关键词:

高原铁路隧道, TBM, 高地应力, 岩爆防控, 软岩大变形, 破碎地层, 施工对策, 变形控制, 控坍防卡

Abstract:  A significant length, large buried depth, and high stresses in the surrounding geological strata of a plateau railway tunnel may induce rockburst and large deformations in weak rocks in high groundstress areas. In this paper, the major challenges associated with rockburst, deformation, and collapse prevention for a tunnel boring machine(TBM) are comprehensively analyzed using comparisons with previous projects, practical construction experience, and technical analyses. Suitable countermeasures are proposed. Generally, the full understanding of the construction project characteristics, TBMtargeted design, and TBM technical innovations are the key considerations. These include the following: (1) TBMtargeted design includes a suitable cutterhead expansion and shield length, shield strength enhancement, shield protection range enlargement, and advance support and emergency support strengthening. (2) Adopting hierarchic, active, and passive prevention and control methods for rockburst in high groundstress areas. (3) Focusing stress resistance and release on areas with soft rock strata with high ground stress and providing continuous and rapid excavation and timely support. (4) Emphasizing stable excavation, advance reinforcement, timely support, and backfill grouting in deeply buried broken strata.

Key words: plateau railway tunnel, tunnel boring machine(TBM), high ground stress, rockburst prevention and control, soft rock large deformation, construction countermeasures for broken ground, deformation control, collapse control and TBM jam prevention