Kobe University Repository : Kernel

タイトルTit le

Lateral bearing behavior on pile with mult i-stepped two diametersunder inclined load

著者Author(s)

Shoda, Daisuke / Kawabata, Toshinori / Uchida, Kazunori / Nadamoto,Yuta

掲載誌・巻号・ページCitat ion 神戸大学都市安全研究センター研究報告,11:357-366

刊行日Issue date 2007-03

資源タイプResource Type Departmental Bullet in Paper / 紀要論文

版区分Resource Version publisher

権利Rights

DOI

JaLCDOI 10.24546/00518541

URL http://www.lib.kobe-u.ac.jp/handle_kernel/00518541

PDF issue: 2021-07-25

神戸大学都市安全研究センター

研究報告,第11号,平成19年3月

LATERALBEARmGBEHAVIORON

PILEWITHMULTI-STEPPEDTWODIAMETERS

UNDERINCLINEDLOAD

DalSukeShodat)

ToshmoriKawabataヱ)

KazunonUchlda3)

YutaNadamoto4)

Thepilewithmulti-steppedtwodlameterS(MS-pi一e)hasthecylinderorconvexandconcavepartsalongdepthalternatcLy･

lnthlSPaper,uSlngtheMS-p-leswlththedlfferencelengthoftheconvexandconcaveparts,thesollbehavlOraroundtheplle

andtheu)(1matebeanngcapac)tyunder】ateralandincllnedIoadwerelnVeStlgated.Themodelloadlngtestslnthedrysand

wereconductedtoclarjfythcfundamentahTleChanjsrn.Astheresultofinclinat)onloadingtests,theincreaseofthe)ateral

bearlngCaPaCltylSCausedbytheeffectonthepushofthcbottomfaceoftheconvexpart･Further,basedontheSOIIpressure

dlStrlbutlOnObtalnedfromthetestsalongMS-plle,theultimatelateralbcanngcapacltyWasCalculated･ThepredlCted

pressuredjstrjbutlOnisinagreerrcntwlththemeasuredsollpressuredlStribut10nattheultlmatebearingcapaclty･

Keywords:Pile,Beanngcapacity,LateralsoilpresstEe,m(deHest,sand

1.1mtrodllCtion

ThepilewlthmultトStePpedtwodiameters(MS-pile)hasthecyllnderofconvexandconcavepartsalongdepthalternately･

Theauthorelal.(2006,2007)conductedtheverticalmode一test,DEanalysis,theevaluatlOnOrultlmatebearingcapacityand

soon,Astheresult,itwasclarlfiedthattheshearraHurearoundtheconcavepartseffectedonthefalluTemeChanlSmandthe

concave一engthofMS-pilealsoinf一uencedonfailuremode,However,undertheotherdlr∝tionloadingexceptvertical

loadlng,theanalystsOfbearlngCapaCltyandthefalluremechaniSrnhasnotbeenverified･

UsingthenodularpHethatlSthesamefhctionpileasMS-pi一e,YamagataetaL(1982a,1982b)reportedthatAlenodularptle

islargerbearingcapacitythanthecylindershard pileattheverticalloading.OguraetaI.(1987,1988)verifiedthatthe

bearingeffectontheumboofthenodu)arpllecontnbutestotheIncreaseOfbeanngcapaclty･Theultimatebearmgcapacity

formu一aefornodalbaseofnodularcast-1n-P一aceconcretepilewereleduslngaXISymmetricanalytlCalmodelbasedonngjd

plastictheorybyYaoelal.(2002)･However,On一yverlicalloadwasappliedonthesestudies･LateraHoadingleslsonthe

-357-

fdctionpilearehardlyconducted･Lateralloadwasappliedtotheunderreamedpilewlthslmllarshape toMS-pileby

Chandra,PLetall(2004).ltwasshownthatananalytlCalprocedurehasbeensuggestedtopredicttheultimatelateralload

capacltyOftheunderreamedplle･Lateralloadingtestsofpllewlthenlargedbase,whoseshapelSthatpllebaselStheconvex

partandtheotherpartistheconcavepart,wereconductedbyWen, S.(1996)tolnVeStlgatethelateralresistancebehavior.

