摘要
为精确计算分析盾构隧道反复近接侧穿诱发高架桥桩及周边地层的变形规律,结合相关工程案例,运用三维有限元数值计算分析方法.计算结果表明:盾构隧道反复近接侧穿既有高架桥桩,对桥梁桩基的影响较大.施工中临近隧道一侧的桩基桩顶沉降远大于远离隧道一侧,且盾构隧道反复近接侧穿诱发桥梁桩基力学行为及周边地层的变形影响具有叠加效应.桩身纵向呈“S”型挠曲变形,盾构中轴线范围内桩身变形最大,桩顶呈向盾构掘进方向的变形.而桩身横向在盾构中轴线15m范围内沿垂直盾构掘进方向反复变形.桩身下部临近桩端附近的水平位移越来越小,桩端处水平位移几乎为零.盾构隧道反复穿越后地表横向沉降槽宽度约有50m,未加固工况下地表沉降最大值约为25mm.施工前在地面对折返线与下行线之间的3~4号桥墩桥桩范围内土体进行袖阀管注浆预加固,可以减少因盾构反复近接侧穿扰动而诱发的桩基变形,一定程度上抑制地表的变形进一步扩大.加固工况下的计算值与实测值基本一致,说明采用三维数值模拟计算分析盾构隧道反复近接侧穿诱发高架桥桩及周边地层变形的方法的可行性.
In order to accurately calculate and analyze the deformation law of viaduct piles and surrounding strata induced by shield tunnels repeated proximal lateral penetration,three-dimensional finite element numerical analysis method combined with relevant engineering cases is used.The results show that the shield tunnels pass through the existing viaduct piles repeatedly,which has a great influence on the pile foundation of the bridge.In construction,the settlement of pile top near the tunnel is much larger than that far away from the tunnel,and the mechanical behavior of the bridge pile foundation and the deformation of surrounding stratum induced by repeated proximal lateral penetration of shield tunnel have superposition effect.The longitudinal deformation of the pile is S-shaped,the deformation of the pile is the largest in the range of the central axis of the shield,and the deformation of the top of the pile is in the direction of shield tunneling.The transverse deformation of the pile body along the vertical shield tunneling direction is within the range of 15m of the shield axis.The horizontal displacement near the pile tip near the pile bottom is smaller and smaller,and the horizontal displacement at the end of the pile is almost zero.The width of the transverse settlement trough is about 50m after shield tunnel crossing repeatedly,and the maximum value of the surface settlement is about 25mm under unreinforced condition.Sleeve valve tube grouting pre-reinforcement before construction can reduce the deformation of pile foundation caused by shield tunneling repeated proximal lateral penetration disturbance and restrain the further expansion of surface deformation to a certain extent.The calculated values under the reinforcement condition are basically consistent with the measured values,which shows that the method of three-dimensional numerical simulation is feasible to analyze the deformation of the viaduct piles and surrounding strata induced by shield tunnel repeated proximal lateral penetration.The research results have important guiding significance for similar projects.
作者
张邦通
王步翔
曹亚鹏
ZHANG Bangtong;WANG Buxiang;CAO Yapeng(Pan-China Group of Nanjing Design Branch,Nanjing 210009,China;MCC Huatian of Nanjing Engineering & Technology Corporation,Nanjing 210009,China;StateKey Laboratory of Frozen Soil Engineering,Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China;University of Chinese Academy of Sciences,Beijing 100049,China)
出处
《大连交通大学学报》
CAS
2019年第4期98-103,共6页
Journal of Dalian Jiaotong University
关键词
盾构隧道
反复近接侧穿
数值模拟分析
现场实测
shield tunnel
repeated lateral wear
numerical simulation analysis
field measurement
