暗挖地铁车站柱洞法施工梁-柱结构防偏技术研究

柱洞法是无水砂层条件下地铁车站浅埋暗挖施工的重要选择,施工过程中梁-柱结构容易发生左右偏转。依托石家庄地铁长城桥车站暗挖段,从施工技术角度提出一系列控制梁-柱结构偏转的措施。首先,通过辅助工法大管棚+深孔注浆+超前小导管加固土体,减小开挖时地层变形;其次,在梁-柱结构安装时加强梁-柱结构和初期支护的连接,及时在左右纵梁间架设临时横撑来提高结构的刚度;同时,在左右洞开挖和临时支护拆除过程中保持对称施工,使结构受力更加均衡;最后,施工过程中加强梁-柱结构的监控,及时反馈信息,动态指导施工。由现场施工和监测结果表明:梁-柱结构在几种控制措施共同作用下,未发生明显的偏转,说明控制方法有效,可为类似工程提供参考。

Misalignment Prevention of Beam-column Structures by Column-draft Approach for Excavated Metro Station

Column-hole approach has become an important choice for the construction of shallow subway station in dry fine sand. The beam column structure is likely to deflect during construction stage. The paper puts forward a series of control measures based on the underground excavation section of the Changchengqiao metro station. Firstly,the soil is reinforced with such auxiliary methods as deep hole grouting and pipe shed to reduce the deformation of strata during excavation. Secondly,in order to improve the rigidity of the structure,the connection between the beam column structure and the initial support is strengthened during the beam column structure installation,and the temporary steel tube columns are erected between the left and the right longitudinal beams. In addition,the related working processes in the left and right holes are symmetrically conducted to make the structure more balanced. Finally, the monitoring of the beam column is enhanced with immediatefeedback of related information to guide the construction. Site construction and monitoring results show that the beam column structure shows no obvious deflection due to control measures,which justifies the effectiveness of the method and may serve as reference for similar engineering projects.