TUNNELLING IN COMPRESSIBLE SOILS: LARGE GROUND MOVEMENTS AND STRUCTURAL IMPLICATIONS

When a tunnel is driven through soil by the conventional shield method, ground losses are inevitable due to face take proper and to shield and post-shield radial take. The relaxed soil movements inwards at the tunnel are propagated upward and outward, decreasing in magnitude because of the increasing volume disturbed, so that an inverted bell-shaped depression develops at the ground surface. This settlement trough moves forward as tunnelling progresses. If any buildings, roads or buried services lie within the settlement zone, it becomes necessary to estimate the magnitude of those settlements and to evaluate the risk of damage to the constructions. A well-constructed tunnel driven through stiff clays may cause surface settlements of less than 10 mm. However, when a tunnel is driven through soft, variable, compressible soils, consolidation settlements greater than 100 mm may occur. The effects of soil movements upon buried pipes and on structures can be assessed using a linear elastic form of soil-structure analysis. The consequences of small, short-term settlements and also of very large, time-dependent soil movements upon pipelines and foundation slabs are considered in the paper. This paper was first presented at the Third International Conference on Underground Space and Earth-Sheltered Buildings, held September 1-6, 1988, in Shanghai, China.

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  • Corporate Authors:

    Pergamon Press, Incorporated

    Maxwell House, Fairview Park
    Elmsford, NY  United States  10523
  • Authors:
    • Attewell, P B
    • SELBY, A R
  • Publication Date: 1989

Language

  • English

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Filing Info

  • Accession Number: 00606386
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Mar 31 1991 12:00AM