TUNNELLING IN POROUS SOILS FOR BRASILIA'S METRO

This paper discusses the construction of the metro system in the southern area of Brasilia, the capital of Brazil. This system comprises a tunnel, two construction shafts, and nine stations. The tunnel is 6.8km long, 9.6m in diameter and 14.3m deep, and was constructed by the New Austrian Tunnelling Method (NATM), and the stations were excavated by cut and cover. The ground consists of porous clay, 8-40m thick over slate residual soils. The clay layer has large pores and is unstable and liable to structural collapse, causing deformations. The ground water is deep except for a short part of the route. The geotechnical properties of the clay were analysed by the University of Brasilia. The metro construction had the following main stages: (1) excavation; (2) placement of lattice girders 0.6-1.0m apart; (3) shotcreting the 210mm thick primary lining layer; and (4) placing the 200mm thick secondary lining layer and two layers of steel mesh. One full-face and three partial-face excavation methods were used; their choice depended on excavation and deformation conditions. The first was cheapest, and used where the face was stable and negligible damage to neighbouring structures was expected. More sensitive sections were excavated under a ground control regime without instability problems.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/0041414X
• Corporate Authors:

  Miller Freeman

  Calderwood Street
  London,   United Kingdom  SE18 6QH
• Authors:
  • ASSIS, A P
• Publication Date: 1999-1

Language

• English

Media Info

• Features: References;
• Pagination: p. 16-8
• Serial:
  • Tunnels & Tunnelling International
  • Volume: 31
  • Issue Number: 1
  • Publisher: Progressive Media Markets, Ltd
  • ISSN: 0041-414X

Subject/Index Terms

• TRT Terms: Clay; Construction; Cut and cover tunneling; Excavation; Excavations; Full face tunneling; Groundwater; Public transit; Railroad stations; Railroad tracks; Subways; Tunneling; Tunneling machines; Tunnels; Urban areas
• Identifier Terms: Austrian tunneling method
• Uncontrolled Terms: Partial face tunneling machines; Site investigation
• Geographic Terms: Brazil
• ITRD Terms: 3386: Austrian tunnelling method; 8012: Brazil; 4177: Clay; 3655: Construction; 3395: Cut and cover; 5155: Excavation (process); 3383: Full face tunnelling machine; 4383: Ground water; 3393: Partial face tunnelling machine; 744: Public transport; 5722: Site investigation; 3374: Tunnel; 1191: Underground railway; 313: Urban area
• Subject Areas: Bridges and other structures; Construction; Public Transportation; Railroads; Terminals and Facilities;

Filing Info

• Accession Number: 00767201
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD
• Created Date: Aug 6 1999 12:00AM