Within certain limits the alignment of a tunnel has to be studied in relation to many factors which interact in such a way that the evaluation of their relative significance is the principal task of the engineer. The principal factor is the characteristics of the ground which must be known in as much detail as possible. But between the geomechanical parameters, statistical indices of rock quality and test results on the one hand and the drawing up of specific plans on the other hand, there is a gap which can be bridged only by intuition and experience. The alignement has to have sufficient flexibility for the tunnel to be sited in the area with optimum ground conditions. It is of great importance to locate the entrances in areas where ground conditions are satisfactory since in the stretches next to the entrance geomechanical conditions tend to be bad owing to weathering and lateral thrust from the hillside. Equally, the construction method to be used is of great importance in planning a tunnel, and it is recommended to bore an exploratory gallery wherever possible to avoid delays during construction. See also IRRD abstracts nos. 216638 to 216643 and 216645. /TRRL/

  • Corporate Authors:

    Ministry of Public Works, Spain

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


  • Spanish

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00131789
  • 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