COMMENTS OF THE STABILITY OF TUNNELS IN CHALK

QUELQUES REMARQUES SAR LA STABILITE DES TUNNELS DANS LA CRAIE

Sound chalk without any cracks is a material out of which underground structures can be satisfactorily excavated (satisfactory strength, low permeability, easy excavation). However if there are weathered and fissured zones, zones, difficulties can arise. Sound chalk witout cracks behaves, in the short term, in an elastic and brittle manner, and when the thickness of the lining increases markedly, standard decompression failures occur; they are not sudden and can be easily dealt with by means of bolts. Chalk shows large differed deformations. It is possible to observe during creep tests in the laboratory differed failure caused by stresses, which are clearly smaller than the strength measured during rapid loading. Linings must be calculated as a function of this rheological behaviour, as they are subjected to increased stresses in time while resisting differed converging deformations. /TRRL/

  • Corporate Authors:

    Laboratoire Central des Ponts et Chausees (LCPC)

    Boulevard Lefebvre 58
    Paris Cedex 15,   France  F-75732
  • Authors:
    • Panet, M
  • Publication Date: 1973-10

Language

  • French

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00127919
  • Record Type: Publication
  • Source Agency: Laboratoire Central des Ponts et Chausees (LCPC)
  • Report/Paper Numbers: ANALYTIC
  • Files: ITRD, TRIS
  • Created Date: Dec 29 1975 12:00AM