地铁车站单跨PBA工法扣拱施工风险控制研究

以采用单跨PBA工法施工的中国美术馆站工程为依托,通过数值计算及工程实测方法,衡量单跨PBA各工序中存在的风险大小,从设计及施工两方面提出控制扣拱施工风险的建议。监测及数值计算结果表明:当车站扣拱跨度达到一定程度,二衬施工阶段风险将大于扣拱开挖阶段风险,在各工序中风险最大。工程通过扣拱施工采用优化扣拱节点、优化拆撑方案及加快二衬施作功效降低风险,可供类似地层及工法的工程借鉴和参考。

Research on Single-span PBA Method and Risk Control in Center Arch Construction of Metro Station

Based on the National Art Museum Station constructed with single-span PBA method,numerical calculation and settlement monitoring are conducted to measure the existing risks in single-span PBA construction,and suggestions are provided in respective of design and construct to control the risks in center arch construction. The results of settlement monitoring and numerical calculation show that when the center arc span reaches a certain length,the risks in secondary lining construction are greater than those in main arch excavation,and the greatest in each work process. Optimal center arch node design,dismantling temporary shoring and accelerating secondary lining construction are employed to reduce risks,which may serve as references for engineering in the similar formation and with similar construction method.