摘要
为探究近接基坑施工对既有结构的变形影响规律,对近接既有结构的基坑工程案例进行了统计和分析,归纳了不同空间位置关系、基坑支护及开挖方法、既有结构类型等条件下,基坑施工引起的既有结构变形特征与规律;采用有限元软件,构建了不同空间位置条件下基坑近接双层三跨车站与近接盾构区间隧道的三维数值模型;分析了基坑施工引起的既有车站与区间隧道的水平、竖向变形及基坑围护结构变形规律,并与统计数据进行了对比分析,给出了不同的近接距离B与基坑开挖深度H之比下的既有结构变形特性。研究结果表明,当基坑与既有结构近接距离小于0.25B/H时,既有结构呈现上浮趋势,对基坑围护结构变形影响大;当近接距离在0.25~0.75B/H时,对基坑围护结构变形影响较大;当近接距离在0.75~2B/H时,对基坑围护结构变形影响较小;B/H增大至2倍时,基坑开挖卸荷对既有结构影响可忽略不计。本文可为近接既有结构基坑施工监测与既有安全控制措施的制定提供借鉴与指导。
In order to explore the influence of adjacent foundation pit construction on deformation of existing structure,statistics and analysis of foundation pit engineering cases adjacent to existing structure are carried.The deformation characteristics and laws of existing structures caused by foundation pit construction are summarized in terms of different space location relationships,different foundation pit supports and different excavation methods as well as existing structural types.MIDAS-GTS is used to establish the three-dimensional numerical models for the foundation pit adjacent to double-layer three-span station and adjacent shield tunnel under different spatial lo-cation conditions.The influence of foundation pit construction on horizontal displacement,vertical displacement of existing station and shield tunnel,deformation law of foundation pit supporting are analyzed and compared with statistical data.Finally,the influence zone of foundation pit adjacent to existing structure construction is pro-posed.The deformation characteristics of existing structures under different ratios of proximity distance B to exca-vation depth H are given.The research results show that when the close distance between the foundation pit and the existing structure is less than 0.25B/H,the existing structure shows a tendency to float,and the deformation value is the largest;when the proximity distance is between 0.25~0.75B/H,the deformation value is larger;when the proximity distance is 0.75~2B/H,the deformation value is smaller;when B/H is doubled,the impact of excavation and unloading on the existing structure can be ignored.This paper may provide guidance and refer-ence for monitoring and control of existing structure’s deformation caused by foundation pit construction.
作者
杜孔泽
李国良
王煦霖
刘志春
张振波
Du Kongze;Li Guoliang;Wang Xulin;Liu Zhichun;Zhang Zhenbo(China Railway First Survey and Design Institute Group Co.,Ltd.,Engineering Research Center of Railway Industry of Construction Technology for Long Tunnel in Special and Complex Environment,Xi′an 710043,China;State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures,Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《铁道技术标准（中英文）》
2022年第2期20-27,共8页
Railway Technical Standard(Chinese & English)
基金
国家重点研发计划(2018YFC0808703)。
关键词
铁路隧道
设计方法与控制技术
现场试验
挤压性围岩隧道
Foundation pit construction
Adjacent Engineering
Underground structure
Deformation character-istic
Influence degree
