摘要
针对城市地铁隧道下穿高速铁路的施工过程中,CFG桩复合路基对地层沉降的响应机理不明确、路基的沉降预测与控制理论缺乏的问题,依托郑州轨道交通8号线盾构区间下穿郑州东站咽喉区工程,提出CFG桩复合路基沉降预测方法 .基于地基加固理论,分析CFG桩对路基的加固效果,并通过物理模型试验,研究盾构隧道下穿对高速铁路CFG桩复合路基的影响规律.研究结果表明:CFG桩可以大幅提升路基压缩模量,盾构隧道下穿不会影响CFG桩复合路基的整体性,复合路基的变形规律符合Peck沉降曲线;CFG桩复合路基能够将地层的等效内摩擦角提高约50%,降低约23%的地层沉降量;盾构隧道下穿引起CFG桩复合路基的沉降量最大值为1.65 mm,在盾构隧道掌子面距离路基中线10 m时地层开始发生显著沉降变形,其中83.6%沉降量发生在盾构穿越阶段;盾构远离阶段,路基沉降量仍会继续增大,建议沉降监测持续到沉降稳定.研究结果可为盾构隧道下穿高速铁路CFG桩复合路基的沉降预测和加固处理提供参考.
Addressing the unclear response mechanism of CFG pile composite roadbed to ground settlement and the lack of theoretical foundation for predicting and controlling roadbed settlement during the construction of urban subway tunnels beneath high-speed railways,this study leverages the engineering project where the Zhengzhou Rail Transit Line 8 shield section crosses under the throat area of Zhengzhou East Railway Station.It introduces a method for predicting the settlement of CFG pile composite foundations.Analyzing the reinforcement effect of CFG piles on the roadbed based on ground reinforcement theory and employing physical model experiments,this research in⁃vestigates the pattern of influence exerted by shield tunnel crossings on the CFG pile composite foun⁃dations of high-speed railways.The research results indicate that CFG piles significantly enhance the roadbed’s compression modulus without compromising the composite foundation’s integrity.The deformation pattern of the composite roadbed aligns with Peck’s settlement curve.Addition⁃ally,CFG pile composite roadbed increase the ground layer’s equivalent internal friction angle by approximately 50%,thus reducing ground settlement by about 23%.The maximum settlement in⁃duced by shield tunnel crossings in the CFG pile composite foundation is recorded at 1.65 mm.Sig⁃nificant ground settlement deformation begins when the shield tunnel face is 10 m from the roadbed centerline,with 83.6%of the settlement occurring during the shield crossing phase.As the shield moves away,the settlement of the roadbed continues to increase,suggesting the need for settlement monitoring to persist until stabilization is achieved.These results offer valuable insights for the settlement prediction and reinforcement of CFG pile composite roadbed in scenarios involving shield tunnel underpassing high-speed railways.
作者
杜家庆
豆海涛
郭华伟
史小萌
邓廷邦
王承亮
DU Jiaqing;DOU Haitao;GUO Huawei;SHI Xiaomeng;DENG Tingbang;WANG Chengliang(Zhengzhou Metro Group Co.,Ltd.,Zhengzhou 450000,China;China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China)
出处
《北京交通大学学报》
CAS
CSCD
北大核心
2024年第1期11-19,共9页
JOURNAL OF BEIJING JIAOTONG UNIVERSITY
基金
北京市自然科学基金(8214052)。
关键词
盾构下穿
高铁路基
CFG桩
地层沉降
影响规律
shield tunnel underpass
high-speed railway roadbed
CFG pile
ground settlement
im⁃pact pattern
