八导洞洞桩法地铁车站施工方案优化分析  

Optimization analysis of construction schemes for subway station with eight-drift by PBA method

作　　者：解毅 陈伟[2] XIE Yi;CHEN Wei(China Railway Fifth Survey and Design Institute Group Co.,Ltd.,Beijing 102600,China;Heilongjiang Province Academy of Cold Area Building Research,Harbin 150080,China)

机构地区：[1]中铁第五勘察设计院集团有限公司,北京102600 [2]黑龙江省寒地建筑科学研究院,哈尔滨150080

出　　处：《低温建筑技术》2024年第11期114-117,122,共5页Low Temperature Architecture Technology

基　　金：中铁第五勘察设计院集团有限公司科研课题(T5Y2021-B03、T5Y2023-C26、T5Y2023-C26)。

摘　　要：随着洞桩法地铁车站宽度的增加,导洞数量也逐渐增多,因此造成的扰动影响越大,施工风险也会增加。依托采用八导洞洞桩法施工的北京地铁12号线大钟寺站,建立了二维数值分析模型,通过对不同导洞初期支护厚度、加固方案、导洞开挖顺序下地表沉降和拱顶下沉的数值分析,开展了施工方案优化分析。结果表明导洞开挖阶段地表沉降量最大;车站施工横向影响范围约为2.5倍车站宽度;地表最大沉降与导洞初期支护厚度近似成指数衰减关系;导洞顶部加固对地表沉降改善的贡献大于扣拱顶部加固;导洞初期支护厚度变化和加固对1倍车站宽度范围内地表沉降改善较为明显;先中间两个导洞再两侧导洞为最优导洞开挖顺序;初期支护厚度的变化对中间两个导洞拱顶下沉控制效果优于两侧导洞;上导洞拱顶下沉控制的关键在于两侧导洞顶部加固。研究结论可为类似工程设计提供借鉴与参考。As the width of subway stations constructed using the open-cut pile method increases,the number of guiding tunnels also increases,leading to greater disturbance and heightened construction risks.This study focuses on the Dazhongsi station of Beijing metro line 12,which employs eight guiding tunnels:A two-dimensional numerical analysis model is established to optimize construction plans by analyzing ground settlement and crown subsidence under various conditions,including different initial support thicknesses,reinforcement schemes,and excavation sequences.The findings indicate that ground settlement is maximized during the guiding tunnel excavation phase.The lateral impact range of the station construction is approximately 2.5 times the station width.The maximum ground settlement shows an exponential decay relationship with the initial support thickness of the guiding tunnels.Additionally,reinforcement at the top of the guiding tunnels contributes more significantly to ground settlement improvement than reinforcement at the crown.Changes in initial support thickness and reinforcement are particularly effective in improving ground settlement within a range of one station width.The optimal excavation sequence for the guiding tunnels is to first excavate the two central tunnels,followed by the side tunnels.The effect of changes in initial support thickness on controlling crown subsidence is more effective for the central tunnels than for the side tunnels,while controlling the subsidence of the upper guiding tunnel is primarily dependent on reinforcement at the tops of the side tunnels.The conclusions drawn from this study can serve as valuable references for engineering design and planning under similar conditions.

关 键 词：八导洞洞桩法车站 初支厚度 导洞顶部加固 

分 类 号：TU94.2[建筑科学—建筑技术科学]