复杂环境条件下富水卵石地层暗挖地铁车站建造方案研究

北京地铁16号线红莲南里车站为地下双层三跨车站,该站初步设计采用8导洞PBA工法施工。车站邻近城市河道布置,车站周边建筑物和地下管线密集,车站穿越地层为富水卵石地层。在充分考虑车站部位地质条件及环境条件的基础上,分析了初步设计方案的弊端,为有效控制地面沉降及车站施工对周围环境的影响,提出了优化的单层4导洞PBA工法,并详细讨论了该方案的优势。采用有限元数值模拟方法,对原设计方案和优化方案进行施工力学机理分析。计算结果表明:无论是从围岩塑性区分布、车站结构受力还是地层变形来看,4导洞方案均优于8导洞方案。施工实践表明:所提出的车站施工优化方案是可行的。

Study on the Construction Scheme of shallow Buried Underground Subway Station in Water-rich Pebble Stratum Constrained by Complex Environmental Conditions

The Honglian Nanli Station of line 16 of Beijing Metro is designed as an underground double-layer and three-span structure. The station is close to the river and is located in the water-rich pebble stratum with dense buildings and underground pipelines around. On the basis of considering the geological conditions and environmental conditions, the disadvantages of the PBA construction method of 8 pilot tunnels proposed in the preliminary design are analyzed in detail. In order to control the strata deformation and the influence of construction on the surrounding environment effectively, the PBA construction method of 4 pilot tunnels is proposed and the advantages of the scheme are analyzed in detail. The mechanical mechanism of construction is analyzed by finite element numerical simulation based on the original design scheme and optimization scheme. The calculation results indicate that the 4 pilot tunnels scheme is superior to the 8 pilot tunnels scheme in terms of surrounding rock plastic zone distribution, station structure stress and stratum deformation. The construction practice indicates that the construction optimization scheme is feasible.