1.Load-induced tawg
Cracks generated nyob rau hauv pob zeb nyob rau hauv cov pa zoo li qub thiab dynamic loads thiab lwm yam kev ntxhov siab yog hu ua load cracks, uas yuav summed li direct stress cracks thiab lwm yam kev ntxhov siab tawg. Cov kab nrib pleb ncaj qha xa mus rau cov kab nrib pleb uas tsim los ntawm kev ntxhov siab ncaj qha los ntawm cov khoom siv sab nraud, thiab cov kab nrib pleb theem nrab yog hais txog cov kab nrib pleb uas tsim los ntawm cov kev ntxhov siab thib ob uas tshwm sim los ntawm cov khoom sab nraud. Cov yam ntxwv ntawm cov kab nrib pleb qhia cov yam ntxwv sib txawv nyob ntawm qhov load. Xws li cov kab nrib pleb feem ntau tshwm sim hauv cheeb tsam nro, shear cheeb tsam lossis qhov chaw vibration hnyav. Txawm li cas los xij, nws yuav tsum tau taw qhia tias yog tias muaj tev lossis tawg luv luv raws li cov kev taw qhia compression hauv thaj chaw compression, feem ntau yog ib qho cim qhia tias cov qauv tau mus txog qhov txwv ntawm cov kabmob muaj peev xwm thiab yog qhov ua ntej rau kev ua haujlwm tsis ua haujlwm. Qhov laj thawj feem ntau yog qhov seem me me dhau.
2. Kev tawg los ntawm qhov kub thiab txias
Qhob muaj cov khoom ntawm thermal expansion thiab contraction. Thaum qhov chaw sab nraud lossis qhov kub thiab txias ntawm cov qauv hloov, cov pob zeb yuav deform. Yog tias qhov deformation raug txwv, kev ntxhov siab yuav tshwm sim hauv cov qauv. Thaum qhov kev ntxhov siab tshaj qhov tensile lub zog ntawm cov pob zeb, qhov kub thiab txias yuav tshwm sim. Hauv qee qhov txuas txuas ntev, qhov kev ntxhov siab thermal tuaj yeem ncav cuag lossis ntau tshaj qhov kev nyuaj siab nyob. Lub ntsiab feature ntawm kub fractures uas txawv lawv los ntawm lwm yam kev puas tsuaj yog hais tias lawv yuav nthuav los yog kaw nrog kub hloov.
3. Cov kab nrib pleb tshwm sim los ntawm shrinkage
Nyob rau hauv kev tsim engineering, cov kab nrib pleb tshwm sim los ntawm kev ua vaj tse shrinkage yog feem ntau. Ntawm cov hom pob zeb shrinkage, yas shrinkage thiab shrinkage shrinkage (qhuav shrinkage) yog lub ntsiab yog vim li cas rau lub ntim deformation ntawm pob zeb, thiab kuj muaj autogenous shrinkage thiab carbonization shrinkage.
- Yas shrinkage. Nws tshwm sim thaum lub sij hawm tsim kho thiab li 4 mus rau 5 teev tom qab lub pob zeb yog poured. Lub sijhawm no, cov cement hydration cov tshuaj tiv thaiv yog khaus, cov saw molecular yog maj mam tsim, los ntshav thiab evaporation sai ntawm cov dej tshwm sim, cov pob zeb poob dej thiab shrinks, thiab tag nrho cov dab dej vim nws qhov hnyav. Thaum lub pob zeb tseem tsis tau hardened, nws yog hu ua yas shrinkage. Qhov loj ntawm cov yas shrinkage yog loj heev, txog li 1 feem pua. Nyob rau hauv tus txheej txheem ntawm aggregate sinking, yog hais tias nws yog thaiv los ntawm steel tuav, cov kab nrib pleb raws cov kev taw qhia ntawm cov hlau tuav yuav tsim. Ntawm txoj kab ntsug ntawm tus tswv cuab, xws li kev sib tshuam ntawm lub vev xaib ntawm T beam thiab lub thawv girder nrog lub ru tsev thiab hauv pem teb, cov kab nrib pleb ntawm lub vev xaib yuav tshwm sim vim tsis sib haum xeeb ua ntej hardening. Yuav kom txo tau cov yas shrinkage ntawm cov pob zeb, cov dej-cement ratio yuav tsum tau tswj thaum lub sij hawm tsim kho, kom tsis txhob ntev stirring, cov khoom yuav tsum tsis txhob raug txiav ceev heev, lub vibration yuav tsum compact, thiab ntsug variable seem yuav tsum tau poured. hauv txheej.
