介绍北京地铁14号线某段采用内径9 m大盾构隧道的情况，阐述隧道直径确定、线路选取、管片设计、盾构机选型等的依据，结合已完成段的大盾构沉降规律、车站区间结合方法等实际施工经验，总结北京地铁采用大直径盾构的成功经验和需要改进之处，对地铁大盾构的推广应用提出建议。

This paper introduces the application of a largediameter shield tunnel ( 9m in diameter) on Beijing metro Line No． 14． The basis for the choice of shield tunnel diameter， line design，segment design and selection of shield machine is introduced in detail． Based on the study of strata settlement regularity for large-diameter shield tunneling and the combined station and running tunnel excavation， the experience of adopting a large-diameter shield in Beijing metro is summarized． Some suggestions on the application of largediameter shield in metro are put forward in the end．

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