地铁盾构区间下穿挡墙式铁路路堤变形控制措施研究

为解决盾构区间小角度下穿挡墙式铁路路堤及接触网立柱的安全施工问题,首先采用理论分析的方法,对下穿施工存在的工程风险进行了分析并提出了针对性的保护措施;再建立三维有限元模型对盾构下穿施工过程进行数值模拟,并将数值计算结果与实测数据进行了对比分析。研究结果表明:(1)轨道沉降曲线整体呈“W”形,挡墙沉降曲线在两隧道间呈平缓变化,挡墙的变形量小于轨道,证明其抗变形能力优于轨道;(2)采取注浆加固措施后,沉降值约为不采取注浆加固措施时的50%,说明基底注浆加固措施对控制挡墙及路堤沉降效果显著;(3)接触网立柱实测沉降值为计算沉降值(数值计算未考虑立柱加固措施)的41%左右,说明对受下穿影响较大的接触网立柱采取加固措施是必要的;(4)实测沉降曲线与计算预测的沉降曲线基本一致,验证了数值模拟结果的可靠性。

Study on Deformation Control Measures for Metro Shield Tunneling Crossing Underneath Retaining Wall Railway Subgrade

In order to solve the safety problem of metro shield tunnel crossing underneath retaining wall,railway subgrade and OCS column with small angle,the risk was analyzed by theoretical method and the targeted protection measures were put forward.A numerical simulation was carried out to study the effect caused by the construction of a shield tunnel,and a comparative analysis was made between numerical result and measured data.The results show that:(1)the overall settlement curve of the track is W-shaped,and the settlement curve of the retaining wall changes smoothly between the two tunnels,the deformation value of the retaining wall is smaller than that of the track.Deformation resistance of the retaining wall is believed to be better than track;(2)the deformation value after applying grouting reinforcement measures is about 50%of that without grouting reinforcement measures,the results show that the basement grouting reinforcement measures have significant effects on controlling the deformation of retaining wall and subgrade;(3)the measured deformation value of the OCS column is about 41%of the calculated deformation value(the reinforcement measures of the column are not considered in the numerical calculation),which indicates that it is necessary to take reinforcement measures for the OCS column which is greatly affected by the underpass;(4)the measured settlement curve is basically consistent with the calculated settlement curve,which verifies the reliability of the numerical simulation results and the effectiveness of the engineering measures taken.