铁路隧道高精度悬臂边墙施工关键技术研究

Research on Key Technology of High Precision Cantilever Side Wall Construction of Railway Tunnel

采用矿山法施工时,隧道二次衬砌模筑混凝土在施工过程中易出现脱空、厚度不足、掉块等质量缺陷,对此,提出采用“拱部预制衬砌+悬臂现浇边墙”的新型装配式衬砌结构,以保证悬臂现浇边墙满足拼装要求。以重庆铁路枢纽东环线胡家沟隧道为依托,采用数值仿真+现场试验的方法,研究了悬臂边墙混凝土浇筑、边墙接头精度控制等工艺,形成了一套完整的高精度悬臂边墙施工技术。研究结果表明:1)通过“荷载+结构法计算模型”计算分析,悬臂边墙具备结构自稳定性;2)通过采用刚度大强度高的悬臂模板台车对称分次浇筑、台车二次精调、全过程监测等措施,保证了悬臂边墙的高精度和施工稳定性、安全性。

In view of the quality defects such as void,insufficient thickness and falling block in the construction process of tunnel secondary lining molded concrete,a new prefabricated lining structure of"arch prefabricated lining+cantilever cast-in-place side wall"is proposed.In order to ensure that cantilever cast-in-place side wall meets the assembly requirements,Hujiagou tunnel in the east ring line of Chongqing Railway is used as the support.By means of numerical simulation and field test,the technology of concrete placement and joint precision control of cantilever side wall is studied,and a complete set of high precision construction technology of cantilever side wall is formed.The results show that:1)The cantilever side wall has structural self-stability through the calculation and analysis of"load+structure method;2)By adopting the cantilever formwork trolley with high stiffness and strength,the symmetrical placement,the second fine adjustment of the trolley,the whole process monitoring and other measures,the high precision and the construction stability and safety of the cantilever side wall are ensured.