Underinclinedloading,themodeltestswereconductedbyMeyerhof,G.G.etal.(1985)todlSCuSSthelateralsoilpressure

onthesha允ofplle･ThernodeltestswerealsoconductedbySakataetal.(1996,1998)anditwasanalyzedhorizontal

reactiononplastlCground.Astheresult,thebeanngcapacltyunderlnCllnedloadwaslargerthantheoneunderhonzontd

andvertlCalloadseparately,espcclally,thelateralcomponentenhancedpromlnently.

0mtheoreticalmethodsorgroundreactlOnunderlateralload,ScvcralstudleSWereCamedoutbyassumlngrelatlOnShipof

sollresIStanCeandplledenect10n,failurewedgeandsollpressuredistnbutlOnS.Thenon-1lnearltyOfthesol】resistancePand

piledeflectionywasrlrStdevelopedbyMcClelland,B.etal.(1958),andthebi-llneantyOftherelationshlPWasProposedby

Kishldaetal.(1977).TheultlmateSOllreactlOnWasCOmputedfromthegeometnesofthewedgenearthegroundsurfaceby

Reeseetal.(1974)andagalnStthepileataconslderabledepthtntheclayandsandgr()undbyBroms,B.B.(1964).A

simplifiedmethodtopredlCttheultimatepllecapacltybasedonthesollpressuredlStnbutlOnWasSuggestedbyPrasadetal.

(1999).

TheMS-plleisconstructedbymlXlngSOllandcementln-SltuandcanbeappliedtothesmalトscaleinstltutlOn.Thefailure

mechanlSmandtheanalysisOfultlmatebeanngcapacityunderverticaHoadhavebeenvenfied.However,thesollbehavior

andtheanalystsunderotherloadhavenotbeenclarified.

lnthispaper,theInclinedloadtests,loadedthelateraldlreCtlOnWlthconstantvertlCalload,andlateralloadtestswere

conductedonrigidpllebunedindrysand･ThemodelMS-pilesassh()wnlnFlg･1,havlngdifferentintervalsofconvexand

concave,wereused.Fromtheresult,thesoilbehaviorandtheultlmatebearingcapacltyunderlateralandlnCllnatlOnload

werevenfiedatx)uttheMS-plleswlththedlfferencelengthoftheconvexandconcaveparts.

2.Modeltests

ThemodelMS-pilemade斤omsteellStheconvexpartdlameterOf35mmandtheconcavepartdlameterOf25mm.The

cylindershapepilereferringc｣)ileinthispaperlS35mmofdlameter･TheMS-pllesrefemngp7),p5_5andp3j havethe

lengthproportion7:3,55and3:70ntheconcavepartandtheconvexpa止respectively･

Themodeltestswereca汀iedoutlnaSteelpltOfL400mm,W.600mmandH.500mm.Fig.2ShowstheschematlCVleWOf

expenmentalset-up.ln)nclinedloadlngtest,VertlCalload(241Nor500N)1SloadedasshownlnFig･2,andlateraHoadon

thepilewasappliedwithhydraullCJaCkattheheightof60mmabovethegroundsurface.tnlateralloadingtest,lateralload

onthepilewasappliedatthesamehejght･

Alateralloadandadisplacementweremeasuredattheloadedhelght.Anotherdtsptacementtransducerswereattachedat

thehelghtof130mmabovethegroundsurfacelaterallyandatthevertlCaHoadapparatusvertlCally.Thepllewasattached

thepressuretransducersateachdepthshowninFig･2tomeasurethe一ateralsollpressure･Anotherloadcellwasfixedpile

basetoapplytotheprorx)sedequation.LoadingSpeedwasO･35mm(1%ofplledlameter)/minute･

