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Rock mass classification in highway tunnel engineering during exploration phase and case study

Yanqiang Du, Bing Xie

Archives of Civil Engineering

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2023

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Vol. 69, nr 2

141--153

EN

It is the foundation of tunnel engineering to classify the rock mass surrounding tunnels. However, it is not easy to precisely determine the class of rock mass in practice as sufficient geological exploration need to be completed before rock mass classification, and there exists some disputes referring to the rationalization of dozens of methods for rock mass classification through the world. The principles and procedures of the basic quality method, which are widely used in China, are presented in this paper, and the application process of the basic quality method is showed with a project case of Zhongnanshan highway tunnel which has operated in safety for nearly a decade. Then, both the advantages and disadvantages of the basic quality method are analyzed in terms of practical engineering applications. In consideration of the defects of the basic quality method, the concept of the subclassing of surrounding rock in grade III-V is developed in the end and the criterion is given to determine the subclass of rock mass. This study is aimed at providing some useful ideas and a reference for rock classification in highway tunnel engineering.

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Calculation model and analysis for lay-by spacing in highway tunnel

Liang Bo, Xiao Yao

Archives of Civil Engineering

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2022

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Vol. 68, nr 4

347--357

EN

Tunnel lay-by spacing is directly related to traffic safety and engineering investment. Nevertheless, its mechanism is not clear, and the rationality of the exiting norms with respect to tunnel lay-by spacing needs to demonstrate. A calculation model for tunnel lay-by spacing was derived by considering the headway and the physical kinematics of the two vehicles chasing and encountering. With it, the influence of various parameters on lay-by spacing were analysed and the rationality of the model were discussed through comparing with existing norms. Results shows longitudinal gradient rate, daily average traffic flow, rolling resistance coefficient, posted speed limit are significant to determine the lay-by spacing, and the most important parameter is longitudinal gradient rate. Existing tunnel lay-by spacing norm values are not reasonable enough, either too strict or too loose. These findings provide scientific support for how to select tunnel lay-by spacing value, which can improve tunnel traffic safety and make engineering investment reasonable.

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Branisko – first highway tunnel in Slovakia; photoreport from the opening ceremony

Certik P., Snopko J.

Budownictwo Górnicze i Tunelowe

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2004

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nr 2

22-25

EN

Branisko tunnel is first motorway tunnel in the Slovakian Republic. Its inauguration, with participation of supreme state authorities, took place on 29 June 2003. The Tunnel is a part of Motorway D1 from Bratislava to Kosice and is 4,877 km long. The article presents a concise information on construction of the most difficult section of the motorway between Beharovce and Fričovce along the distance of 15,1 km. It presents the most important advantages of Branisko tunnel, which belongs to the safest tunnels operating at present in Europe. This standard was achieved by application of exhaust ventilation system with central exhaust of polluted air. It is provided with thirteen escape ways into the escapee tunnel. This tunnel is provided with autonomous positive pressure ventilation system preventing smoke from penetrating to those spaces. The authors expressed their appreciation to all engaged in the construction of Branisko tunnel.

PL

Tunel Branisko jest pierwszym tunelem autostradowym w Republice Słowacji. Jego otwarcie, z udziałem przedstawicieli najwyższych władz państwowych odbyło się 28 czerwca 2003 roku. Tunel jest częścią autostrady D1 z Bratysławy do Koszyc i ma długość 4,877 km. W artykule podano zwięzłą informację o budowie najtrudniejszego odcinka autostrady pomiędzy miejscowościami Behárovce a Fričovce o długości 15,1 km. Przedstawiono najważniejsze zalety tunelu Branisko, który należy do najbardziej bezpiecznych tuneli czynnych obecnie w Europie. Zastosowano w nim system wentylacji wydechowej odprowadzającej zanieczyszczone powietrze przez szyb wentylacyjny, zlokalizowany w środkowym odcinku tunelu. W tunelu tym wybudowano trzynaście przekopów ucieczkowych do chodnika ucieczkowego. W chodniku tym zastosowano system wentylacji z nadciśnieniem powstrzymującym możliwość dostania się do niego dymów. Autorzy artykułu wyrazili uznanie wszystkim zaangażowanym w budowę tunelu Branisko.