Seismic Capacity Assessment of
Sanyi Old Railway Tunnel
Jin - Hung Hwang , Chih - Chieh Lu
Department of Civil Engineering...
DATE: 10th Nov, 2010
CET Hall
www.cesnitsilchar.wordpress.com Fanpage MISSION 2015::NIT Silchar www.twitter.com/cesnitsilcha
Outline
Introduction
Basic Data of the Tunnels
Assessment Methods
Analysis procedure of MCSRD
Case analysis – Sanyi O...
Introduction
Underground structures are traditionally
considered to be more earthquake-resistant.
Extremely strong shaki...
Basic Data of the tunnels
Topography
 DTM topography
 Max. overburden depth
Geology
 Gravel and soft rock formations
...
Cross section and lining
 Cross section
 Lining thickness and materials
Current state of the tunnels
 Cracks
 Seepin...
Assessment Methods
The empirical method (Langefors and
Kihlstrom, 1963)
 Damage criterion
 Allowable PGV for concrete a...
The Modified Cross-Section Racking
Deformation Method (MCSRD)
 Analysis procedure of MCSRD
 Case analysis-Sanyi old rai...
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 1:Set up the grid mesh
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 2:Apply geostatic stresses
vσ
vh Kσσ 0= vh Kσσ 0=
vσ
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 3:Excavate the tunnel and install
the lining support
vσ
vh Kσσ 0= vh Kσσ 0=
vσ
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 4:Apply a seismic shear strain
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 5: Check the lining strength curves
Mu
Pu
Vu
Pu
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 6: Decide the allowable seismic
shear strain
 The allowable seismic shear strain is the shear strain
that just cause...
Analysis procedure of MCSRD
Set up the grid mesh
Apply geostatic stresses
Excavate the tunnel and install the lining
su...
Step 7: Calculate the allowable peak
ground velocity (PGV)
......(1)....................asa V γυ ×=
is the allowable peak ...
Case Analysis
Sanyi old railway tunnels
Input data
The enlarged deformation behavior of
tunnel
The distribution of bend...
Input data
The parameters of the ground formation
Ground
formation
Unit weight
(KN/m3
)
E
(GPa)
c
(MPa)
φo Poison
ratio
Vs...
The enlarged deformation behavior of tunnel
original
deformed
Shear direction
0.01剪應變
The distribution of bending moment,
shear force, and axial force on the tunnel
0.002剪應變 0.01剪應變Shear forceBending ...
Check the lining strength curves
shear strain= 0.005
Mu (tf-m)
shearstrain= 0.001
-500
0
500
1,000
1,500
2,000
2,500
3,000...
The allowable peak ground velocity (PGV)
Bending failure mode Shearing failure mode
0
0.2
0.4
0.6
0.8
1.0
1.2
10 15 20 25 ...
Seismic capacity of the tunnels
gravel formation
Seismic capacity of the tunnels
soft rock formation
bending failure mode shearing failing mode
JMA
scale
Lining strength(k...
Summary of the assessed seismic capacity
JMA IV in gravel at least
JMA V in soft rock at least
One scale larger than th...
Comparison with Field Performances
in the Past Earthquakes
1935 Hsinchu-Taichung Earthquake
 Historic iso-seismal map
 ...
Comparison
 Assessed JMA=IV~V at least
 JMA=VI in 1935 earthquake → serious damage
 JMA= IV~V in 1999 earthquake →no d...
Conclusion
 A modified cross-section racking deformation
(MCSRD) method is proposed to assess the
seismic capacities of t...
The assessed seismic capacities of Sanyi
old railway tunnels agree well with their
field performances in the past
earthqu...
Thanks for your attention
Upcoming SlideShare
Loading in …5
×

Seismic Capacity Assessment of Sanyi Old Railway Tunnel

1,276
-1

Published on

Lecture Details:

Seismic Capacity Assessment of Sanyi Old Railway Tunnel

By Prof. Jin-Hung Hwang

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
1,276
On Slideshare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
32
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Seismic Capacity Assessment of Sanyi Old Railway Tunnel