Table-IshowsthephysICalPropertleSOftheslllCaSandusedlnthemodelground･TestswereconductedlnSilicasand

correspondlngtOadensestate(Dr-93195%)･ThemodelgroundlSSetbypluⅥatingsandlnairintothepitatthehelghtof

I200-1660mm,uslngfivesteppedsandspread:rshavingrectangularopenlng1127mTTl･

Totaltestswerecamedoutthesameembeddedlengthof500mm,andlnStmmentedtherollerbetweenthepl】eheadandthe

vertlCalloadaprnratustoreducethefrictlOnunderinclinationtests

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3,TestresultsanddisnlSSion

Flg.3showslateralload-dlSp】acementratiocurves

underverticalloadof241N. ThedlSplacementratlO

equals the measured dlSPlacemenldivided by the

diameteroftheconvexpart.InMS-pilecurvesofthis

figtlre,thebearingcapacltyincreaseswiththefrontal

prqJeCtedarea.Comparedp3_7wlthc_pile,thebeanng

capacityofc_pllehavingthelargeTfrontalprojectedarea

wassmallerthanthatofp3_7･

Latera一load-dlSplacementratiocuⅣesunderlateral

loadtestispresentedinFig.4tocornparewithresultsof

lnCllnedloadtest.FromtheresultsoflateralToadtests,

thebeanngcapacltyIncreasesWithtllefronlalprojected

area. Foreachpile,the)aleralbeanngcapacityon

Inclinedtoadtests(Ftg.3)lSlargerthanthatonlateral

loadtests(Flg.4).

Tovenfytheincreaseoflateralbeanngcapac】tycaused

byverticalload,horizontalloadatdlSPlacernentratlOOr

20% ineachcasewasdivldedbyloadatdlSplacernent

ratioor20% inlateralloadtestorcJ)ile･ Theyare

presentcd ln Table-I. The beanng capaclty rat)0

IncreasesWlththevertlCalloadforeachplle.tneach

verticalload,theMSIPllewiththelaTgefrontalprojected

areahaslargebearingcapac】ty relatlVely,asabove-

mentIOned. Comparedp3_7withc｣州e,thebearing

capacltyratlOOfcJ311ehavlngthelarger斤ontalprojected

areawasapproximatelythesameaSthatofp3-7.llcan

beseentTlatthelateralbearlngCapaCltylSanlectedbythe

bottomfaceortheconvexpanwithrotationofMS-pile

sutりCCtedtolateralloadlng.

FlguTe6showsthedepthorrotat]OncenterttlrOughout

thetests Assumedthatthepllescanbeconsldcrcdasthe

ngld shownln Flgure5,thepolntSOfrotat)onare

catculatedasfわllows.

-130u+6()b(I)

wherex:depthofrotationcenter

a:dlSPIacementmeasurdaHhehelghtof60mm

ftomgroundsurface

t■■■

骨■ヽiメ言｢ーift Convex

ヽ畠.メ part

国 【=くしたJ Concave

PaTt

Figure1PilewithmultトStePpedtwodial旺terS(MS-pile)

Omm25mm

75mm1125mm125mm

137.5mm175mm

2換言詔rnm2375mm275mm

,ae,ni=it.u.sad→ ト へD慧 eum:,nl那 L

- +

A- Loadccll

130mm IMS-pile一一 .-!=- '■

60m=1 -'A-L

…1蒜蒜蒜㌻二二才 JK

300mm150mm3SmalH dcell25m

-

35mm

-

450mm3(泊mm

00mm .ll

Figure2Schenuticyiewofexperlmentalset-up

250

200z150

TO【qOJ loo

50

--O-C｣)il°+p3_7-一ゝ-P5_5十P7ー3fVertica124lNl

▼

Z Y'10 20

DISPlacementRatio(%)

Figure3Lou-disphcementratiocurves(lncllnedloadingI:sts)

-359-

b:displacementmeasuredattheheightof130mmfrOmgroundsurface

ThedepthofrotationcenterlneverypilelSalmostsamedepthof225mmbelowthegroundsurfacebeyond4%.However

within4%,rotatlOnCenterChangesalotlneveryPlle･Broms(1964)reportedthatfalluretakesplacewhenthepllerotatesas

aunltaroundapolntlocatedbelowthegroundsurface.ItlSconsideredthatfalluretakesplacearound4% ineverypile･

Further,differencesinpileshapedldnothavetheeffectonthedepthofrotationcenter.

