GEOTECHNICAL

ENGINEERING:NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WINDTURBINE

FOUNDATION敦樸文化（）GEOTECHNICAL

ENGINEERING:NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATIONMOTIVATIONSOURCES

OF

NONLINEARITYSTRUCTUREMATERIALUPLIFTINGLOAD

CYCLESMETHODOLOGYCLASSICAL

-YTICAL

METHODK

SUBGRADE

REACTION

METHOD3D

FULLY

MEF

–

MC

&

HSSMYSIS

CASEINFLUENCE

OFUPLIFTINFLUECE

OF

FOOTING

STIFFNESINFLUECE

OF

PLASTIC

STRAINSADVANCEDCONSTITUTIVE

MODELS:

HSSMCYCLIC

LOADING

(HSSS)BEN

ARKFURTHER

ADVANCED

CAPACITIES:

STRUCTURAL

NONLINEARITIESCONCLUSIONSGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）MOTIVATION

(I)um

powerSource:

Design

and

construction

of

wind

turbine

towers

forgeneration.

University

of

Windsor

(2016)INCREASING

TOWER

HEIGHT

(>150m)HIGHER

INFLUENCEOF

THE

FOUNDATIONIN

THE

TOWERDESIGN-

FOUNDATION

FLEXIBILITY-SOIL

–

STRUCTUREINTERACTIONGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）um

power

generation.Source:

Design

and

construction

ofwind

turbine

towers

forUniversity

of

Windsor

(2016)MOTIVATION

(II)TOWER

DESIGN

–

Campbell

diagram

(

r)Eigenfrequencies

related

to

excitations

(natural

frequency

(Hz)/

rotor

speed

(rpm))Beforehard

designTall

towerssoft

designNatural

frequencieslimits

±10%DOES

OUR

FOUNDATIONSTIFFNESS

ESTIMATIONHAVE

TH CURACY

???GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）AIM

&SCOPEAIMImprove

the

prediction

of

the

foundation

stiffness

estimationEvaluate

the

influence

of

different

non

linearitiesSCOPEShallow

foundationCircular

shapeDrained

condition

terrainGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）SOIL-STRUCTUREINTERACTIONSOURCES

OF

NON

LINEARITIESSTIFFNESS-

RIGIDCRACKED-STRUCTURALFLEXIBILITYNON

LINEARMATERIALGEOTECHNICALCYCLICLOADINGSOILPLASTICITYGEOTECHNICALUPLIFTGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）METHODOLOGYCLASSICALAPPROACHyticalexpresionsK

MODULUS

OFSUBGRADEREACTION3D

FEM

&

SpringelementsFULLY

3D

FEMSolid

and

interfaceelementsNonlinearitiesGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）vBased

on ytical

expressions.Standard

and

GuidesVariables:G:

Equivalent

dynamic

shear

modulusν:Poisson’s

ratioFoundation

geometryPros:Simple

and

fastDirect

measurement

of

soil

parameterCons:Rigid

foundation

(v/h

<

2)

(≈15-17m)Elastic

soil

behaviourNo

uplift

of

foundationLACK

OF

ACCURACY

IN

BIG

FOUNDATIONShCLASSICAL

APPROACH:YTICAL

METHODSDNVGL-ST-0126

Support

structures

for

wind

turbines)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）K

MODULUS

OF

SUBGRADE

REACTION:

3D

FEM

Spring

elementsSpring

boundary

elements

based

onsubgrade

reaction

modulus.FEM

Models

–

s /solid

elements.Variables:Kv:

Modulus

of

subgradereactionFoundation

geometry

andstiffnessPros:Foundation

lifting

(gap)Non

linear

behaviour(springs)Low

computationalcost

(fast)Cons:Subgrade

reaction

modulus obtained

by

correlationsNo

direct

parameter

measurementScale

effectson

testsNEED

TO

CALIBRATE

THE

MODELWHY

NOT

A

FULLY

3D

MODEL

??GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）FULLY

3D:

