卵石层中长距离大直径盾构换刀地面加固研究

Research on Ground Reinforcement for Replacing Cutters for Long-distance and Large Diameter Shield Driving in Pebble Layer

研究目的:卵石层中长距离大直径盾构掘进是盾构施工的世界性难题。某工程采用一台12 m的大直径盾构独头掘进5.2 km,卵石地层中盾构掘进,刀具(盘)磨损严重,须有计划地设置盾构停机点和对盾构刀盘进行全面检修并更换刀具,为确保施工安全,需对配套的地面加固措施进行研究。研究结论:无论是带压进仓作业,还是常压进仓作业,为确保施工安全,都需采取辅助的地面加固措施,以提高盾构机周围地层的稳定性和密实性;带压进仓换刀,可采用后退式分段注浆地面加固措施;常压进仓换刀,可采用钻孔桩+桩间注浆地面加固措施。

Research purposes： The long -distance and large diameter shield driving in the pebble layer is a worldwide problem in the shield driving. A 12m diameter shield machine was used for one project and driving 5.2km was realized by one cutter head. When the shield machine drove in pebble layer,its cutters and cutter head were abrased seriously. So the place of stopping the shield machine was planned for checking and replacing the cutters and cutter heads. In order to make sure the safety of whole project, it was necessary to research the corresponding measures for reinforcing the ground surface for replacing the cutters of the shield machine. Research conclusions：No matter entering the chamber under the working pressure or under the normal pressure, it was necessary to take the corresponding ground reinforcement measures to improve the stability and compactness of the stratum around the shield machine for guaranteeing the safety of construction. When entering chamber under working pressure for replacing the cutters, the back grouting could be used step by step for reinforcing the ground surface, when entering chamber with normal pressure for replacing cutters, the drilled pile could be used along with grouting between piles for reinforcing the ground surface.