公路隧道施工变形监测精度要求探讨

隧道周边收敛和拱顶下沉监测是判断围岩支护效果、二次衬砌施作时间、隧道动态信息化设计与施工以及保证隧道施工安全的重要措施。现有JTG F60-2009《公路隧道施工技术规范》对隧道周边收敛和拱顶下沉监测的精度要求为0.1 mm，明显高于铁路隧道施工和基坑工程变形监测0.5~1.0 mm的精度要求，且公路隧道的实际监测精度很难达到规范规定的精度要求。总结现有公路隧道、铁路隧道和其他规范的具体监测内容和要求，结合现有隧道施工监测仪器的精度技术指标，参照隧道设计规范规定的预留变形量、隧道施工阶段变形监测统计结果和基坑工程监测规范的精度要求等，建议将公路隧道周边收敛和拱顶下沉监测的精度要求修改为0.5~1.0 mm。0.5~1.0 mm的监测精度要求可以保证公路隧道的施工安全，促进高精度全站仪等非接触量测方法和仪器在公路隧道施工变形监测中的应用和推广，提高公路隧道施工变形的监测效率，避免因达不到JTG F60-2009《公路隧道施工技术规范》规定的监测精度要求而引发的监测数据造假现象。

Discussion on Deformation Monitoring Accuracy of Highway Tunnel Construction

The monitoring of tunnel surrounding convergence and arch crown settlement is the key to safe construction of tunnel, surrounding rock supporting effect estimation, secondary lining time determination and design and construction of dynamic informationization of tunnel. The monitoring accuracy of tunnel surrounding convergence and arch crown settlement in WTBX]JTG F60—2009 Technical Specifications for Construction of Highway TunnelWT] is 0.1 mm, which is larger than that in criterions for railways and foundations JP3](0.5-1.0 mm). In this paper, the monitoring items and requirements in criterions for highway tunnels and railway tunnels are summarized; and then the authors suggest that the monitoring accuracy of tunnel surrounding convergence and arch crown settlement of highway tunnels should be 0.5-1.0 mm according to existing monitoring devices, design reserved deformation, monitoring results and related foundation monitoring requirements. The suggested value of monitoring accuracy of tunnel surrounding convergence and arch crown settlement of highway tunnel can guarantee the safe construction of tunnel, so as to promote the application and popularization of non contact monitoring method and device (high accuracy total station) and improve the monitoring efficiency of tunnel deformation.