THE FAILURE OF SHIH-KANG DAM

1
THE FAILURE OF SHIH-KANG DAM
by
Amokomowo Aderemi Dawoud Adenaiye Oluwaleke
2
Contents

• Introduction
• Geology of the dam
• Failure of the dam
• Cause of failure
• Solutions adopted
• Rehabilitation Process
• Conclusion

3
Introduction

• Shih-kang dam is located about 100km southwest of
  Taipei and built in 1977

• Dam dimensions 357m long 25m high and 540m wide
  at the base

• Reservoir Capacity 3.38million m3

• Dam failed in 1999 as the first concrete dam to
  be directly damaged by the active fault in the
  history of the hydraulic structures

4
Geology of the dam
Geological Map of Shih-Kang map

• The geology of the Shih-Kang Dam site is composed
  of about 6-meter thick deposition layer on the
  surface and the next is the soft bedrock of the
  Cho-Lan formation.

• The deposition layer is formed by unconsolidated
  gravel, sands, silts and clay. The bedrock, soft
  and easily weathered, is mainly formed by
  slate-gray sandy-shale and silty-sandstones.

5
FAILURE OF THE DAM

• Effects of the large ground motion.

• Impact type damage.
• Strong contact impact of every adjacent weir
  body during the earthquake.

• Fault rupture type.
• Most complicated type.

6
Cause of failure

• Strong motion of earthquake
• Remarkable rupture of fault
• Large displacement of ground surface.

7
Solutions adopted

• Construction of a new reservoir in the upstream
  of the Shih Kang Dam away from the Che-Lung-Pu
  fault

• Rehabilitation work was carried out in an
  economic, efficient, and effective way.

8
REHABILITATION PROCESS

• First phase
•  
• Repairing of the intake structure and the tunnel.
  
• The ruined concrete lining tunnel was coated by
  steel pipe lining.
• The wing wall of the left abutment was rebuilt.
•  

• Second phase
• Repair the dam-body out of the fault aligning
  area.
• The cement grouting was taken in the dam
  foundation.
• Epoxy cement was injected into the cracks of the
  dam-body and stilling basin.
• The new downstream tail dam was installed.

• Third phase
• To reserve the right part of the dam, which was
  located on the fault aligning area, to be a
  memorial of Chi-Chi earthquake.
• To install a cofferdam in front of the right part
  of the dam.

9
RECOMMENDATION

• Adequate Site Investigation

• Construction Monitoring

• Periodical Long term Monitoring

10
CONCLUSION

• Dam failure caused strong motion of earthquake
  and remarkable rupture of fault

• New dam construction away from the fault
  followed adequate site investigation after the
  failure

11
QUESTIONS?
QUESTIONS?
QUESTIONS?
QUESTIONS?