超大断面地铁车站暗挖施工优化设计研究——以重庆地铁9号线五里店车站工程为例

Op timization Design of Super-Large Cross-Section Metro Station Constructed by Mining Method:a Case Study on Wulidian Station of Chongqing Metro Line 9

在城市地铁超大断面车站暗挖施工中,传统双侧壁导坑法面临施工速度慢、施工机械操作不方便、施工风险系数大等难题。为解决此类问题,基于重庆地铁9号线五里店车站超大断面暗挖施工实践,通过改变开挖顺序、调整核心土支护形式为直墙式、减少临时横撑数量及选择施作时机、设置可快速拆卸和循环使用的临时竖向支撑等方式,以优化传统双侧壁导坑法,并对优化后的施工方案进行数值模拟分析和现场施工效果分析。结果表明:在地层较稳定、地下水不发育的情况下,超大断面暗挖车站采用优化施工方案,可有效控制围岩变形,且可提高施工进度,降低施工风险和成本。依托工程实际施工后节约工期1个月,节约成本180万元。

The double-side-drift method used in the mining construction of metro stations with super-large cross-section has many disadvantages,such as slow construction speed,inconvenient operation of construction machinery,and high construction risk coefficient.To address these problems,a case study is conducted on mined Wulidian station of Chongqing metro line 9 with super-large cross-section.Then,the traditional double-side-drift method is optimized by changing the excavation sequence,adjusting the support form of core soil to the straight wall type,reducing the number of temporary braces and modifying the construction time,and setting up assemble and reusable temporary vertical support.Furthermore,the numerical simulation analysis and site construction effect analysis are carried out regarding the optimized construction method.The results show that the recommended method can effectively control the deformation of surrounding rock,improve the construction efficiency,and reduce the construction risk and cost in stable stratum without rich water.The construction period and cost of the project are reduced by 1 month and RMB 1.8 million yuan,respectively.