小半径曲线隧道盾构施工始发技术

Starting Technique of Shield Tunneling in Curved Tunnel with Small Radius

盾构进出洞施工为盾构隧道施工的关键,也是盾构施工的重难点。小半径、大纵坡、浅覆土盾构始发的情况更加大了盾构始发的技术难度,如何采取安全可靠的技术措施以保证盾构始发的施工质量,是需要研究的关键课题。本文以工程实例作为研究对象,通过端头加固、割线始发、堆载反压和洞门密封等技术,有效解决了盾构始发存在的管片上浮、隧道渗漏水、地表沉降隆起大、管片姿态偏移超限和隧道成型效果难以控制等问题,既保证了施工过程的顺利进行,也保证了隧道的成型质量,对今后类似工程施工具有重要的借鉴意义。

Shield tunneling in and out of the tunnel is the key to shield tunnel construction, but also the key point of shield construction.The initiation of shield with small radius, large longitudinal slope and shallow covering soil makes it more difficult for shield to start. How to adopt safe and reliable technical measures to ensure the construction quali. ty of shield is a key subject that needs to be studied. In this paper, the engineering example was taken as the research object. Through the technology of end reinforcement, secant initiation, surcharge backpressure and tunnel door seal. ing, the problems of segment floating, tunnel leakage, large surface settlement uplift, excessive segment attitude devi. ation and difficult control of tunnel forming effect were effectively solved. This not only guarantees the smooth prog. ress of the construction process, but also guarantees the quality of tunnel formation, which has important reference significance for similar projects in the future.