平潭海峡公铁两用大桥非通航孔引桥围堰设计与施工.pdf

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1、桥梁建设２０１６年第４６卷第３期（总第２３８期）BridgeConstruction，Vol．４６，No．３，２０１６（TotallyNo．２３８）１文章编号：１００３－４７２２（２０１６）０３－０００１－０５平潭海峡公铁两用大桥非通航孔引桥围堰设计与施工王东辉（中铁大桥局集团有限公司，湖北武汉４３００５０）摘要：平潭海峡公铁两用大桥浅水区非通航孔（水深１５m以内）引桥为跨径４８m的预应力混凝土梁桥，采用钻孔桩基础，基础采用围堰施工。围堰采用钢吊箱结构，平面尺寸为１４．８m×２３m，高１２．３m，围堰内设２层内支撑，经围堰封底后抽水抗浮和浇注承台后抗沉工况计算，确定封底混凝土厚２m。

2、结合平潭海域海况特点，充分考虑波浪力的作用以及潮差大的影响，钻孔桩施工后，整体拼装吊箱围堰，利用千斤顶整体下放围堰至设计标高；在围堰内设置了３层导向限位装置，以保证入水后的围堰安全；在围堰封底抽水后，对围堰吊挂系统进行二次安装，再次安装吊杆和吊挂牛腿，以满足承台施工需要；围堰侧板和底板间通过销轴连接，并焊接斜撑杆，将底板和侧板固定，以抵抗波浪振动。关键词：跨海大桥；公路铁路两用桥；钻孔桩基础；钢吊箱围堰；设计；桥梁施工中图分类号：U４４８．１２１；U４４３．１６２文献标志码：ADesignandConstructionofCofferdamforNon‐NavigableSpanAp

3、proachBridgeofPingtanStraitsRail‐cum‐RoadBridgeWANGDonghui‐（ChinaRailwayMajorBridgeEngineeringGroupCo．，Ltd．，Wuhan４３００５０，China）Abstract：Thenon‐navigablespanapproachbridgeofthePingtanStraitsRail‐cum‐RoadBridgeovertheshallowwaterarea（thewaterdepthbeinglessthan１５m）isa４８‐mspanprestressedcon‐cretegir

4、derbridge．Thefoundationsforthebridgearetheboredpilesthatwereconstructed，usingthecofferdams．Acofferdamfortheconstructionofthepilesisthesteelboxedcofferdamstructurethathastheplandimensionsof１４．８×２３mandtheheightof１２．３mandinthecofferdam，twotiersoftheinternalsupportswerearranged．Throughthecalculatio

5、noftheloadcasesofanti‐buo‐yingofthecofferdambypumpingoutthewaterandanti‐sinkingofthecofferdamaftercastingtheconcreteforthepilecapundertheconditionofbasesealingofthecofferdam，itwasdeterminedthatthedepthofthebasesealingconcreteforthecofferdamshouldbe２m．Withreferencetotheseaconditioncharacteristic

6、ofthePingtanStraitsandinthoroughconsiderationofthewaveforceactionandthegreattidaldifferenceinfluence，thecofferdamwasintegrallyassembledandwasin‐tegrallyloweredtoitsdesignedelevation，usingthejacksaftertheboredpileswereconstructed．Inthecofferdam，３tiersoftheguidingandlimitingdeviceswerealsoarrange

7、dinordertoensurethesafetyofthecofferdamatthetimethecofferdamwasbeingloweredintothewater．Afterthebaseforthecofferdamwassealedandthewaterinthecofferdamwaspumpedout，theslingingsystemofthecofferdamwasinstalledforthesecondtime，thehange