下穿天巉公路近接隧道施工技术

On the Construction Techniques for a Tunnel Project Under-Crossing the Tianyan Highway

宝兰客专中川隧道近距离下穿天巉公路,隧道顶距离公路路面仅有6.07m,而隧道开挖宽度达到15.02m。在如此大断面、小净距情况下进行隧道开挖,必须采取可靠措施既要保证新建铁路隧道施工安全,又要使公路保持运营状态,不产生较大的沉降。工程采用大管棚超前支护、简易栈桥等措施保证了施工安全,对类似工程有借鉴意义。

The Zhongchuan Tunnel of the Baoji-Lanzhou Passenger-oriented Railway under-crosses the Tianyan Highway, with the distance between the top of the tunnel and the pavement of the highway being no more than 6.07m, and the excavated width being as large as 15.02m. The excavation of a tunnel in the case of such a large cross-section and small clearance is extremely difficult to perform, in which case reliable measures have to taken to not only ensure the security of the construction of the new- ly-built railway tunnel but also enable the existing highway to maintain its normal operation with no comparatively serious set- tlement happening. In such a case, technical measures such as the large tube-shed advanced support, the simplified jetty and the like are applied to the construction of the project,as a result of which the security of the construction of the project is ensured. The project may serve as a useful reference for other projects of similar types.