地铁出入口顶管下穿运营高架桥桩基变形与受力特性研究

Study on Deformation and Mechanics of Operational Viaduct Piles under Metro Entrance Pipe Jacking

摘要: 本文依托实际工程，采用通用岩土有限元软件建立三维有限元模型，模拟顶管下穿运营高架桥梁桩基的全过程。依托工程中地下通道段长81.21 m，地下埋深约10.5 m，采用顶管法施工，距离最近桥墩仅5.4 m。模型考虑地层与结构相互作用，采用修正摩尔–库伦弹塑性本构模型模拟土层，弹性模型模拟桥梁桩基及管片衬砌，施加自重、上部结构恒载及掌子面压力，约束模型侧面水平位移和底面全部位移，地表自由。本文分析了顶管施工引起的地层变形、桥梁基础位移及桩基受力变化，并与安全控制标准对比，核实了桥梁桩基的安全性，对类似工程的安全性评价具有一定借鉴性。

Abstract: Based on an actual project, this paper uses general geotechnical FEM software to establish a 3D FEM model, simulating the full process of pipe jacking underpassing operational viaduct piles. The project’s underground passage is 81.21 m long, buried ~10.5 m deep, constructed by pipe jacking, and only 5.4 m from the nearest pier. Considering soil-structure interaction, the model adopts modified Mohr-Coulomb elastoplastic model for soil, elastic model for bridge piles and segment linings, applies self-weight, superstructure dead load, and face pressure, with constrained lateral displacement of sides, full displacement of bottom, and free ground surface. It analyzes stratum deformation, bridge foundation displacement, and pile force changes induced by pipe jacking, compares with safety criteria to verify pile safety, providing reference for similar projects’ safety evaluation.