-Shrinkage shrinkage (qhuav shrinkage). Tom qab cov pob zeb tawv tawv, raws li cov av noo noo maj mam evaporates, cov av noo maj mam txo, thiab qhov ntim ntawm cov pob zeb txo, uas yog hu ua shrinkage (qhuav shrinkage). Vim tias cov dej poob ntawm cov pob zeb ua kom nrawm nrawm thiab qhov poob sab hauv yog qeeb, qhov tsis sib xws ntawm qhov loj ntawm qhov shrinkage thiab me me hauv shrinkage tshwm sim. Qhov saum npoo shrinkage thiab deformation yog txwv los ntawm cov pob zeb sab hauv, ua rau cov pob zeb saum npoo dais lub zog tensile. Thaum lub pob zeb nto bears lub zog tensile tshaj nws lub zog tensile, shrinkage tawg tshwm sim. Lub ntsiab shrinkage ntawm qhob tom qab hardening yog shrinkage shrinkage. Rau cov khoom uas muaj qhov sib npaug loj (ntau dua 3 feem pua), qhov kev txwv ntawm qhov kev txhawb nqa ntawm qhov shrinkage ntawm cov pob zeb yog pom tseeb, thiab cov pob zeb nto yog qhov ua rau tawg.
- Autogenous shrinkage. Autogenous shrinkage yog cov tshuaj tiv thaiv dej ntawm cov cement thiab dej thaum lub sij hawm hardening txheej txheem ntawm pob zeb. Qhov shrinkage no tsis muaj dab tsi cuam tshuam nrog cov av noo sab nraud thiab tuaj yeem ua tau zoo (xws li shrinkage, xws li Portland cement pob zeb zoo tib yam) lossis tsis zoo (xws li nthuav dav, xws li slag cement pob zeb thiab ya tshauv cement pob zeb).
- Charcoal shrinkage. Lub shrinkage deformation tshwm sim los ntawm cov tshuaj tiv thaiv ntawm carbon dioxide nyob rau hauv cov huab cua thiab hydrate ntawm cement. Carbonization shrinkage tsuas yog tshwm sim ntawm kwv yees li 50 feem pua ntawm cov av noo, thiab nws nrawm nrog qhov nce ntawm carbon dioxide concentration. Carbonization shrinkage feem ntau tsis suav.
Cov yam ntxwv ntawm cov pob zeb shrinkage tawg yog tias feem ntau ntawm lawv yog cov kab nrib pleb, qhov dav ntawm cov kab nrib pleb kuj me me, thiab cov kab nrib pleb yog crisscrossed nyob rau hauv ib qho kev sib tsoo zoo li tsis muaj qhov tsis tu ncua ntawm cov duab.
4. Cov kab nrib pleb tshwm sim los ntawm lub hauv paus deformation
Vim yog qhov tsis sib luag ntsug lossis kab rov tav hloov pauv ntawm lub hauv paus, kev ntxhov siab ntxiv yog tsim nyob rau hauv cov qauv, uas tshaj lub peev xwm tensile ntawm lub pob zeb ua qauv, uas ua rau cov txheej txheem tawg.
5. Cov kab nrib pleb tshwm sim los ntawm corrosion ntawm steel tuav
Vim yog qhov tsis zoo ntawm cov pob zeb lossis cov tuab tsis txaus, txheej tiv thaiv ntawm cov pob zeb yog eroded thiab carbonized rau saum npoo ntawm steel bar los ntawm carbon dioxide, uas txo cov alkalinity ntawm cov pob zeb nyob ib ncig ntawm lub steel bar, los yog chloride ion. Cov ntsiab lus nyob ib ncig ntawm lub steel bar yog siab vim muaj kev cuam tshuam ntawm chloride, uas tuaj yeem ua rau saum npoo ntawm cov hlau bar rau oxidize. Lub membrane puas lawm, thiab cov hlau ions nyob rau hauv steel bar teb nrog cov pa oxygen thiab ya raws nkag mus rau hauv cov pob zeb, thiab lub ntim ntawm cov xeb hlau hydroxide nce li ntawm 2 mus rau 4 npaug ntawm qhov qub, uas yuav ua rau muaj kev ntxhov siab ntxiv mus rau hauv cov pob zeb. puag ncig pob zeb, uas ua rau tawg thiab tev ntawm cov pob zeb tiv thaiv. , Nyem qhov no mus download tau cov ntaub ntawv kev tsim kho dawb. Cracks tshwm sim raws longitudinal kev taw qhia ntawm steel bar, thiab xeb seeps rau hauv lub pob zeb nto. Vim yog corrosion, qhov zoo ntawm qhov chaw seem ntawm steel bar yog txo, tuav ntawm steel bar thiab cov pob zeb tsis muaj zog, lub peev xwm ntawm cov qauv raug txo, thiab lwm yam kev tawg yuav raug ntxias, uas yuav ua rau hnyav dua. corrosion ntawm steel bar thiab ua rau kev puas tsuaj ntawm cov khoom.
