大直径盾构隧道全预制结构拼装技术实践

京张高铁清华园隧道是国内首座全预制拼装铁路盾构隧道,包括管片衬砌、轨下箱涵结构及附属结构均实现了工厂化预制,机械化拼装工艺。轨下结构全预制拼装工艺不但加快了施工进度,节约工期,免了大量植筋,提高结构了耐久性,而且还大幅度改善了施工作业环境。介绍轨下全预制结构的设计及施工技术创新应用,通过对现场的拼装错缝统计,分析得出箱涵拼装机无预紧功能,预制件间无螺栓连接、密封材料及施工精度低等因素是产生拼装误差的直接原因。提出采用微膨胀525快硬型硫铝酸盐水泥浆填充预制结构缝隙的改进措施,并采用数值模拟计算分析该方案可靠性与稳定性,结果表明:注浆填充施工误差缝隙后,结构的稳定性及长期运营的安全性均显著提高。

The Practice of Fully-prefabricated Construction in Large-Diameter Shield Tunnels

The Tsinghuayuan Tunnel on the Beijing-Zhangjiakou High-speed Railway is China's first shield tunnel constructed by fully-prefabricated assembling technology. Tunnel lining segments and sub-structures are all prefabricated and mechanically assembled, which not only speeds up the construction progress, improves the durability of the structure, but also greatly improves construction environment. This paper introduces the design and innovative application of the fully-prefabricated construction. The analysis of rail joints concludes that the causes of assembly errors are the failure of the erecting robot to pre-tighten sub-structures, no bolted joint between the prefabricated parts, sealing material and low precision construction. The paper also provides an improvement measure to fill the gaps in prefabricated structure with 525 Sulfoaluminate cement slurry. The results show that after filling the gaps, the security of long-term operations of the shield tunnels has been significantly improved.