Abstract:

The universal ring segment can be orderly assembled to form metro shield segment, and the capacity of line fitting and construction rectification of the universal ring segment can be affected by taper of segment. In order to determine the calculation method for taper of universal ring segment in metro shield tunnel, detailed comparison among 4 kinds of methods for calculating the taper of the universal ring segment, i.e. method similar to the straight joint, adjacent interleaving, asymmetric interval interleaving and symmetric interval interleaving, are carried out. And then, by taking Line Z2 project of Tianjin Binhai New District rail transit for example, the elevation fitting situation of DTA (design axis of tunnel) by several calculation methods for the taper of universal ring segment and the fitting situation of the universal ring segment with different tapers to the whole typical interval are systematically analyzed. Finally, a multilevel control design flowchart for calculating the taper of universal ring segment in metro shield tunnels is obtained and proposed. The study results show that: (1) The symmetric interval interleaving calculation method is superior to others when preliminarily calculating the taper of universal ring segment. (2) The preliminarily designed taper of universal ring segment can be determined rapidly by reducing the minimum curve radius by 50100 m. (3) It should be verified that whether the calculated taper of the universal ring segment meets the control requirements or not; and the elevation deviation of DTA is an important control factor.

Key words: metro, shield tunnel, universal ring, taper of segment