盾构隧道穿越既有混凝土桥梁结构的风险控制指标  

Risk Control Values of Shield Tunnel Crossing Existing Concrete Bridge Structure

作　　者：张海彦[1] 何平[1] 胡友刚[1,2] 秦东平[1,2] 闫国新 

机构地区：[1]北京交通大学隧道及地下工程教育部工程研究中心,北京100044 [2]北京市轨道交通建设管理有限公司,北京100037 [3]中国新兴保信建设总公司,北京100037

出　　处：《中国铁道科学》2014年第3期47-55,共9页China Railway Science

基　　金：国家自然科学基金资助项目(50778012);北京市轨道交通建设管理有限公司科研试验项目(地铁十(二)线科技字第2013A173号)

摘　　要：基于《公路桥梁承载能力检测评定规程》,确定桥梁承载能力计算参数;采用有限元法计算盾构隧道穿越既有混凝土桥梁结构时桥梁结构的剩余承载力和结构内力;选取桥梁结构的内力不大于剩余承载能力时的桥梁结构差异变形值,作为工程的最终风险控制指标;根据每个阶段控制步各监测控制点的变形规律,将最终风险控制指标分配给每个阶段控制步,得到工程的阶段风险控制指标。以地铁公主坟站—西钓鱼台站区间双洞盾构隧道穿越普惠桥工程为例进行仿真分析。结果表明:该工程的最终风险控制指标为中幅桥台竖向差异沉降不大于10.0mm;边幅桥台竖向差异沉降不大于5.0mm;桥台水平位移均不大于5.1mm;边幅桥台的差异变形越大,使得其各工况的内力相差较大;中幅及边幅桥台的变形随着隧道开挖面的接近及穿越南桥台逐渐增加,随着隧道开挖面离开北桥台逐渐减小;中幅桥台的竖向阶段风险控制指标明显高于边幅桥台的竖向风险控制指标,而二者水平向的阶段风险控制指标较为接近。The calculation parameters of bridge bearing capacity were determined by the code of ＂Specification for Inspection and Evaluation of Load-bearing Capacity of Highway Bridges＂.Residual bearing capacity and structure internal force were analyzed by finite element numerical calculations when shield tunnel crossing the existing concrete bridge.Differential deformation was taken as the final risk control value in the project when the structure internal force was less than the residual bearing capacity of bridge.According to the deformation regularity of phase control steps at each monitoring control point,the phase risk control values were obtained through the final risk control values assigned to each phase.The twin-tube shield tunnel crossing Puhui Bridge between Gongzhufen subway station and west Diaoyutai station was taken as a case study to carry through simulation analysis.The results show that,the final risk control values in the project should be：the vertical differential settlement of the central abutment and side abutment less than 10.0 and 5.0 mm respectively,and all of the horizontal displacement of abutment less than 5.1 mm.The more is the differential deformation of side abutment,the greater is its internal force under each working condition.The deformations of central and side abutment increase with the approaching of tunnel excavation face and crossing the south abutment,but decrease gradually with tunnel excavation face leaving the north abutment.The vertical phase risk control values of central abutment are obviously higher than those of side abutment,but the horizontal phase risk control values of both are closer.

关 键 词：盾构隧道 桥梁结构 风险控制 剩余承载力 结构内力 差异变形 

分 类 号：U455.43[建筑科学—桥梁与隧道工程] U441.7[交通运输工程—道路与铁道工程]