基坑开挖对已建地铁站结构的安全性影响研究

Research on the Existing Subway Station Structure Safety Effected by Foundation Pit Excavation

研究目的:已建地铁站后续物业开发时,超大基坑施工过程对地铁车站结构的影响较大,为了保证地铁运营的安全性,本文运用数值仿真分析模型,研究了基坑施工过程土体应力、应变特征,分析了基坑开挖对地铁车站结构的影响,评估了地铁车站结构的安全性,对项目进行可行性分析,并给出建议措施。研究结论:(1)地铁车站后续物业开发会对车站结构及轨道产生不利的变形影响;(2)基坑开挖过程中,地层的变形主要出现在基坑底部,施工时,应制定合理的施工方案,遵循"时空效应"原则,避免大块土体开挖;(3)模拟过程中,基坑沉降对地铁车站的影响主要表现在引起局部应力集中,需要对施工过程的关键点进行合理的简化,以保证模拟的准确性和计算的完备性;(4)施工过程中需加强对近邻地铁车站结构的变形监控工作,以保证线路安全营运和施工的顺利进行;(5)本文根据实际工程进行分析研究,其成果可应用于地铁后续物业开发对已建地铁结构影响问题的处理。

Research purposes： During the process of subsequent property development on the existing station, the larger foundation pit excavation impacts on the subway station structure obviously. In order to guarantee the safety of metro operation, the paper analyses the characteristics of stress and strain of soil during foundation pit construction process by numerical simulation model, and studies the effect of foundation pit excavation on subway station structure, then evaluates the safety of subway station structure, at last, it gives some suggests for the project. Research conclusions： （ 1 ） The subsequent property development has a adversely influence for the close neighbour existing subway station structure and rail. （2） In the process of foundation pit excavation, the deformation mainly appears at the bottom of the foundation pit, it should make a reasonable construction scheme, and follow the ＂ time - space effect＂ principle, to avoid large soil excavation. （3） In the process of simulation, the influence to the subway station because of the foundation pit settlement is the local stress concentration, it need reasonable simplification on the key point of construction process, which could ensure the simulation accuracy and calculation completeness. （4） It needs to strengthen the deformation monitoring of the near subway station structure during the process of construction, which could ensure safe operation and construction smoothly. （5） According to the practical engineering for analysis, the study results in this paper can be applied in treatment of the influence of the existing subway structure because of the subsequent property development.