impact - wp4 dam-break induced floods and sediment movement progress report

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IMPACT - WP4 Dam-break induced floods and sediment movement Progress report. Université catholique de Louvain Yves Zech, Benoit Spinewine and Sandra Soares Frazão. Aims and objectives. Improve the prediction of the motion of sediments in association with catastrophic floods. Motivation. - PowerPoint PPT Presentation

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  • IMPACT - WP4

    Dam-break induced floodsand sediment movement

    Progress reportUniversit catholique de Louvain

    Yves Zech, Benoit Spinewine and Sandra Soares Frazo

    Dam-break floods and sediment movement

  • Aims and objectives

    Improve the predictionof the motion of sedimentsin association with catastrophic floods

    Dam-break floods and sediment movement

  • MotivationDike breachingBitterfeldRiver ElbeGermanyAugust 2002

    Dam-break floods and sediment movement

  • MotivationDike-breaching waveGlashtteMglitzGermanyAugust 2002

    Dam-break floods and sediment movement

  • MotivationDebris flowWeisensteinRiver ElbeGermanyAugust 2002

    Dam-break floods and sediment movement

  • Issues of IMPACT WP4 researchExtreme flows intense erosion and solid transport Intense sediment transport affects flood-wave predictionArrival timeMaximum water levelMorphological changes

    Dam-break floods and sediment movement

  • Scope of the researchNear-field Uniform debris flowSevere transient debris flowFar-field Intense transportBank erosion and geomorphic changes

    Dam-break floods and sediment movement

  • Near field : problems to be solvedInitiation of movementActing forcesVertical effectsInertial effectsSediments bulkingPropagationIntense scouringDebris-flow front

    Dam-break floods and sediment movement

  • Debris flow : research programmeExperiments : acting forces (UDT)Uniform material Months 1-18

    Graded materialMonths 18-32 BM UDT ?

    Dam-break floods and sediment movement

  • Debris flow : research reportUniform material experimentsTilting flume (L = 6 m, S0 = 0 to 23)

    Uniform cylindrical PVC particlesEquivalent spherical D = 3.5 mmDensity = 1540 kg/m

    Dam-break floods and sediment movement

  • Debris flow : research reportMature debris flow: collisional + frictional

    Rigid-bed debris flow collisional

    Dam-break floods and sediment movement

  • Debris flow : research report Mature debris flow

    Dam-break floods and sediment movement

  • Debris flow : research reportMathematical description (collisional)Normal stress local equilibriumSubmerged weight overlying grainsInter-granular collisional contacts(pressure related to granular temperature)Tangential stress local equilibriumRelation between external and internal tangential stressEffect of added mass

    Dam-break floods and sediment movement

  • Debris flow : research reportRigid bed debris flowConcentration

    Velocity profile

    Dam-break floods and sediment movement

  • Near-field dam break : programmeExperiments: uniform material (UCL)Same bed levels Months 1-9

    Initial step in bed levelsMonths 1-9 BM UCL 1

    Dam-break floods and sediment movement

  • Near-field dam break : research reportExperiments: uniform material (UCL)Same bed levels

    Dam-break floods and sediment movement

  • Near-field dam break : programmeMathematical modelling (UCL)1D model: months 1-6

    2D-V model: months 21-32

    Dam-break floods and sediment movement

  • Mathematical modelling (UCL)1D model:Velocity distribution(Concentration distribution)Near-field dam break : research report

    Dam-break floods and sediment movement

  • Near-field : research programmeValidation of codes (UDT, UCL, Cem)Uniform debris flow (to be clarified)Months 11-12BM UDT ?

    Dam-break floods and sediment movement

  • Near-field : research programmeValidation of codes (UDT, UCL, Cem)1D dam-break flow in the near fieldMonths 11-12

    2D-V dam-break flowMonths 34-35 BM UCL 2BM UCL 1BM UCL 3

    Dam-break floods and sediment movement

  • Far field : problems to be solvedTransition from near-field to far-fieldGeomorphic changesBank erosion and failureTractive forces appliedFailure mechanismChannel wideningDeposition of materialDe-bulkingDistribution of sedimentsFormation of secondary dams

    Dam-break floods and sediment movement

  • Far field : research programmeLaboratory experimentsDam-break in an initially prismatic valley (UCL)Uniform materialGraded materialMonths 13-20BM UCL 4

    Dam-break floods and sediment movement

  • Far field : research programmeLaboratory experimentsLarge-scale model (Chtelet)Prismatic valleyEnlargementMonths 24-31

    BM Chat

    Dam-break floods and sediment movement

  • Far field : research programmeField experimentsNorwegian dam (SG)Geomorphic survey (to be checked)Months 9-12 and 19-21

