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3. EARTH FILL DAMS
• EARTH FILL DAMS ARE COST-EFFECTIVE STRUCTURES MADE OF COMPACTED
SOIL OR ROCK FOR STORING WATER. PROPER DESIGN, CONSTRUCTION, AND
MAINTENANCE ARE CRUCIAL FOR THEIR STABILITY, WITH MEASURES TAKEN TO
CONTROL SEEPAGE AND MITIGATE RISKS FROM EARTHQUAKES AND OTHER
HAZARDS.

5. ABSTRACT
• EARTH-FILL DAMS, MADE OF EARTH AND ROCK-FILL MATERIALS, ARE KNOWN
AS EMBANKMENT DAMS OR FILL-TYPE DAMS.
• INDIA HAS ACHIEVED REMARKABLE PROGRESS IN DESIGNING AND
CONSTRUCTING DAMS THAT CAN WITHSTAND SEISMIC VIBRATIONS.
• DAMS ARE CRUCIAL FOR STORING WATER AND MEETING IRRIGATION NEEDS,
ESPECIALLY IN DEVELOPING COUNTRIES.
• DESIGNING DAM-LIKE STRUCTURES TO RESIST SEISMIC VIBRATIONS
REQUIRES SPECIAL CONSIDERATIONS BEYOND STATIC ANALYSIS.
• ANALYZING THE BEHAVIOR OF EARTH-FILL DAMS DURING AND AFTER SEISMIC
LOADING IS ESSENTIAL FOR THEIR SURVIVAL.

6. INTRODUCTION
• EARTHQUAKES POSE A SIGNIFICANT RISK TO DAMS, WITH 2% OF DAM
FAILURES ATTRIBUTED TO SEISMIC ACTIVITY.
• DAM FAILURES DUE TO EARTHQUAKES CAN RESULT IN EXTENSIVE DAMAGE,
LOSS OF LIFE, AND THE COLLAPSE OF ESSENTIAL INFRASTRUCTURE.
• DAMS ARE CRUCIAL FOR WATER SUPPLY, POWER GENERATION, TOURISM, AND
FLOOD CONTROL, BUT THEIR FAILURE CAN HAVE DEVASTATING
CONSEQUENCES FOR LAND, PEOPLE, AND THE ECONOMY.

7. INTRODUCTION
• EARTH DAMS ARE THE MOST COMMON TYPE GLOBALLY AND ARE COST-
EFFECTIVE, SERVING MULTIPLE PURPOSES.
• MANY COUNTRIES, PARTICULARLY IN SOUTHEAST ASIA, ARE UNPREPARED FOR
EARTHQUAKES, LEADING TO DAMS BEING DESIGNED AND CONSTRUCTED
BASED ON STATIC LOADING.
• URGENT SEISMIC SAFETY EVALUATION OF EXISTING DAMS IS NECESSARY TO
PROTECT DOWNSTREAM COMMUNITIES FROM POTENTIAL DISASTERS CAUSED
BY FUTURE EARTHQUAKES.

8. THE CAUSES OF DAM FAILURES
• OVERTOPPING
• FOUNDATION DEFECTS
• CRACKING
• INADEQUATE MAINTENANCE AND UPKEEP
• PIPING
• DISASTERS
• LIQUIFACTION

9. OVERTOPPING
• OVERTOPPING CAUSED BY WATER SPILLING OVER THE
TOP OF A DAM.
• OVERTOPPING OF A DAM IS OFTEN A PRECURSOR OF DAM
FAILURE. NATIONAL STATISTICS SHOW THAT
OVERTOPPING DUE TO INADEQUATE SPILLWAY DESIGN,
DEBRIS BLOCKAGE OF SPILLWAYS,
• SETTLEMENT OF THE DAM CREST ACCOUNT FOR
APPROXIMATELY 34% OF ALL U.S. DAM FAILURES.

10. SOIL DEFECTS
• DAM FAILURES CAN OCCUR DUE TO FOUNDATION DEFECTS, WHICH REFER TO
ISSUES OR WEAKNESSES IN THE UNDERLYING SOIL OR ROCK ON WHICH THE
DAM IS CONSTRUCTED.
• FOUNDATION DEFECTS CAN INCLUDE INADEQUATE SITE INVESTIGATION,
UNSTABLE OR WEAK FOUNDATION MATERIALS, GEOLOGICAL FAULTS, OR
INADEQUATE FOUNDATION PREPARATION.
• THESE FOUNDATION DEFECTS CAN COMPROMISE THE STABILITY AND
STRUCTURAL INTEGRITY OF THE DAM, MAKING IT MORE VULNERABLE TO
FAILURE, ESPECIALLY DURING SEISMIC EVENTS LIKE EARTHQUAKES.

