IN-SITU MEASUREMENTS IN TUNNELS

LES MESURES IN SITU DANS LES TUNNELS

This paper was presented to the Zuerich Symposium: "Field Measurements in Rock Mechanics". Modern methods of tunnel design and construction oscillate between two opposite approaches: trial and error methods to discover the most economical lining or calculations of the lining with theoretical models. In-situ measurements offer a compromise between the two approaches and they ensure safety during the lifetime of the structure. (1) Measurements before construction to give data on the nature, structure and conditions of stress of the rock mass. Then measurements taken in galleries: natural stress measurements with a flat jack; measurements of natural stresses by means of core drilling; plate measurement of deformability; seismic measurements; relative convergence measurements. (2) MEasures during construction. They control the validity of the mechanical model and the numerical value of important parameters, they facilitate the design of temporary and permanent linings as a function of real behaviour. The most useful are: relative convergence measurements, measurements of absolute displacements, measurements of stresses in Anchorage bars. (3) Measurements when the tunnel is open to traffic to evaluate the safety of the structure. Different types of equipment are required. The ideal instrument is reliable in the long-term, automatic and can be read at a certain distance. The most useful measurements are: measurements of stresses in the lining, measurements of relative or absolute displacements, automatic warning measurements. /TRRL/

  • Authors:
    • Londe, P
  • Publication Date: 1978-6

Language

  • French

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00195653
  • Record Type: Publication
  • Source Agency: Laboratoire Central des Ponts et Chausees (LCPC)
  • Files: ITRD, TRIS
  • Created Date: Dec 19 1979 12:00AM