THE RELIABILITY OF ESTIMATING ROCK EXCAVATION COST IN TUNNELLING SPECIFICATIONS

Statistical evaluation of collections of unit prices and quantities for the rock excavation classes for 14 (10) tunnels of varying lengths and with varying cross-sections through the Central Austrial Alps leads to the conclusion that their frequency function has the form of a Gaussian distribution, which has a remarkably small dispersion, insofar as one starts from the quantities in the final measurement. The cost for rock excavation in the final measurement considerably exceeded the tender price, when the standard deviation, i.e. The scatter in the frequency distribution, was more than 35%, both in relation to a weighted average price for the various excavation classes and also the unit price for that class most prevalent in any particular project. The dispersion can thus be regarded as a measure of the reliability of cost estimates for excavation work. The economy of the new Austrian tunnelling method could be further increased by an appropriate relation between measurements of convergence to the particular means of support employed, further by standardisation of bills of quantities for underground works and finally by the publication of tender prices and the associated rates in the final measurement, where the excavation classes and the associated support systems together with unit rates and quantities are made public. A method of comparison which avoids the disclosure of the commercial secrets of the firm involved is presented in the paper. (TRRL)

  • Availability:
  • Corporate Authors:

    Springer Verlag

    175 5th Avenue
    New York, NY  United States  10010
  • Authors:
    • Kurzmann, E
  • Publication Date: 1978-10

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 53-65
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00309534
  • Record Type: Publication
  • Source Agency: Bundesanstalt für Straßenwesen (BASt)
  • ISBN: 3-211-81498-1
  • Report/Paper Numbers: Supplement
  • Files: ITRD, TRIS
  • Created Date: Mar 12 1981 12:00AM