Exploring the three-dimensional response of water storage and sewage tunnel based on 3D finite element modeling

Abstract Due to the presence of varying inner water head, the mechanical behavior of water storage and sewage tunnel is different from normal transportation tunnels. This paper investigated the three-dimensional response of a staggeredly fabricated water storage and sewage tunnel through sophisticated 3D finite element (FE) modeling, in which detailed configuration of the segmental joints and interactions between different connecting components were reproduced. The FE model and input parameters were validated against precedent full-scale loading testing data under both normal operational and cyclic loading paths considering the periodic variation of inner water head. The characteristics of internal force transmission between longitudinal joints and adjacent segments in the longitudinal direction was investigated, and its spatial variability and loading path dependency were discussed. It is found that this self-adaptive internal force transmission mechanism yields a more compatible loading bearing mode, which is beneficial for deformation control. The influences of some important factors on the three-dimensional response of the lining structure were investigated, including the largest inner water head in loading history, distributions of the longitudinal joints and magnitude of longitudinal thrust force, based on which recommendations for practical design and construction were provided.