Construction of a Large-Span Tunnel with Small Overburden in Soft Rocks

This paper presents a construction case history of a shallow-buried large-span short tunnel in soft rocks, mainly composed of altered phyllite, in the central area of mainland China. During construction, convergence deformation is large and a collapse occurs at a mined section. A two-side-drifting method is used to control the ground deformation. The large deformation and collapse are analyzed in terms of rock mass features and stress state, the influence of excavating method and the effectiveness of the support system, as shown by instrumentation results. The large deformation and collapse are mainly attributed to the low strength of the wall rocks and the strength degeneration due to moisture effects. The stand-up time of the wall rocks is so short that the shapes of excavation and the sequence of excavating and supporting have a significant influence on the stability of the tunnel.

Language

  • English

Media Info

  • Media Type: Web
  • Pagination: pp 3295-3304
  • Monograph Title: GeoCongress 2012: State of the Art and Practice in Geotechnical Engineering

Subject/Index Terms

Filing Info

  • Accession Number: 01530366
  • Record Type: Publication
  • ISBN: 9780784412121
  • Files: TRIS, ASCE
  • Created Date: Nov 12 2013 2:07PM