摘要
研究目的:以地铁区间隧道长距离并行侧穿邻近桥梁桩基工程为研究背景,本文采取洞内深孔注浆、地面跟踪注浆措施超前预加固隧道洞周围岩,刚度加强以提高初期支护承载力,注浆填充初期支护壁后空洞以减少围岩变形,注浆填充二次衬砌壁后间隙以尽快形成整体永久承载力等措施,辅以三维有限元手段对相关措施进行数值分析。结合现场监测数据,对工程措施的有效性进行验证,并对桥梁的沉降变形和使用安全性进行评价。研究结论:(1)受土体自承载效应和桩基与隧道距离影响,1号桩位沉降量最大,4号桩位沉降量较小;(2)实测桩基最大沉降量为6.8 mm,横向最大差异沉降量为4.2 mm,纵向最大差异沉降量为2.6 mm,均小于沉降控制指标值,满足正常使用要求;(3)洞周围岩超前加固区可有效提高夹土体承载力,发挥深层隔离作用,减少隧道开挖对桩基的扰动;(4)保持两线隧道掌子面纵向错开50 m,可有效避免在先行隧道扰动围岩尚未稳定情况下后行隧道二次扰动的叠加效应,确保建设安全性;(5)本研究成果可为矿山法隧道侧穿重要建(构)筑物的修建技术和保护措施提供工程借鉴指导。
Research purposes:With the background of metro mine method tunnel construction side-crossing the adjacent bridge pile foundation in long distance,this paper adapted deep hole grouting in tunnel and tracking grouting on the ground to reinforce the surrounding rock in advance,strengthened the stiffness to enhance the primary support bearing capacity;grouting filling blanks behind the primary support to reduce surrounding rock deformation,grouted cavity behind the initial supporting wall to reduce the deformation of surrounding rock,and grouted the gap behind the secondary lining wall to form the overall permanent bearing capacity as soon as possible.The relevant measures were numerically analyzed by three-dimensional finite element method.Combined with the site monitoring data,the effectiveness of the engineering measures was verified,and the settlement and deformation and use safety of the bridge were evaluated.Research conclusions:(1)Impacted by soil self-loading capacity and distance between pile foundation and tunnel,the max-settlement appeared in the No.1 pile location,the min-settlement appeared in the No.4 pile location.(2)The measured maximum settlement is 6.8 mm,the maximum lateral differential settlement is 4.2 mm,the maximum longitudinal differential settlement is 2.6 mm,all of which are lower than the settlement control index values,and meet the normal operation requirements.(3)Reinforced zone around the tunnel can effectively improve the bearing capacity of soil,deep isolation effect can largely reduce disturbance of tunnel excavation to pile foundation.(4)50 m longitudinal staggered between tunnels can effectively avoid the superposition effect of secondary disturbance in the case of unstable soil due to the first tunnel excavation,significantly ensure project construction safety.(5)The research results can provide engineering reference and guidance on the construction technology and protective measures of mine method construction tunnel accompany important structures.
作者
曾东洋
白东锋
ZENG Dongyang;BAI Dongfeng(CCCC First Highway Consultants Co.Ltd,Xi'an,Shaanxi 710075,China)
出处
《铁道工程学报》
EI
北大核心
2021年第9期68-73,80,共7页
Journal of Railway Engineering Society
关键词
地铁矿山法隧道
桥梁桩基
洞内注浆
初期支护
有限元数值分析
metro mine method tunnel
bridge pile foundation
grouting in tunnel
primary support
FEM numerical analysis