Txhawm rau tiv thaiv kev xeb ntawm cov hlau tuav, qhov tawg qhov dav yuav tsum tau tswj raws li qhov yuav tsum tau ua ntawm cov lus qhia tshwj xeeb, thiab cov txheej txheem tiv thaiv txaus yuav tsum tau siv (ntawm chav kawm, txheej tiv thaiv yuav tsum tsis txhob tuab dhau, txwv tsis pub qhov siab ntawm qhov zoo ntawm cov tivthaiv yuav raug txo kom tsawg, thiab qhov dav ntawm qhov tawg yuav nce ntxiv thaum raug kev ntxhov siab); Tswj cov dej-cement piv ntawm cov pob zeb, ntxiv dag zog rau kev co, ua kom lub compactness ntawm pob zeb, tiv thaiv cov pa oxygen nkag mus, thiab nruj me ntsis tswj tus nqi ntawm admixture uas muaj chloride ntsev, tshwj xeeb tshaj yog nyob rau hauv ntug hiav txwv dej los yog lwm qhov chaw uas muaj zog corrosive huab cua thiab dej hauv av.
6.Cracks tshwm sim los ntawm Frost Heave
Thaum qhov kub ntawm atmospheric qis dua xoom, cov dej-saturated qhob khov, cov dej dawb hloov mus rau hauv dej khov, thiab qhov ntim nthuav tawm los ntawm 9 feem pua, yog li cov pob zeb ua kom muaj kev ntxhov siab ntxiv; Nyob rau tib lub sijhawm, cov dej supercooled hauv cov pob zeb gel pores (qhov txias txias yog qis dua -78 degrees)) kev tsiv teb tsaws thiab rov ua dua tshiab hauv cov txheej txheem microstructure ua rau osmotic siab, uas ua rau kom muaj zog nthuav dav hauv cov pob zeb, txo lub zog ntawm cov pob zeb, thiab ua rau cov tsos ntawm cov kab nrib pleb. Tshwj xeeb, cov pob zeb yog qhov khov heev thaum nws pib, thiab lub zog poob ntawm cov pob zeb tom qab kev laus tuaj yeem ncav cuag 30 feem pua rau 50 feem pua. Thaum lub sij hawm tsim kho nyob rau hauv lub caij ntuj no, Frost heave tawg nyob rau hauv lub pipeline kev taw qhia yuav tshwm sim yog hais tias thermal rwb thaiv tsev ntsuas tsis tau coj tom qab grouting lub prestressed qhov.
7. Cov kab nrib pleb tshwm sim los ntawm kev tsim cov khoom siv zoo
Pob zeb yog tsim los ntawm cov cement, xuab zeb, aggregate, sib tov dej thiab cov khoom sib xyaw. Cov khoom siv los teeb tsa lub pob zeb yog qhov tsis zoo thiab tuaj yeem ua rau tawg ntawm cov qauv.
8. Kev sib tsoo tshwm sim los ntawm kev ua haujlwm zoo ntawm kev tsim kho
Nyob rau hauv cov txheej txheem ntawm pob zeb ua qauv pouring, tivthaiv ntau lawm, formwork, tsheb thauj mus los, stacking, sib dhos thiab hoisting, yog hais tias tus txheej txheem ntawm kev tsim kho yog tsis tsim nyog thiab kev tsim kho tsis zoo, nws yog ib qho yooj yim los tsim ntsug, kab rov tav, oblique, ntsug, kab rov tav, nto. , sib sib zog nqus thiab nkag mus rau hauv cov kab nrib pleb, tshwj xeeb tshaj yog slender thiab nyias-walled lug, muaj feem yuav tshwm sim. Qhov chaw thiab kev taw qhia ntawm cov kab nrib pleb, thiab qhov dav ntawm cov kab nrib pleb sib txawv nyob ntawm qhov ua rau.
