ABSTRACT
The Taoyuan International Airport Access MRT line by Metro Taipei is aiming for providing a high speed, convenient connection between Taoyuan International Airport and Taipei City. The total length is 51.5 km consisting of 7 underground stations and 15 elevated stations. The Contract CA450A is one of the most challenging sections of the Airport MRT line awarded on April 2007. The length of the contract is approximately 4 km starting from Airport MRT Taipei Station and ending at the Airport MRT Sanchong station. It includes not only viaducts, but also 1.585 km length of Double-O-Tube (DOT) tunnel across under the Danshui River.
DOT-TBM is the tunnel boring machine with the combination of two cutter-head sets on at the cutter face. There are several advantages of the application of DOT-TBM in tunnel construction. First, the cutting section of the tunnel can be minimized which leads to economical design and construction. Another advantage is the freedom in combination of two circular tunnel sections in both vertical and horizontal direction. This provides the alternatives of design when it approaches existing structures or where it reaches complicate intersections area. Furthermore, due to the use of two cutting surfaces in the same plane, the machine is stable during excavation and it provides high stability of cutting face and machines. The DOT-TBM is introduced in CA450A as the first DOT-TBM in Taiwan. The most significant advantage in this project is that the cross passage construction can be omitted. The machine is used for constructing the tunnel with internal diameter of 5.6m and the internal width of 10.6m. The minimum radius of the tunnel alignment is 280m. The civil construction of CA450A is planned to complete by the end of this year and the DOT-TBM contributes significantly to construction program and construction cost of the project.
Keywords: DOT-TBM, Taoyuan international airport access MRT, Rolling.
