地铁盾构隧道侧穿高铁桥群桩设置隔离桩影响分析
赵晓勇
Influence Analysis of Setting Separation Piles for Metro Shield Tunnel Sidecrossing Highspeed Railway Bridge Pile Groups
ZHAO Xiaoyong
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作者信息:1.1. 中铁第一勘察设计院集团有限公司, 710043 西安；
2.2. 陕西省铁道及地下交通工程重点实验室， 710043， 西安
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Affiliation:China Railway First Survey and Design Institute Group Co., Ltd., 710043, Xi′an, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.2021.05.024
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中图分类号/CLCN:U25
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栏目/Col:研究报告
摘要:
结合某盾构隧道侧穿高铁桥群桩基础，研究了盾构隧道侧穿高铁桥桩施工过程中对群桩的影响。通过采取隔离桩措施降低对群桩的影响，对隔离桩设置范围、位置和深度等进行了对比计算分析，得出如下结论：1）当群桩基础与隧道轴线存在夹角时，桩基和承台产生不均匀沉降，承台刚度会影响群桩的变形;距离盾构隧道近的基桩和承台位置一般为沉降变形，越近的基桩变形越大；远侧由于群桩作用效应和承台刚度影响，局部可能会产生隆起变形，应特别关注不均匀变形的影响。2）基桩变形最不利位置位于盾构隧道底部以上部位，而在底部以下基桩变形普遍较小。因此，采取土体改良措施时应主要针对盾构底部以上部分土体。3）采取隔离桩措施能降低盾构隧道施工对高铁桥桩的影响达40%以上，对桥桩起到很好的保护作用。4）隔离桩最优设置范围为桩基垂直于隧道轴线投影范围以外1.0 D~1.5 D（D为隧道直径），超出1.5 D范围的隔离桩作用不大。5）从设置隔离桩改善既有桥桩的变形考虑，隔离桩的设置应尽量靠近后施工隧道，这样对既有高铁桥基础的影响会减少，而且隔离桩自身施工对既有桥桩的影响也会减少。6）隔离桩深度宜取隧道底部以下1~3 m，在此范围内按需设置，效果最优，也最经济。
Abstracts:
Taking the case of certain shield tunnel side-crossing high-speed railway bridge pile group foundation as an example, the influence of shield tunnel side-crossing construction on high-speed railway bridge pile groups is studied. By taking separation piles measure to reduce the impact on pile groups, different scopes, locations, and depths of separation piles are analyzed and compared. Following conclusions are obtained: 1) When there is an angle between tunnel axis and the foundation of pile groups, uneven settlement will take place in pile foundation and bearing platform. The deformation of pile groups is affected by the platform rigidity. The position of piles and the platform near the tunnel are generally settlement deformation, and the deformation increases with the distance decreasing. Affected by platform rigidity and group piles effects, the partial position on the far side to the tunnel are upward deformation. Extra attention should be spared on the uneven deformation. 2) The maximum deformation position of piles is located above the shield tunnel bottom. The value of piles deformation below the shield tunnel bottom is small. Therefore, the measure of soil improvement is mainly for the upper piles above the bottom of tunnel. 3) Adopting separation piles measure can reduce the deformation by up to 40%. The separation piles play an important protection role. 4) The optimal scope of separation piles is 1.0 D~1.5 D (D is the shield tunnel diameter) outside the projection of pile groups. Separation piles are less useful when the scope excesses 1.5 D. 5) Considering using separation piles to decrease the deformation of existing bridge piles, it should be designed as close as possible to the tunnel, so that the impact of the tunnel, as well as that of the construction of separation piles, to the existing high-speed railway bridge foundation will be smaller. 6) It is most effective and most economical to design the separation piles 1~3 m below the tunnel bottom and set up according to demand.
引文 / Ref:
赵晓勇.地铁盾构隧道侧穿高铁桥群桩设置隔离桩影响分析[J].城市轨道交通研究，2021，24（5）：116.
ZHAO Xiaoyong.Influence Analysis of Setting Separation Piles for Metro Shield Tunnel Sidecrossing Highspeed Railway Bridge Pile Groups[J].Urban mass transit，2021，24（5）：116.
ZHAO Xiaoyong.Influence Analysis of Setting Separation Piles for Metro Shield Tunnel Sidecrossing Highspeed Railway Bridge Pile Groups[J].Urban mass transit，2021，24（5）：116.
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