Deflections of discontinuous buried pipelines induced by shield tunnelling based on Pasternak foundation

An accurate prediction of deflections of the buried pipelines induced by shield tunnelling is essential to their damage evaluation and control. By introducing the Pasternak foundation model, the finite difference method is used to deduce a solution to the deflections of jointed pipelines subject to shield tunnelling-induced ground loss. The applicability of this solution and its advantage in computational efficiency are verified by the results of a centrifuge model test and the elastic-continuum solution. Furthermore, a proposal is made for determination of the value of the subgrade shear stiffness. Afterwards, the parametric studies show that the deflection of the pipeline is significantly influenced by the stiffness of the joints. With the increase of their stiffness, the maximum deflection of the pipeline decreases, and the deflection of a jointed pipeline approaches to that of a continuous one. In addition, the deflection of the pipeline is affected by the amount and distribution of the joints to some extent. However, this effect decreases with an increase of the number of the joints.