Abstract：
Full-face tunnel boring machines (TBMs) can be classified as open, single shield, double shield, and compound machines. The proper selection of a TBM is key to guaranteeing the safe and rapid construction of urban rail transit projects. This paper describes the principles for TBM selection and, using the Chongqing metro line 6 as an example, the most appropriate TBM is selected after an analysis of the alignment conditions, tunnel depths, geological and hydrological conditions, tunnel operating requirements, support and lining forms, and construction schedule and costs for this specific line. It is recommended that open TBM option is prefered than compound TBM option for an urban rail transit project in hard rock.
2013, Vol. 50 