An increasing share of traffi c tunnels are
designed as twin-tube systems. The tubes
are inter-connected by galleries. During the
construction, operation and refurbishment
phases of the tunnel’s lifecycle, these crosspassages
may serve di.erent purposes:
• To connect an incident tube with a safe
area by providing an egress path for
evacuees or an access path for rescue
services during an emergency
• To o.er a temporary shelter or waiting
area for evacuees or rescue services
during an emergency
• To provide an aerodynamic, fi re- and
smoke-safe separation between di.erent
tubes during all operation modes
• To house technical equipment in a
controlled environment during all
operation modes
• To provide an access path for sta. to
technical equipment inside the crosspassage
or in the opposite tube(s)
during maintenance mode of operation
• To support ventilation purposes and
the environmental control of the tunnels
during all operation modes
• To provide a passage for tunnel works
and transportation (conveyor belts,
pipes, cables, drainage, vehicles, etc.)
during construction and refurbishment
phases.
Because of these various requirements and
boundary conditions, the layout of crosspassages
in tunnels may vary considerably.
In addition, the construction of crosspassages
in twin-tube tunnels may be a
risk-prone activity and become a costly
task depending on the ground conditions.
Therefore, the design of cross-passages
requires particular attention in order to meet
the numerous technical, legal, safety and
economic requirements.
Specifi c aspects of the aforementioned
requirements of cross-passages are the
tasks to provide operational safety and the
consideration of the specifi c requirements of
rail and metro tunnels.
Safety guidelines for road tunnels have reached
a high level of detail and exhibit a substantial
degree of international harmonization. In
contrast, safety requirements for rail tunnels
and underground systems are limited to more
basic requirements and are less uniform
(e.g. TSI-SRT [1], NFPA 130 [15], UIC
[5]). This applies as well to cross-passage
design of rail and metro tunnels. Therefore,
a comprehensive overview of state-of-the-art,
safety-oriented cross-passage design for rail
and metro tunnels is desirable.
The layout and key parameters characterizing
cross-passages, including maximum distance,
minimum dimensions, technical equipment
and level of protection, depend on a number
of regulations and vary signifi cantly from
country to country. Such di.erences are only
partly due to the specifi c characteristics of
a tunnel but are related to a large extent to
the lack of explicit regulations or references
on such issues. An overview appears helpful
to present similarities and di.erences and
facilitate the proper inclusion of operational
safety requirements in tunnel design.