文档名:风积沙填筑铁路路基累积塑性变形及临界动应力试验研究
摘要:目前用于铁路基床的填料大多数为级配优良的填料,而对风积沙作为路基填料在列车荷载作用下的累积塑性变形特性和临界动应力研究不多,但风积沙作为路基填料已在沙漠铁路建设中得到运用.为探究列车荷载作用下风积沙填料填筑铁路路基的累积塑性变形演变特性及临界动应力,考虑围压、动应力幅值、压实系数和含水率等因素的影响,开展一系列动三轴试验.试验结果表明:风积沙累积塑性应变随压实系数、围压的增大而减小,随动应力幅值的增大而增大.以最优含水率为分界点,低于最优含水率时,风积沙累积塑性应变随含水率的增加而减小;高于最优含水率时,风积沙累积塑性应变随含水率的增加而增大.风积沙试样的累积塑性应变曲线可分为:稳定型、临界型和破坏型.根据对累积塑性应变曲线的分类,获得了不同条件下风积沙填料的临界动应力.风积沙临界动应力随围压和压实系数的增大而增大,饱和含水率下风积沙填料的临界动应力明显小于天然含水率和最优含水率下风积沙填料的临界动应力.临界动应力和围压具有较好的线性关系.构建了可考虑围压和含水率影响的风积沙临界动应力经验公式,通过临界动应力公式确定了不同工况下风积沙作为路基填料的适用范围.试验结果可为沙漠铁路的设计、施工以及运营提供经验和理论依据.
Abstract:Atpresent,mostofthefillersusedforrailwaysubgradebedarewell-gradedfillers.Therearefewstudiesoncumulativeplasticdeformationcharacteristicsandcriticaldynamicstressofaeoliansandassubgradefillersundertrainload.Butaeoliansandassubgradefillerhasbeenusedindesertrailwayconstruction.Aseriesofdynamictriaxialtestsofaeoliansandsamples,consideringtheinfluenceofconfiningpressure,dynamicstressamplitude,compactioncoefficientandmoisturecontent,werecarriedouttoinvestigatetheevolutionlawsofcumulativeplasticdeformationanditscriticaldynamicstress.Thetestresultsaredrawnasfollows.Thecumulativeplasticstrainofaeoliansandincreaseswiththeincreaseofdynamicstressamplitude,anditdecreaseswiththeincreaseofcompactioncoefficientandconfiningpressure.Takingtheoptimalmoisturecontentasthecut-offpoint,thecumulativeplasticstrainofaeoliansanddecreaseswiththeincreaseofmoisturecontent,whenthemoisturecontentislowerthantheoptimalmoisturecontent.Thecumulativeplasticstrainofaeoliansandincreaseswiththeincreaseofmoisturecontent,whenthewatercontentishigherthantheoptimalmoisturecontent.Theaccumulativeplasticstraincurvescanbeclassfiedintothreetypes:stable,criticalandfailure.Accordingly,thecriticaldynamicstressofaeoliansandfillerwasobtained.Thecriticaldynamicstressofaeoliansandincreaseswiththeincreaseofconfiningpressureandcompactingcoefficient.Thecriticaldynamicstressofaeoliansandundersaturatedmoisturecontentisobviouslysmallerthanthatundernaturalmoisturecontentandoptimalmoisturecontent.Therelationshipbetweencriticaldynamicstressandconfiningpressurecouldbewellfittedbylinearfunction.Theempiricalformulaofcriticaldynamicstresstakingconfiningpressureandmoisturecontentintoaccountareobtained.Theapplicabilityofaeoliansandassubgradefillerunderdifferentworkingconditionsweredeterminedbythecriticaldynamicstressformula.Thetestresultsprovideexperienceandtheoreticalbasisforthedesign,constructionandoperationofdesertrailway.
作者:韦朝Author:WEIZhao
作者单位:新疆铁道勘察设计院有限公司,新疆乌鲁木齐830011
刊名:铁道科学与工程学报
Journal:JournalofRailwayScienceandEngineering
年,卷(期):2024, 21(1)
分类号:TU411.8
关键词:铁路路基 风积沙 累积塑性应变 临界动应力 动三轴试验 基床表层
Keywords:railwaysubgrade aeoliansand cumulativeplasticstrain criticaldynamicstress dynamictriaxialtest subgradesurfacelayer
机标分类号:U416.1U270.3TU411
在线出版日期:2024年2月26日
基金项目:中国铁路乌鲁木齐局集团有限公司科技研究开发计划课题,国家自然科学基金风积沙填筑铁路路基累积塑性变形及临界动应力试验研究[
期刊论文] 铁道科学与工程学报--2024, 21(1)韦朝目前用于铁路基床的填料大多数为级配优良的填料,而对风积沙作为路基填料在列车荷载作用下的累积塑性变形特性和临界动应力研究不多,但风积沙作为路基填料已在沙漠铁路建设中得到运用.为探究列车荷载作用下风积沙填料填...参考文献和引证文献
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