In order to study the seismic response of shallow diversion tunnel considering sloshing amplitude of the water

an analytical model of tunnel-soil-fluid is proposed taking account of nonlinear material behavior of soil

viscoelastic artificial boundary

the effective rigidity ratios and fluid-solid coupling. Firstly

the hoop

radial and axial structural rigidities of tunnel lining are obtained by numerical rigidity reduction tests. Furthermore

the orthotropic material is used in tunnel lining model. As an application

the seismic responses of a project of large-diameter parallel diversion tunnels

which is one of the key projects in Shanghai

are calculated using the multi-material arbitrary Lagrangian-Eulerian (ALE) method. The equivalent density method is then used to validate the established simulation model. Finally

two seismic input modes

the uniform and nonuniform excitations

are involved in the seismic analyses of the tunnel-soil-fluid system. The numerical results show that under horizontal earthquake excitation the influence of fluid on tunnel's displacement is small; however

the influences of fluid on both stress and deformation of the section are great. The tunnel moment are always focused on the position of the tunnel 45° cross-hatched. Comparing with the uniform seismic input

the results show that the nonuniform excitation can remarkably increase both displacement and deformation responses of the tunnel.