川藏铁路TBM隧道建设挑战及装备创新设计探讨

Challenges in Tunnel Construction and Preliminary Study on Innovative TBM Design for Sichuan-Tibet Railway

川藏铁路具有显著的地形高差、强烈的板块活动、频发的山地灾害、脆弱的生态环境、严重的高寒缺氧等特征,是目前国内外最具有挑战性的铁路工程。为充分应对川藏铁路隧道建设过程中将面临的长大隧道多、地应力高、活动断层频繁等重大挑战,详细阐述各类复杂工况下采用TBM施工所面临的相应挑战。系统分析川藏铁路TBM创新设计理念及特点,从高原高寒、长距离硬岩掘进、岩爆、断层破碎带、大变形、涌水突泥、高岩温等方面进行了TBM针对性创新设计分析,并提出:1)超前地质探测和处理是用于川藏铁路隧道TBM施工风险控制的主要手段;2)对于以岩爆为主的隧道,创新设计“双护盾+锚喷支护”的双护盾TBM或双支护TBM显得尤为重要;3)对于以大变形为主的隧道,宜首选双结构的敞开式TBM或进行其他结构方面的创新设计。

Sichuan-Tibet Railway is the most challenging railway project worldwide to date due to its great elevation difference,intensive tectonic activities,frequent mountain disasters,fragile ecological environment and severe hypoxia at high altitude.In this paper,the challenges to be encountered during TBM construction for Sichuan-Tibet Railway under various complex conditions,including numerous long and large tunnels,high in-situ stresses,and highly active faults etc.,are described in details.Innovative design concepts and characteristics of TBMs for construction of Sichuan-Tibet Railway are systematically analyzed in eight aspects such as alpine-cold condition,long-distance driving in hard rock and rockburst etc.From these analysis,conclusions are drawn as follows:(1)Advanced geological probing and treatment is a main means of risk control for TBM tunneling during construction of Sichuan-Tibet Railway tunnels.(2)It is particularly necessary to adopt innovative design TBM with"dual shield+rock bolt&shotcrete"or dual-support TBM for constructing rockburst prone tunnels.(3)For tunnels prone to large deformation,open dual-mode TBMs or TBMs with innovative structure design are preferred.It is expected to provide some reference for targeted TBM design and tunnel construction in the later stage.