Analytical solution for lateral displacement of underground combined walls considering influences of construction procedure

Connecting the diaphragm wall to the basement sidewall can enhance underground structure stability. However, the absence of prediction methods for combined walls' mechanical response poses safety risks during construction. This paper presents an analytical method for predicting the mechanical response of combined walls. First, a nonlinear foundation model is developed using the Pasternak model and p - y curves, describing soil deformation continuity and nonlinearity. Next, pole system finite element and incremental methods solve load increments on the combined wall at different stages, and the equilibrium differential equation of the combined wall was derived. The transfer matrix method is then employed to calculate the mechanical response, validated against monitoring data. Additionally, the influence of structural parameters on lateral displacement is analyzed. The findings show that the analytical solutions closely match the monitoring results. A combined wall can reduce the lateral displacement of sidewalls, allowing thinner sidewalls to increase the distance between underground structures and adjacent buildings. Moreover, increasing the sidewall and diaphragm wall thickness can reduce the lateral displacement of the sidewall and diaphragm wall. When the diaphragm wall’s embedded section length meets safety requirements, the lateral displacement of the sidewall and diaphragm wall decreases gradually as the embedded section length increases.