  1. 1. Seismic Capacity Assessment of Sanyi Old Railway Tunnel Jin - Hung Hwang , Chih - Chieh Lu Department of Civil Engineering National Central University November 9, 2005
  2. 2. DATE: 10th Nov, 2010 CET Hall
  3. 3. www.cesnitsilchar.wordpress.com Fanpage MISSION 2015::NIT Silchar www.twitter.com/cesnitsilcha
  4. 4. Outline Introduction Basic Data of the Tunnels Assessment Methods Analysis procedure of MCSRD Case analysis – Sanyi Old Railway Tunnel Conclusion
  5. 5. Introduction Underground structures are traditionally considered to be more earthquake-resistant. Extremely strong shaking might induce damages of rock tunnel  1995 Kobe earthquake About 10 tunnels required countermeasures  1999 Taiwan Chi-Chi earthquake A total of fifty tunnels were reported to be damaged An important issue to tunnel engineers in seismic active area
  6. 6. Basic Data of the tunnels Topography  DTM topography  Max. overburden depth Geology  Gravel and soft rock formations  Geotechnical parameters and wave velocities
  7. 7. Cross section and lining  Cross section  Lining thickness and materials Current state of the tunnels  Cracks  Seeping of the ground water
  8. 8. Assessment Methods The empirical method (Langefors and Kihlstrom, 1963)  Damage criterion  Allowable PGV for concrete and brick linings  Threshold PGA and JMA scale in the gravel and soft rock formation  Correlation of PGV with JMA intensity scale  Assessment results
  9. 9. The Modified Cross-Section Racking Deformation Method (MCSRD)  Analysis procedure of MCSRD  Case analysis-Sanyi old railway tunnels
  10. 10. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  11. 11. Step 1:Set up the grid mesh
  12. 12. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  13. 13. Step 2:Apply geostatic stresses vσ vh Kσσ 0= vh Kσσ 0= vσ
  14. 14. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  15. 15. Step 3:Excavate the tunnel and install the lining support vσ vh Kσσ 0= vh Kσσ 0= vσ
  16. 16. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  17. 17. Step 4:Apply a seismic shear strain
  18. 18. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  19. 19. Step 5: Check the lining strength curves Mu Pu Vu Pu
  20. 20. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  21. 21. Step 6: Decide the allowable seismic shear strain  The allowable seismic shear strain is the shear strain that just causes the lining internal forces reach the limit state. Mu Pu Vu Pu
  22. 22. Analysis procedure of MCSRD Set up the grid mesh Apply geostatic stresses Excavate the tunnel and install the lining support Apply a seismic shear strain Check the lining strength curves Decide the allowable seismic shear strain Calculate the allowable peak ground velocity (PGV)
  23. 23. Step 7: Calculate the allowable peak ground velocity (PGV) ......(1)....................asa V γυ ×= is the allowable peak ground velocity where, is the allowable seismic shear strain aγ av sV is the wave velocity of the ground
  24. 24. Case Analysis Sanyi old railway tunnels Input data The enlarged deformation behavior of tunnel The distribution of bending moment, shear force and axial force on the tunnel Check the lining strength curves The allowable peak ground velocity (PGV) Seismic capacity of the tunnels
  25. 25. Input data The parameters of the ground formation Ground formation Unit weight (KN/m3 ) E (GPa) c (MPa) φo Poison ratio Vs (km/sec) Vp (km/sec) soft rock 24 1.96 0.2 32 0.3 0.6 ~ 1.5 2 ~ 3 The cross section and strength properties of the linings lining thickness (m) 0.3 0.45 0.6 0.8 1 cross section (m2 ) 0.3 0.45 0.6 0.8 1 moment inertial (m4 ) 0.00225 0.00759 0.018 0.0427 0.0833 lining strength (kg/cm2 ) 140 、 210 、 280 、 350
  26. 26. The enlarged deformation behavior of tunnel original deformed Shear direction
  27. 27. 0.01剪應變 The distribution of bending moment, shear force, and axial force on the tunnel 0.002剪應變 0.01剪應變Shear forceBending moment Axial force0.01剪應變
  28. 28. Check the lining strength curves shear strain= 0.005 Mu (tf-m) shearstrain= 0.001 -500 0 500 1,000 1,500 2,000 2,500 3,000 0 50 100 150 200 250 300 Mu (tf-m) Pu(tf) shear st r ai n=0 -500 0 500 1,000 1,500 2,000 2,500 3,000 0 50 100 150 200 250 300 Mu (tf-m) Pu(tf) -500 0 500 1,000 1,500 2,000 2,500 3,000 0 50 100 150 200 250 300 Pu(tf) shear strain =0.005 0 50 100 150 200 0 50 100 150 200 Vu (tf) Pu(tf) Shear strain=0.002 0 50 100 150 200 0 50 100 150 200 Vu (tf) Pu(tf) shear strain=0 0 50 100 150 200 0 50 100 150 200 Vu (tf) Pu(tf)
  29. 29. The allowable peak ground velocity (PGV) Bending failure mode Shearing failure mode 0 0.2 0.4 0.6 0.8 1.0 1.2 10 15 20 25 30 ground velocity(cm/s) Liningthickness(m) fc'=140 fc'=210 fc'=280 fc'=350 0 0.2 0.4 0.6 0.8 1.0 1.2 30 35 40 45 50 ground velocity(cm/s) liningthickness(m) fc'=140 fc'=210 fc'=280 fc'=350
  30. 30. Seismic capacity of the tunnels gravel formation
  31. 31. Seismic capacity of the tunnels soft rock formation bending failure mode shearing failing mode JMA scale Lining strength(kg/cm2 ) JMA scale Lining strength(kg/cm2 ) 140 210 280 350 140 210 280 350 Liningthickness(m) 0.3 V V V V Liningthickness(m) 0.3 V V V V 0.45 V V V V 0.45 V V V VI 0.6 V V V V 0.6 V V Ⅵ VI 0.8 V V V V 0.8 V VI VI VI 1.0 V V V V 1.0 VI VI VI VI
  32. 32. Summary of the assessed seismic capacity JMA IV in gravel at least JMA V in soft rock at least One scale larger than that assessed by the empirical method
  33. 33. Comparison with Field Performances in the Past Earthquakes 1935 Hsinchu-Taichung Earthquake  Historic iso-seismal map  ML=7.1,JMA=VI,PGA≥400 gal  Damage condition 1999 Chi-Chi Earthquake  ML=7.3, iso-seismal map  Estimated PGV, PGA and JMA scale  JMA=IV~V  No damage
  34. 34. Comparison  Assessed JMA=IV~V at least  JMA=VI in 1935 earthquake → serious damage  JMA= IV~V in 1999 earthquake →no damage  Agree field performance well
  35. 35. Conclusion  A modified cross-section racking deformation (MCSRD) method is proposed to assess the seismic capacities of the tunnel structures. It is easy ,fast, and able to automatically consider nonlinear SSI effect and to consider complex rock formation and irregular tunnel shape.
  36. 36. The assessed seismic capacities of Sanyi old railway tunnels agree well with their field performances in the past earthquakes
  37. 37. Thanks for your attention
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×