Earthquake Engineering Committee, JSCE

1
Possible Guidelines for the Seismic Design of
Tunnels
Earthquake Engineering Committee, JSCE
2
What are Seismic Intensity Levels1and2?
3
What are the 1st and 2nd Stages of soil strain ?
Ishihara, K. Soil Behavior in Earthquake
Geotechnics
4
Underground Structures follow the motion of their
surrounding soils.
essentially important
5
Stage 2

• liquefaction

A box tunnel of Niigata St. was squeezed up
causing rails to be bent.
The tunnel was half immersed in the liquefied
sand.
6
Stage 2

• Damage to pipes

Alternate push and pull ?
Buckled pipe with22.5bend (100 mm?Oga city)
Pipes cut into one another(100 mm?Oga city)
Mid-Japan Sea Earthquake of 1983
7
Stage2

• Slope failure(clay)

clack
Akasaka tunnel, Uetsu line and slope failure
Nezugaseki tunnel, Uetsu line
8
Stage 2

• Slope failure(rock)

The 2nd Shiraito tunnel, National Highway Rt. 229
South-North off Hokkaido Earthquake of 1993
9
Stage2
Inatori tunnel
Damage caused by the activated fault
10
What are Concrete Damage Extents ?
1
2
3
4
11
Soil spring for concrete structure (Damage level
1)
A
m
u q(r) f(r - vt)
12
Contact force p is obtained as
13
When q(r) r
1/2