地基基礎(chǔ)檢測 技術(shù) Theoretical knowledge of deep plate load tests for foundation testing technology-深層 平板載荷試驗理論知05課件講解

地基基礎(chǔ)檢測技術(shù)深層平板載荷試驗理論知識

Theoreticalknowledgeofdeepplateloadtestsforfoundationtestingtechnology深層平板載荷試驗

Deepplateloadtest010101深層平板載荷試驗

Deepplateloadtest1.適用范圍

1.ScopeofApplication深層平板載荷試驗

Deepplateloadtest深層平板載荷試驗適用于確定深部地基土層及大直徑樁樁端土層在承壓板下應力主要影響范圍內(nèi)的承載力和變形參數(shù)。

Thedeepplateloadtestissuitablefordeterminingthebearingcapacityanddeformationparametersofthedeepfoundationsoillayerandthesoillayerattheendofthelarge-diameterpilewithinthemainstressinfluenceunderthebearingplate.深層平板載荷試驗

Deepplateloadtest試驗深度不應小于5m

Thetestdepthshallnotbelessthan5m1.適用范圍

1.ScopeofApplication深層地基土

Deepfoundationsoil大直徑樁的樁端土

Thesoilattheendofthelarge-diameterpile深層平板載荷試驗

Deepplateloadtest2.數(shù)量要求

2.Quantityrequirement①單位工程檢測數(shù)量為每500㎡不應少于1點，且總點數(shù)不應少于3點；②復雜場地或重要建筑地基應增加檢測數(shù)量。

①Thetestquantityofunitworksshallnotbelessthan1pointper500m2,andthetotalnumberofpointsshallnotbelessthan3;②Thetestquantityshallbeincreasedforfoundationsofcomplexsitesorimportantbuildings.深層平板載荷試驗

Deepplateloadtest3.儀器設(shè)備

3.Instrumentsandequipment試驗儀器設(shè)備性能指標應符合下列規(guī)定：

Theperformanceindicatorsofthetestinstrumentsandequipmentshallmeetthefollowingrequirements:壓力傳感器的測量誤差不應大于1%，壓力表精度應優(yōu)于或等于0.4級；

Themeasurementerrorofthepressuresensorshallnotbegreaterthan1%,andtheaccuracyofthepressuregaugeshallbebetterthanorequaltograde0.4;試驗用千斤頂、油泵、油管在最大試驗荷載時的壓力不應超過規(guī)定工作壓力的80%。

Thepressureofjack,oilpumpandoilpipefortestundermaximumtestloadshallnotexceed80%ofthespecifiedworkingpressure.深層平板載荷試驗

Deepplateloadtest3.儀器設(shè)備

3.Instrumentsandequipment試驗儀器設(shè)備性能指標應符合下列規(guī)定：

Theperformanceindicatorsofthetestinstrumentsandequipmentshallmeetthefollowingrequirements:荷重傳感器、千斤頂、壓力表或壓力傳感器的量程不應大于最大加載量的3.0倍,且不應小于最大加載量的1.2倍；

Therangeofloadsensor,jack,pressuregaugeorpressuresensorshallnotbegreaterthan3.0timesofthemaximumloadingcapacityandshallnotbelessthan1.2timesofthemaximumloadingcapacity;位移測量儀表的測量誤差不應大于0.1%FS，分辨力應優(yōu)于或等于0.01mm。

Themeasurementerrorofdisplacementmeasuringinstrumentshallnotbegreaterthan0.1%offullscale,andtheresolutionshallbebetterthanorequalto0.01mm.深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints（1）場地處理

(1)Sitetreatment試井直徑宜等于承壓板直徑,當試井直徑需要大于承壓板直徑時,緊靠承壓板周圍土的高度不應小于承壓板直徑。

Thediameterofthewelltestshallbeequaltothediameterofthebearingplate.Whenthediameterofthewelltestneedstobegreaterthanthediameterofthebearingplate,theheightofthesoilimmediatelyaroundthebearingplateshallnotbelessthanthediameterofthebearingplate.深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints當試井直徑需要大于承壓板直徑時,緊靠承壓板周圍土的高度不應小于承壓板直徑,這是為什么?

