This paper introduces an advanced method for calculating the deformation of immersed tunnels when accounting for the impact of repeated siltation loads during maintenance. Based on the insights into the force and deformation characteristics of segmental immersed tunnels, the Timoshenko beam model, which considers bending and shear deformation and is based on the Kerr foundation model (KTM), is used to accurately simulate tunnel-foundation interactions, which simulates the continuity between foundation spring elements and more adequately represents the connection and distinction between the easily compressible soil layer and the less compressible soil layer of the foundation. By its application to the Yongjiang immersed tunnel, this method demonstrates significant improvements in predictive accuracy compared to the two-dimensional settlement (TDM), Euler-Bernoulli (WEM), and Timoshenko model based on the Winkler foundation (WTM). Of note, settlements that result from siltation loads display exponential growth over time, with dredging frequency exerting a discernible influence. These findings have substantial implications for the design and operational management of immersed tunnels, which offer advanced insights to enhance their structural integrity and operational longevity.

This paper presents a method to predict the impact of underground tunnel construction on nearby piles using non-linear soil-pile-tunnel interaction. Two stage analysis method have been used considering Kerr foundation model. Greenfield ground settlements have been compared with site-specific instrumentation data of East-West Metro Project, Kolkata, India and results obtained were found to be in good agreement. It has also been observed that the Kerr foundation model considers soil spring over Pasternak's model and hence yields reduced pile deflection compared to Pasternak's model. Non-linear analysis considers non-linear stress-strain relationship and so yields more pile deflection than linear analysis under large deformation. Validation has been performed with case studies in published literature. Irrespective of end conditions, critical bending moment in pile develops at the tunnel centreline depth and at the fixed ends. Soil is a non-elastic material and due to its own shearing strength, the soil also absorbs some portion of the ground deformation before transferring that to the pile. So, consideration of non-linear Kerr model captures a realistic response of the pile. An accurate and cost-effective solution method of non-linear tunnel-soil-pile interaction model has been developed for easy application by practicing engineers using MATLAB software which is commonly available in most of the design.