北京地铁无水砂卵石地层盾构施工技术难点及施工对策研究

针对土压平衡盾构在砂卵石地层掘进中经常出现土压建立困难,刀盘推力与扭矩大且磨损严重,经常出现刀盘"卡死"、螺旋输送机磨损严重及抱死现象,采取对土体进行塑流化改良、刀盘改造及刀具优化、调整注浆配比等措施,很好地控制了地面沉降,确保了该区间的顺利贯通。

Research on Technology Difficulties and Construction Countermeasures of Shield Tunneling of Beijing Metro with Waterless Sandy Gravel Stratum

It was hard to establish earth pressure balance for an earth pressure balance shield machine(EPBM) tunneling in a sandy gravel stratum.Moreover,because there were far too strong thrust force and torque force with heavy wearing in shield cutterhead,some adverse phenomena frequently appeared in shield machine such as: deadlocking of cutterhead,and the heavy wearing or locking of screw conveyor.Aimed at above-mentioned phenomena,these countermeasures were employed: improving the soil body towards good plastic flow property,transforming the cutters,optimizing the cutterhead,adjusting the grouting proportion and so on,so that the ground subsidence was able to be controlled effectively and this section with sandy gravel stratum was able to be tunneled through successfully.