Verticaldisplacementrat10 -lateraldisplacementrat10CurvesareShownlnFlg･7･ltlSfoundthattheam ountofvertlCal

displacementisverysmallwithlateralloadlng,thustheamountofverticaldlSp】acementlSalmostsameforeachpile･

ー }lc｣)il°一 一p3_7--ムーp5_5十 p7_3 JLaterall

a -▲▼

10 20nlSPlacementRat10(%)

Figure4Load-displa:ementratiocurves(Lateralloadtests)

o

0

0

0

0

0

5

0

5

0

5

-

-

｢]

]ヽ

(uJuJご

31u3U

uOTJt:tOtfuOq

tdao

FlgurC5r)epthonRotationCenter

Tab)e-2Beanngcapacityratioatdtsplacementrat1020%

I -一一､一_ C｣)il° p3_7 p5ー5 p7_3ON 1.00 0.97 0.82 0.80

241N 1.23 1.26 1.16 I.12

500N 1.34 1.35 1.29 1.23

B.C.(20%)/B.C.(ON,C｣)de,2O%)

O cJ)ile+ p3)+ p5_5十 P7ー3 lverticaI241Nl

rh

_ _ 一 ヘ ー

0 10 20

DisplacementRatio(%)

2

(㌔)oTlt:tl一UaE

3UtZTdsTu

一t23Tu3^

10 20LateralDISPlacementRatio(%)

FlgurC6Depthofrotalioncenter-displacementratlOCurves Figure7VertlCaldlSPlacementrat10-lateraldlSphcementratio(Incllnedloadtests) curves([ncllned一oadtests)

FlgS.8and9ShowsollpressuredlStnbutlOnatdisplacementratlOOf5% underlateralandincllnedload･From the

dlStnbut10nOftests,thesoilpressureiszeroatthegroundsurfaceandthepressureIncreasesWlthdepthupto125mrn.The

pressurethendecreasesllnearlyuntlHtdecreasestozeroatthedepthofabout240mm.Be一ow240mm,thenetsoilpressure

lSinopposltetOdlreCtlOnandIncreaseslinearlyfromzeroatdepth240mm,toamaximumatthetipofpile.ThlSdtstrlbution

isthesameformastheresultofngidmodelpileglVenbyPrasadetal･(1999).

-360-

Forp5r5andc｣'i]e,so】1pressuredlStrjbutlOnat5%isshowninFlgS･10andI1･Fromtheresultofp5_5(Fig.10),the

latera)soilpressureincreasesduetotheverticalload.nglntheconcaveparts(depth0-50,loo-150,200-250mnl).Indepth0-

50mm･theincreaseisnotlargebecauseOftheshaHowdepth･lnverticaHoadof24)Nand500日,thesoiJpressureaHhe

concavepartofp5-5lS】argeTthanthatatsamedepthofc｣}ile･Further(heso)IpressurealtheconcavepartorotherMSI

pi一esISalsolargerthanthatatsamedepthofc｣).le斤om theresultofFlg･8･lnc_pile(F)g･11),theso.1pressure

dlStributionsareapproxlmatelythesameregardless()ftheIncreaseOnVertlCalload.Itcanbeconslderedthatthe)aterals｡1l

pressureincreasesaroundtheconcaveparHobepushbyverticalLoad,thustheIncreaseoflateralbeanngcapacltylSCaused

bythtsincreaseoflateralsollpressure.

