人教版生物教案必修二第三章第二节地形平坦开阔，地层由第四系全新冲积层，第四系上更新统冲层组成，局部表覆第四系全新统人工堆积层。第四系全新统冲积层厚度约25～50m，岩性主要为黏土、粉质黏土、粉土、粉砂、细砂；第四系上更新统冲积层厚度大于50m，岩性主要为黏性土、粉土、粉细砂等。管桩深度范围内地层主要为：粉土、黏土、粉质黏土，局部表层为杂填土。couplingCentreshallbechecked,thesecondpouredconcretestrengthofmorethan70%.Intheprocessofreamingorboring,apartfromthespecialprovisionsinfactory,doesnotallowanyworkthatmayaffectthecouplingCentre,suchasirrigation,tocylinderconnectionstofloodthecondenserpipesandsoon.Wellboring,hingeboltholeflangewithcouplingofvertical,notoblique.Mountingboltsshouldbeaddedlubricants,typinggentlywithasmallhammer,nottoolooseortootight,packedtheboltswiththecorrespondingsealscrewholeshouldbemarked.6.4.5.4.2couplingreamedandpairingsisclosetothediameterofboltbearinggoodhingeholes,dressedwithagoodtwocouplingboltsbeforeyoucanmovetherotor,boring-reamingholeinturn.Couplingboltsmustbetightcouplingissymmetricaldiameter,inboring,reaming,twoboltsout.Wellboring,hingeboltholeflangewithcouplingofvertical,notoblique.Duetothecouplingboltsinaccordancewithhingeholescorrespondingtothediameterofthescrewholesonebyoneafterprocessing,processingbackboltinstallationlocationcannotbechanged,soaccordingtoboltaftertheactualweightdifferenceofnutandlockwashertomatch.Generalrequirementsforcouplingtwosymmetricaldiameterbolt,nutandlockwasher'stotalweightdifferenceshouldnotbegreaterthan10gandknocksstampedmark.(SeeFigure18)Thecouplingboltsapplylubricant,andthengentlywithcopperhome,nottoolooseortootight.BoltAssemblyisfinished,symmetricaltighteningallboltsto30%,50%,70%,100%force,andcheckthecouplingflutterandbeforeconnectingthecirclegraduallychangesitsvalueshouldbelessthan0.02mm.Tighteningtorqueofthecouplingboltsshallcomplywiththetechnicalrequirementsmanufacturersdrawings,withadynamometricwrenchorlogtensiontools.Threewheelrotorswingtestcouplingconnectionsshouldbechecked:takingleave,地形平坦开阔，地层由第四系全新冲积层，第四系上更新统冲层组成，局部表覆第四系全新统人工堆积层。第四系全新统冲积层厚度约25～50m，岩性主要为黏土、粉质黏土、粉土、粉砂、细砂；第四系上更新统冲积层厚度大于50m，岩性主要为黏性土、粉土、粉细砂等。管桩深度范围内地层主要为：粉土、黏土、粉质黏土，局部表层为杂填土。couplingCentreshallbe