近接基坑开挖对既有地铁结构影响的数值模拟分析

Numerical simulation Analysis for Effects on Existing Metro Structure Due to Excavation Nearby

随着城市轨道交通工程建设的不断加快,越来越多的工程将在既有地铁线附近施工,新工程施工必然会对既有地铁结构产生不良影响,以天津西站南广场基坑工程为例,研究天津地区地铁近接工程施工对既有地铁结构的影响。通过数值分析的方法,采用P laxis对南广场基坑开挖过程进行了模拟,通过计算结果分析近接工程施工对既有地铁1号线西站站结构的影响。计算表明,基坑开挖对既有地铁1号线西站站存在不利影响,基坑开挖引起的结构变形主要表现在水平位移,无论断面1或是断面2,基坑开挖引起的水平位移均要大于竖向位移,竖向位移很小,可以忽略不计。

With the development of metro project,more and more excavations have to be executed near the existing metro lines.The existing structure will be affected by the excavation inevitably.The influences on Tianjin area are researched based on the example of excavation work of the south plaza of Tianjin West Station.General finite element analyses software Plaxis is applied to simulate the excavation process.The influence of the excavation on the existing structure of Xizhan Station of Metro line I nearby is analyzed based on the computation.It appears that the horizontal displacement of the existing structure caused by the excavation is much bigger than the vertical one that can be ignored.In Tianjin area even the excavation is rather closed to the existing metro structure,the influence can be restricted to a safe level by precise design and construction,therefore the safety of the metro structure and the operation can be guaranteed.