ODABIRANJE DIMENZIJA PODGRADA PODZEMNIH PROSTORIJA

• Published in: Rudarsko-geološko-naftni zbornik 2000-12, Vol.12 (1), p.67
• Main Authors: Hudec, Mladen, Frgic, Lidija, Tor, Kresimir
• Format: Article
• Language: hrv ; eng
• Subjects: Design engineering; Geology; Rocks; Tunnels
• ISSN: 0353-4529; 1849-0409

The most questionable are the values of pressures between rock and support resulting from common deformations on the contact area between rock and support. Therefore the modelling and design of the tunnel support is not reliable, if it is based on active rock pressure resulting from this common deformations. The inversion of the design procedure is proposed. Instead of the active extreme pressure of the rock on support, the influence of ultimate reaction of the support on the rock has to be analysed. This procedure can be performed using the ultimate load principle, as proposed by Eurocode 7 (Geotechnics). Normally, the rock has the tendency to increase the common convergence until the support reaches its ultimate state. So, loading of profile boundary with the ultimate possible reaction of the support is very plausible. The reactive support pressures have to be probable and itself in equilibrium. The ultimate reactive load has to be reduced by Eurocode safety factor for structural elements and applied on the rock with given properties, or alternatively (as proposed by Eurocode 7) the soil or rock properties have to be diminished and calculated with full ultimate support pressures. If the rock with given (or proposed) properties, and loaded with ultimate reactive pressures resulting from supposed support, satisfy its failure criterion, then is the compound system support-rock verificated. By this procedure, the number of relevant material properties is reduce to the primary stress ratio and the constants defining the failure criterion. The verification can be performed by any of numerical methods, but we prefer here used boundary elements method. [PUBLICATION ABSTRACT]