软岩隧道安全快速施工技术经济性分析研究

Technical and Economic Analysis on the Safe and Rapid Construction Method for Soft Rock Tunnels

文章结合大临铁路某隧道软岩地层段施工实践,提出了采用玻纤锚杆加固掌子面的新型三台阶七步法,给出了软弱地层隧道快速施工工序总体流程,明确了总体流程中各工序管理要点,分析了隧道快速施工管理技术对隧道建设施工效率以及经济效益的影响。研究表明:通过优化软弱围岩隧道炮孔设置、起爆顺序,在施工安全情况下采用工序搭接与不同台阶并行作业等技术和管理手段等,可以实现软弱围岩隧道的安全快速施工。与常规施工技术相比,软岩隧道采用安全快速施工技术,可使出碴和立架两道工序的作业时间节省53%,喷锚作业时间节省17%,总循环时间节省28%,明显提升了施工工效。隧道快速施工管理体系使劳务成本、机械设备成本以及管理成本明显降低,累计节省1635.8万元,极大地提高了软弱地层隧道施工的经济效益。

Based on the construction practice of a soft rock tunnel on Dalin railway, a modified three-bench sevenstep construction method which uses glass fiber anchor bolts to reinforce working face is proposed, an overall process of rapid construction of tunnels in soft rock is given, the key points of process management are defined, and the effects of management techniques for rapid construction on tunnel construction efficiency and economic benefit are analyzed. The research shows that safe and rapid construction of the soft rock tunnel can be realized by optimizing arrangement of blast holes and initiation sequence, overlapping of working procedures and parallel working of different benches;compared with the conventional construction technique, the construction time of two procedures of mucking and steel arch setting, construction time of anchoring and shotcreting and total cycle construction time can be saved by 53%, 17% and 28% respectively, thus the construction efficiency is significantly improved in condition of safe and rapid construction. Further the total cost saving in terms of labour, mechanical equipment and management is $16.358 million, greatly improving the economic benefit of tunnel construction in soft rock.