| 盾构开挖顶推力对下平行隧道影响的数值分析 |
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| 引用本文： | 矫永刚.盾构开挖顶推力对下平行隧道影响的数值分析[J].福建工程学院学报,2020,0(1):46-52. |
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| 作者姓名： | 矫永刚 |
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| 作者单位： | 中铁十八局集团第一工程有限公司 |
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| 摘 要： | 以滨海软土地层中盾构隧道平行上穿既有隧道为背景，通过数值仿真软件对开挖动态过程进行了精细化模拟，研究盾构隧道施工顶推力对周边地层及其内部既有隧道受力变形的影响。结果表明，在新建隧道上穿施工过程中，开挖扰动对地层的影响范围主要集中在距离开挖面-1.0~1.5D区域内(D为盾构隧道外径)，扰动效果以新建隧道轴线为中心呈环状向外扩散，盾构顶推力从0.1MPa增至0.4MPa时，地表变形及1.0D范围内地层压力均增大20%以上；新建隧道平行上穿既有隧道过程中，既有隧道断面变形从横向鼓曲变为竖向拉伸，且整体出现上浮现象，顶推力达0.3MPa后，既有隧道拱底和拱顶隆起速度增加，以拱底为基准，顶推力自0.1MPa增加至0.4MPa时，隧道上浮量增大34.2%；施工过程中除保证常规地表变形监测外，对于近接平行上穿施工还需加强对既有隧道竖向变形的监控，必要时采取结构加固措施和施工参数综合调整办法，以降低开挖扰动对周边地层和结构物的影响。
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| 关 键 词： | 盾构隧道 软土地层 平行上穿 顶推力 数值模拟 |
Numeric alanalysis of the influence of shield excavation jacking force on the lower parallel tunnel |
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| JIAO Yonggang.Numeric alanalysis of the influence of shield excavation jacking force on the lower parallel tunnel[J].Journal of Fujian University of Technology,2020,0(1):46-52. |
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| Authors: | JIAO Yonggang |
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| Affiliation: | The First Engineering Co., Ltd. of China Railway 18 Bureau Group |
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| Abstract: | Taking the shield tunnel in the coastal soft soil layer running parallel with the existing tunnel beneath it as the background, the numerical simulation software was used to finely simulate the dynamic excavation process, focusing on the influence of the jacking force of the shield tunnel on the surrounding stratum and the internal tunnel. Results show that during the construction process of the new tunnel, the influence of excavation disturbance on the stratum and internal structures is mainly concentrated in the area that is -1.0~1.5D from the excavation surface(D repestents external diameter of the shield tunnel). The disturbance effect spreads outward in a ring shape around the axis of the new tunnel. When the shield excavation jacking force increases from 0.1 MPa to 0.4 MPa, the surface deformation and the formation pressure within the 1.0D range increase by more than 20%. During the process of new tunnel running parallel above the existing lower tunnel, the deformation of the tunnel sections changes from lateral drum to vertical tension, and the overall floating phenomenon occurs. After the jacking force reaches 0.3 MPa, the bulging speed of the tunnel arch bottom and the dome of the existing tunnel increases. Based on the arch bottom, when the jacking force increases from 0.1 MPa to 0.4 MPa, the floating amount of the tunnel increases by 34.2%. In the construction process, in addition to ensuring the regular deformation monitoring, it is necessary to strengthen the monitoring of the vertical deformation of existing tunnel so as to ensure the parallel construction above it. Structural reinforcement measures and comprehensive adjustment of construction parameters shall be taken when necessary to reduce the impact of excavation disturbances on surrounding strata and structures. |
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| Keywords: | shield tunnel soft soil layer running parallel above jacking force numerical simulation |
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