关键词: 新建隧道, 既有盾构隧道, 纵向变形, Euler-Bernoulli梁, Kerr地基模型

Abstract: To accurately predict the longitudinal deformation of an existing shield tunnel caused by newlybuilt overcrossing tunnel, the Kerr foundation model is introduced that can more reasonably simulate the tunnelsoil interaction and the existing tunnel is simplified as the EulerBernoulli beam on the Kerr foundation. Then, based on the Mindlin solution, the additional stress generated on the axis of the existing tunnel by the newlybuilt tunnel excavation is determined. Furthermore, based on the finite difference method, the solution of longitudinal deformation of the existing shield tunnel induced by the overcrossing of the newlybuilt tunnel is obtained. Finally, three engineering cases are used to verify the effectiveness of the proposed method, and some parameters are analyzed and discussed. The results show that the proposed method can predict the longitudinal deformation of the existing shield tunnel induced by the new tunnel overcrossing more accurately than predicted by the Winkler and Pasternak foundation models. The results of the analytical parameters reveal that with the increase in the newlybuilt tunnel′s diameter, the uplift value and influence range of the existing tunnel increase simultaneously, while the increase in the clearance slightly reduces the uplift value of the existing tunnel, but does not affect the influence range of the existing tunnel. Thus, deformation monitoring and safety measures should be adopted for the existing tunnels when a newlybuilt tunnel is crossing above with a large crosssection or small clearance.

Key words: newlybuilt tunnel, existing shield tunnel, longitudinal deformation, EulerBernoulli beam; Kerr foundation model