12. CRACKING
• CRACKING CAUSED BY MOVEMENTS LIKE THE NATURAL SETTLING OF A DAM.

13. INADEQUATE MAINTENANCE AND UPKEEP
• REGULAR INSPECTIONS AND PROACTIVE MAINTENANCE MINIMIZE THE RISK OF
INADEQUATE UPKEEP AND ENSURE THE LONG-TERM SAFETY OF DAMS.
• ESTABLISHING A COMPREHENSIVE MAINTENANCE PLAN AND IMPLEMENTING
PROACTIVE PRACTICES MINIMIZE THE POTENTIAL FOR INADEQUATE
MAINTENANCE, REDUCING THE LIKELIHOOD OF DAM FAILURES.

14. PIPING
• PIPING IS WHEN SEEPAGE THROUGH A DAM IS NOT PROPERLY FILTERED AND SOIL PARTICLES CONTINUE
TO PROGRESS AND FORM SINK HOLES IN THE DAM.
• SEEPAGE OFTEN OCCURS AROUND HYDRAULIC STRUCTURES, SUCH AS PIPESAND SPILLWAYS; THROUGH
ANIMAL BURROWS; AROUND ROOTS OF WOODY VEGETATION; AND THROUGH CRACKS IN DAMS,
• DAM APPURTENANCES, AND DAM FOUNDATIONS.

15. DISASTERS LIKE NATURAL HAZARDS
• SUCH AS EARTHQUAKE, LANDSLIDES, FAULTS ETC.

16. LIQUIFACTION
• LIQUEFACTION CAN COMPROMISE DAM STABILITY BY
WEAKENING SATURATED SOILS, INCREASING THE
RISK OF FAILURE DURING SEISMIC EVENTS.

17. 1983 NIHON-KAI-CHUBU EARTHQUAKE
• THE 1983 NIHON-KAI-CHUBU EARTHQUAKE, WITH A MAGNITUDE OF 7.8,
OCCURRED IN THE SEA OF JAPAN, WEST OF NOSHIRO IN AKITA PREFECTURE,
JAPAN.
• THE EARTHQUAKE LASTED FOR APPROXIMATELY 60 SECONDS AND RESULTED
IN SIGNIFICANT DAMAGE, PARTICULARLY DUE TO SOIL LIQUEFACTION.
• LIQUEFACTION CAUSED THE COLLAPSE OF HOUSES, ROADS, AND NUMEROUS
DAMS, WITH ABOUT 145 DAMS FAILING AND SUSTAINING DAMAGE.
• FAILURES IN THE DAMS INCLUDED SLOPE SLIDING, WIDE LONGITUDINAL AND
TRANSVERSE CRACKS

18. TOHOKU EARTHQUAKE IN JAPAN IN 2011
• THE 2011 TŌHOKU EARTHQUAKE, WITH A MAGNITUDE OF 9.0-9.1, STRUCK OFF
THE PACIFIC COAST OF JAPAN, RESULTING IN DEVASTATING CONSEQUENCES.
• THE EARTHQUAKE TRIGGERED POWERFUL TSUNAMI WAVES, REACHING
HEIGHTS OF UP TO 40.5 METERS (133 FT) IN SOME AREAS.
• AS A RESULT OF THE EARTHQUAKE, 86 RESERVOIR AND AGRICULTURE DAMS
WERE DAMAGED ACROSS SEVEN PREFECTURES, INCLUDING AOMORI, IWATE,
MIYAGI, FUKUSHIMA, IBARAGI, TOCHIGI, AND GUNMA.

19. TOHOKU EARTHQUAKE IN JAPAN IN 2011
• FUJINUMA DAM IN SUKAGAWA CITY EXPERIENCED SIGNIFICANT DAMAGE,
LEADING TO EIGHT CASUALTIES. THE DAM, CONSTRUCTED 62 YEARS PRIOR,
WAS LOCATED APPROXIMATELY 240 KM FROM THE DAMAGED FUKUSHIMA
NUCLEAR PLANT.
• THE FAILURE OF THE EMBANKMENT DAM OCCURRED WITHIN 20 MINUTES OF
THE EARTHQUAKE, WITH A SECTION OF THE DAM BANK, 18 METERS IN HEIGHT
AND 133 METERS IN LENGTH, COLLAPSING. THE DAM HAD NOT BEEN
DESIGNED TO WITHSTAND SEISMIC FORCES, AND ITS FAILURE WAS
EXACERBATED BY THE RESERVOIR BEING AT FULL CAPACITY AT THE TIME OF
THE EARTHQUAKE.

20. BHUJ EARTHQUAKE 2001-
• THE CHANG RESERVOIR WAS NEARLY EMPTY DURING THE EARTHQUAKE, BUT THE
ALLUVIUM SOILS UNDERNEATH THE DAM WERE POSSIBLY SATURATED.
• THE EARTHQUAKE CAUSED A COMPLETE COLLAPSE OF THE DAM, INCLUDING
DAMAGE TO THE IMPERVIOUS CORE AND THE MASONRY WALL.
• SAND BOILS WERE OBSERVED NEAR THE UPSTREAM TOE OF THE DAM, INDICATING
WIDESPREAD LIQUEFACTION WITHIN THE FOUNDATION SOILS.

