超浅埋棚盖法暗挖地铁车站管幕支护技术研究与应用——以北京地铁19号线平安里站为例

Research and Application of Pipe-Roof Support Technology for Mined Metro Stations with Ultra-Shallow-Buried Pipe-Roof Cover Method:a Case Study of Ping′anli Station of Beijing Metro Line 19

为解决繁华城市密集建(构)筑物区超浅埋棚盖法暗挖地铁车站管幕超前支护施工技术难题,依托北京地铁19号线平安里站工程,采用理论推导、数值模拟、现场试验及实践总结的方法,建立管幕超前支护力学模型及其计算方法,验证并总结管幕受力及变形机制,优化有限空间作业条件下管幕施工工装及工艺,总结管幕支护施工关键技术。实践表明:1)棚盖管幕支护技术能够满足超浅埋棚盖法暗挖地铁超前支护受力及变形要求,适宜与PBA工法结合实现“盖挖暗作”修建地下车站;2)弹性薄板理论及计算方法能够契合实际工况,为超浅埋棚盖法暗挖地铁车站设计施工提供理论依据;3)管幕支护技术机械化程度高、施工效率高,能够满足繁华城市超浅埋有限空间作业。

A case study is conducted on the Ping′anli station of the Beijing metro line 19 to implement advance pipe-roof support for mined metro stations in dense building areas of prosperous cities using the ultra-shallow-buried pipe-roof cover method.A mechanical model and calculation method are established for advance pipe-roof support using theoretical derivation,numerical simulation,field tests,and practice summaries.The stress and deformation mechanism of the pipe roof are analyzed and validated,and the equipment and technology of pipe-roofing in limited space are optimized and summarized.Practical results show the following:(1)The pipe-roof cover method can fulfill the requirements of stress and deformation for the advance support of ultra-shallow-buried mined tunnels and can be combined with the pile-beam-arch method for mined station construction.(2)The elastic thin plate theory and calculation method can meet the actual working conditions requirements and provide a theoretical basis for designing and constructing mined metro stations using the ultra-shallow-buried pipe-roof cover method.(3)The pipe-roof support technology is characterized by high mechanization and construction efficiency,making it suitable for limited space construction in prosperous cities.