北京地铁九号线玉渊潭区间在富水条件下穿越砾岩及卵砾、圆砾地层，该区域间分布有连续、粒径超过1 000 mm的漂石，可见漂石粒径有1 500 mm×1 700 mm，且区间隧道大部分处于高透水地层中。为保证盾构在施工过程中能安全、顺利掘进，通过分析常规破岩机制和盾构破岩机制，最终选择了尖锐划割挤压破碎机制。通过对盾构设备进行改进、设定盾构推进参数、掘进管理及其他辅助技术的改革，解决了用盾构刀盘、刀具连续破碎漂石、孤石等技术难题。通过对进度、刀盘刀具磨损情况等推进情况进行分析，并对盾构刀盘刀具的磨损情况等进行仿真验证，可知撕裂刀在解决漂石破碎、孤石等起了重要作用，最后对盾构设备及刀盘刀具的优化等提出了建议。

Yuyuantan section of line 9 of Beijing Metro runs through waterrich largediameter boulder strata. The conventional stone crushing mechanisms and the mechanisms of stone crushing by shield machines are analyzed and the mechanism of stone crushing by means of sharp cutting and pressing is adopted for the project. The shield machine is optimized, proper shield boring parameters are selected, the shield boring management is improved and assistant technologies are used, so that the boulders can be crushed by the cutter head and cutting tools of the shield machine successfully. The progress rate and the wearing of the cutter head and cutting tools of the shield machine are analyzed and simulated, which demonstrates that ripper teeth have played an important role in the crushing of the boulders. Finally, suggestions are made on the optimization of the shield machine, including the optimization of the cutter head and the cutting tools.