0

50

0050

0050

1

1

2

2

(ULLU)Lltda

o

0

0

0

0

5

0

1

-

2

(LuuL)LTtdacL

vemica124INl也 -

J#

長 野 ーコ-C｣)i]e+ p3)-→ゝ -p5_5一▼-p7_3A

～

80 0

SollPressure(kPa)

Figure8SollpressIJredlSlrlbudonforeachpILeat5%

(lncllnedloadtests)

包 垣ヨ /班 -イー-ON0 24tN-→1--SOON

/ 耳

# +

＼ 癌 ＼

､ ､ 丑

O

SoilPressure(kPa)

FlgUre10SoJIpressuredIStnbutlontわrp5_5pkLa15%

050

00

50

0050

-

･-

2

2

(∈∈)tJ】daQ

...EZZ

#

a ー ｣-C｣)jle一一●-pj_7--A-p5,5+ p7}ト も ÷＼

- 0 60SollPressure(kPa)

f･JgUre9SoilpressurcdlSLnbul10nrOreaChpIkat5%

(LateraHoadtests)

00

<U

八日

0

0

5

0

5

0

5

1･~

-

2

2

(∈∈)LtdaC

L

du 出 ノレ -イ~トーON0 241N-イゝ -500N♂

感

㌔ヾ

0 80

SoIIPr岱Sure(kPa)

FLgureH SollpressuredlSDlbu110nforC_pileat5%

4.ultimatelateralcapacityonhepile

(1)U一timate)atera)CapacitylndcrlateraHoadingtests

a)Assumedme(hod

AmethodwassuggestedbyPrasadctaL(1999)topredlCtSOjlpressuredistTlbut10nandultjma(ela(eraIcapacityforngld

pllesincoheslOnlesssolls.ThetestsconductedbyPrasadetal(I999)weresjml】arcondltlOntOtheoneofthlSPape r.lnthls

paper,basedonthepressured】shbutlOnatultlmateCapaCltySuggestedbyPrasadetal.(1999),theultlmatelateralcapacl【y

-361-

underInclinedandlateraHoadofMS-pllewasca】culated･Further,ComparedthetestdjstTlbutionofultlmatelateralcapacity

withtheproposedone,ltWasVenfiedlftheassumeddisbibutionwasvalld.

SoilpressuredlStTibutlOnproposedbyPrasadetal.(1999)lSPresentedlnFlg.12.Whentheultlmateloadi/awasloadedat

theheightofefromthegroundsurface,thesoilpressurelsZeroatthegroundsurfaceandthepressureIncreasesWlthdepth

upto0.6x(where.r=thedistancetothepolntOfrotat10n).¶1emaXlmumpressureatthisdepthwasassumedasfollows:

p.6.-L10'H t-4･0"レ (0.6,) (2)

Thepressurethendecreases】1nearlyuntilltdecreasestozeroatthedepthofx.Below,rthenetsollpressurelSinOPTX)Slte

todirectlOnandincreasesllnearly斤omzeroatdepthI,toamaxlmurnatthetlpOfplle.ThesollpressureattheplletlplS17

timesthesoilpressureatO血 depth.tnpressuredlStrlbutlOnacrossthediameter,ttWasalsoassumedbyPrasadetal.(1999)

thattheaveragepressurejs0.8timesthepeakmeasuTCdvaluewhenthevarymgpressurelSaveragedasanuniformpressure

distributlOnacrossthepilesect10nS.UslngthlSpressuredistrlbutionshownlnFlg.12,thepolntOfrotat10n.randtheultlmate

loadJl..wereexpressedbyPrasadetal.(1999)asfo‖ows'

Hu-0.24(10(■11Jn仰 )h,x･B(2.7x-1.7L)

x- [-((,･567L･ 2･7e)十 (5･3 07古 7 ･29e2･10･54.eLY 5] ′211996

(3)

(4)

b)Calculatedresultsanddiscussion

tnlateralloadingtests.thebeanngcapaclty1nCreaSedwlththe什ontalproJCCtCdareashownlnF1g.4,1tmeansthatlateral

beanngcapacitydependsmoreonfrontalprojectedareathanontheshape ofconve," ndconcave.tnthispaper,regardmg

MS-plleasc｣)Ile,theult1matebanngcapacltylSPredicted.DlameterOftheassumedc｣)il°lSdetermlnedfromaverage

diameterofeachMS-pilelnembeddd part,asshownlnTable4.ThecalculatedresullsareshowninTable4.As thesoll

pressuredistributionForeachpilelSSame,Calculatedresultsdependonthefrontalprojectedarea.Themeasuredultlmate

valuelStheexpeTlmCntVa)ueclosetothecalculatedonc･Thedlsp)acementratlOatuhlmateValuelSalsoshown)nTable4.

