双模盾构TBM转EPB模式转换位置的合理性研究

Study on the position of TBM to EPB mode conversion in dual-mode shield tunneling

目前双模盾构在我国的地铁隧道建设中进行了初步尝试,已有的研究成果和施工案例不多,可借鉴的经验较少,诸多关键问题还需要深入研究并予以实践,其中双模盾构模式转换位置的合理选取尤为重要。为研究双模盾构TBM转EPB模式转换的合理位置,首先对已有的工程经验进行总结,归纳模式转换适用范围及位置的选取原则;其次依托深圳地铁13号线留仙洞~白芒站双模盾构区间工程,利用FLAC^(3D)软件分析复合地层中TBM-EPB双模盾构施工时围岩应力与变形规律,并对双模盾构在软岩段及硬岩段施工时的影响范围进行研究,得出TBM转EPB时的安全转换位置;最后根据该工程特点对其双模盾构模式转换位置的合理性及施工的安全性进行了分析。研究结果表明,双模盾构应该在全断面硬岩段进行模式转换;该工程TBM转EPB较合理的位置是盾构机位于全断面硬岩段,且刀盘前方全断面硬岩段长10m;该工程模式转换的设计位置在理论上满足围岩稳定性要求,研究成果可为类似工程提供参考。

At present, a preliminary attempt has been made in the tunnel construction of dual-mode shield in our country,There are few research results and construction cases, and there are few experiences to be used for reference. Many key problems need to be further studied and put into practice, the selection of mode transfer location is particularly important in the construction of dual-mode shield tunneling. The existing engineering experience was firstly summarized, and the selection principle of mode transfer applicable scope and location was summarized. Secondly, based on Shenzhen Metro Line 13 Liuxiandong to Baimang dual-mode shield tunneling interval project, Flac^(3D) software was used to analyze the surrounding rock stress and deformation laws during the construction of TBM-EPB dual-mode shield in composite strata,and the influence range of dual-mode shield construction in soft and hard rock sections was studied, and the safe transfer position of TBM mode to EPB mode was proposed. Finally, combining with the characteristics of the project, the rationality of the dual-mode shield tunneling mode transfer position and the safety of the construction were analyzed.Research results showed that the dual mode of shield should be in whole section hard rock to convert. The optimal position of TBM to EPB is that the shield machine is located in the full-section hard rock segment and the length of the full-section hard rock segment is 10 m in front of the cutter head, the selection of the mode conversion position in this project satisfies the surrounding rock stability requirement in theory, and the research results can provide a reference for similar projects.