FEM

SOLID

&

INTERFACE

ELEMENTS

(I)Based

on

solid

FEM

models

with

interfaceelementsand

soil

constitutive

laws.Variables:Soil

strength

parameters:

c

,

φ,

ψ,

emaxSoil

deformability

parameters:

Edyn,

νFoundation

deformability

parameters:

EcPros:Direct

measurement

of

soil

parametersAll

soil

rangesGeneral

foundation

geometryConstruction

stagesCons:More

computationalcostMore

engineering

hoursGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）FULLY3D:

FEM

SOLID

&

INTERFACE

ELEMENTS

(II)

-

CONSTITUTIVE

LAWSMohr

Coulomb

(MC)Elastic-

perfectly

plastic

soil

behaviour

modelSoil

strength

parameters:

c

,

φ,

ψ,

emaxSoil

deformability

parameters:

Edyn,

νFoundation

deformability

parameters:

EcHardeningSoil

Small

Strain(HSSS)Nonlinear

stress-strain

relation

(Hardin-Drnevich)Soil

strength

parameters:

c

,

φ,

ψ,

emaxSmall

strain

stiffness:

E0,

γ0.7Elasticcharacteristics:vur,

Eur,

E50,

mCap,

load

history:

Eoed,

OCR,

K0(NC)Cons:More

geotechnical

testing

neededCons:Constant

load-

reload

modulus

(E)E

modulus

should

be

adjusted

tothe

operational

range

you

expectBetter

adjust

with

sands

soilsGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）METHODOLOGY

COMPARISONCLASSICAL

APPROACHytical

expresionsMODULUS

OF

SUBGRADEREACTION3D

FEM

Spring

elementsFULLY

3D

FEMSolid

and

interface

elementsNon

linearitiesGAP-

UpliftFoundation

stiffnessSoilplasticityCyclic

loadingMohr

CoulombHardeningSoilSmall

StrainSOIL

CONSTITUTIVE

LAWGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）METHODOLOGY

COMPARISONCLASSICAL

APPROACHytical

expresionsMODULUS

OF

SUBGRADEREACTION3D

FEM

Spring

elementsFULLY

3D

FEMSolid

and

interface

elementsNon

linearitiesCons

MC:Constant

load-

reload

modulus

(E)·E

modulus

should

be

adjusted

tothe

operational

range

you

expectBetter

with

sands·Direct

measurement

of

soilparametersAll

soil

rangesGeneral

foundationgeometryConstruction

stagesSubgrade

reaction

modulusobtained

by

correlationsNo

direct

parameter

measurementScale

effects

on

testsNEED

TO

CALIBRATE

THEMODELWHY

NOT

A

FULLY

3D

MODEL

??Foundation

uplift

(gap)·Non

linear

behaviour(springs)Low

computational

cost

(fast)·

Simple

and

fast·Direct

measurement

of

soilparameters·Rigid

foundation

(v/h

<

2)(≈15-17m)Elastic

soil

behaviourNo

liftingof

foundationLACK

OF

ACCURACY

IN

BIGFOUNDATIONSPROSCONSGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）YSIS

CASE

-

PROBLEM

DESCRIPTIONTypical

wind

turbine

foundationMaterials:ConcreteE.rigid

=

InfinitestiffnessE.secantFULLY

3D

MODELSUBGRADE

REACTION

MODULUSYTICALGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）INFLUENCE

OF

UPLIFTGAP/UPLIFTFOUND.

STIFFNESSEFFECTSK.r

%GAP

/

UPLIFT-15%FOUNDATIONSTIFNESS-20%UPLIFT+STIFF-32%SUBGRADE

REACTION

MODULUSYTICALGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）AN

v.s

3D

MChard

soilK.r

%GAP

/

UPLIFT-5%FOUNDATIONSTIFNESS-37%UPLIFT+STIFF-40%FULLY

3D

MODELSUBGRADE

REACTION

MODULUSYTICALSpring

vs

3DMCK.r

%GAP

/

UPLIFT-10%FOUNDATIONSTIFNESS+10%INFLUENCE

OF

FOOTING

STIFFNESS

(I)MOHR

COULOMBHard

soil?=45

c=10kPaNo

phreatic

levelGAP/UPLIFTFOUND.

