Abstract: Underground lined tunnels are sometimes exposed to hydraulic fracturing, blasting loading and sudden excavations in operation. The loadings mentioned above are idealized the uniform axially symmetric transient radial loads acted on the internal lined tunnel and the dynamic responses of lined cylindrical tunnels due to the suddenly applied constant load, step load and triangular pulse load are analyzed. The governing equations of the lining and the surrounding saturated medium are derived based on Biot’s theory and elastodynamic theory, respectively. The straight boundary of half space is modeled as a convex arc with the maximum large radius. A set of general solutions in rectangular coordinate system is transformed into solutions in polar coordinate system using addition theorem proposed by Graff. According to the boundary conditions, ground displacement, hoop stress in the lining and pore pressure between the lining and saturated soil are obtained in Laplace transform space and then transformed to solutions in time domain using the numerical calculation method of inverse Laplace transform. The distribution of ground displacement and hoop stress of lined cylindrical tunnel and pore pressure between the lining and saturated soil are obtained.

Key words: lined tunnels, saturated half space, transient loads, Laplace transform, solution in time domain