ThedlSplacernenlTat10Wasaround4%t'oreveryptle･Figl13showstheprcssuTedistTjbutlOnCOrreSPOndingtotheultimate

loadlndlCated)nTable4andthepressuredlStnbutlOnProposedbyPrasadetal.(I999).Fromthisrlgure,thedlStrjbutlOnS

wereappTt)Xlmatelythesame

(2)U)timatelateralcapacityof'MS-pHeunderinclinedload

a)Proposedassunpion

Flg.14showsthelateralsoilpressuredlStrlbutlOnProposedlnthlSPaperunderlnCllnedload.ThlSdistnbutlOnlSProposed

byconsidenngthepressuredistrlbut)onunderlateraHoadandthe)ateralSOHbehavlOrduetoincllnedloadlngtests.The

behaviorconsistsorthreeassumptlOnSbasedonprecedlngdiscusslOn,aSdescribd inthefollowingparagraph.I)Lateral

soilpressureattheconcavepartsunderlnCllnatlOnloadlSlargerthanthatatsamedepthunderlateraHoad.2)The一engthor

concaveandconvexandthevertlCaHoadhardlyhaveeffectonthedepthofrotatlOnCenter.3)ThelatcTalbearlngCaPaCL(yis

affectedbythebottomfaceoftllCCOnVeXPartWlthrolaL10nOrMS-pi)esubJeCLcdtolatera=oad.

))TTlelateralSOHpressureIncreasesduetotheverticaHoadattheconcaveparts,asshownlnFig10.Itwasassumedthat

thedensltyaroundtheconcavepartsbecomeshighduetoverticaHoad.thusthesoilpressureIncreases.ApplledthlS

assumptlOntOtheequa110n.YinF.q.(3)wassubstitutedtoyn,∫.randQlnEq(3)wasdetermlnedusingtherclatlOnShlpbetween

vo∫drat10andlntCrnaHhctlOnProposedbyMogami(1966).JnIncreaseanddecreaseonsollpressure,themaxlrnurnand

-362-

050

0050

的5

-.-･

｢∠2

(UJE)tJ)d30

一一亡ト.C｣)ile(61.7N)

+ p3)(58.2N)一一ムーp5_5(54-2N)十 P7_3(51.ON)+ PTaSadetal_(1999)

60 40 20 0 20 40 60 80Sollpressure(kPa)

Figure12Proposedsoilpressuredistnbution Figure13CoTTPanSOnOfpredlCtedandr代 aSuredsollpressure

underlaterallod undeT･IateraHoad

Table4CalculatedresultsinlaleraHoadingtest

Pile B(m ) Calculated(N),1999 Measured(N) Measurddisplacement(%)

cAile 35 62.82 61.70 3.(:汐

p3_7 32 57.44 58.20 3.ー9

p5_5 30 53.85 54.21 4.37

p7_3 28 50.26 50.96 4.93

mlmmumappearalsamedepthastheoneunderlatcTalload･Further,thepressuredlslrjbut)onofconvexpartlSthesameas

theoneofPrasadetal.(1999).Lateralsoilreactionforeachdepthcanbeobtalnedasfollows:

o≦Z≦o･6x hLJ･-J諾 -BO･8･zdz

o16x≦Z≦J h,,2-I-%(Z-∫,B O･8dz

･≦Z≦o･3 h",- J憲 警 (I-I,BO･8dz

(5)

(6)

(7)

whereB.dlameteTOfpileateachdepth･

2)DlffcrenceslnPlleshapeandverticalloaddldnothavetheeffectonthedepthofrotatloncenlcr,asshowninFigs.10and

I1.FromthlSreSUlいhedepthofrotatjoncenterlSCa)culatcdbyEq.(4)derjved斤omlateraHoadtests.