    BM Norway

    Dam-break floods and sediment movement

  • Far field : research programmeNumerical modellingExtension of 2D-H model (UCL)Bank erosionMonths 12-20

    503785Vbank

    Dam-break floods and sediment movement

  • Far field : research programmeValidation (UCL, UDT, Cemagref, IST)Laboratory testsPrismatic valley (UCL)Enlargement (Chtelet)BM UCL 4BM Chat

    Dam-break floods and sediment movement

  • Far field : research programmeValidation (UCL, UDT, Cemagref, IST)Field testsWP2 Norwegian dam ?Lake Ha!Ha!Months 33-35BM Ha!Ha!BM NorwayBrooks and Lawrence1999

    Dam-break floods and sediment movement

  • Benchmark summaryNear field

    Far fieldBM Ha!Ha!BM NorwayBM UCL 4BM ChatBM UCL 3BM UCL 2BM UCL 1BM UDT ?

    Dam-break floods and sediment movement

  • IMPACT - WP4

    Dam-break induced floodsand sediment movement

    Progress reportUniversit catholique de Louvain

    Yves Zech, Benoit Spinewine and Sandra Soares Frazo

    Dam-break floods and sediment movement

    Exprience plus longue : dbut ombre devant le front, puis, aprs le montant, eau passe par dessus le front qui se ralentit. Derrire = charriage intense plutt que debris flow.Derrire le front, le dcouplage intervient plus vite, avec une hauteur deau dailleurs plus importante et du charriage. Le comportement debris flow ne prvaut donc que prs du front.Exprience plus longue : dbut ombre devant le front, puis, aprs le montant, eau passe par dessus le front qui se ralentit. Derrire = charriage intense plutt que debris flow.Derrire le front, le dcouplage intervient plus vite, avec une hauteur deau dailleurs plus importante et du charriage. Le comportement debris flow ne prvaut donc que prs du front.Immature debris flows, mature debris flows and under-saturated debris flows are in equilibrium with a bed made of the same loose material, while rigid bed debris flows are characterised by a non-equilibrium condition. Debris flow characterised by a mixture of granular material and water flowing not in equilibrium with the bed is called rigid bed debris flow and the regime is wholly collisional.Collisional regime has been studied for rigid bed debris flows.Normal stress local equilibriumNormal stress local equilibrium is expressed as a local relation between the submerged weight of the overlying granular flow and the intergranular normal stress obtained from kinetic theories.This equilibrium is based on the hypothesis that the submerged weight of grains is entirely supported by intergranular collisional contacts, not taking into account turbulence effects.The equilibrium between normal external stress (Bagnold, 1954) and normal internal stress can be written assuming that the collisional pressure can be related to the local granular temperature T Tangential stress local equilibriumTangential stress local equilibrium is expressed as a local relation between external and internal tangential stress due to the water-granular mixture introducing the effect of added mass.Collisional regime has been studied for rigid bed debris flows.Normal stress local equilibriumNormal stress local equilibrium is expressed as a local relation between the submerged weight of the overlying granular flow and the intergranular normal stress obtained from kinetic theories.This equilibrium is based on the hypothesis that the submerged weight of grains is entirely supported by intergranular collisional contacts, not taking into account turbulence effects.The equilibrium between normal external stress (Bagnold, 1954) and normal internal stress can be written assuming that the collisional pressure can be related to the local granular temperature T Tangential stress local equilibriumTangential stress local equilibrium is expressed as a local relation between external and internal tangential stress due to the water-granular mixture introducing the effect of added mass.Exprience plus longue : dbut ombre devant le front, puis, aprs le montant, eau passe par dessus le front qui se ralentit. Derrire = charriage intense plutt que debris flow.Derrire le front, le dcouplage intervient plus vite, avec une hauteur deau dailleurs plus importante et du charriage. Le comportement debris flow ne prvaut donc que prs du front.Exprience plus longue : dbut ombre devant le front, puis, aprs le montant, eau passe par dessus le front qui se ralentit. Derrire = charriage intense plutt que debris flow.Derrire le front, le dcouplage intervient plus vite, avec une hauteur deau dailleurs plus importante et du charriage. Le comportement debris flow ne prvaut donc que prs du front.Exprience plus longue : dbut ombre devant le front, puis, aprs le montant, eau passe par dessus le front qui se ralentit. Derrire = charriage intense plutt que debris flow.Derrire le front, le dcouplage intervient plus vite, avec une hauteur deau dailleurs plus importante et du charriage. Le comportement debris flow ne prvaut donc que prs du front.Exprience plus longue : dbut ombre devant le front, puis, aprs le montant, eau passe par dessus le front qui se ralentit. Derrire = charriage intense plutt que debris flow.Derrire le front, le dcouplage intervient plus vite, avec une hauteur deau dailleurs plus importante et du charriage. Le c