STIFFNESSMOHR

COULOMBGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）INFLUENCE

OF

FOOTING

STIFFNESS

(II)rigidelasticSUBGRADE

REACTION

MODULUSGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）INFLUENCE

OF

FOOTING

STIFFNESS

(III)FULLY

3D

MODELGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）MC

hardv.smedium

soilK.r

%Plasticstrain-

Found

Rigid-17%Plasticstrain-FoundElastic-9%FULLY

3D

MODELYTICALMOHR

COULOMBHard

soil?=45

c=10kPaMedium

soil?=30

c=0.1kPaNo

phreatic

levelFOUND.

STIFFNESSINFLUENCE

OFPLASTIC

STRAINS

(I)GAP/UPLIFTR-hardAN

v.s

MCmedium

soilK.r

%GAP

/

UPLIFT-22%FOUNDATIONSTIFNESS-30%UPLIFT+STIFF-45%R-medF-hardF-medAN

v.s

3D

MChard

soilK.r

%GAP

/

UPLIFT-5%FOUNDATIONSTIFNESS-37%UPLIFT+STIFF-40%GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）INFLUENCE

OFPLASTIC

STRAINS

(II)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）INFLUENCE

OFPLASTIC

STRAINS

(III)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）FULLY

3DMODELADVANCED

CONSTITUTIVE

MODELS:

HSSM

(I)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）ADVANCED

CONSTITUTIVE

MODELS:

HSSM

(II)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）CYCLIC

LOADING:

HARDENING

SOIL

SMALL

STRAIN

(HSSS)Second

looploadingreloadingunloadingThird

loopInitial/

loopWHAT

ABOUTCYCLIC

LOADING

?Model

independent

of

theoperational

rangeIn

a

single

model

we

have

all

theoperational

range

:

initial,service,

al…All

soil

layersGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）ADVANCED

CONSTITUTIVE

MODELS

(HS-SMALL

STRAIN):

BEN ARK

(I)REAL

LARGE

SCALE

TEST:

“Large-Scale

LoadTestand

Data

Base

of

Spread

Footings

on

Sand”Publication

NO.

FHWA-RD-97-068.

U.S

Department

of

TransportationThefoundation

3.0

x

3.0

m

footingloaded.Texas

A&M

University’s

National

Geotechnical

Experimental

Site.HOW

ACCURA Y

CYCLIC

LOADING

CAN

BE

PREDICTED

?GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）ADVANCED

CONSTITUTIVE

MODELS

(HS-SMALL

STRAIN):

BENARK

(II)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）ADVANCED

CONSTITUTIVE

MODELS

(HS-SMALL

STRAIN):

BENARK

(II)SimulationReal

testGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）FURTHERADVANCEDCAPACITIES:

STRUCTURAL

NONLINEARITIES

(I)FOUNDATION

PART

FEM

MODEL

DETAILS

-REINFORCEMENTSMODEL

SIZE:

STRUCTURAL

PARTSolid

elementsEmbedded

reinfoNodes373392382960920FEATURESTotal

strain

crack

modelElasto-plastic

embedded

reinfoPretensioned

anchor

barsInterface

tower

bottom/

foundationGE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）Not

so

important

for

stiffness10%Remarkable

influence

in

reinfoties

optimizationFURTHERADVANCED

CAPACITIES:

STRUCTURAL

NONLINEARITIES

(II)GE:

NONLINEAR

3D

SOIL-STRUCTURE-INTERACTION

OF

WIND

TURBINE

FOUNDATION敦樸文化（）CONCLUSIONSF