考虑多溶洞耦合效应的盾构隧道地层扰动分析

Study on Ground Movements Caused by Shield Tunnelling Considering Multiple Karst Caves Coupling Effect

  • 摘要: 针对岩溶地区盾构隧道连续侧穿溶洞引起的地层扰动问题,依托广州东至花都天贵城际铁路工程,建立盾构连续侧穿双溶洞的三维有限元数值模型,并结合现场监测数据进行模型验证,系统分析多溶洞耦合效应下溶洞处理方式、填充材料参数及盾构掘进参数对地层扰动与变形的影响规律。研究结果表明,未处理溶洞会使地表沉降量增加15%~40%,距观测点最近的溶洞在盾构侧穿过程中对该观测点变形影响最大,溶洞尺寸与观测点沉降量呈正相关关系;在溶洞完全填充条件下,填充浆液的弹性模量对地表沉降影响有限;掌子面压力降低25%将导致地表沉降增幅达100%;溶洞与隧道水平距离超过2倍溶洞宽度时,隧道正上方地表沉降趋于稳定;溶洞位于隧道侧下方时,拱顶沉降可降低约12%。建议在岩溶地区隧道施工中优先处理邻近大尺寸溶洞,并严格控制掌子面压力。

     

    Abstract: To address the ground movement caused by shield tunnels successively side-crossing karst caves, this study establishes a three-dimensional finite element model simulating shield tunnelling through dual adjacent caves along the Guangzhou East to Huadu Tiangui Intercity Railway project. The model was validated through field monitoring data to systematically investigate the impacts of cave treatment methods, grouting material parameters, and shield tunnelling parameters on ground deformation. The results reveal that untreated caves increase surface settlement by 15%-40%, with the nearest cave exerting dominant influence on adjacent monitoring points. Settlement exhibited positive correlation with cave dimensions. Although increasing grout elastic modulus to 100 MPa moderately reduced surface settlements, its effectiveness became constrained under full-cave filling conditions. A 25% reduction in face pressure doubled surface settlement. Critical thresholds were identified: horizontal cave-tunnel distances exceeding twice cave width stabilized surface settlement above the tunnel, and caves located at tunnel's lower side reduced vault settlement by 12%. The study proposes prioritizing treatment of adjacent large-scale caves and maintaining optimal face pressure as essential control measures, providing theoretical guidance for hazard prevention in karst tunnel engineering.

     

/

返回文章
返回