The excavation process of deep and large foundation pits in cities will inevitably be treated with dewatering, and the excavation and dewatering of foundation pits will cause changes in the free displacement field of surrounding soil, which will further cause uneven deformation of existing tunnels. The majority of research studies are paying more attention to the excavation‐induced unloading stress on the underlying tunnel, ignoring the foundation pit dewatering for tunnel–soil interaction. Based on this condition, first, the Mindlin solution and the soil effective stress principle are used to obtain the additional stress at the axis of the tunnel under the action of foundation pit excavation and dewatering. Then, the existing tunnel is simplified as a Timoshenko beam lying on the three‐parameter Kerr foundation model. The theoretical solution of tunnel–soil interaction is obtained by Fourier cosine series. Compared with the actual engineering monitoring data, the rationality of the method is verified. Comparison with the results from the Pasternak model and without considering the influence of foundation pit dewatering, the outcomes from the suggested method play a closer resemblance to the measurements. The parametric study shows that increasing the permeability coefficient of soil and depth of dewatering cause the deformation and internal force of the tunnel to decrease slowly. Increasing the depth of the tunnel will cause the deformation and internal force of the tunnel to decrease.
Liao et al. (Thu,) studied this question.