Damage prog[r]ession on rubble-mound breakwaters

224 Pages·1999·5.6 MB·English

by  Melby, Jeffrey A

Technical Report CHL-99-17
July 1999
US Army Corps
of Engineers
Waterways Experiment
Station
Damage Progression on Rubble-Mound
Breakwaters
by JeffreyA. Melby
Approved ForPublicRelease; Distribution IsUnlimited
Preparedfor Headquarters, U.S. Army Corps of Engineers
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Technical Report CHL-99-17
July 1999
Damage Progession on Rubble-Mound
Breakwaters
by JeffreyA. Melby
U.S. ArmyCorpsofEngineers
Waterways ExperimentStation
3909 Hails FerryRoad
Vicksburg, MS 39180-6199
Final report
Approvedforpublicrelease;distributionisunlimited
Preparedfor U.S. Army Corps of Engineers
Washington, DC 20314-1000
Under Civil Works Research Work Unit 32792
us Army Corps
of Engineers
Waterways Experiment
Station
FORINFORMATIONCONTACT:
PUBLICAFFAIRSOFFICE
U.S.ARMYENGINEER
WATERWAYSEXPERIMENTSTATION
3909HALLSFERRYROAD
VICKSBURG.MISSISSIPPI 39180-6199
PHONE:[phone]
AREAOFRESERVATION:
WaterwaysExperimentStationCataloging-in-Pubiication Data
Melby,JeffreyA.
Damageprogressiononnjbbie-nnoundbreakwaters/byJeffreyA. Melby;preparedfor
U.S.ArmyCorpsofEngineers.
216p. : ill. ;28cm.--(Technical report;CHL-99-17)
Includesbibliographicreferences.
1. Rubble-moundbreakwaters--Stability-Testing. 2. Breakwaters-Stability~
Testing. 3. Coastalengineering. 4. Flumes-Testing. 5. Hydrodynamics. I. United
States. Army.CorpsofEngineers. II. U.S.ArmyEngineerWaterways Experiment
Station. III. CoastalandHydraulicsLaboratory(U.S.ArmyEngineerWaterways
ExperimentStation) IV.Title. V.Series:Technicalreport(U.S.ArmyEngineer
WaterwaysExperimentStation); CHL-99-17.
TA7W34no.CHL-99-17
1
TABLE OFCONTENTS
Preface - xv
Chapter
INTRODUCTION
1 1
2 INCIPIENTSTABILITYOFBREAKWATERARMORUNITS 6
2.1 ArmorStabilityEquations 6
2.2 ArmorIncipientMotionStudies 10
2.3 ExperimentalSetup 12
2.4 IncipientMotionObservations 17
2.5 ExperimentalMeasurements 18
2.6 IncipientMotionPrediction 22
2.7 ConclusionsfromIncipientMotionStudy 32
3 HISTORICALDAMAGEMEASUREMENTANDDESCRIPTION . . 33
3.1 DamageModelingStandards 33
3.2 DamageMeasurementMethods 34
3.2.1 Erodedvolumemethod 34
3.2.2 Stonecountmethod 40
3.2.3 Recentdamagemeasurementmethods 40
3.3 DamageMeasurementExperiments 41
3.4 DamageProgressionPrediction 44
3.5 VariabilityinStabilityResults 50
4 DETERIORATIONEXPERIMENT 53
4. Overview 53
4.2 ExperimentalSetup 54
11
4.2. Flumeandstructure 54
4.2.2 Experimentaltestconditions 56
4.2.3 Armorlayerandiinderlayer 56
4.2.4 Model-Prototypesimilitude 60
4.3 WaveGenerationandMeasurementinInitialExperiment 62
4.3. Wavegeneration 62
4.3.2Wavemeasurement 64
4.4 EffectofOvertoppingonStability 74
4.5 ArmorProfilerandProfileMeasuringTechnique 74
DAMAGEMEASUREMENTS
5 81
5.1 Overview 81
5.2 DamageandErodedProfileParameters 83
5.3 ProbabilityDensityFunctionsofDamage,ErodedDepth,and
CoverDepth 85
5.4 TemporalDamageDevelopment 90
5.5 CharacteristicsofProfileErosion 100
6 DAMAGEANDERODEDPROFILEPREDICTION 110
6.1 DamageVariability 110
6.2 ErodedProfilePrediction Ill
6.3 TemporalDamageDevelopment 117
7 EFFECTOFWAVEPERIODANDARMORGRADATIONON
DAMAGEPROGRESSION 127
7.1 ExperimentalSetupandTestConditions 127
7.2 ProbabilityDensityFimctionsofDamage,ErodedDepth,and
CoverDepth 131
7.3 DamageVariability 133
7.4 ErodedProfilePrediction 134
7.5 TemporalDamageDevelopment 139
8 SUMMARYANDCONCLUSIONS 144
IV
Appendix
A SUMMARYOFWAVEMEASUREMENTS
152
B SUMMARYOFDAMAGEANDPROFILEMEASUREMENTS
.... 187
REFERENCES
196
SF298
1
LISTOFFIGURES
1.1 Breakwaterfailuremodes 2
