大埋深富水砂卵石地层泥水盾构带压换刀及动火焊接技术

摘要

Based on the tunneling experience in Beijing Zhijingxian Tunnel Project,we summarized technologies of cutting tools replacing and welding technology under high pressure of slurry shield under deep-embedded and water-rich sand-gravel stratum,in which two technologies play main roles in cutting tools replacing and welding works.First,it is better to choose an appropriate position and an appropriate working pressure to ensure the stability of working face.Second,replacement of high density slurry in excavation chamber is needed and pumping high density slurry into intermediate shield to avoid air leaking is required.During tunneling,more than 250 times of intervention under high pressure were successfully taken,as well as the working pressure increased from 0.9 bar to 2.8 bar (1 bar=100 kPa) without any accidents.%通过北京铁路地下直径线工程盾构施工实践经验,总结了大埋深富水砂卵石地层泥水盾构施工中带压换刀技术以及特殊情况下的带压动火焊接技术.带压换刀的技术主要有两个方面,一是选择合理换刀地点及进舱工作压力,保证掌子面土体的稳定；二是进行开挖舱高浓度泥浆的置换和中盾高浓度泥浆的注入,有效地防止了气体的逃逸.在施工中成功实现了带压进舱250余次,工作压力从0.9 bar(1 bar=100 kPa)增加到2.8 bar,未发生任何安全事故.