CRITERION FOR THE ANALYSIS OF THE STABILITY OF THE EXCAVATION FACE OF A TUNNEL

CRITERIO PARA EL ANALISIS DE LA ESTABILIDAD DEL FRENTE DE LA EXCAVACION DE UN TUNEL

A brief description is given of the method developed by Broms, Bermermark, Deere et al. and Peck for forecasting the possible instability of the excavation face of a tunnel; it is critically examined in the light of the experience gained after its application to the tunnels of the Seville underground railway, in Spain. According to this method, the stability of the tunnel face is governed by a stability factor, of = (pz - pa)/su, when pz = total vertical pressure at the height of the tunnel axis, Pa = air pressure within the tunnel, and su = undrained shear strength. It is concluded that the least favourable conditions exist when pz is high and the cohesion is low. The measures usually taken to ensure stability at the face can be of two types: 1) improvement in the of factor by increasing Pa or su (grouting of sandy soils); 2) creating conditions inhibiting the development of failure: series of grouting operations or horizontal inspection of the roof level of the tunnel above and ahead the face. See also IRRD abstracts nos. 216638, 216640 to 216645. /TRRL/

  • Corporate Authors:

    Ministry of Public Works, Spain

    Calle Alfonso XII 3
    Madrid 7,   Spain 
  • Authors:
    • Bernal, A
  • Publication Date: 1975-5

Language

  • Spanish

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00131783
  • Record Type: Publication
  • Source Agency: Transportation & Soil Mechanics Laboratory, Spain
  • Report/Paper Numbers: Conf Paper
  • Files: ITRD, TRIS
  • Created Date: Jun 5 1976 12:00AM