the load increases. The dynamic stresses decay rapidly as the buried depth of the tunnel increases, while the acceleration responses decay relatively slowly.