Whenthediameterofthewelltestneedstobegreaterthanthediameterofthebearingplate,theheightofthesoilimmediatelyaroundthebearingplateshallnotbelessthanthediameterofthebearingplate.Whyisthis?以盡量保持半無限體內(nèi)部的受力狀態(tài),避免試驗時土的擠出。

Soastokeepthestressstateinsidethesemi-infinitebodyasmuchaspossibleandavoidsoilextrusionduringtest.深層平板載荷試驗

Deepplateloadtest試井截面應為圓形,直徑宜取0.8m～1.2m:并有安全防護措施

Thesectionofthewelltestshallbecircular,andthediametershallbe0.8m~1.2m,withsafetyprotectionmeasures4.試驗要點

4.Testpoints深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints承壓板直徑不應小于0.8m,應具有足夠的強度和剛度。

Thediameterofthebearingplateshallnotbelessthan0.8mandshallbeofsufficientstrengthandstiffness.(2)承壓板面積

(2)Areaofbearingplate深層平板載荷試驗

Deepplateloadtest可直接在外徑為800mm的鋼環(huán)或鋼筋混凝土管柱內(nèi)澆筑

Canbecastdirectlyinasteelringwithanouterdiameterof800mmorinareinforcedconcretepipecolumn

4.試驗要點

4.Testpoints承壓板直徑取800mm時，采用厚約300mm的現(xiàn)澆混凝土板或預制的剛性板

Whenthediameterofbearingplateis800mm,cast-in-placeconcreteslaborprecastrigidslabwithathicknessofabout300mmisadopted深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints承壓板直徑不應小于0.8m,應具有足夠的強度和剛度。

Thediameterofthebearingplateshallnotbelessthan0.8mandshallbeofsufficientstrengthandstiffness.(3)加載反力裝置

(3)Loadingreactiondevice傳力柱應有足夠的剛度

Theforcetransmissioncolumnshallbeofsufficientstiffness傳力柱宜高出地面50cm

Theforcetransmissioncolumnshallbe50cmabovetheground深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints(3)加載反力裝置

(3)Loadingreactiondevice傳力柱宜與承壓板連接成為整體

Theforcetransmissioncolumnshallbeconnectedwiththebearingplateasawhole傳力柱的頂部可采用鋼筋等斜拉桿固定

Thetopoftheforcetransmissioncolumncanbefixedwithdiagonaltierodssuchassteelbars深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints用力柱與地面的加荷裝置連接,亦可利用井壁護圈作為反力,加荷試驗時應直接測讀承壓板的沉降。

Theforcecolumnisconnectedwiththeloadingdeviceontheground,andtheshaftwallretainercanalsobeusedforreaction.Duringtheloadingtest,thesettlementofthebearingplateshallbedirectlymeasuredandread.深層平板載荷試驗

Deepplateloadtest傳力柱

Forcetransmissioncolumn位移測量桿

Displacementmeasuringrod4.試驗要點

4.Testpoints位移傳遞裝置宜采用鋼管或塑料管做位移測量桿

Steelpipeorplasticpipeshallbeusedasdisplacementmeasuringrodfordisplacementtransmissiondevice(4)沉降測量

(4)Settlementmeasurement深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints(4)沉降測量

(4)Settlementmeasurement位移測量桿的底端應與承壓板固定連接

Thebottomofthedisplacementmeasuringrodshallbefixedlyconnectedwiththebearingplate深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints(4)沉降測量

(4)Settlementmeasurement位移測量桿宜每間隔一定距離與傳力柱滑動相連

Displacementmeasuringrodisconnectedwiththeforcetransmissioncolumnbyslidingatcertaindistance深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints(4)沉降測量

(4)Settlementmeasurement位移測量桿的頂部宜高出孔口地面20cm

Thetopofthedisplacementmeasuringrodshallbe20cmabovethegroundoftheorifice深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints預壓荷載：宜為最大加載量的5%

