隧道开挖条件下地埋管线的非线性响应分析

Nonlinear analysis of response of buried pipelines induced by tunneling

隧道开挖引起的地层不均匀沉降造成附近的地埋管线产生额外的变形,甚至破坏。被动管线与土体的相互作用的研究表明,不考虑土体的刚度衰减,较大的土体弹性模量使得管线的最大弯矩计算结果过大,偏于保守,造成不必要的浪费。在被动管线Winkler地基模型分析基础上,引入土体刚度衰减模型考虑土体非线性特性,提出了隧道开挖作用下管线响应的等效线性分析方法。基于自由土体位移场计算管周土体由于隧道开挖引起的附加应变,基于水平受荷桩的环状弹性介质模型考虑由于管土相互作用引起的管周土体应变,从而对被动Winkler地基模型的土体弹性参数进行修正,计算得到管线的最大弯矩。通过与现有的弹性理论方法、离心模型试验结果的对比,验证了针对隧道开挖引起的被动管土相互作用问题,该方法考虑土体非线性特性的合理性。

The ground movement caused by tunneling will induce extra deformation on adjacent buried pipelines, even damage. Research on soil-pipeline interaction indicates that higher soil stiffness will lead to a conservative bending moment. An equivalent linear method based on Winkler subgrade model is proposed for modifying soil modulus and evaluating the maximum bending moment for continuous pipelines affected by excavation. The method takes account of tunneling-induced soil nonlinearity by a stiffness degradation model, in which soil average deviatoric strains caused by green field displacement are calculated together with a multi-layer-disc elastic model in order to consider soil nonlinearity induced by soil-pipeline interaction. The validity and rationality of the approach is proved by comparing with elastic theoretical solution and centrifuge model test.