地连墙围护作用下大直径沉井施工对邻近轨道交通桥梁变形影响分析
陈伟1倪蕾1曹占林2
Impact Analysis of Large-diameter Caisson Construction on Adjacent Rail Transit Bridge Deformation under Diaphragm Wall Retaining Effect
CHEN Wei1NI Lei1CAO Zhanlin2
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作者信息:1.南京上铁地方铁路开发有限公司, 210003， 南京
2.同济大学道路与交通工程教育部重点实验室， 201804， 上海
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Affiliation:1.Nanjing Shanghai Railway Local Railway Development Co., Ltd., 210003, Nanjing, China
2.Key Laboratory of Road and Traffic Engineering of the Ministry of Education, Tongji University, 201804, Shanghai, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.20253063
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中图分类号/CLCN:443.13+1
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栏目/Col:土建工程
摘要:
［目的］大直径沉井施工易引发周边土体位移，进而可能影响其邻近运营轨道交通桥梁的稳定性和安全性。因此，有必要研究地连墙围护作用下大直径沉井施工引起的周边土体位移对邻近运营轨道交通桥梁变形的影响。［方法］以南通市2#墙-井复合结构及沪苏通长江铁路大桥为研究对象，对沉井下沉过程进行现场监测，总结并分析沉井周边土体位移变化情况及该变化对其邻近运营轨道交通桥梁变形的影响规律。［结果及结论］沉井下沉过程中易出现姿态倾斜现象，特别是在首次下沉阶段和更换取土下沉方法阶段，所导致的姿态倾斜表现较为明显；沉井开挖下沉过程会引起周围土体大范围变形，但在地连墙围护结构的限制约束下，其周围土体径向变形量显著低于当前沉井工程中周围环境扰动的控制量0.3%H(H为下沉深度)；在地连墙围护结构的隔离和支护作用下，可将沉井施工中轨道交通桥梁桥墩的水平位移及沉降分别控制在2.0 mm和0.2 mm以内。沉井采用地连墙围护结构，能够保护其邻近运营轨道交通桥梁的安全。
Abstracts:
［Objective］ Large-diameter caisson construction tends to induce displacement in surrounding soil, which may affect the stability and safety of nearby operational railway bridges. Therefore, it is necessary to study the impact of surrounding soil displacement caused by large-diameter caisson construction under the confinement of diaphragm walls on adjacent operational rail transit bridge deformation. ［Method］ Taking the No. 2 wall-caisson composite structure in Nantong City and the Shanghai-Suzhou-Nantong Yangtze River Bridge as research objects, field monitoring was conducted on the caisson sinking process. The variation in caisson surrounding soil displacement and its influence law on adjacent operational rail transit bridge deformation are summarized and analyzed. ［Result & Conclusion］ During the caisson sinking process, attitude inclination is prone to occur, especially in the initial sinking phase and the replacing soil excavation sinking method phase, where the inclination is particularly pronounced. The excavation and sinking of caisson may cause large-scale surrounding soil deformation. However, under the confinement of diaphragm wall retaining structure, the radial deformation of surrounding soil is significantly lower than the current 0.3% H (H as sinking depth) control limit for environmental disturbance in caisson projects. With the isolation and support provided by diaphragm wall retaining structure, the horizontal displacement and settlement of rail transit bridge piers during caisson construction can be controlled within 2.0 mm and 0.2 mm, respectively. The use of diaphragm wall retaining structure in caisson construction ensures the safety of adjacent operational rail transit bridges.
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