Seismic Design of Tunnels - Parsons Brinckerhoff

Based on their study, Dowding and Rozen concluded, primarily for rock tunnels, that:
• Tunnels are much safer than aboveground structures for a given intensity of shaking.
• Tunnels deep in rock are safer than shallow tunnels.
• No damage was found in both lined and unlined tunnels at surface accelerations up to
0.19g.
• Minor damage consisting of cracking of brick or concrete or falling of loose stones
was observed in a few cases for surface accelerations above 0.25g and below 0.4g.
• No collapse was observed due to ground shaking effect alone up to a surface
acceleration of 0.5g.
• Severe but localized damage including total collapse may be expected when a tunnel
is subject to an abrupt displacement of an intersecting fault.
Owen and Scholl (1981)
These authors documented additional case histories to Dowding and Rozens’, for a
total of 127 case histories. These added case histories, in addition to rock tunnels,
included:
• Damage reports on cut-and-cover tunnels and culverts located in soil
• Data on underground mines, including shafts
The authors’ discussion of some of the damaged cut-and-cover structures is of
particular interest. These structures have the common features of shallow soil covers and
loose ground conditions:
• A cut-and-cover railroad tunnel with brick lining (two barrels, each approximately 20
feet wide) was destroyed by the 1906 San Francisco earthquakes. In this case, where
brick lining with no moment resistance was used, the tunnel structure collapsed.
• Five cases of cut-and-cover conduits and culverts with reinforced concrete linings
were damaged during the 1971 San Fernando earthquake. The damages
experienced by the linings included:
- The failure of longitudinal construction joints
- Development of longitudinal cracks and concrete spalling
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