隧道二次衬砌质量控制新技术

为解决隧道二次衬砌背后脱空、混凝土不密实、厚度不够、强度不足、施工缝开裂掉块等施工质量问题，依托在建的张吉怀铁路某隧道工程，施工中采用三维激光隧道扫描测量系统确保初期支护断面不侵限；采用激光定位和磁焊机焊接提升防水板固定效果；研发并使用新型台车分层逐窗自动布料系统，实现隧道拱墙衬砌混凝土自动分层逐窗浇筑；设置刹尖孔、拱顶安装防空洞监测装置和液位器装置，有效防治拱顶空洞；优化拱部振捣方式和施工缝施工工艺；制订并落实隧道二次衬砌质量管理新办法的技术和管理措施。通过以上措施，实现二次衬砌厚度零欠厚，拱部脱空率下降至5%以内，二次衬砌混凝土强度满足设计要求，总体施工质量得到大幅提高，为隧道施工和运营安全提供保障。

New Quality Control Technology for Tunnel Secondary Lining

The construction quality problems such as void behind the secondary lining, uncompacted concrete, insufficient thickness and intensity, cracking of construction seam, etc. often exist in tunnel. During the construction of a tunnel on Zhangjiajie Jishou Huaihua Railway under construction, the 3D laser tunnel scanning and measurement system is used to ensure that the primary support cross section is within limit; the laser positioning and magnetic welding are used to improve the fixation effect of waterproof board; a new type of trolley material system is developed and used to realize the tunnel arch wall lining concrete automatic laying by window pouring; the brake hole is used, the monitoring device and the liquid level device are installed in the crown to effectively prevent and control the void in the crown; the arch vibration mode and construction technology of construction seam are optimized; the technology and management measures of new method for quality control of tunnel secondary lining are formulated and implemented. By adopting the above measures, the missing thickness of secondary lining is zero, the void rate of the arch is reduced to less than 5%, the strength of the secondary lining concrete meets the design requirements, and the overall construction quality is greatly improved, which guarantees the safety of the tunnel construction and operation.