地铁盾构隧道下穿哈大高铁桥梁段沉降控制分析

Settlement Analysis of Metro Shield Tunnel Underpass the Bridge Section of Harbin-Dalian High Speed Railway

本文以大连地铁5号线后盐至后关村区间岩溶地层中盾构隧道下穿哈大高铁桥梁段工程为背景,通过有限元计算软件ANSYS建立了“地层–轨下结构–隧道”三维数值计算模型,结合自动化监测数据分析了盾构隧道施工过程对地表及哈大高铁桥面板、桥墩等既有结构的变形影响。数值计算及实测结果表明下穿施工引起地表沉降模拟值和实测值最大值分别为−0.59和−0.42 mm、桥面板竖向位移最大值分别为−0.45和−0.45 mm、桥墩竖向位位移最大值分别为−0.45和−0.42 mm。通过合理控制盾构施工参数,在中风化白云岩地层中、无地面加固及隔离防护措施条件下地铁盾构隧道下穿哈大高铁线路能够满足沉降控制要求,保证了下穿段哈大高铁段线路运营安全,可为中风化白云岩地层类似工程提供借鉴。

Based on the construction project of shield tunnel underpass the Harbin Dalian high speed railway bridge section in karst stratum from Houyan to Houguancun of Dalian Metro Line 5, this paper proposed the three-dimensional numerical model of “stratum structure tunnel” established by ANSYS and the automatic monitoring data, then, the influence of shield tunnel construction process on the deformation of surface and existing structures such as bridge deck and pier of Harbin-Dalian high speed railway is analyzed. The numerical calculation and measured results show that the maximum values of simulated and measured surface settlement caused by construction are −0.59 mm and −0.42 mm respectively, the maximum vertical displacement of bridge deck is −0.45 mm and −0.45 mm respectively, and the maximum vertical displacement of pier is −0.45 mm and −0.42 mm respectively. The results of numerical calculation and field measurement show that through reasonable control of shield construction parameters, the subway shield tunnel undercrossing Harbin-Dalian high-speed railway line can meet the requirements of settlement control in the moderately weathered dolomite stratum without ground reinforcement and isolation protection measures, which can ensure the operation safety of the undercrossing section, and provide reference for similar projects in the moderately weathered dolomite stratum.