近距离交叠隧道施工影响的数值模拟

Numerical Simulation on Effect of Construction in Closely Overlapped Tunnels

由于地质条件的限制及地下空间的综合开发利用,在工程中有时不可避免地产生近距离交叠隧道。对于这种型式的隧道,新建隧道是在既有隧道完成之后修建的,新建隧道的施工势必影响既有隧道结构的受力状态,引起既有隧道变形。本文应用ANSYS有限元程序采用三维弹塑性数值计算方法对某新建铁路隧道下穿既有高速公路隧道的施工过程进行了模拟,揭示了既有隧道结构受力及位移随新建隧道施工推进的变化规律,可为今后此类隧道的设计与施工提供参考。

Closely overlapped tunnels have emerged because of the limit of geological condition and utilizing the underground space efficiently. For this kind of tunnels, the newly-bulb tunnel is constructed after the existing tunnel, the excavation will inevitably affect the stresses distribution of the existing tunnel and cause the existing tunnel to deform or settle unevenly. In this paper, a three dimensional elasto-plastic finite element model in ANSYS is established to analyze the construction process of a newly-built railway tunnel passing through under an existing highway tunnel. The analysis resuhs show how the stress and displacement of existing tunnel change with the construction process of the newly-built tunnel. The information gained in this paper will provide the reference for the design and construction of similar tunnels.