On the reliability definition of tunnels under the seismic load
Some main approaches to calculating the tunnel strength under the seismic load are examined which could be applied as a basis for making an estimation of the structure᾽s reliability. The main casual and uncertain factors determining the seismic stability are analyzed. The solution of the problem of the tunnel deformation under arbitrary oriented seismic load is given. This example illustrates conservatism of the traditional solution based on the assumption that the seismic wave is propagating along the tunnel axis.