大直径土压盾构机下穿超浅覆土河道施工关键技术

The Key Technology of Large Diameter Earth Pressure Shield Tunneling Machine Under the Construction of Ultra-shallow Soil Covered River

采用土压平衡盾构机下穿既有河道是近年来土压盾构机技术研究探索的重要方向,本文通过借助宁芜铁路改造工程盾构段的工程实际,详细阐述了大直径土压平衡盾构机在下穿极浅覆土河道时遇到的技术难题,并给出了适应性的河道加固解决方案和针对性措施。研究表明:针对河道进行分批次分步围堰加固,是保证盾构安全高效穿越河道的关键技术措施;大直径土压盾构在下穿河道时有针对性地及时调整掘进参数是超浅覆土施工的必要措施,相关处理措施可为该类工程提供参考借鉴。

In recent years,the use of soil pressure balancing shield machine to penetrate existing river is an important direction of research and exploration of soil pressure balancing shield machine technology.Based on the engineering practice of the shield section of the Ningwu Railway reconstruction project,this paper describes in detail the technical problems encountered by large diameter soil pressure balancing shield machine to penetrate extremely shallow soil covered river,and gives adaptive river reinforcement solutions and targeted measures.The research shows that strengthening cofferdams in batches and steps is the key technical measure to ensure safe and efficient crossing of river by shield.It is necessary to adjust the excavation parameters in time when the large-diameter earth pressure shield underpasses the river,and the relevant treatment measures can provide reference for this kind of project.