高速拓宽软土路基差异沉降数值计算及监测分析.pdf

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1、JournalofEngineeringGeology工程地质学报1004—9665／2012／20(3)-o447-O6_---I—冰Cj同速拓宽软土路基差异沉降数值计算及监测分析谭儒蛟①李明生①张建根①徐文杰②(①天津市市政工程设计研究院天津300051)(②清华大学水利土木工程学院北京100084)摘要路基差异沉降控制是软土地区高速拓宽工程中的关键性技术问题之一，本文以北方某高速拓宽工程的试验段为例，运用ABAQUS软件进行了拓宽软土路基变形的有限元数值计算，并与路基现场变形监测数据进行对比

2、分析，数值计算与实测结果基本吻合，结论一致地反映了路堤填筑初始阶段新路基的沉降速率较大，旧路基在填筑后期才产生较明显的附加沉降变形；路基变形在拓宽侧呈现明显的“沉降盆”效应，新、旧路基的差异沉降是造成路基路面纵裂的主要因素；桩端地基土呈现出较明显的侧向挤压效应，则表明采用带帽FYC桩复合地基中用于减沉时，桩端应置于具有较高承载力的有效持力层上。关键词高速拓宽软土路基差异沉降带帽PTC桩数值计算监测分析中图分类号：TU47文献标识码：ANUMERICALCALCULATIoNANDMoNIToRIN

3、GANALYSISONDIFFER-ENTIALSETTLEMENTSoFSoFTSoILSUBGRADEINEXPRESSWAYEXTENSIoNPRoJECTTANRujia0①LIMingsheng①ZHANGJiangen①XUWenjie②(①TianjinMunicipalEngineeringDesignandResearchInstitute，Tianjin300051)((~SchoolofCivilEngineeringofTsinghuaUniversity，Belling1

4、00084)AbstractHowtocontrolofthedifferentialsettlementisakeytaskforthesoftsoilsubgradeinExpresswayexten—sionproject．ThispaperexaminestheexperimentsectionofoneexpresswayextensionprojectinnorthernChina．Thefiniteelementcalculationiscarriedoutforthedeforma

5、tionofwideningsoftsoilsubgrade．TheAbaqussoftwareisused．Thecalculationresultsareinaccordancewiththedeformationmonitoringinformationatfieldtests．Theseresultsconformablydemonstratethedeformationcharacteristicsthatwideningsubgradepresentslargersettlementr

6、ateintheinitialstageofembankmentfilling．Buttheoldsubgradehasobviousadditionalsettlement．Thebasin—curveofsettlementappearsinthebottomofwideningsubgrade．Thedifferentialsettlementbetweenthenewandoldsubgradeisoneofthemainreasonsthatinducinglongitudinalsub

7、gradecracks．Thefoundationsoilnearthebottomofthecompositefoundationofprestressedthin-wallconcrete(PTC)pilewithcappresentsobviousextrusionde—formationinhorizontaldirections，whichshowsthatPTCpiletipshouldbeplacedateffectivebearingstratumwithrelativelyhig

8、hcapacity．KeywordsExpresswayextensionproject，Softsoilsubgrade，Differentialsettlement，PTCpilewithcap，Numeri-calcalculation．Monitoringanalysis收稿日期：2011一l1一O2；收到修改稿日期：2012—04—12．第一作者简介：谭儒蛟，主要从事岩土工程勘察设计及科研咨询等工作．Email：tanmjiao@163．tomJournalofEngin