Page 203 - 捷運技術 第38期

捷運技術半年刊 第38期 97年2月 197

The First Application of Double-O-Tube (DOT) Shield Tunneling in Taipei MRT

Construction
1
Yung-Hwei Yih Chien-Hua Lin 2

Abstract
The bored tunnel section (contract CA450A) of Taiwan Taoyuan International Airport
Access MRT Project is approximately 1,580 meters in length, beginning from Zhongxiao Bridge

in Sanchong City to North Gate Station (G14) of Taipei MRT Songshan Line. The route runs
under the Danshui River crossing the river dikes and the foundations of Zhongxiao Bridge. Due
to safety concerns regarding passengers' evacuation from the tunnel and maintenance needs, cross
passages are to be installed. Due to construction difficulties and high risk, no such cross passage

construction has been carried out in tunnels under the Danshui River before. After comparison with
the traditional twin tubes tunneling method, Double-O-Tube (DOT) shield tunneling was considered
to be adopted for the construction.
DOT shield tunnel construction was first developed in Japan in 1981, and demonstrated in

1988. The first DOT project was completed in Japan in 1991. Up to now, 18 successful construction
cases have been achieved in Japan and Shanghai, China. Among them, 16 cases were implemented
in subway construction. According to the existing technical data: min. overburden 4 meters, min.
radius 102 meters, max slope up to 5.9%, over 25 experienced construction companies and three

DOT shield machine manufacturers, DOT tunneling is now a mature shield tunneling method.
The application of DOT tunneling by the Department of Rapid Transit Systems of Taipei City
Government will not only meet the requirement of promoting shield tunneling techniques, but also
provide an alternative for the construction of future MRT routes.

Key words: DOT tunneling, twin tubes, cross passage, risk assessment, decision tree, rolling,
decayed wood.