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1、摘要隨著鐵路工程的高速發(fā)展,越來越多的基坑工程需要在高速鐵路旁邊進行,控制和預(yù)測列車動荷載對基坑及周圍建筑的變形成為鐵路工程設(shè)計中的一個重要內(nèi)容,因此,列車動荷載對基坑及地基變形的影響已經(jīng)引起越來越多專家和工程師的關(guān)注,對列車荷載進行研究就顯得尤為重要。在火車站附近進行基坑開挖,由于列車車輛的高密度運行,一方面,在換乘車站深基坑開挖過程中,列車動荷載會影響既有車站結(jié)構(gòu)及其周圍土層變形;另一方面,既有車站結(jié)構(gòu)受新建換乘車站基坑開挖的影響產(chǎn)生變形,從而引起車站內(nèi)軌道變形,影響行車安全。對于列車動荷載的模
2、擬,在以往的基坑支護中很少考慮,只是在道路工程中把列車荷載當做等效的靜荷載進行計算。本文以某大型車站基坑開挖過程中實際監(jiān)測數(shù)據(jù)為例,通過FLAC3D模擬基坑在列車運行期間的開挖變形,并將模擬結(jié)果與實際監(jiān)測的數(shù)據(jù)作對比,計算結(jié)果表明:根據(jù)實際監(jiān)測數(shù)據(jù),列車動荷載引起的地基沉降會隨著時間一直增大,但增大的速率越來越小,最終趨于穩(wěn)定;由于錨索與測斜管在有無列車通過時無變化,說明列車動荷載只對其作用周圍某一范圍內(nèi)的土體有影響。因此,為了減小列車動荷載對基坑及土體的影響,可只對列車影響臨界范圍內(nèi)的土體進行加固
3、,從而以最經(jīng)濟的工程成本來達到預(yù)定的設(shè)計目的。哭糊:基坑;地基變形;動荷載;有限元ABSTRACTWiththerapiddevelopmentofrailwayengineering,moreandmorefoundationengineeringneedtobeconstructedbesidetherailway,controllingandpredictingthedeformationofthefoundationengineeringandsurroundingbuildingsthat
4、causedbythedynamictrainloadbecomeanimportantcontentoftherailwayengineeringdesign.Sothedeformationofthefoundationengineeringandgroundthatcausedbydynamictrainloadhaveattractedmoreandmoreexpertsandengineerstoresearch.Sostudyingontrainloadisbecomingveryimp
5、ortant.Whentheexcavationnearthetrainstation,becauseofthehighdensityoftrainvehiclerunning,ononehand,intheprocessofexcavationinthesubwaystation,thedynamictrainloadaffectsthestructureofexistingstationandthedeformationofthesurroundingsoil;ontheotherhand,de
6、formationwillbecausedbecauseoftheexcavationduringtheexistingstationstructure,Causingthedeformationofthestationtrack,andimpactingthesafetyofthetraffic.Thesimulationofthetraindynamicloadisrarelyconsideredinthepastfoundationdesign.Thetrainloadiscalculated
7、asequivalentstaticloadonlyintheroadengineering.Thearticletakesthedataoftheexcavationduringacertainstationasanexample,usingtheFLAC3Dtosimulatethedeformationoftheexcavationduringthetrainoperationandmakingacomparisonbetweenthesimulationresultsandtheactual
8、monitoringdata.Thecalculationresultsshowthataccordingtotheactualmonitoringdata,thegroundsettlementcausedbythedynamictrainloadhasbeenincreasingastimegoesby,buttherateofthegrowthisbecomingmoreandmoresmall,eventuallystabilized.Becausenomat