3)Thebeanngcapacityonc｣)lleandp3_7lSapproximatelythesamelnSpiteofthedlfferenceslnlateralprojectedarea,as

showlnTable1.IHSCOnSlderedthattheIateralbeanngcapaclty)SaffectedbythebottoTTlraceOrtheconvexpanwl(h

TOtatlOnOrMS-pllesubjectedtolateral一oad,addedtotherlrStaSSumPtlOn.TheloadsustalnedbyconvexbaselSCalculated

bysubtT71CtlngthetoadmeasuredatthepiletlP斤omvertlCaHoad･

-363-

FromthreeassumptlOnS,COnSldenngmorrK,ntequilibnumaboutg,oundsurfaceforsollreactionactlngOnh･ontfaceJlul,A..:,

sollreactlOnaCtlngOnbackfacehu3,theloadsustalnedbythebottomfaceoFtheconvexparthu4andtheultlmatelateral一oad

H",asindlCatedlnFlg14,theultlmatelateralloadFl..isobtained.

Figure14PTDpOSedsoilpressuredisbjbutionundqinclinedload

b)CalculatedresultsanddisctJSSion

Table5showstheultlmateloadFl.,undertncllnationloadforp5_5CalculatedfromtheabovemomentequHlbrlum.InthIs

paper.assumedthatthelateralsotlpressuredlStTlbutlOn氏)rthevertlCaHoadof241Nand500Nwasthesame,thedlfference

inthebearingcapacityorbolhcaseslSCausedbythebeanngcapacityofconvexpartA.14.Themeasuredultimateva一uewas

theexpenmentvalueclosetothecalcu)atedone.

Theultimate】ateralloadFINunderlnCllnatlOnloadforp3_7andp7_3ispresentedlnTable6.FromTable5andTable6,jn

thevertlCalloadof241Ntheultmateloadincreaseswlththelengthofconvexpartltwasthesameastheresultsorthetests,

ThemeasuredultlmateValueforp3_7andp73wasalsotheexpenrnentvalueclosetotheca)cu)atedone

ThedlSplacemcntrat)0atultlmateValueisalsoshowninTables5,6 Thedisplacementratiowasaround4%foreveryplle

assameasTable40ftheresultoflateralloadingtests.FromFlg.6,beyond4%thedepthofrotat10nCenterlneverypllewas

almostsamedepth.Ltisconstderedthatfa日uretakesplacearound4%lneveryPilebccauseBroms(I964)alsoreportedthat

falluretakesplacewhentl･K:Pllerotatesasaunltaroundapolntlocaledbelowlhcgroundsurfacc.

Flg.15ShowsthepressuredlStnbutioncorrespondingtotheultimateloadlndlCatedinTable5,thepressureprofileassumed

bythlSPaperandthepressuredlStnbutlOnSPrOrX)SedbyPrasadetal.(1999)･FromthemeasureddlStnbutionfor241Nand

thatfor500N,thedlStributlOnSareaPPrOXtmatelythesame･TtISCOnStderedthattheassumptlOnOfpressuredlStnbutlOnfor

thedifferencesinverticalloadwasvaltd.TtismadeacomparisonbetweenpredlCteddis【nbut10nandmeasuredone,The

predlCteddistnbutlOnOftheconcavepartcanobtalnthepressureIncreaseOntheexperiment･ltmaybeseenthatthe

proposedonepredlCtSthemeasuredonewlthbetteraccuracythantheoneofPrasadetal.(1999).lnthedlSthbutionofthe

convexpart,thepredlCtedpressuredlStribut10nSusingbothmethodsare-∩closeagreementwlthmeasuredvalues･ltcanbe

seenthatthepressureprofileattheconvexpartunderincLmed一oadlsapproximatelythesameastheoneforc｣)lleunder

lateraHoad.Inthedepthonrotationcenter,thereareSlightscatter,howeverltisseenthatbothpredicteddepthgivegood

res山ts.

