Abstract:Based on the effective stress principle of saturated soil, the dynamic interaction model of saturated soil-underground utility tunnel (UUT) system was established by considering the soil as a solid-liquid two-phase medium. During modeling, the Duncan-Chang nonlinear constitutive model was adopted under static condition of geostress balance, and the Davidenkov nonlinear viscoelastic model was adopted under dynamic condition of seismic wave action. Then the dynamic artificial boundary conditions considering the viscoelasticity of saturated soil were used, and the ground motions were transferred to the dynamic loads applied on the nodes of the artificial boundary. The seismic responses of UUT were investigated under different soil materials, different rigidity of the structure, and the soil-structure interaction. The results show the following:(1) The deformation of the structure reaches the maximum when the predominant periods of the site and the earthquake wave are similar; (2) the thinner the UUT wall, the larger the depth, and the greater the structure size; moreover, the larger the structure stiffness, the greater the structure deformation; (3) the deformation of the structure will be enlarged if the state nonlinearity of the interface between soil and structure is neglected.