Approaches to risk assessment in tunnelling and underground spaces were
introduced in 2004 as a result of several serious accidents in tunnels such
as Mont Blanc and Tauern Tunnel in 1999. The EU has published the minimum
safety requirements for tunnels over 500 m on Trans-European Road Network.
The risk assessment is mandatory and should cover all components of the
system, i.e. infrastructure, operation, users and vehicles. The professional
community has started using the QRA (Quantitative Risk Assessment) approach,
where the crucial issue is the consequence analysis of fire scenarios in a
tunnel. Fire development is a complex physical phenomenon and its
calculation is time consuming; therefore, complex models have rarely been
used in QRA approaches. This paper presents the methodology of integrating
fast-processing risk assessment methods with time-consuming CFD
(Computational Fluid Dynamics) methods for fire consequence analysis in the
process of tunnel safety assessment. The main variables are soot density and
temperature, which are analysed in one-minute time steps during the fire.
Human behaviour is considered with the evacuation model, which is needed to
evaluate fatalities during the fire process. The application of the
methodology is presented based on the evaluation of the national tolerable
risk for tunnel transport and compared with referenced EU risk criteria.
Furthermore, the presented methodology links CFD simulation results and the
QRA approach, still representing the collective risk with F-N curves.
Quantitative Risk Assessment Modeling for Nonhomogeneous Urban Road Tunnels
