卵石地层中盾构下穿盾构隧道的设备改造及施工控制

Equipment transformation and construction control of undercrossing shields in existing tunnels of gravel stratum

依托北京地铁16号线双线盾构下穿既有地铁4号线盾构隧道工程,探讨了卵石地层中地铁盾构施工穿越既有盾构隧道工况下的盾构设计改造,结合既有隧道沉降监测数据分析了盾构施工参数的调控经验。研究表明:针对地层特点进行的盾构关键结构设计改造,可提升盾构掘进、耐磨、脱困和防水性能;既有隧道变形受双线盾构先后穿越施工的二次影响显著,通过顶推力、土仓压力等盾构施工参数的及时调整,配合有效的注浆和补浆措施,可减小穿越施工对既有隧道的影响。

The precedent project based on dualshield tunnels of Subway Line 16 undercrossing shield tunnels of Subway Line 4 in Beijing was studied.The equipment transformation of the shield was analyzed,meanwhile,the experience of shield construction parameters adjustment was combined with the in-situ monitoring data of settlement of existing shield tunnels.Research shows that the shield key equipment transformation with the stratum characteristics can improve performances of shield tunneling and wear-resistance,out of stuck and waterproofing.The settlement of existing tunnels is obviously affected by the secondary disturbance of successive traversing construction.The influence of undercrossing construction on existing tunnels can be reduced by adjustment measures of the shield construction parameters control,such as thrust force and the working chamber pressure in time.The effective grouting and the supplementary grouting measures are cooperated.