Page 335 - 360.revista de Alta Velocidad - Nº 5

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número 5 - junio - 2018. Pág 333 - 353

Influence of Aerodynamics in Tunnels Design

Sepúlveda Abad, Silvia

Lastra de la Rubia, Emilia

Ineco
1

Abstract
There are a significant number of factors to consider during tunnels design in order to increase
effectivity in construction, reduce schedules, and provide more appropriate cross-sections
for each tunnel depending on its location, conditions of exploitation and rolling stock among
others.
When a high-speed train enters in a tunnel there is an overpressure and depression in head
and tail that propagates along it at the speed of sound, reflecting each time they reach the
portals of the tunnel. These variations of pressure, in addition to increasing the aerodynamic
drag of the train, can affect the health and comfort of passengers.
Aerodynamically speaking, it is recommended meeting health and comfort criteria. The
health criterion is mandatory in accordance with the Infrastructure Technical Specification
of Interoperability (TSI). The comfort criteria are variable depending on the country and are
usually more restrictive in terms of sizing the free cross-section of the tunnel.
During the last years, designers have developed methodologies and tools to use in calculations
for achieving the best tunnel conditions for all the counterparts.
There are two consequences extracted as a result of the development of the methodologies.
Firstly, the reduction of the free cross-section of the tunnel to the minimum values as
required by the geometrical conditions. Secondly, being able to optimize train speed along
the tunnel while complying with the aforementioned criteria, which leads to reductions in
cost, improved conditions of exploitation and reduced travel times.
However, aerodynamics research cannot be limited to these studies. The future will require
speed improvements and longer tunnels while keeping the same standards of safety and
comfort. Currently new factors such as overpressures or depressions in tunnel installations or
sonic boom effect are being investigated and included in project requirements.
In relation to this, INECO has developed a software capable of calculating the aerodynamic
effects in every specific position within the tunnel, train or the installation. The software
most interesting functionality is the capability of modelling and mitigate sonic boom effect.

Keywords: Aerodynamics, free cross-section, tunnels, speed, comfort criteria, health criterion.

1 Sepúlveda Abad, Silvia. INECO. Email: silvia.sepulveda@ineco.com (corresponding author)
Lastra de la Rubia, Emilia. INECO. Email: emilia.lastra@ineco.com

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