Preloadingload:5%ofthemaximumloadingcapacity預壓時間：宜為5min

Preloadingtime:5min一切正常

EverythingisOK卸載至零

Unloadingtozero記錄位移測試儀表初始讀數(shù)

Recordtheinitialreadingofthedisplacementmeasuringinstrument讀數(shù)穩(wěn)定

Stablereading(5)

預壓

(5)Preloading預

壓

Preloading正式加載

Formalloading深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints地基土平板載荷試驗的分級載荷宜為最大試驗載荷的1/8~1/12。

Thesteploadoftheplateloadtestoffoundationsoilshallbe1/8~1/12ofthemaximumtestload.最大加載量不應小于設(shè)計要求的2倍。

Themaximumloadingcapacityshallnotbelessthan2timesofthedesignrequirements.(6)加卸載

(6)Loadingandunloading主要出于安全系數(shù)的考慮,一般取土層地基安全系數(shù)K=2

Consideringthesafetyfactor,thesafetyfactorofsoilfoundationisgenerallytakentobeK=2深層平板載荷試驗

Deepplateloadtest(6)

加卸載

(6)Loadingandunloading第一級荷載可取分級荷載的2倍

Theloadoffirststepcanbetwicethestepload每級卸載量為分級荷載的2倍;當加載等級為奇數(shù)級時,第一級卸載量宜取分級荷載的3倍

Eachstepofunloadshallbe2timesthestepload;whentheloadinglevelisodd,theunloadingamountoffirststepshallbe3timesofthestepload加、卸載時應使荷載傳遞均勻、連續(xù)、無沖擊,每級荷載在維持過程中的變化幅度不得超過分級荷載的±10%

Duringloadingandunloading,theloadshouldbetransmitteduniformly,continuouslyandwithoutimpact.Thevariationofloadofeachstepduringthemaintenanceprocessshallnotexceed±10%ofthestepload4.試驗要點

4.Testpoints逐級等量加載

Equivalentloadingstep-by-step逐級等量加載

Equivalentloadingstep-by-step深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints每級加載后應按第10min、20min、30min、45min、60min測讀承壓板的沉降量,以后應每隔半小時測讀一次沉降量。

Aftereachstepofloading,thesettlementofthebearingplateshallbemeasuredandreadat10min,20min,30min,45minand60min,andthesettlementshallbemeasuredandreadeveryhalfanhourthereafter.當在連續(xù)兩小時內(nèi),每小時的沉降量小于0.1mm時,則認為已趨穩(wěn)定,可加下一級荷載。

Whenthesettlementshallbelessthan0.1mmperhourwithintwoconsecutivehours,itisconsideredtobestableandtheloadofnextstepcanbeapplied.(6)加卸載

(6)Loadingandunloading深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints卸載時，每級荷載維持1h，應按第10min、30min、60min測讀承壓板沉降量；卸載至零后，應測讀承壓板殘余沉降量,維持時間為3h，測讀時間應為第10min、30min、60min、120min、180min。

Duringunloading,theloadateachstepshallbemaintainedfor1h,andthesettlementofthebearingplateshallbemeasuredandreadat10min,30minand60min;Afterunloadingtozero,theresidualsettlementofthebearingplateshallbemeasuredandread,andtheholdingtimeis3h,andthemeasuringandreadingtimeshallbe10min,30min,60min,120minand180min.(6)加卸載

(6)Loadingandunloading深層平板載荷試驗

Deepplateloadtest4.試驗要點

4.Testpoints當出現(xiàn)下列情況之一時,即可終止加載:

Loadingcanbeterminatedwhenoneofthefollowingconditionsoccurs:①本級荷載的沉降量大于前級荷載沉降量的5倍，荷載-沉降(p-s)曲線出現(xiàn)明顯陡降；

①Thesettlementoftheloadatthislevelisgreaterthan5timesthesettlementoftheprevi