Sharif University of Technology Civil Engineering Department Tehran-Iran

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Sharif University of TechnologyCivil Engineering
DepartmentTehran-Iran

• Dam Safety
• An Approach to Prevent
• Dam Incidents

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Dam failure results in a catastrophic break
followed by a flood wave often with considerable
loss of life or property
Safety during Design, Construction, Operation,
Maintenance, and Surveillance of dams
Past incidents of unacceptable performance can
help us in understanding of method of detection
and expand our knowledge on behavior of dams and
reservoir and this simulates further improvements
in design, maintenance and surveillance of dams
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Main causes of Dam Failure Failure of Concrete
Dams

• Lack of shear strength and discontinuity in
  foundation
• Excessive uplift in the foundation (inadequate
  or non-existent drainage)
• Lack of dam stability
• Excessive or differential deformation of the
  foundation
• Piping and erosion in the foundation caused by
  high permeability
• Flaw in design
• Lack of supervision during construction
• No monitoring or warning system (systems were out
  of order)
• Cont. next page

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Main causes of Dam Failure Failure of Concrete
Dams (cont. )

• Human error during site investigation and design
  and construction and operation
• Inadequate foundation investigation
• Incomplete data on available material
• Poor design
• Negligible construction supervision
• Incomplete first impoundment
• Incorrect operation of flood gates
• Insufficient monitoring and data analysis
• Lack of preventive measures or repair work

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Main Causes of Dam Failure Embankment Dam Failure

• Overtopping during flood discharge because of
  inadequate spillway capacity or non-functioning
  flood gate
• Internal erosion along the dam-foundation
  interface or along embankment with adjoining or
  embeded appurtunent structures or concentrated
  piping in the embankment itself because of
  inadequate or non-existent filter zones
• Nonhomogeneity in the foundation or dam (leading
  to foundation failure or erosion )
• Large settlement in the foundation
• Crack following the settlement, with resulting
  piping effect
• liquefaction

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Failure Prevention

• Failure could have been prevented if some of
  these points had been observed
• Failure is a complex process
• Begins with some abnormality in behaviour (not
  detected)
• Consequent deteriorations (not observed)
• Further damage or disaster

Inspection and Monitoring of dams as well as data
analysis and interpretation has a critical role
in the field of dam safety
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Dam Safety Guidelines

• Intended to offer a comprehensive review
• Dam -design -operation -construction
• maintenance -surveillance
• Recommendations rather than binding regulations
• Guidelines are not standards
• Details dealt with as necessary

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Dam Safety Procedure (adapted for Iran)
Dam Safety Procedure General Plan
Owner
Monitoring
Emergency Action Plan (EAP)
Consultant Companies
Periodic Dam Safety Review
Dam Retrofitting
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MONITORING Instrumentation and Surveillance

• External and internal examination of dams during
  their life time
• Long term surveillance program
• Ensure dams owner of their safe operation
• Monitoring
• Measure Displacement
• Settlement
• Strain
• Piezometric pressure
• Seepage
• Uplift
• Water level
• Alarm System

Compilation of Results, Interpretation, Recommenda
tion, To take appropriate action
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MONITORING Instrumentation

• To characterize dam site and dam structure
  condition
• To verify Design
• To asses safety
• To asses performance

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Thank You