2. Flumeplan(top)andprofile(bottom)viewsforincipientmotion
experiment 13
2.2 Definitionsketchfortypicalstructureprofile 14
2.3 VelocitytimeseriesforonewaveperiodwithH,= \2 cm, T= 1 s,J,=24cm
andd^=8.8cmmeasured 1 cmoutsidethearmorlayer 19
2.4 Velocityvectorforonewaveperiodforarmorliftingmeasured 1 cmoutside
thearmorlayerwithH,=8.4cm, f=2s,d,=24cm, and^^= 17cm 20
2.5 Verticalvelocitytimeseriesoutside(top)andinside(bottom)armorlayer
withH,= 12cm, T= 1 s,d,=24cm,anddi=8.8cmfortheouter
measurementanddi= 13 cmfortheinnermeasurement 20
2.6 MeasurementlocationsforverticalvelocitiesshowninFigure2.5 21
2.7 Maximumverticalvelocityversusthesquarerootofwavesteepnessforwave
periods T= 1 and2sandrelativedepthsrd=0.36,0.5, and0.7 22
2.8 Verticalvariationofverticalvelocityunderasteepwavefi-ontacrossthe
armorlayerasafunctionofwavesteepness 27
2.9 Photographsofspheremotionduringatypicalincipientmotionexperiment
forPlan4 30
2.10 Incipientmotioncriterion(Equation2.14withv^=61.8 cm/s)versuswave
steepness 31
3.1 Sketchofbreakwaterprofilewithdefinitionoferodedareaanddepthof
cover 34
3.2 Damage,characterizedaserodedvolume,asafunctionofmonochromatic
waveheightforangularstone(SPM 1984) 46
3.3 Hudsonstabilitycoefficientversusrelativedepthforangulararmorstone
exposedtoirregularwaves(CarverandWright 1991) 52
4.1 Flumeprofilefordamageexperiments 54
4.2 Modelstructurecrosssectionfordamageexperiments 54
4.3 Photographofmodelstructuresbeforetesting 55
4.4 Armorandunderlayerstonemassdistributionsforinitialexperiment 58
4.5 Flumeprofilenearstructurewithnearshorewavegagelayout 65
4.6 WaveheightvariationthroughoutWaves 1,2,and3 at 11.9cmtoedepth .... 71
4.7 WaveheightvariationthroughoutWaves4,5,and6at 15.8cmtoedepth .... 71
4.8 Plan(top)andprofile(bottom)viewsofbreakwaterprofiler 75
4.9 Photographofbreakwaterprofiler 76
5.1 Sketchofbreakwaterprofilewithdefinitionofdamageparameters 84
5.2 ProbabilitydensityfimctionfornormalizeddamageS* for
Series^',B',andC' 88
5.3 ProbabilitydensityfimctionfornormalizederodeddepthE* for
Series^',B',andC' 89
5.4 ProbabilitydensityfimctionfornormalizedcoverdepthC*for
Series^',B',mdC' 89
5.5 PhotographsofimdamagedstructurespriortoSeriesA' 91
5.6 ProfilesatbeginningofSeriesA damagelevelof5= 92
',
5.7 ProfilesmidwaythroughSeries^',damagelevelof5^=6.5 93
5.8 ProfilesfollowingcompletionofSeries^',damagelevelofS= 12.8 94
1
5.9 PhotographsofstructuresfollowingcompletionofSeriesA damagelevel
',
5=
of 12.8 95
5.10 Niimberofwavesversusmeandamage±onestandarddeviationfor
SeriesA' 96
5.1 Numberofwavesversusmeandamage±onestandarddeviationfor
SeriesB' 99
5.12 Nximberofwavesversusmeandamage±onestandarddeviationfor
C
Series 99
5.13 Numberofwavesversusmeanmaximum erodeddepth±onestandard
deviationforSeriesA' 101
5.14 Numberofwavesversusmeanminimumcoverdepth±onestandard
deviationforSeriesA' 102
5.15 Numberofwavesversusmeanmaximum erodedlengthforSeriesA' 102
5.16 Meandamageversusmeanmaximumerodeddepthandmeanminimum
coverdepthforSeriesA' 103
5.17 MeandamageversusmeanmaximumerodedlengthforSeriesA' 104
5.18 Nimiberofwavesversusmeanmaximumerodeddepth±onestandard
deviationforSeriesB' 105
5.19 Numberofwavesversusmeanmaximumerodeddepth±onestandard
C
deviationforSeries 105
5.20 Nxmiberofwavesversusmeanminimumcoverdepth±onestandard
deviationforSeriesB' 106
5.21 Numberofwavesversusmeanminimum coverdepth±onestandard
C
deviationforSeries 106
5.22 NumberofwavesversusmeanmaximimierodedlengthforSeriesB' 107
C
5.23 NumberofwavesversusmeanmaximximerodedlengthforSeries 107
5.24 Meandamageversusmeanmaximumerodeddepthandmeanminimum
coverdepthforSeriesB' 108
VIII