Browsing by Subject "NATM"

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Access status: Open Access ,
Tunneling through highly squeezing ground - a case history
(Wydawnictwa AGH, 2005) Pöttler, Rudolf; Starjakob, Franz; Spöndlin, Daniel
The adaptability of the New Austrian Tunneling Method in design and construction has been proven once more at the Strenger Tunnel, where highly squeezing rock mass caused considerably high deformations and loadings of the primary and secondary lining. By adjusting the support measures especially rock bolting and yielding steel elements installed in slots of the shotcrete lining large deformations up to 0.5 m due to progressive fracturing could be successfully mastered. Calculations using FE-models have been found to be helpful for decision making on site and therefore should increasingly by used in future. Calculations also showed that asymmetric rock mass behavior is not necessarily decisive for the loading of the inner concrete lining in case of extensive fracture processes. Thereby the general practice used in Austria to employ an unreinforced concrete lining was verified. For this decision it was considered that the shotcrete lining which undergoes repair works at the most critical sections will not completely fail but keep apart of its load bearing capacity with respect to normal forces.
Access status: Open Access ,
Zastosowanie metody zbiorów losowych do obliczeń tunelu budowlanego nową metodą austriacką (NATM)
(Wydawnictwa AGH, 2005) Sysik, Paweł; Siemińska-Lewandowska, Anna
In the article a method of capturing uncertainty in geotechnical engineering based on random sets' theory was proposed. This approach allows for assignation of probability masses to sets or intervals. Assumption regarding probability distribution is not required. Information about soil parameters from different sources appearing as intervals can be used. Practical application was demonstrated by means of tunnel excavation problem. The runnel was excavated according to the principles of New Austrian Tunneling Method (NATM). In the analysis deformation of tunnel lining was investigated. As a result ranges of displacements were obtained. This showed possible behavior of the structure. One of calculation steps was sensitivity analysis. On its basis soil parameters which have the biggest influence on displacements were identified. Only these parameters were used as variables in further analysis. Thus computational effort was reduced significantly.