摘要
随着地铁近接工程逐步向叠交隧道数量多、空间位置复杂的趋势发展,盾构施工对土体反复扰动的叠加效应使得规划出合理的近接施工顺序变得更加重要。针对昆明地铁4、5号线新建隧道群近接下穿2号线既有隧道,形成“三层六线”叠交的少见工况,采用室内模型试验系统研究了新建隧道群3种不同下穿施工顺序对地表沉降、既有隧道变位及纵向弯矩的影响。得出以下几点结论:(1)随着新建隧道下穿数量增多,地表沉降逐步增大,地表最终沉降为4次穿越叠加的结果,沉降峰值大致位于新建隧道群的中心线位置;(2)地表最终沉降量与新建隧道施工顺序有关。“先下后上”、“交错先下后上”工序的沉降较小;“先上后下”的沉降最大,是其他两工序的1.25和1.18倍。既有隧道的存在对其周边土体变形有一定的约束作用;(3)既有隧道在靠近新建隧道群中心线位置的沉降量受施工顺序影响较大,较远位置的基本不受影响;(4)穿越施工顺序对管片横向弯矩变化的影响不大,但对既有隧道结构纵向弯矩有一定影响,纵向弯矩差异可达15.82%;(5)综合周边环境变形控制与既有隧道结构保护的效果,推荐采用“先下后上”和“交错先下后上”的工序。研究结果对类似叠交盾构隧道的设计和施工有一定的参考价值。
As the subway proximity engineering gradually develops towards the direction of more tunnels and more complex relative positions in space,the increasing number of tunneling disturbances and complex superposition effects make it more important to plan a reasonable proximity construction sequence.In view of the rare condition that the new tunnel group of Kunming rail transit Line 4 and 5 passes through the existing tunnel of Line 2,forming three layers and six lines overlapping,an indoor model test system was used to study the influence of three different underpass construction sequences of the new tunnel group on the ground settlement,the force and deformation of the existing tunnel.The main conclusions are as follows:(1)With the increase of the number of new tunnels,the land surface settlement gradually increases,and the final land surface settlement is the result of the superpositions of four passes,and the peak settlement is roughly located at the center line of the new tunnel group.(2)The final settlement of the ground surface is related to the construction sequence of the new tunnel.The settlement of“first down and then up”and“staggered first down and then up”processes is small;the“first up,then down”process has the highest settlement,1.25 and 1.18 times that of the other two processes.The existing tunnel constrains the soil deformation around it to some extent.(3)It can be seen from the settlement time history curve that the settlement of existing tunnels near the center line of the new tunnel group is greatly affected by the construction sequence,while the settlement far away from the center is basically not affected.(4)Different crossing construction sequence also has significant influence on the longitudinal bending moment of the existing tunnel structure,and the difference of the longitudinal bending moment is up to 15.82%,but it has little influence on the transverse bending moment of the segment.(5)From the perspective of deformation control of the surrounding environment and protection of
作者
桂跃
吕祎晔
裴利华
杨醒宇
罗胜阳
GUI Yue;LV Yiye;PEI Lihua;YANG Xingyu;LUO Shengyang(Department of Architectural Engineering,Kunming University of Science and Technology,Kunming 650050,China;Southwest Survey and Design Co.,Ltd.,of China Railway Fourth Institute Group,Kunming 650504,China;City College,Kunming University of Science and Technology,Kunming 650051,China)
出处
《贵州大学学报（自然科学版）》
2023年第6期1-12,共12页
Journal of Guizhou University:Natural Sciences
基金
国家自然科学基金资助项目(52068039)
中铁第四勘察设计院集团有限公司科技研发计划资助项目(2020K145)。
关键词
盾构隧道
多线叠交
近接施工
施工顺序
模型试验
shield tunnel
multi-line overlap
approach construction
construction sequence
model test
