Deformation Prediction Study of the Adjacent Pile Foundation Caused by Oblique Underpass Construction of a Shield Tunnel

In order to investigate the deformation law of pile foundation caused by the construction of a tunnel shield that obliquely penetrating into the pile foundation of adjacent existing bridges, the influence of the relative positional relationship between the bridge pile foundation and the shield tunnel is considered by taking the circular cross-section pile as an example. Using the Kerr beam foundation model, differential evolutionary algorithm and energy variational method, a prediction model for the deformation of adjacent piles caused by the diagonal tunneling of the shield tunnel is established. The engineering applicability of the prediction model is verified by the monitoring results at the construction site, and the discrepancy between the prediction results of different methods and the measured results is analyzed in terms of error. The results show that the model can predict the horizontal and vertical displacements of pile foundations caused by the construction of pile foundations at different locations, and can be used in two working conditions, positive underpassing and diagonal underpassing, with a wide range of engineering applicability, and the maximum error between the prediction results and the monitoring results does not exceed the 20% engineering error limit, which is of good applicability to the project. Under the condition of Kerr beam foundation model, the model in this paper also considers the relative position relationship between pile and tunnel, and effectively sets the shear layer parameter c. Compared with other methods, the prediction accuracy is significantly improved, which can provide theoretical guidance for the deformation control of adjacent piles caused by similar tunnel shield tunnel underpassing construction.