21. FATEHGADH DAM:
• THE FATEHGADH RESERVOIR WAS NEARLY EMPTY DURING THE EARTHQUAKE, BUT
THE ALLUVIUM SOILS UNDERNEATH THE UPSTREAM PORTION OF THE DAM WERE
SATURATED.
• THE EARTHQUAKE TRIGGERED FAILURE NEAR THE BOTTOM PORTION OF THE
UPSTREAM SLOPE, POSSIBLY DUE TO LOCALIZED LIQUEFACTION NEAR THE
UPSTREAM TOE OF THE DAM.
• CRACKS AS DEEP AS 1.5 TO 1.7 M WERE FOUND WITHIN THE UPSTREAM PORTION
OF THE DAM, INDICATING INSTABILITY NEAR THE TOP PORTION OF THE
DOWNSTREAM SLOPE.
• THE APPEARANCE OF LONGITUDINAL CRACKS MAY INDIRECTLY RELATE TO
LIQUEFACTION OF FOUNDATION SOILS.

23. SAN FRANCISCO EARTHQUAKE 1906-
• MAGNITUDE: THE EARTHQUAKE HAD A MAGNITUDE OF 8.25.
• PROXIMITY: THERE WERE 33 EARTH DAMS WITHIN 56 KM OF THE FAULT AND 15
DAMS WITHIN 8 KM THAT WERE DAMAGED, WITH SOME FAILING.
• GROUND MOTIONS: IT IS LIKELY THAT ALL THESE DAMS EXPERIENCED
GROUND MOTIONS WITH PEAK GROUND ACCELERATIONS GREATER THAN 0.25
G. DAMS WITHIN 8 KM PROBABLY EXPERIENCED ACCELERATIONS GREATER
THAN ABOUT 0.6 G.
• LACK OF SIGNIFICANT DAMAGE: DESPITE THE STRONG GROUND MOTIONS,
NONE OF THE OLD DAMS SUFFERED SIGNIFICANT DAMAGE.
• SLOPES: THE DAMS HAD FAIRLY STEEP SLOPES, TYPICALLY RANGING FROM 1:2
TO 1:3.
• CONSTRUCTION MATERIALS: THE DAMS WERE CONSTRUCTED MAINLY OF
CLAYEY SOILS ON ROCK OR CLAYEY SOIL FOUNDATIONS. TWO DAMS WERE
BUILT LARGELY OF SAND, BUT IT WAS NOT SATURATED.

24. SAN FERNANDO EARTHQUAKE 1971
• OCCURRENCE: THE EARTHQUAKE TOOK PLACE ON FEBRUARY 9, 1971, IN THE
FOOTHILLS OF THE SAN GABRIEL MOUNTAINS IN SOUTHERN CALIFORNIA.
• LIQUEFACTION: THE EARTHQUAKE CAUSED LIQUEFACTION, WHICH IS A SERIOUS
PROBLEM FOR DAMS CONSTRUCTED ON OR WITH LOW-DENSITY, SATURATED
SANDS.
• SETTLEMENT: THE CREST OF THE LOWER SAN FERNANDO DAM, WHICH WAS 40 M
HIGH, SETTLED BY 8.5 METERS DURING THE EARTHQUAKE.
• DAM CONSTRUCTION: THE DAM WAS BUILT USING HYDRAULIC FILL, WHICH IS
HIGHLY SUSCEPTIBLE TO LIQUEFACTION DUE TO ITS LOW DENSITY.
• WATER LEVEL: FORTUNATELY, BEFORE THE EARTHQUAKE, THE WATER LEVEL IN
THE DAM WAS ABOUT 10 METERS BELOW THE CREST.
• DAMAGE: FOLLOWING THE EARTHQUAKE, ONLY 1.5 METERS OF BADLY CRACKED
MATERIAL REMAINED AT THE DAM.
• EVACUATION: AS A RESULT OF THE DAMAGE AND POTENTIAL RISK, APPROXIMATELY
80,000 PEOPLE LIVING DOWNSTREAM OF THE DAM HAD TO BE EVACUATED.

25. CONCLUSION
• PROPERLY DESIGNED STORAGE DAMS HAVE INHERENT RESISTANCE TO
EARTHQUAKES.
• LARGE DAMS HAVE NOT FAILED DUE TO EARTHQUAKE SHAKING.
• EARTHQUAKES POSE MULTIPLE HAZARDS TO DAMS.
• UNCERTAINTIES REMAIN ABOUT DAM BEHAVIOR DURING STRONG GROUND
SHAKING.
• DAMS MUST WITHSTAND STRONG GROUND SHAKING TO PREVENT
UNCONTROLLED WATER RELEASE.
• SMALL DAMS MADE OF HOMOGENEOUS MATERIALS HAVE EXPERIENCED
FAILURES IN EARTHQUAKES.
• LIQUEFACTION OF EMBANKMENT MATERIALS OR FOUNDATIONS CAN CAUSE
SIGNIFICANT DAMAGE TO DAMS.
• LOOSE SANDY MATERIALS ARE PARTICULARLY SUSCEPTIBLE TO LIQUEFACTION.