Prediction of tunnel localized water leakage influences on adjacent lateral pile responses in saturated clay

In the realm of constructing urban underground spaces, it is imperative to address the impact of tunnel leakage on the surrounding environment. This paper introduced a theoretical analysis to investigate the localized water leakage's influence on adjacent pile foundations. A pore pressure distribution function, accounting for localized leakage water, was formulated. Integrated with the seepage control equation, this function facilitated the calculation of additional stress imposed on piles due to tunnel localized water leakage. Employing the Pasternak foundation model, an analytical solution was developed to assess the lateral performance of adjacent piles under localized water leakage conditions. This approach was compared with numerical simulations to validate the reliability of soil seepage fields and pile lateral performance resulting from localized tunnel leakage at different positions. Through comprehensive parameter analysis, it was observed that the width of the leakage joint significantly influenced pile lateral responses, manifesting in three distinct stages: linear increase, nonlinear gradual augmentation, and stabilization. Different positions of the lining leakage joint yielded varying effects on adjacent piles' lateral responses, with closer proximity intensifying the impact on the pile. When leakage joints were situated near the pile toe, a pronounced negative bending moment was generated. Furthermore, this study summarized the influence range of tunnel localized leakage adjacent to piles. It established that the maximum pile-tunnel horizontal distance inducing lateral pile responses due to tunnel localized leakage was set at 8 times the pile diameter (8 D_p). Additionally, tunnel leakage influences should be considered when the pile length exceeded 0.6 times the depth of the tunnel axis.