bultar och sprutbetong i norra lnken - en tillmpning av tunnel 95

SUMMARY
The Northern Link (of the Stockholm Ringroad) is the part of the planned infrastructure
development in Stockholm that will be situated between Haga Norra in the west,
Frescati in the north and Lidingövägen in the east. The engineering design work of this
road tunnel system was performed over a period of more than three years ending in the
spring of 1997.
During the design period, the Swedish National Road Administration’s new regulations
for road tunnels - Tunnel 95 - were introduced. This document included new
requirements on design and durability of rock support elements.
The Swedish national building norms BKR 94, BBK 94 and BSK 94 were all published
during the second half of 1994. When Tunnel 95 was finally introduced in July 1995,
the National Road Administration had based the environmental classification
paragraphs in Tunnel 95 on BSK 94 and BBK 94. These regulations, however, do not
really apply to rock tunnel conditions. To a large extent the design of the Northern Link
up to that time had been based on accepted working traditions and practice within the
rock engineering field in Sweden. Because the design work of the Northern Link at that
time had been under way for more than 1,5 years, an adjustment was required. The
enforce-ment of the regulations of BBK 94 on corrosion protection required extensive
changes to the design documents. This lead to extensive discussions and studies on the
applicability and interpretation of the meaning of the norm regarding rock tunnels. The
outcome was that the National Road Administration decided to implement certain
deviations from Tunnel 95 concerning the environmental classification of rock support
of tunnels.
This paper describes the conditions, principles and methods regarding the
environmental classification (corrosion protection) of rock support elements
implemented in the Roslagstull and the Värtan design documents in order to meet the
durability requirements of Tunnel 95.