紧邻高架城轨站深基坑支护数值模拟与施工控制

目的 城市轨道是综合交通系统中最重要的组成部分，对变形控制要求极高。一直以来，避免或降低临近深基坑等外部作业对轨道承台桩结构造成的不利影响，确保轨道结构的正常使用和运营是一项重点和难点工作。 方法 以毗邻广珠城际轨道交通前山站的某深基坑为项目依托，采用土工试验、数值模拟、经验分析与现场监测等多种方法，分析了深基坑开挖过程中遇到的难点、变形要求及诸多工程问题，研究了深基坑开挖对毗邻高架城轨站承台桩等结构的影响和基坑支护体系的变形特征。 结果 研究结果表明：城轨站承台桩计算的各项变形指标与实际监测的各项变形指标均小于允许值，满足城轨站承台桩结构的变形要求及施工控制要求；毗邻城轨站段采用地下连续墙+三道内支撑，其余各段采用排桩+三道内支撑的支护方案安全可靠、科学合理、切实可行；提出的施工控制措施有效地解决了施工控制难、变形要求高、场地条件复杂等诸多工程问题。 结论 合理的支护方案、可靠的数值分析、有效的施工控制措施和相应的研究方法、思路可为相似工程问题研究提供参考借鉴。

Numerical Simulation and Construction Control of Deep Foundation Pit Support Adjacent to Urban Rail Station

Introduction Urban rail is the most important part of the integrated transportation system, which requires an extremely high degree of deformation control. For a long time, it is a key and difficult work that the adverse effects of bearing platform pile are avoided or reduced because of external operations adjacent to the deep foundation pit and the normal use and operation of the track structure is ensured.    Method   A deep foundation pit adjacent to Qianshan station of Guangzhou Zhuhai intercity rail transit was taken as an example, the difficulties, deformation requirements and many engineering problems encountered in the process of deep foundation pit excavation were analyzed by means of geotechnical test, numerical simulation, empirical analysis and field monitoring, the influence of deep foundation pit excavation on bearing platform pile and the deformation characteristics of deep foundation pit were studied.    Result   The research results show that: the deformation indexes of bearing platform pile of the urban rail station calculated and monitored actual are less than the allowable values, which meet the deformation requirements and construction control requirements of the bearing platform pile of the urban rail station; it is proved to be safe, reliable, scientific, reasonable and practical that the supporting scheme of the underground continuous wall + three internal supports and the other sections adopt the row pile + three internal supports; the construction control measures proposed effectively solve many engineering problems such as difficult construction control, strict deformation requirements and complex site conditions.    Conclusion   The reasonable support scheme, reliable numerical analysis, effective construction control measures and research methods and ideas in this paper can provide reference for similar engineering problems.