摘要
随着城市基础设施建设的迅速发展,运营地铁线路安保区范围内不可避免地受到新建工程施工的影响,地铁车站及盾构区间两侧深大基坑开挖和卸载会给地铁的安全运营带来隐患。以西安咸阳国际机场三期扩建工程为依托,旨在研究深大基坑开挖对邻近运营地铁区间所受内力和位移的影响。结果表明:采用对称开挖的施工方法能够降低基坑施工对既有区间的影响;基坑开挖过程中,既有区间最大主应力分布多集中于顶板与底板,且以既有区间中线为界呈椭圆形分布,最大主应力值变化不大,基本浮动范围均在5%以下;非对称开挖工况下,既有区间竖向位移总体变化为先隆起后沉降,最大沉降值为3.25 mm,对称开挖工况下的最大沉降值为2.44 mm,减少了24.9%;在排桩支护、横撑及脚撑的支护作用下,既有区间上方的沉降量较小,对称开挖工况下地表沉降最大值为5.73 mm;实际监测数据与三维数值模拟结果具有较高的吻合度,地表沉降监测值与数值模拟结果的误差为6.8%,既有区间竖向位移监测值与数值模拟结果的误差为1.7%。
With the rapid development of urban infrastructure construction,the security zone of the operating subway lines is inevitably affected by the construction of new projects.The excavation and unloading of deep and large foundation pits on both sides of subway stations and shield tunnels will bring hidden dangers to the safe operation.Based on 3rd phase expansion project of Xi'an Xianyang International Airport,the impact of deep and large foundation pit excavation on the internal force and displacement of adjacent operating subway sections is studied.The results indicate that symmetrical excavation construction methods can reduce the impact of foundation pit construction on existing sections;During the excavation,the maximum principal stress distribution in the existing interval are mostly concentrate at the top and bottom plate,and distributed in elliptical-shape bounded by the existing interval centerline.The maximum principal stress value changes little with the basic floating range of below 5%;Under asymmetric excavation conditions,the overall vertical displacement of the existing section changes from uplift to settlement with a maximum settlement of 3.25 mm.Under symmetric excavation conditions,the maximum settlement is 2.44 mm and decreases by 24.9%;Under the support of row piles,horizontal braces and foot braces,the settlement above the existing section is relatively small.Under symmetrical excavation conditions,the maximum surface settlements is5.73 mm;The actual monitored data has a high degree of consistency with 3D numerical simulation results.The error between the surface settlement monitoring values and the numerical simulation results is 6.8%,and the error between the existing interval vertical displacement monitoring values and the numerical simulation results is 1.7%.
作者
党涛
雷伟
任利军
苗苗
吴征
陈强
Dang Tao;Lei Wei;Ren Lijun;Miao Miao;Wu Zheng;Chen Qiang(Shaanxi Huashan Road and Bridge Group Co.,Ltd.,Xi'an 710016,China;Shaanxi Zhengcheng Road&Bridge Engineering Research Institute Co.,Ltd.,Xi'an 712000,China;Shanai Construction Engineering Group Co.,Ltd.,Xi'an 710003,China)
出处
《市政技术》
2023年第8期235-244,252,共11页
Journal of Municipal Technology
关键词
黄土地层
深大基坑
近接施工
地铁车站
数值模拟
loess stratum
deep and large foundation pit
proximity construction
subway station
numerical simulation
作者简介
党涛,男,工程师,硕士,主要从事公路及市政工程方面的科研及管理工作;通讯作者:苗苗,男,助理工程师,硕士,主要从事公路及市政工程方面的技术及科研工作。
