Improved vertical settlement calculation model for prefabricated subway stations considering shear effect under time-varying loads

Soil backfilling marks the completion of prefabricated subway stations, exhibiting notable spatio-temporal specificity. Soil backfilling can cause uneven longitudinal settlement, leading to disasters such as joint opening, dislocation, water seepage, and leakage, seriously affecting the service of prefabricated subway stations. The longitudinal deformation of prefabricated subway stations during soil backfilling is governed by the spatio-temporal coupling effects of joint nonlinearities and time-varying loads. According to the longitudinal equivalent continuous beam and Winkler foundation, a calculation model for predicting longitudinal deformation under backfill soil is established, considering the shear and bending deformation characteristics at the joints. Based on the continuity conditions of bending moments and shear forces between components, an improved analytical model for longitudinal deformation under time-varying loads is proposed. The proposed model is validated through a case study in the field. The predictions of longitudinal settlement and joint gap opening fit well with the measured data. The longitudinal deformation of a prefabricated subway station comprises the deformation of components and joints, exhibiting spatio-temporal specificity. The proposed model provides a valuable tool for predicting station deformation in similar engineering contexts, thereby contributing to the safety control of urban infrastructure.