那国隧道下穿高速公路段施工技术

介绍了那国隧道下穿隆百高速公路施工段，大管棚和小导管超前支护，采用双侧壁导坑法和临时仰拱台阶法的开挖方法。施工过程中做好监控量测工作，安全、顺利地完成了隧道下穿段施工任务。高速公路路基沉降在允许范围内。隧道没发生任何异常状况，证明采取的技术措施是正确的。成功经验可供同类工程参考。

Techniques for the Construction of the Naguo Tunnel Under-Crossing an Expressway

Introduced in the paper is the excavation method used for the section of the Naguo Tunnel under-passing the Longbai Expressway,where the large-tube-shed-and-smal-guide-tube pre-supports, the dual side-wall-pilot-pit method and the tempora- ry-inverted-arch-bench method are used for the excavation operation. During the construction,a good job is done of the survey and monitoring work so as to ensure the safe and smooth construction of the under-passing tunnel, with the settlement of the roadbed kept within the permissible range and no abnormal situation arising in the tunnel. Practice shows that the technical meas- ures taken for the project are correct. The successful experience may serve as a useful reference for projects of the same type.