关键词: 下穿工程, 夯管, 小净距隧道, 南水北调中线总干渠

Abstract: With the improvement and development of China′s infrastructure construction, structure being crossed is inevitable. For the construction of structure under-passing through existing railway hub, the risks increase greatly due to busy transportation of passenger and cargo as well as strict deformation control demand. Combining with the Middle Route Project of South-to-North Water Diversion under-passing railway hub, this paper puts forward some targeted measures, such as advanced pre-support of ramming pipe curtain, double layer composite lining, CRD method, dynamic monitoring and measurement, track reinforcement in the light of the complex engineering geological conditions such as shallow bury of tunnel with large-span, multiple tunnels with small-interval busy railway transportation, strict deformation demand and high construction risk. Engineering practice show that ground subsidence and deformation of railway track and tunnel have been successfully controlled, the safety of tunnel construction and the normal operation of the railway hub are guaranteed.

Key words: under-passing project, ramming pipe, small interval tunnels, Middle Route Project of South-to-North Water Diversion