摘要
为研究盾构下穿既有盾构隧道施工过程中既有隧道管片环分块变形规律,依托北京地铁19号线盾构近距离下穿7号线既有盾构隧道的工程实例,采用FLAC3D软件建立考虑管片分块拼装的三维计算模型,并结合实时监测技术对盾构穿越过程中既有隧道管片环分块变形进行监测。研究结果表明:在盾构近距离下穿既有线施工过程中,既有线管片沉降呈现“双峰式”,且新建隧道先行盾构上方既有隧道管片沉降更大;既有线管片整体向新建隧道掘进方向偏移,管片环分块水平位移程度在不同点位表现出差异化,其中各环两侧管片的水平位移最为明显且互相对称,拱顶和拱底仅发生整体偏移;既有隧道受后行盾构掘进影响时间较先行盾构更长,引起既有线管片向开挖方向偏移量更大,引发的管片水平位移也更加显著。既有线在发生整体偏移的同时,管片向两侧发生水平位移,最终管片水平位移表现取决于管片整体朝下穿隧道掘进方向的偏移量与管片环自身形变的叠加作用。
To study the deformation behavior of segment rings in existing shield tunnels during the construction process of the shield tunnels underneath them,a case study of Beijing Metro Line 19 shield tunnel passing closely under the existing shield tunnel Line 7 was conducted.A three-dimensional calculation model was established using FLAC3D software,considering the segmental assembly of tunnel rings.Real-time monitoring technology was employed to observe the deformation of the segment rings in the existing tunnel during the tunneling process.The research results showed that during the close-distance tunneling under the existing line,the segment settlement of the existing line exhibited a"double-peak"pattern,with greater settlement in the existing tunnel segments directly above the new tunnel's leading shield.The entire segment rings of the existing line shifted towards the excavation direction of the new tunnel,with varying degrees of horizontal displacement at different points within the segment rings.The horizontal displacement was most pronounced and symmetrical on both sides of the segments rings,while the crown and invert experienced overall displacement only.The existing tunnel was affected by the tunneling of the following shield for a longer period than by the leading shield,resulting in greater displacement of the existing tunnel segments toward the excavation direction,and a more significant horizontal displacement of the segments.As the existing line underwent overall displacement,the segments also experienced horizontal displacement to both sides,with the final horizontal displacement of the segments determined by the combined effect of the overall displacement of the segments toward the direction of tunneling and the inherent deformation of the segment rings.
作者
刘志坚
曹伍富
黄俊鸿
寇鼎涛
邵小康
王炳禄
江玉生
LIU Zhijian;CAO Wufu;HUANG Junhong;KOU Dingtao;SHAO Xiaokang;WANG Bingu;JIANG Yusheng(China Railway 14th Bureau Group Corporation Limited,Ji'nan 250101,China;Beijing MTR Construction Administration Corporation,Beijing 100068,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China)
出处
《铁道标准设计》
北大核心
2024年第9期132-139,共8页
Railway Standard Design
基金
国家自然科学基金项目(U1261212)。
关键词
地铁
盾构隧道
下穿施工
管片变形
环分块
数值模拟
近距离施工
metro
shield tunnel
undercrossing construction
segment deformation
ring block
numerical simulation
close-distance construction