ー364-

TtlePressuredistTlbutlOncorrespond)nglotheultimaleloadlndiL.aledinTab一e6,thepresstJrePrOfllcassumedbythispaper

andtllePressuredlStrlbutionproposedbyr'rasadctal.(1999)areshownlnF]g･161ltmaybcseenthattheproposed

dlslnbullOnforolhcrMS-pllealsoprcdicLSthemeasuredonewithbetteraccuracythantheoneofPrasadet{11.(I999).

Tab)e5Ultlmatelateralloadforp5_5underlnCllnatlOnload '】able6川tltnate一ateralloadforp3_.7ardp7_3underlnCllnatlOnload

ハU

(り

ハU

nU

0

Lr1

0

Lr.

∩U

lヽJ

l

▲-

2

つ▲

言tu)LLtdu

c[

早//A ' p5_5+ l'rotX)各edPrasad(l999)-∠トーE_tp-(V二24lN.ll:I)2_I)N)A-JExp.(V:500 N.H二一79.｡N)

8() 6O 40 20 () コ0 40 60 80

SoltPressure(kF'a)

Llgure15(loITIParlSOnOrprcdlctcdandmeasured

soIIPressureJISblblltlOnlbrp5_5

＼ V:24lNCalculated(N) mesured(N) mesureddisp.(%)

p3) 97.3 96_9 3_69

ハU0

0

nU

0

nU

5

0

LヽJ

nU

Lr,

1

-

2

2

(tutu言d

UCl､/′●l ＼

p3_7一一)-Proposed+ Exp(Vコ4tN,ll:(枯9N)

p7}-く7--PTOrDSCd

6O 4O 20 0 20 40 60 80

S｡11Pressure(kPa)

1:lgUreI6('omparlSOn(1rPredtctedandmeasured

sollllrCSSurCdlStrlbLL‖Onllcrp3__7andp7)

4.Conc一usions

ThemodeltestsinthedrysandwcrcconductedtolnVCStlgatethesollbchavl()TandtheultllllatCbcanngcapacltyaboutthe

MS-pllesunderlnCHnedload Sthercsult,ZttsconcludL.dasthero‖ows.

1)Foreachplle,thelateralbearingcapacityunderlnCl】natlOnloadlSlargerthanthatunderlateralload･

2)TllebearingcapacItyratioincreaseswlththevertlCaHoadforeachptle･

3)MSIPllewlththetargc什ontalprojectedareahaslargebeanngcapacltyrelatlVeLy･

4)LateralbeanngcapacitylSaffectedbythebottom raceortheconvexpartwlthrotatlOnOfMS-pllesubjectedtolateral

Joadmg.

5)DlfTcrcncestnpllcshapedonothvetheeRlectonthedepthoFrotatlOnCenter

6)ThesollpressuredlStrlbutlOnlnthIslestlSthesamefomlaStheresultofngldmodelplleglVenbyearlierrcscarchl

7)LateralsollpressureIncreasesarC･UndtheconcaveparHobepushbyvcrticalload.

8)Consldcnngeffectofthefrontalprojectedarea,theassumedpressuredistnbutlOnpredictsthemeasuredonewlthgood

accuracyunderlateTaHoadL

9)TheprofXlSedpressuredlStrlbutlOnforMSIPHepredictsthemeasuredonewithgoodaccuracyunderInclinationload

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AuthorsI1)DalSukeShoda,GraduateschoolofagrlCulturalsclenCe,Student:2)roshlnOrlKawabata,Graduateschoolof

agriculturalsclenCe.associateprOreSS｡rこ3)Ka7unOnUchlda,GraduateschoolofagriculturalsclenCe,Professor,4)Yuta

Nadamoto,GraduateschoolofagnculturalsclenCC,Student

ー :ち(i(トー-